JP6460787B2 - Liquid discharge head and liquid discharge apparatus - Google Patents

Description

  The present invention relates to a liquid discharge head and a liquid discharge apparatus that discharge liquid.

  In general, a liquid discharge apparatus that discharges liquid and records an image on a recording medium is equipped with a liquid discharge head that discharges the liquid. As a liquid discharge mechanism of a liquid discharge head, a mechanism using a pressure chamber whose volume can be contracted by a piezoelectric element is known. In this mechanism, the pressure chamber contracts due to the deformation of the piezoelectric element to which a voltage is applied, so that the liquid in the pressure chamber is discharged from the discharge port communicating with the pressure chamber. As one of liquid discharge heads having such a mechanism, a so-called thin film piezoelectric element type head using a piezoelectric element formed in a thin film shape is known. The thin film piezoelectric element is characterized by a large amount of displacement due to low rigidity.

  In a liquid discharge head having a pressure chamber, bubbles may enter the pressure chamber together with the liquid, or bubbles may be generated in the pressure chamber. In this case, bubbles may absorb the pressure for ejecting ink, so that a desired ejection amount and ejection speed cannot be obtained, and further, ejection may become impossible. In addition, the ink adhering to the vicinity of the ejection port that has not ejected liquid for a long period of time increases in viscosity and clogs the ejection port, which may cause problems such as deterioration in ejection performance and ejection failure. Therefore, Patent Document 1 discloses a technique for solving these problems.

  Patent Document 1 discloses a so-called through flow technique that generates a circulating flow from a supply channel to a recovery channel via a pressure chamber even during recording by a recovery channel communicating with an ejection port. According to this technique, bubbles in the pressure chamber can be removed by being placed on the circulation flow. Furthermore, since fresh ink is always supplied in the vicinity of the ejection port by the circulating flow, the diffusion of the thickened ink content in the ejection port is promoted, and the ink viscosity can be suppressed.

Special table 2011-520665 gazette

  In recent years, there has been an increasing demand for a liquid discharge head capable of forming a high-resolution image for high image quality, mainly in a printing apparatus for commercial use such as Print On Demand. In such a liquid discharge head, it is necessary to reduce the size of the pressure chamber in order to arrange the discharge ports with high density. However, since the area of the deformed wall surface (diaphragm) is reduced when the pressure chamber is simply reduced in size, there is a concern that the amount of deformation of the pressure chamber is reduced and the discharge force is weakened. For this reason, it is necessary to reduce the size of the pressure chamber while ensuring a size capable of obtaining a sufficient amount of deformation for ejecting ink.

  In the liquid discharge head disclosed in Patent Document 1, the supply flow path and the recovery flow path are alternately arranged, and the discharge is made to communicate the pressure chamber and the discharge port between the supply flow path and the recovery flow path. A side flow path is arranged. The supply channel is formed so as to overlap the pressure chamber. A region on the opposite side of the supply flow channel across the discharge flow channel is occupied by the recovery flow channel. That is, a region between two pressure chambers adjacent to each other is occupied by the recovery flow path. As described above, in order to arrange the discharge ports at a high density, it is necessary to secure a size of the pressure chamber that can obtain a deformation amount sufficient to discharge ink. However, in the liquid ejection head disclosed in Patent Document 1, since the region between the pressure chambers is occupied by the recovery flow path, a space for forming the pressure chambers must be secured in the region excluding this occupied region. As a result, the space for forming the pressure chamber is limited, which prevents the discharge port from being densified.

  Therefore, an object of the present invention is to provide a technique capable of arranging discharge ports at high density in a liquid discharge head having a supply flow path and a recovery flow path.

In order to achieve the above-described object, the present invention provides a liquid discharge head having a discharge port, a pressure chamber for storing the liquid discharged from the discharge port, and a supply for supplying the liquid to the pressure chamber A flow path, a recovery flow path for recovering liquid that has not been discharged from the discharge port among liquids supplied to the pressure chamber, and a first recovery port that communicates with the recovery flow path in the vicinity of the discharge port And a second recovery port that communicates with the recovery channel at an end of the pressure chamber, and at least a part of the pressure chamber is in the direction perpendicular to the formation surface of the discharge port. It overlaps the channel and the recovery channel.

  In the present invention, since the pressure chamber is formed so as to overlap the supply flow path and the recovery flow path, the space for forming the pressure chamber is not limited by the supply flow path.

  According to the present invention, since the space for forming the pressure chamber is not limited by the supply flow path, the discharge ports can be arranged at high density in the liquid discharge head having the supply flow path and the recovery flow path.

It is a figure which shows the liquid head in the 1st Embodiment of this invention. It is the top view which showed each layer which comprises a head chip. It is an enlarged view of a 1st film layer. It is an enlarged view of a pressure chamber formation layer. It is an enlarged view of a 2nd film layer. It is an enlarged view of a flow path formation layer. It is a figure which shows the flow path in a head chip. It is a figure which shows the flow path in the head chip in the 2nd Embodiment of this invention. It is a figure which shows the flow path in the head chip in the 3rd Embodiment of this invention.

(First embodiment)
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing an embodiment of a liquid discharge head according to the present invention. FIG. 1A is a perspective view showing the overall configuration of the liquid discharge head according to the first embodiment. FIG. 1B is a plan view of the liquid discharge head shown in FIG. 1A viewed from the liquid discharge port formation surface side (−Z direction). FIGS. 1A and 1B illustrate a state in which main flow paths are seen through in order to make the configuration of the liquid discharge head easier to understand.
The liquid discharge head 100 of this embodiment includes a manifold 101, a chip plate 102, an FPC (flexible printed circuit board) 103, an inlet joint 104, and an outlet joint 106.

The manifold 101 is mainly composed of a resin member. As shown in FIG. 1B, a head chip 108 is fixed to the chip plate 102, and a flow path for communicating the head chip 108 with the manifold 101 is formed. The FPC 103 is formed with wiring for transmitting a drive signal from a main body (not shown) of the liquid discharge apparatus to which the liquid discharge head 100 is attached to the head chip 108. In the present embodiment, a configuration in which two sets of head chips 108 are mounted is shown. However, the liquid discharge head of the present invention may include not only two sets of head chips 108 but also a plurality of head chips 108.
The inlet joint 104 communicates with an inlet channel 105 formed in each of the manifold 101 and the chip plate 102 and guides ink supplied from a main body (not shown) of the liquid ejection device to the head chip 108. The outlet joint 106 communicates with outlet channels 107 formed in the chip plate 102 and the manifold 101, respectively, and guides the ink collected from the outlet channel 107 to the main body of the liquid ejection device.

FIG. 2 is a plan view of each layer constituting the head chip 108. The head chip 108 includes six layers of a circuit wiring layer 201, a first film layer 202, a pressure chamber forming layer 203, a second film layer 204, a flow path forming layer 205, and a discharge port forming layer 206. It is configured and stacked in this order. In FIG. 2, the blacked out portions are through holes and mainly indicate the flow paths in the head chip 108. The role and flow path of each layer will be explained.
The circuit wiring layer 201 is composed of a silicon substrate. A drive circuit (not shown), a wiring 317 (see FIG. 7B), a connection terminal 306 (see FIG. 7B), and an FPC connection terminal (not shown) are formed on the back surface of the circuit wiring layer 201. Has been. Since the circuit wiring layer 201 has an FPC connection terminal connected to the FPC 103, the length in the Y direction (short direction) is longer than the other layers. In the circuit wiring layer 201, an opening of the parallelogram-shaped supply main channel 301 is formed at one end in the Y direction, and an opening of the parallelogram-shaped recovery main channel 303 is formed at the other end. The supply main channel 301 communicates with the inlet channel 105, and the recovery main channel 303 communicates with the outlet channel 107.

  FIG. 3 is an enlarged view of the first film layer 202 shown in FIG. The first film layer 202 is composed of a photosensitive film. As shown in FIG. 3, a part of the supply main channel 301 is formed at one end in the Y direction of the first film layer 202, and a part of the recovery main channel 303 is formed at the other end. A through hole 323 is formed between the supply main channel 301 and the recovery main channel 303. The through hole 323 is formed to electrically connect the individual electrode 401 (see FIG. 7B) and the wiring 317 via the connection terminal 306.

  FIG. 4 is an enlarged view of the pressure chamber forming layer 203 shown in FIG. The pressure chamber forming layer 203 is composed of a silicon substrate. A plurality of thin film diaphragms 307 (see FIG. 7B) are formed on one side of the substrate, and a hole serving as a pressure chamber 308 for storing ink by drilling and anisotropic wet etching is formed on the other side (back side). Part is formed. A part of the supply main passage 301 is formed at one end of the pressure chamber forming layer 203 in the Y direction, and a part of the recovery main passage 303 is formed at the other end. The opening width of the recovery main passage 303 formed in the pressure chamber forming layer 203 is wider than that of the recovery main passage 303 formed in the first film layer 202. A plurality of parallelogram-shaped pressure chambers 308 form a plurality of rows between the supply main channel 301 and the recovery main channel 303.

  FIG. 5 is an enlarged view of the second film layer 204. The second film layer 204 is composed of a photosensitive film. A square filter portion 321 for removing foreign matters in the supply main passage 301 is formed at one end of the second film layer 204 in the Y direction, and a part of the recovery main passage 303 is formed at the other end. Between the filter unit 321 and the recovery main flow path 303, a supply port 312 that connects the supply flow path 302 (see FIG. 6) and the pressure chamber 308, and the pressure chamber 308 and the discharge side flow path 309 (see FIG. 6). And an opening that communicates with each other.

FIG. 6 is an enlarged view of the flow path forming layer 205. The flow path forming layer 205 is composed of a silicon substrate. Various through holes are formed in the substrate. Specifically, a supply channel 302, a recovery channel 304, and a discharge side channel 309 are formed. The supply channel 302 and the recovery channel 304 are alternately arranged in the X direction (longitudinal direction). The discharge-side channel 309 is formed at a position facing the pressure chamber 308 between the position supply channel 302 and the recovery channel 304.
The discharge port forming layer 206 is composed of a plurality of photosensitive films. In the discharge port forming layer 206, a discharge port 310 that faces the discharge side flow channel 309 and a concave portion that functions as a first recovery port 313 (see FIG. 7B) are formed.

  In the present embodiment, the circuit wiring layer 201, the pressure chamber forming layer 203, and the flow path forming layer 205 are configured by a silicon substrate having a crystal lattice plane of (110) plane orientation. This silicon substrate is processed by laser drilling and anisotropic wet etching, and is manufactured without using dry etching such as DRIE (deep reactive ion etching). Since all the processed holes are masked so as to have a convex shape on the XY plane, it is not necessary to manage the etching time for the purpose of shaping, and also has resistance to alkaline ink. Circuit generation in the (110) plane orientation is inferior in transistor performance compared to the (100) plane orientation. However, since the circuit wiring layer 201 can be used on the entire surface other than the through holes (the main supply channel 301 and the main recovery channel 303), a sufficient circuit space can be secured in consideration of the wiring space even if the area of the transistor is increased to maintain performance. Is possible. In anisotropic wet etching, the (111) plane other than the wall (Z direction) perpendicular to the (110) plane orientation appears depending on the aspect ratio depending on the shape width of the mask drawing and the thickness of the silicon substrate. Is omitted.

In the present embodiment, the supply channel 302 and the recovery channel 304 are disposed at an angle of 70.53 ° with respect to the X direction of the head chip 108. In single crystal silicon, the etching rate varies greatly depending on the crystal direction, and two vertical walls of (111) planes appear by anisotropic wet etching of (110) plane orientation. The directions in which the two (111) planes grow can be represented by two <112> directions on the XY plane.
In the present embodiment, the thickness of the circuit wiring layer 201 is 725 μm. The thickness of the first film layer 202 is 25 μm. The thickness of the pressure chamber forming layer 203 is 100 μm. The thickness of the second film layer 204 is 100 μm. The thickness of the flow path forming layer 205 is 725 μm. The discharge port forming layer 206 has a thickness of 40 μm.

In the pressure chamber forming layer 203, energy generating means 311 (see FIG. 7B) is formed on the vibration plate 307. An individual electrode 401 and a common electrode (not shown) are connected to the energy generating means 311. Each electrode is covered with a protective layer (not shown). The individual electrode 401 is electrically connected to the wiring 317 through the connection terminal 306. In this embodiment, the energy generating means 311 is a thin film piezoelectric element. However, in the present invention, the energy generating means 311 may be an element such as a piezoelectric element using bulk PZT (lead zirconate titanate) or a heating element used for a thermal liquid discharge head.
When a driving voltage is applied to the individual electrode 401, the piezoelectric element 311 is deformed, and this deformation causes a decrease or increase in the volume of the pressure chamber 308 via the vibration plate 307. In this embodiment, the pressure chamber 308 is expanded to draw the meniscus of the discharge port 310 toward the pressure chamber 308, and then the ink is discharged by contracting the pressure chamber 308 at the timing when the pressure in the pressure chamber 308 increases. Is adopted.

FIG. 7A shows a perspective view of the flow path formed in the head chip 108. FIG. 7B is a cross-sectional view along the cutting line AA shown in FIG. Hereinafter, the flow path in the head chip 108 will be described.
With reference to FIG. 7A, the flow path configuration of the entire head chip 108 will be described. The supply main flow path 301 is a through hole that opens over the entire region in the X direction in the region where the plurality of pressure chamber rows 305 are arranged and penetrates from the circuit wiring layer 201 to the second film layer 204. The recovery main channel 303 is a through hole that is disposed on the opposite side of the supply main channel 301 and penetrates from the second film layer 204 to the circuit wiring layer 201. In the recovery main channel 303, a portion from the second film layer 204 to the pressure chamber forming layer 203 is a through hole having a long opening width, and a portion from the first film layer 202 to the circuit wiring layer 201 is the opening width. A short through hole. In the flow path forming layer 205, the supply main flow path 301 communicates with each supply flow path 302, and the recovery main flow path 303 communicates with the recovery flow path 304.

Next, referring to FIG. 7B, the flow path configuration near the ejection port and the ink flow near the ejection port will be described. In the flow path forming layer 205, only one of the supply flow path 302 and the recovery flow path 304 is disposed between the discharge side flow paths 309 arranged side by side in the X direction. That is, the pressure chambers 308 belonging to the pressure chamber rows 305 adjacent to each other communicate in common with either the supply channel 302 or the recovery channel 304.
The ink flowing through the supply channel 302 passes through the supply port 312 and is supplied to the pressure chamber 308. Of the ink supplied to the pressure chamber 308, the ink that has not been ejected from the ejection port 310 flows from the ejection side channel 309 through the first recovery port 313 to the recovery channel 304. When the fresh ink that has passed through the discharge-side flow path 309 flows in the vicinity of the discharge port 310, it is possible to suppress the increase in the viscosity of the ink attached to the discharge port 310.

  According to the liquid discharge head of this embodiment described above, the pressure chamber 308 is formed in the pressure chamber forming layer 203, and the supply flow path 302 that supplies ink to the pressure chamber 308 and the recovery that collects ink from the pressure chamber 308. The flow path 304 is formed in the flow path forming layer 205. A part of the pressure chamber 308 overlaps each of the supply flow path 302 and the recovery flow path 304 in the thickness direction (Z direction) perpendicular to the formation surface of the discharge port 310. Thus, by arranging both the supply flow path 302 and the recovery flow path 304 so as to overlap the pressure chamber row 305, the space for forming the pressure chamber forming layer 203 is not limited by the recovery flow path 304. Therefore, the discharge ports 310 can be arranged with high density while ensuring the size of the pressure chamber 308 sufficient for liquid discharge.

  In the present embodiment, the pressure chambers 308 belonging to the two adjacent pressure chamber rows 305 share either the supply flow path 302 or the recovery flow path 304. As a result, the entire region sandwiched between the discharge side flow channels 309 communicating with the two pressure chambers 308 adjacent to each other in the X direction can be occupied by one supply flow channel 302 or the recovery flow channel 304. Since the flow resistance is inversely proportional to the square of the flow path cross-sectional area, the flow resistance of the supply flow path 302 or the recovery flow path 304 can be greatly reduced. As a result, it is possible to reduce the pressure required for flowing ink when performing the through flow.

The liquid discharge head of the present invention can be applied to a coating apparatus or a modeling apparatus in addition to the liquid discharge apparatus.
In the present invention, the supply channel 302 and the recovery channel 304 may be opposite. In that case, the supply port 312 of this embodiment functions as a recovery port, and the recovery port 313 of this embodiment functions as a supply port. As a result, ink is supplied from the recovery port 313 to the pressure chamber 308. Of the supplied ink, the ink that has not been ejected from the ejection port 310 is collected from the supply port 312.

(Second Embodiment)
A second embodiment of the present invention will be described. The following description will focus on items that differ from the first embodiment, and descriptions of items that are common to the first embodiment will be omitted. The liquid discharge head of this embodiment is different from the liquid discharge head of the first embodiment in the configuration of the head chip.
FIG. 8A is a perspective view of the flow path formed in the head chip 108a of the present embodiment. FIG. 8B is a cross-sectional view along the cutting line AA shown in FIG. In FIGS. 8A and 8B, the same components as those in the first embodiment are denoted by the same reference numerals.

  In the head chip 108a of this embodiment, the first recovery port 313 (see FIG. 7B) described in the first embodiment is not formed. Instead, as shown in FIG. 8B, a second recovery port 314 is formed. The second recovery port 314 is formed at the end of the pressure chamber 308 on the opposite side of the supply port 312 with the discharge side channel 309 interposed therebetween, and allows the pressure chamber 308 and the recovery channel 304 to communicate with each other.

According to the present embodiment, since both the supply flow path 302 and the recovery flow path 304 are arranged so as to overlap with a different layer from the pressure chamber row 305 as in the first embodiment, the discharge ports 310 are arranged with high density. Can be arranged.
Furthermore, in this embodiment, the pressure chamber 308 communicates with the recovery channel 304 at the end opposite to the supply port 312 with the discharge side channel 309 interposed therebetween, so that bubbles do not accumulate at the end. Thereby, the bubbles in the pressure chamber 308 can be more reliably removed.

  In the present invention, the supply channel 302 and the recovery channel 304 may be opposite. In that case, the supply port 312 of this embodiment functions as a recovery port, and the second recovery port 314 of this embodiment functions as a supply port. As a result, the ink is supplied from the second recovery port 314 to the pressure chamber 308. Of the supplied ink, the ink that has not been ejected from the ejection port 310 is collected from the supply port 312.

(Third embodiment)
Next, a third embodiment of the present invention will be described. In the following description, the description will focus on matters different from those of the first and second embodiments, and description of matters common to these embodiments will be omitted.
FIG. 9A is a perspective view of a flow path formed in the head chip 108b of the present embodiment. FIG. 9B is a cross-sectional view along the cutting line AA shown in FIG. FIG. 9C is a cross-sectional view taken along a cutting line BB shown in FIG.

The liquid ejection head of this embodiment has a first recovery port 315 and a second recovery port 316. The first recovery port 315 allows the discharge side flow path 309 and the recovery flow path 304 to communicate with each other. The second recovery port 316 is formed on the opposite side of the supply port 312 with the discharge side channel 309 interposed therebetween, and allows the pressure chamber 308 and the recovery channel 304 to communicate with each other. According to the first recovery port 315, it is possible to suppress the increase in ink viscosity in the vicinity of the ejection port 310. On the other hand, according to the second recovery port 316, it is possible to remove bubbles remaining in the space on the opposite side of the supply port 312 with the discharge-side flow channel 309 in the pressure chamber 308 interposed therebetween.
Further, as shown in FIGS. 9B and 9C, the pressure chamber 308 located on the right side of the supply flow path 302 in the X direction and the pressure chamber 308 located on the left side of the supply flow path 302 are The pressure chambers 308 constituting the chamber row 305 are arranged so as to be shifted from each other in the arrangement direction (Y direction). That is, the pressure chambers belonging to one of the two pressure chamber rows adjacent to each other across the supply flow path 302 and the pressure chambers belonging to the other pressure chamber row are shifted from each other in the arrangement direction of the pressure chambers. Similarly, with respect to the recovery flow path 304, the pressure chambers adjacent to each other on the left and right sides of the recovery flow path 304 are shifted from each other in the arrangement direction of the pressure chambers. By thus arranging the pressure chambers 308 in a staggered manner with respect to the supply flow path 302 and the recovery flow path 304, the supply ports 312 communicating with the adjacent pressure chambers 308 across the supply flow path 302 do not face each other in the X direction. It is like that. Similarly, the first recovery port 315 and the second recovery port 316 that communicate with the adjacent pressure chamber 308 across the recovery flow path 304 do not face each other in the X direction. In this way, the supply port 312 that communicates with the pressure chambers 308 adjacent to each other, the first recovery port 315, and the second recovery port 316 do not face each other. Fluidic crosstalk can be reduced.

  In the present invention, the supply channel 302 and the recovery channel 304 may be opposite. In that case, the supply port 312 of this embodiment functions as a recovery port, the first recovery port 315 of this embodiment functions as a first supply port, and the second recovery port 316 serves as a second supply. Acts as a mouth. As a result, ink is supplied from the first recovery port 315 and the second recovery port 316 to the pressure chamber 208. Of the supplied ink, the ink that has not been ejected from the ejection port 310 is collected from the supply port 312. In each of the above embodiments, a configuration in which a part of the pressure chamber 308 overlaps each of the supply flow path 302 and the recovery flow path 304 in the thickness direction (Z direction) perpendicular to the formation surface of the discharge port 310 will be described. did. The present invention is not limited to this, and may be configured to overlap each of the supply flow path 302 and the recovery flow path 304 in the entire region of the pressure chamber.

302 Supply channel 304 Recovery channel 308 Pressure chamber 310 Discharge port

Claims (9)

A liquid discharge head having a discharge port,
A pressure chamber for storing liquid discharged from the discharge port;
A supply flow path for supplying the liquid to the pressure chamber;
A recovery flow path for recovering the liquid that has not been discharged from the discharge port out of the liquid supplied to the pressure chamber;
A first recovery port communicating with the recovery channel in the vicinity of the discharge port;
A second recovery port communicating with the recovery flow path at an end of the pressure chamber ,
The liquid discharge head, wherein at least a part of the pressure chamber overlaps the supply flow path and the recovery flow path in a direction perpendicular to a formation surface of the discharge port. The liquid discharge head according to claim 1 , further comprising a discharge port forming layer in which the discharge port and the first recovery port are formed. A liquid discharge head having a discharge port,
A pressure chamber for storing liquid discharged from the discharge port;
A supply flow path for supplying the liquid to the pressure chamber;
A recovery flow path for recovering the liquid that has not been discharged from the discharge port out of the liquid supplied to the pressure chamber;
A first supply port communicating with the supply channel in the vicinity of the discharge port ;
And a second supply port communicating with the supply channel at the end of the pressure chamber,
The liquid discharge head , wherein at least a part of the pressure chamber overlaps the supply flow path and the recovery flow path in a direction perpendicular to a formation surface of the discharge port . The liquid discharge head according to claim 3, further comprising a discharge port forming layer in which the discharge port and the first supply port are formed. A liquid discharge head having a discharge port,
A pressure chamber for storing liquid discharged from the discharge port;
A supply flow path for supplying the liquid to the pressure chamber;
A recovery flow path for recovering the liquid that has not been discharged from the discharge port out of the liquid supplied to the pressure chamber;
A first supply port communicating with the supply channel in the vicinity of the discharge port;
Anda discharge port formation layer in which the discharge port and said first supply port is formed,
The liquid discharge head , wherein at least a part of the pressure chamber overlaps the supply flow path and the recovery flow path in a direction perpendicular to a formation surface of the discharge port . The plurality of pressure chambers form a plurality of pressure chamber rows, and a plurality of pressure chambers respectively belonging to two pressure chamber rows adjacent to each other are in common communication with one of the supply flow path or the recovery flow path. liquid discharge head according to any one of claims 1 to 5. The liquid ejection head according to claim 6 , wherein the pressure chamber belonging to one of the two pressure chamber rows and the pressure chamber belonging to the other pressure chamber row are arranged to be shifted from each other in the arrangement direction of the pressure chambers. . Wherein provided in the pressure chamber, a piezoelectric element for generating energy for discharging the liquid stored in the pressure chamber from the discharge port, the liquid discharge head according to any one of claims 1 to 7. Including plural liquid ejecting apparatus of liquid ejection head according to any one of claims 1 to 8.

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