JP2013063588A - Liquid discharge head and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that adjacent crosstalk occurs in a through hole part communicating a pressure chamber and a nozzle thereby it is not possible to stably discharge liquid.SOLUTION: A groove part 30 forming a wall surface member side pressure chamber 12 and a groove part 31 being in communication to the groove part 30 and forming a fluid resistance part 13 are formed in a flow channel plate 2, a groove part 32 being a fluid introducing part 14 opening to a common liquid chamber 16 is formed in a nozzle plate side, a first through hole 21 passing through the flow channel plate 2 in a thickness direction, opening to the groove part 31 being the fluid resistance part 13, being a part of a fluid supplying channel communicating the fluid resistance part 13 and the liquid introducing part 14 is formed, an end part wall surface 31a is formed in the groove part 31 forming the fluid resistance part 13 with an end part in an opposite side of the pressure chamber 12 in a direction perpendicular a nozzle arranging direction closed.

Description

  The present invention relates to a liquid discharge head and an image forming apparatus.

  As an image forming apparatus such as a printer, a facsimile, a copying machine, a plotter, or a complex machine of these, for example, a liquid discharge recording type image forming using a recording head composed of a liquid discharge head (droplet discharge head) that discharges ink droplets. Devices such as ink jet recording devices are known.

  The liquid discharge head includes a nozzle plate in which a plurality of nozzles for discharging liquid droplets are arranged, a flow path plate in which grooves such as a plurality of pressure chambers each communicating with the nozzles are arranged with a partition wall interposed therebetween, and the grooves. There are known ones including a diaphragm member forming a wall surface of a pressure chamber and a wall member such as a substrate provided with a heating resistor.

  In such a liquid discharge head, in order to prevent the liquid in the pressure chamber from flowing in the direction opposite to the nozzle when the liquid in the pressure chamber is pressurized by the actuator means, a flow path is provided on the upstream side of the pressure chamber. A constricted fluid resistance is provided. Since discharge is controlled by the fluid resistance of the fluid resistance portion, the shape accuracy of the fluid resistance portion is extremely important.

  Conventionally, a silicon substrate (Si substrate) having a crystal plane orientation <110> is used as a flow path plate, and a pressure chamber having a more perpendicular partition wall by etching and a fluid resistance portion and a liquid introduction portion leading to the fluid resistance portion are on the same surface. (Patent Document 1).

  In addition, there is also known one that forms a fluid resistance portion with high accuracy by joining a nozzle plate having a groove portion serving as a fluid resistance portion and a flow path plate having a partition wall portion facing the groove portion of the nozzle plate. (Patent Document 2).

JP 2004-209921 A JP-A-9-239978

  However, in the configuration in which the fluid resistance portion having a narrow flow path is formed using the <110> Si substrate as described above, the thinned corner portion is a higher-order surface of the crystal orientation, so that the etching rate is high. Since it is fast and not stable, there is a problem that it is difficult to control the length of the fluid resistance portion.

  Further, in the configuration in which the flow path plate in which the pressure chamber is formed and the nozzle plate in which the groove portion serving as the fluid resistance portion is joined, the groove portion must be formed on the nozzle plate side, and the nozzle plate is processed. There is a problem of becoming complicated.

  The present invention has been made in view of the above-described problems, and has an object to form a highly accurate fluid resistance portion with a simple configuration and perform stable droplet ejection with little variation in droplet ejection characteristics. And

In order to solve the above-described problem, a liquid discharge head according to the present invention includes:
A pressure chamber to which each of a plurality of nozzles for discharging droplets communicates;
A flow path plate that forms at least a liquid supply path having a fluid resistance section that supplies liquid to the pressure chamber on the upstream side of the pressure chamber;
The flow path plate is formed by etching a silicon substrate having a crystal plane orientation <110>,
On one surface of the flow path plate, a groove portion serving as the fluid resistance portion is formed continuously with the groove portion serving as the pressure chamber,
The groove portion serving as the fluid resistance portion has a configuration in which an end opposite to the pressure chamber is closed in a direction orthogonal to the nozzle arrangement direction.

  According to the present invention, it is possible to perform stable droplet ejection with little variation in droplet ejection characteristics.

FIG. 2 is an external perspective explanatory view of the liquid discharge head according to the first embodiment of the present invention. FIG. 5 is a cross-sectional explanatory view taken along line A1-A1 of FIG. FIG. 5 is a cross-sectional explanatory view taken along line A2-A2 of FIG. FIG. 3 is a cross-sectional explanatory view taken along line B1-B1 of FIG. It is sectional explanatory drawing which follows the A3-A3 line | wire of FIG. 6 of a comparative example. FIG. 6 is a cross-sectional explanatory view taken along line B2-B2 of FIG. It is sectional explanatory drawing similar to FIG. 2 with which it uses for effect description of the embodiment. FIG. 11 is an explanatory cross-sectional view of the liquid ejection head according to the second embodiment of the present invention, taken along line A4-A4 in FIG. It is sectional explanatory drawing which follows the A5-A5 line | wire of FIG. It is sectional explanatory drawing which follows the B3-B3 line | wire of FIG. FIG. 14 is an explanatory cross-sectional view of the liquid ejection head according to the third embodiment of the present invention taken along line A6-A6 of FIG. It is sectional explanatory drawing which follows the A7-A7 line | wire of FIG. It is sectional explanatory drawing which follows the B4-B4 line | wire of FIG. It is sectional explanatory drawing similar to FIG. 12 with which it uses for effect description of the embodiment. FIG. 18 is a cross-sectional explanatory view taken along line A8-A8 in FIG. 17 of a liquid ejection head according to a fourth embodiment of the present invention. It is sectional explanatory drawing which follows the A9-A9 line | wire of FIG. It is sectional explanatory drawing which follows the B5-B5 line | wire of FIG. FIG. 21 is a cross-sectional explanatory view taken along line A10-A10 in FIG. 20 of a liquid ejection head according to a fifth embodiment of the present invention. FIG. 21 is a cross-sectional explanatory view taken along line A11-A11 of FIG. It is sectional explanatory drawing which follows the B6-B6 line | wire of FIG. FIG. 24 is a cross-sectional explanatory view taken along line A12-A12 of FIG. 23 of a liquid ejection head according to a sixth embodiment of the present invention. It is sectional explanatory drawing which follows the A13-A13 line | wire of FIG. FIG. 22 is a cross-sectional explanatory view taken along line B7-B7 of FIG. FIG. 27 is a cross-sectional explanatory view taken along line A14-A14 of FIG. 26 of a different example of the liquid ejection head according to the seventh embodiment of the present invention. It is sectional explanatory drawing which follows the A15-A15 line | wire of FIG. FIG. 25 is an explanatory sectional view taken along line B8-B8 of FIG. It is sectional explanatory drawing which follows the C1-C1 line | wire of FIG. 24 of a 1st example. It is sectional explanatory drawing which follows the C1-C1 line | wire of FIG. 24 of 2nd example. FIG. 32 is a cross-sectional explanatory view taken along line A16-A16 of FIG. 31 of a liquid ejection head according to an eighth embodiment of the present invention. FIG. 32 is an explanatory cross-sectional view taken along line A17-A17 of FIG. 31. FIG. 30 is an explanatory cross-sectional view taken along line B9-B9 of FIG. FIG. 35 is a cross-sectional explanatory view taken along line A18-A18 in FIG. 34 of a liquid ejection head according to a ninth embodiment of the present invention. FIG. 35 is an explanatory sectional view taken along line A19-A19 in FIG. 34. It is sectional explanatory drawing which follows the B10-B10 line | wire of FIG. FIG. 39 is an explanatory cross-sectional view of the liquid ejection head according to the tenth embodiment of the present invention, taken along line A20-A20 in FIG. It is sectional explanatory drawing which follows the A21-A21 line | wire of FIG. It is sectional explanatory drawing which follows the A22-A22 line | wire of FIG. FIG. 36 is a cross-sectional explanatory view taken along line B11-B11 of FIG. FIG. 44 is an explanatory cross-sectional view of the liquid ejection head according to the eleventh embodiment of the present invention, taken along line A23-A23 in FIG. FIG. 43 is an explanatory sectional view taken along line A24-A24 of FIG. 42. FIG. 43 is an explanatory cross-sectional view taken along line A25-A25 of FIG. 42. It is sectional explanatory drawing which follows the B12-B12 line | wire of FIG. FIG. 46 is an explanatory cross-sectional view of the liquid ejection head according to the twelfth embodiment of the present invention taken along line A26-A26 in FIG. It is sectional explanatory drawing which follows the A27-A27 line | wire of FIG. It is sectional explanatory drawing which follows the B13-B13 line | wire of FIG. FIG. 49 is an explanatory cross-sectional view of the liquid ejection head according to the thirteenth embodiment of the present invention, taken along the line A28-A28 in FIG. FIG. 49 is an explanatory sectional view taken along line A29-A29 in FIG. 48. It is sectional explanatory drawing which follows the B14-B14 line | wire of FIG. FIG. 50 is an explanatory cross-sectional view of the liquid ejection head according to the fourteenth embodiment of the present invention, taken along the line A30-A30 in FIG. It is sectional explanatory drawing which follows the A31-A31 line | wire of FIG. It is sectional explanatory drawing which follows the B15-B15 line | wire of FIG. It is a plane explanatory view, a bottom face explanatory view, and a cross-sectional explanatory view for explaining a manufacturing process of a flow path plate in the liquid discharge head according to the present invention. Similarly, it is a plane explanatory view and a cross-sectional explanatory view of the process following FIG. Similarly, it is a plane explanatory view and a cross-sectional explanatory view of the process following FIG. 53. Similarly, it is a plane explanatory view and a cross-sectional explanatory view of the process following FIG. 54. Similarly, it is a plane explanatory view and a cross-sectional explanatory view of the process following FIG. Similarly, it is a plane explanatory view and a cross-sectional explanatory view of the process following FIG. Similarly, it is a plane explanatory view and a cross-sectional explanatory view of the process following FIG. 57. 59 is also a plan explanatory view and a cross-sectional explanatory view of the process following FIG. 58. FIG. Similarly, it is a plane explanatory view and a cross-sectional explanatory view of the process following FIG. 59. Similarly, it is a plane explanatory view and a cross-sectional explanatory view of the process following FIG. It is a side explanatory view of a mechanism portion showing an example of an image forming apparatus according to the present invention. It is principal part plane explanatory drawing of the mechanism part.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. A liquid discharge head according to a first embodiment of the present invention will be described with reference to FIGS. 1 is an external perspective view of the head, FIG. 2 is a cross-sectional view taken along the line A1-A1 of FIG. 4, FIG. 3 is a cross-sectional view taken along the line A2-A2 of FIG. 4, and FIG. FIG. 6 is a cross-sectional explanatory view taken along line -B1 (along line XX in FIG. 1). Although FIG. 1 shows the state in which the droplet discharge direction is directed upward, FIGS. 2 to 4 show the state in which the droplet discharge direction is directed downward.

  This liquid discharge head is formed by laminating and joining a nozzle plate 1, a flow path plate 2, and a diaphragm member 3 that is a wall surface member. A piezoelectric member 4 is disposed on the opposite side of the vibration plate member 3 from the flow path plate 2, and a direction orthogonal to the nozzle arrangement direction of the flow path plate 2 and the vibration plate member 3 (also referred to as “flow path member”). The common liquid chamber member 5 forming the common liquid chamber 16 is disposed at the end.

  A plurality of nozzles 11 for discharging droplets are arranged in a staggered pattern on the nozzle plate 1. The nozzle plate 1 is formed of, for example, stainless steel by press working, and the nozzle plate 1 is made of other resin such as Ni electroforming, polyimide resin film, silicon, and combinations thereof. Can do. Further, a water repellent film is formed on the nozzle surface by a known method such as a plating film or a water repellent coating. The nozzle plate 1 is bonded to the flow path plate 2 with an adhesive.

  The flow path plate 2 includes a through hole 15 that communicates with the nozzle 11, a pressure chamber 12 that communicates with the nozzle 11 via the through hole 15, a fluid resistance portion 13 that forms part of a liquid supply path that supplies liquid to the pressure chamber 12, One through hole 21 and a liquid introduction part 14 are formed. The flow path plate 2 is formed by etching a silicon substrate having a crystal plane orientation <110>.

  The diaphragm member 3 is a wall surface forming member that forms wall surfaces such as the pressure chamber 12 and the fluid resistance portion 13. This vibration plate member 3 has a displaceable vibration region 3a which becomes a part of the wall surface of the pressure chamber 12, and a piezoelectric member (piezoelectric element) which is an actuator means on an island-shaped convex portion 3b provided in the vibration region 3a. 4 is joined. The diaphragm member 3 has a two-layer structure and is formed by Ni electroforming.

  As the piezoelectric member 4, a laminated piezoelectric member joined to a base member (not shown) is grooved by half-cut dicing to form a plurality of columnar piezoelectric elements in a comb-like shape at predetermined intervals. Used.

  The common liquid chamber member 5 also serves as a frame member of the head, accommodates liquid supplied from the outside, and forms a common liquid chamber 16 for supplying to each pressure chamber 12. The common liquid chamber member 5 is different in level, and is joined to the nozzle plate 1 and the diaphragm member 3 so that the common liquid chamber member 5 is shared outside the end portions of the flow path plate 2 and the diaphragm member 3 in the direction perpendicular to the nozzle arrangement direction. A liquid chamber 16 is disposed.

  In this liquid discharge head, for example, the piezoelectric member 4 contracts by lowering the voltage applied to the piezoelectric member 4 from the reference potential, the vibration region 3a of the diaphragm member 3 descends, and the volume of the pressure chamber 12 expands. Then, the ink flows into the pressure chamber 12, and then the voltage applied to the piezoelectric member 4 is increased and extended in the stacking direction, and the vibration region 3 a of the vibration plate member 3 is deformed in the direction of the nozzle 11, so that the volume of the pressure chamber 12 is increased. By contracting the ink, the ink in the pressure chamber 12 is pressurized, and ink droplets are ejected (ejected) from the nozzle 11.

  Then, by returning the voltage applied to the piezoelectric member 4 to the reference potential, the vibration region 3a of the diaphragm member 3 is restored to the initial position, and the pressure chamber 12 expands to generate a negative pressure. Ink is filled from the chamber 16 into the pressure chamber 12. Therefore, after the vibration of the meniscus surface of the nozzle 11 is attenuated and stabilized, the operation proceeds to the next droplet discharge.

  Note that the driving method of the head is not limited to the above example (pulling-pushing), and it is also possible to perform striking or pushing depending on the direction to which the driving waveform is given.

  Next, the details of the channel structure of the channel plate in the present embodiment will be described.

  In the flow path plate 2, a groove portion 30 that forms the pressure chamber 12 and a fluid resistance portion 13 are formed on the surface side (hereinafter referred to as “wall surface member side”) that joins the diaphragm member 3. A groove 31 is formed. In the direction orthogonal to the nozzle arrangement direction, the width of the groove portion 31 is narrower than the width of the groove portion 30, so that this portion becomes the fluid resistance portion 13.

  Further, the flow path plate 2 has an opening 14 a that opens to the common liquid chamber 16 on the surface side (hereinafter referred to as “nozzle plate side”) that is joined to the nozzle plate 1. A groove portion 32 that forms the liquid introduction portion 14 that is a part of the liquid supply path for introducing the liquid into the flow path is formed.

  And in the flow path plate 2, the flow path plate 2 is penetrated in the thickness direction on the upstream side of the groove portion 31 that becomes the fluid resistance portion 13, and the groove portion 31 that becomes the fluid resistance portion 13 is opened on the wall surface member side, A first through hole 21 is formed in the groove 32 serving as the liquid introduction part 14 on the nozzle plate side, and serves as a part of the liquid supply path through the fluid resistance part 13 and the liquid introduction part 14.

  Here, the groove portion 31 forming the fluid resistance portion 13 has an end wall surface 31a formed by closing an end portion on the opposite side of the pressure chamber 12 in a direction orthogonal to the nozzle arrangement direction. In the present embodiment, the end wall surface 31 a of the groove 31 is continuous with the side wall surface 21 a of the first through hole 21.

  Since it comprised in this way, the length L of the fluid resistance part 13 is prescribed | regulated as a distance between the position of the side wall surface 21b by the side of the pressure chamber 12 of the 1st through-hole 21, and the starting point which spreads toward the pressure chamber 12 side. Is done.

  Therefore, when the silicon substrate having the crystal plane orientation <110> is etched to form the groove 31 serving as the fluid resistance portion 13 in the flow path plate 2, the end wall surface 31a in the direction orthogonal to the nozzle arrangement direction of the groove 31 is It becomes a recess with respect to the crystal orientation and becomes the (111) crystal orientation plane with the slowest etching rate, and the etching rate by anisotropic etching becomes extremely slow and stable.

  However, the wall surface 30a of the connecting portion between the end portion of the pressure chamber 12 of the groove portion 31 to be the fluid resistance portion 13 and the groove portion 30 to be the pressure chamber 12 is a convex portion with respect to the crystal orientation, and the higher order crystal orientation Since the surface is exposed to the etchant, etching is performed at a fast and unstable etching rate, and the positional accuracy is lowered.

  However, since the one end portion of the groove portion 31 can be formed with high accuracy, the length of the fluid resistance portion 13 can be controlled with high accuracy compared to the case where both end portions are open. That is, in the case where the connection portions similar to those on the pressure chamber side are provided at both end portions of the groove portion 31, both become convex portions with respect to the crystal orientation and the length of the fluid resistance portion cannot be controlled with high accuracy. .

  As for the operational effects of the present embodiment, in relation to the crystal orientation with the silicon substrate, one end portion is compared to the comparative example (FIGS. 5 and 6) in which both ends of the groove portion serving as the fluid resistance portion are open. The effect of the closed embodiment (FIG. 7) will be described.

  First, in the comparative example shown in FIGS. 5 and 6, the pressure chamber 12, the fluid resistance portion 13, and the liquid introduction portion 14 are formed by a series of groove portions on one surface (surface on the wall member side) of the flow path plate 2. It is a thing.

  In the configuration of this comparative example, higher-order crystal orientation planes 410 appear on the four wall surfaces of the connecting portion between both ends of the fluid resistance unit 13 and the pressure chamber 12 and the liquid introduction unit 14. As for other wall surfaces, a (111) plane 411 or a (100) plane 412 which is a crystal orientation plane having a slow etching rate and a stable etching rate appears. In addition, in the etching rate, the (111) plane is the slowest, the (100) plane is the next slowest, and the (110) is fast.

  Higher-order crystal planes are difficult to control the rate of anisotropic etching, and also have a high etching rate. Therefore, the etching amount varies at both ends of the fluid resistance portion 13 due to variations in etching solution concentration and temperature during etching, and variations in etching solution concentration and temperature due to different etching lots.

  Here, since the length of the fluid resistance portion 13 is defined as the length of the portion having the same groove width (width in the nozzle arrangement direction), as shown in FIG. For example, the length L2 becomes longer than the specified length L1 (L = L1), or the length L3 becomes shorter.

  As described above, when the length of the fluid resistance portion 13 varies, the droplet discharge characteristics vary among the nozzles.

  On the other hand, in this embodiment, as shown in FIG. 7, the higher-order crystal orientation surface 410 appears only on the two surfaces of the connecting portion between the fluid resistance portion 13 and the pressure chamber 12, and other surfaces. Is formed of a (111) plane 411 and a (100) plane 412 which are crystal orientation planes with a stable etching rate.

  Therefore, only the higher-order crystal plane on the pressure chamber 12 side of the fluid resistance portion 13 varies. For example, the length of the fluid resistance portion 13 varies such as a length L12 that becomes longer than a specified length L1 (L = L1) or a length L13 that becomes shorter.

  However, in this embodiment, since the length of the fluid resistance portion 13 is determined based on the position of the side wall surface 21b of the first through-hole 21, the variation in the etching rate of the higher-order crystal orientation surface is a comparative example. If it is the same, the variation in the length of the fluid resistance portion can be halved compared to the comparative example.

  Next, a liquid ejection head according to a second embodiment of the present invention will be described with reference to FIGS. 8 is a cross-sectional explanatory view taken along line A4-A4 of FIG. 10 of the head, FIG. 9 is a cross-sectional explanatory view taken along line A5-A5 of FIG. 10, and FIG. 10 is a cross-sectional explanatory view taken along line B3-B3 of FIG. It is.

  In the present embodiment, the fluid resistance portion 13 is divided into two in the nozzle arrangement direction by the partition wall portion 33 extending from the first through hole 21 side, and the two fluid resistance portions 13 are provided for one pressure chamber 12. The configuration is arranged.

  Also in this case, the groove part 31 forming each fluid resistance part 13 is closed in the direction orthogonal to the nozzle arrangement direction and on the opposite side of the pressure chamber 12 to form an end wall surface 31a. In the present embodiment, the end wall surface 31 a of the groove 31 is continuous with the side wall surface 21 a of the first through hole 21.

  Even if comprised in this way, the effect similar to the said 1st Embodiment can be acquired.

  Next, a liquid ejection head according to a third embodiment of the present invention will be described with reference to FIGS. 11 is a sectional explanatory view taken along the line A6-A6 of FIG. 13 of the head, FIG. 12 is a sectional explanatory view taken along the line A7-A7 of FIG. 13, and FIG. 13 is a sectional explanatory view taken along the line B4-B4 of FIG. It is.

  In the present embodiment, the common liquid chamber member 5 is disposed on the surface of the diaphragm member 3 opposite to the pressure chamber 12 side, and the liquid is supplied through the opening 17 provided in the diaphragm member 3.

  In the flow path plate 2, a groove portion 30 that forms the pressure chamber 12 and a groove portion 32 that becomes the liquid introduction portion 14 that communicates with the opening portion 17 are formed on the wall surface member side.

  Further, the flow path plate 2 is formed with a groove portion 31 that becomes the fluid resistance portion 13 on the nozzle plate side.

  The flow path plate 2 is provided with a first through hole 21 and a second through hole 22 that are part of the liquid supply path that penetrates the flow path plate 2 in the thickness direction. The fluid resistance portion 13 is disposed between the holes 22.

  The first through hole 21 opens to the downstream side of the groove portion 31 that becomes the fluid resistance portion 13 and communicates with the pressure chamber 12, and the second through hole 22 opens to the upstream side of the groove portion 31 that becomes the fluid resistance portion 13 and is liquid It leads to the introduction part 14.

  Here, the groove portion 31 forming the fluid resistance portion 13 is closed at both ends in the direction orthogonal to the nozzle arrangement direction to form end wall surfaces 31a and 31c. In the present embodiment, the end wall surface 31 a of the groove 31 is continuous with the side wall surface 21 b of the first through-hole 21, and the end wall surface 31 c of the groove 31 is continuous with the side wall surface 22 a of the second through-hole 22. ing.

  Since it comprised in this way, the edge part wall surfaces 31a and 31c of the groove part 31 used as the fluid resistance part 13 become a recessed part of a crystal orientation, and the etching rate by anisotropic etching is very slow, and is stabilized.

  Thereby, fluid resistance part length precision can be formed with high precision. Note that the length of the fluid resistance portion 13 of the present embodiment is defined by the position of the side wall surface 21 a of the first through hole 21 and the side wall surface 22 b of the second through hole 22.

  The effect of this embodiment will be described with reference to FIG. 14 in relation to the crystal orientation plane.

  In the configuration of the present embodiment, as shown in FIG. 14, the groove portions 30, 31, and 32 of the flow path plate 2 are (111) planes 411 that are crystal orientation planes that are slow in etching rate and stable in etching rate. And (100) plane 412.

  Therefore, since the variation in the length of the fluid resistance portion hardly occurs due to the variation in the etching rate of the higher-order crystal orientation plane, the length of the fluid resistance portion can be formed with higher accuracy than in the first and second embodiments, Stable droplet ejection characteristics with less variation can be obtained.

  Next, a liquid ejection head according to a fourth embodiment of the invention will be described with reference to FIGS. 15 is a sectional explanatory view taken along line A8-A8 in FIG. 17 of the head, FIG. 16 is a sectional explanatory view taken along line A9-A9 in FIG. 17, and FIG. 17 is a sectional explanatory view taken along line B5-B5 in FIG. It is.

  In the present embodiment, the fluid resistance portion 13 is divided into two in the nozzle arrangement direction by the partition wall portion 34, and the two fluid resistance portions 13 are arranged for one pressure chamber 12.

  Also in this case, both end portions of the groove portion 31 forming each fluid resistance portion 13 are closed to form end wall surfaces 31a and 31c. Also in this embodiment, the end wall surface 31 a of the groove portion 31 is continuous with the side wall surface 21 b of the first through hole 21, and the end wall surface 31 c of the groove portion 31 is continuous with the side wall surface 22 a of the second through hole 22. .

  Even if comprised in this way, the effect similar to the said 3rd Embodiment can be acquired.

  Next, a liquid ejection head according to a fifth embodiment of the invention will be described with reference to FIGS. 18 is a sectional explanatory view taken along line A10-A10 in FIG. 20, FIG. 19 is a sectional explanatory view taken along line A11-A11 in FIG. 20, and FIG. 20 is a sectional explanatory view taken along line B6-B6 in FIG. It is.

  In the present embodiment, in the first embodiment, as in the third embodiment, the common liquid chamber member 5 is arranged on the surface of the diaphragm member 3 opposite to the pressure chamber 12 side, and the diaphragm member 3 is arranged. The liquid is supplied through the opening 17 provided in the channel plate 2, and the liquid introduction portion 14 of the flow path plate 2 is configured by a through hole 35 and a groove portion 32 that penetrate the flow path plate 2 in the thickness direction.

  And it forms in the nozzle arrangement direction and the groove part 31 used as the fluid resistance part 13 with respect to the groove part 30 used as the pressure chamber 12 formed in the surface at the wall surface member side of the flow-path plate 2. FIG. Here, the one wall surface in the nozzle array direction of the groove portion 30 and the one wall surface in the nozzle array direction of the groove portion 30 are the same surface.

  As a result, a convex portion is formed with respect to the crystal orientation, and a higher-order surface of the crystal orientation is exposed to the etchant. Therefore, the portions that are etched at a fast and unstable etching rate and the positional accuracy is deteriorated are the groove portions 30 and 31. It is only one place of one wall surface 31b which connects the other wall surface.

  Therefore, compared to the first and second embodiments, the length accuracy of the fluid resistance portion 13 can be further improved, and management by inspection or the like is facilitated.

  Next, a liquid ejection head according to a sixth embodiment of the present invention will be described with reference to FIGS. 21 is a sectional explanatory view taken along line A12-A12 in FIG. 23 of the head, FIG. 22 is a sectional explanatory view taken along line A13-A13 in FIG. 23, and FIG. 23 is a sectional explanatory view taken along line B7-B7 in FIG. It is.

  In the present embodiment, in the fifth embodiment, the positions of the pressure chambers 12 and the first through holes 21 are shifted in the nozzle arrangement direction.

  Even if it does in this way, the effect similar to the said 5th Embodiment can be acquired. And when it is set as the multi-row head which raises a nozzle density by making the multi-row which arranges a plurality of nozzle rows, it is necessary to shift the nozzle position to the nozzle arrangement direction for every nozzle row. With such a multi-row head, the nozzle position can be easily shifted in the nozzle arrangement direction by configuring as in the present embodiment, so that the density can be increased.

  Next, different examples of the liquid ejection head according to the seventh embodiment of the present invention will be described with reference to FIGS. 24 is a sectional explanatory view taken along line A14-A14 in FIG. 26 of the head, FIG. 25 is a sectional explanatory view taken along line A15-A15 in FIG. 26, and FIG. 26 is a sectional explanatory view taken along line B8-B8 in FIG. 27 is a sectional explanatory view taken along line C1-C1 of FIG. 24 of the first example, and FIG. 28 is a sectional explanatory view taken along line C1-C1 of FIG. 24 of the second example.

  The configuration of the fluid resistance portion 13 and the first through hole 21 in the present embodiment is the same as that in the first embodiment, and the configuration on the liquid introduction portion 14 side is the same as that in the fifth embodiment.

  And in the 1st example shown in FIG. 27, the connection part of the groove part 31 used as the 1st through-hole 21 and the fluid resistance part 13 is made into the taper shape.

  Such a tapered shape can be easily formed by etching the connecting portion by anisotropic wet etching. Thereby, the flow of the liquid becomes smooth, the change in the flow velocity is reduced, and the trapping of bubbles is less likely to occur.

  In the second example shown in FIG. 28, the connecting portion between the first through hole 21 and the groove portion 31 that becomes the fluid resistance portion 13 has a flat step shape.

  Such a step shape can be easily formed by processing with the same etching as that of the channel groove when etching the connecting portion by anisotropic wet etching. Alternatively, when the first through hole 21 is made to penetrate after the groove portion 31 is formed, the upper surface of the portion other than the groove portion 31 is protected by boron doping or a metal sputtering mask and then easily formed by penetrating the first through hole 21. can do.

  Since the fluid resistance of the fluid resistance portion 13 is determined by the length of the narrowest flow path portion, the length of the narrowest portion can be easily managed by forming a flat stepped shape.

  Next, a liquid ejection head according to an eighth embodiment of the invention will be described with reference to FIGS. 29 is a sectional explanatory view taken along line A16-A16 in FIG. 31 of the head, FIG. 30 is a sectional explanatory view taken along line A17-A17 in FIG. 31, and FIG. 31 is a sectional explanatory view taken along line B9-B9 in FIG. It is.

  In the present embodiment, only the planar shape of the common liquid chamber 16 is different from that of the first embodiment. Here, the liquid introduction part 14 for introducing the liquid into the flow path in the flow path plate 2 is provided on the surface of the flow path plate 2 on the nozzle plate side, as in the first embodiment.

  As described above, the common liquid chamber member 5 is bonded to the vibration plate member 3 and the nozzle plate 1 with an adhesive in a step difference. It is necessary to increase the thickness of the adhesive 130 between the plate member 3.

  A part of the thickly applied adhesive 130 may flow out to the end portions of the vibration plate member 3 and the flow path plate 2 in the nozzle arrangement direction and block the liquid introduction portion 14.

  As in the present embodiment, the adhesive 130 is provided by providing the liquid introducing portion 14 on the nozzle plate side surface of the flow path plate 2 away from the joint portion between the common liquid chamber member 5 and the vibration plate member 3 by the adhesive. Even if a part of the liquid flows out, the possibility of closing the liquid introducing portion 14 is reduced.

  Next, a liquid ejection head according to a ninth embodiment of the invention will be described with reference to FIGS. 32 is a sectional explanatory view taken along line A18-A18 in FIG. 34 of the head, FIG. 33 is a sectional explanatory view taken along line A19-A19 in FIG. 34, and FIG. 34 is a sectional explanatory view taken along line B10-B10 in FIG. It is.

  In this embodiment, in the said 8th Embodiment, the opening part 14a by the side of the common liquid chamber 16 of the liquid introduction part 14 is made into the taper shape which spreads toward the common liquid chamber 16 side.

  Such a tapered shape can be easily formed by masking the individual flow paths by anisotropic etching.

  Thereby, it becomes easy to introduce the liquid, and it is possible to prevent problems such as bubbles trapped in the corners of the liquid introduction part 14.

  Next, a liquid ejection head according to a tenth embodiment of the invention will be described with reference to FIGS. 35 is a sectional explanatory view taken along line A20-A20 in FIG. 38 of the head, FIG. 36 is a sectional explanatory view taken along line A21-A21 in FIG. 38, and FIG. 37 is a sectional explanatory view taken along line A22-A22 in FIG. FIG. 38 is an explanatory sectional view taken along line B11-B11 in FIG.

  In this embodiment, the liquid introducing | transducing part 14 of the separate flow path (The pressure chamber 12, the fluid resistance part 13, the 1st through-hole 21) is connected with each separate flow path.

  That is, the response speed with respect to the pressure fluctuation of each individual channel depends on the volume after each individual channel is separated from the common portion into the individual channel. Therefore, by connecting the liquid introduction part 14 with each individual flow path, the volume of each individual flow path can be reduced, the response speed to pressure fluctuations can be increased, and liquid droplets can be ejected at high speed.

  It should be noted that the degree of connection of the liquid introduction part 14 may be all up to the portion facing the first through hole 21 or the front side of the first through hole 21 (the first through hole 21 is the liquid introduction here) (A state facing the portion 14).

  Next, a liquid ejection head according to an eleventh embodiment of the present invention will be described with reference to FIGS. 39 is a sectional explanatory view taken along line A23-A23 of FIG. 42 of the head, FIG. 40 is a sectional explanatory view taken along line A24-A24 of FIG. 42, and FIG. 41 is a sectional explanatory view taken along line A25-A25 of FIG. 42 is a cross-sectional explanatory view taken along line B12-B12 of FIG.

  In this embodiment, in the tenth embodiment, ribs 131 are arranged and connected for each of the plurality of liquid introducing portions 14.

  That is, if a large space region is provided at the joint portion with the nozzle plate 1, there is a possibility that a problem may occur due to deflection due to the external force of the nozzle plate 1.

  Therefore, by providing the rib 131 in a part, a reinforcing part is provided in a part of a large space area at a joint part with the nozzle plate 1 to prevent a deflection due to an external force.

  Next, a liquid ejection head according to a twelfth embodiment of the present invention will be described with reference to FIGS. 43 is a sectional view taken along the line A26-A26 in FIG. 45 of the head, FIG. 44 is a sectional view taken along the line A27-A27 in FIG. 45, and FIG. 45 is a sectional view taken along the line B13-B13 in FIG. It is.

  In the present embodiment, in the configuration of the eighth embodiment, the convex portion 132 is provided at the end of the flow path plate 2.

  The convex portion 132 can be easily formed by providing a step in a mask for forming the flow path and a mask or dicing line for separating the flow paths.

  With this configuration, even if part of the adhesive 130 flows out from the joint between the common liquid chamber member 5 and the diaphragm member 3, the adhesive 130 is dammed up and flows into the liquid introduction part 14. Can be prevented.

  Next, a liquid ejection head according to a thirteenth embodiment of the present invention will be described with reference to FIGS. 46 is a sectional explanatory view taken along line A28-A28 in FIG. 48 of the head, FIG. 47 is a sectional explanatory view taken along line A29-A29 in FIG. 48, and FIG. 49 is a sectional explanatory view taken along line B14-B14 in FIG. It is.

  When the flow path plate 2 is manufactured using a silicon substrate (wafer) having a crystal plane orientation <110>, depending on the etching plane orientation with respect to the wafer, as shown in FIG. 46, the pressure chamber 12, the through hole 15, the fluid resistance, The angles α and β of the end portions in the direction along the direction orthogonal to the nozzle arrangement direction such as the portion 13 and the liquid introduction portion 14 can be set to different angles.

  Here, the position where the surface 412 having the angle α and the surface 411 having the angle β intersect each other in the first through hole 21, the second through hole 22, or both of the first through hole 21 and the second through hole 22. Is positioned at a substantially central portion in a direction orthogonal to the nozzle arrangement direction of the groove portion, thereby allowing the first through hole 21, the second through hole 22, or both the first through hole 21 and the second through hole 22. The liquid can easily pass through, and the bubble removing property (bubble discharging property) can be improved.

  In this case, the above-described shape can be easily manufactured by changing the ratio of the surface having the angle α and the surface having the angle β in the optical mask.

  Next, a liquid ejection head according to a fourteenth embodiment of the present invention will be described with reference to FIGS. 49 is a sectional explanatory view taken along line A30-A30 in FIG. 51 of the head, FIG. 50 is a sectional explanatory view taken along line A31-A31 in FIG. 51, and FIG. 51 is a sectional explanatory view taken along line B15-B15 in FIG. It is.

  As described above, when the flow path plate 2 is manufactured using a silicon substrate (wafer) having a crystal plane orientation <110>, depending on the etching plane orientation with respect to the wafer, as shown in FIG. The angles α and β of the end portions in the direction along the direction orthogonal to the nozzle arrangement direction such as the holes 15, the fluid resistance portion 13, and the liquid introduction portion 14 can be different angles.

  In the present embodiment, with respect to the through hole 15 side end of the pressure chamber 12 and the through hole 15, the position where the surface 412 having the angle α and the surface 411 having the angle β intersect is a direction orthogonal to the nozzle arrangement direction. It is formed by shifting from the central part.

  Thereby, the linear region length L11, L12 of the side wall surface of the nozzle arrangement direction both ends of the groove part which forms the pressure chamber 12 can be varied.

  By adopting such a shape, the groove part shape can be freely changed, the liquid can easily flow in the groove part, and the bubble removability can be enhanced. Such a shape can be easily manufactured by changing the ratio of the surface 411 having the angle α to the surface having the angle β in the optical mask.

  Next, an example of a method for manufacturing a flow path plate for a liquid discharge head according to the present invention will be described with reference to FIGS. Each figure (a) is a plane explanatory view, (b) is a bottom view, (c) is a cross-sectional explanatory view taken along line X1-X1 in (a) and (b), and (d) is (a), (b). It is sectional explanatory drawing in alignment with line X2-X2.

  First, using a silicon substrate 303 with a crystal plane orientation (110), as shown in FIG. 52, a front side dry etching protective film 301, a front side wet etching pattern 302, a back side wet etching pattern 304, a back side wet etching pattern 305, and a back side The wet etching pattern 306 and the back side dry etching pattern 307 are patterned.

  For patterning, a silicon oxide film, a silicon nitride film, or the like can be used, and patterning using a resist can also be used.

  Thereafter, as shown in FIG. 53, a substantially vertical etching hole 308 is formed by dry etching.

  Next, as shown in FIG. 54, the back side dry etching pattern 307 is peeled off.

  Thereafter, as shown in FIG. 55, etching is performed with an anisotropic etching solution. Then, etching spreads from the dry etching hole 308, and is etched into a mask pattern shape (becomes an etching hole 309).

  Thereafter, as shown in FIG. 56, the back side wet etching pattern 306 is peeled off.

  Next, as shown in FIG. 57, etching is performed again with an anisotropic etchant. Then, a wet etching hole 310 is formed on the back side.

  Then, as shown in FIG. 58, the front side wet etching protective film 301 and the back side wet etching pattern 305 are peeled off.

  Next, as shown in FIG. 59, etching is again performed with an anisotropic etching solution. Then, the wet etching hole 310 is etched deeper on the back side. Further, the grooves 312 and 311 are etched on the front and back surfaces. Here, it is difficult to control the etching rate, and the high-order crystal surface 313 having a high etching rate is etched faster and unstablely than the other surfaces forming the partition walls of the pressure chamber 12, and the etching resist pattern 314 Etching progresses underneath.

  Thereafter, as shown in FIG. 60, etching is performed until the grooves 311 and 312 reach a predetermined depth.

  Thereafter, as shown in FIG. 61, when all the etching patterns are peeled off, the flow path plate of the liquid ejection head according to the present invention is completed. In FIG. 61, the pressure chamber 12, the fluid resistance portion 13, the through hole 15, the first through hole 21, and the liquid introduction portion 14 are also appended.

  In the above process, it is difficult to control the etching rate, and only two high-order crystal planes 313 are generated. Therefore, as described in FIG. 7, the variation in the length of the fluid resistance portion is compared. It can be reduced to half of the example, and stable and uniform discharge becomes possible.

  In addition, the flow-path board in other embodiment can also be manufactured by the process similar to the above.

  Note that a head-integrated liquid cartridge (cartridge-integrated head) can be obtained by integrating the above-described liquid discharge head and a tank that supplies liquid to the liquid discharge head.

  Next, an example of the image forming apparatus according to the present invention including the liquid discharge head according to the present invention will be described with reference to FIGS. 62 is a schematic side view for explaining the mechanism of the apparatus, and FIG. 63 is a plan view for explaining the main part of the mechanism.

  This image forming apparatus is a serial type image forming apparatus, and a carriage 233 is slidably held in the main scanning direction by main and slave guide rods 231 and 232 which are guides horizontally mounted on the left and right side plates 221A and 221B. The main scanning motor moves and scans in the arrow direction (carriage main scanning direction) via the timing belt.

  The carriage 233 includes a plurality of recording heads 234 including the liquid ejection head according to the present invention for ejecting ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (K). Nozzle rows composed of nozzles are arranged in the sub-scanning direction orthogonal to the main scanning direction, and are mounted with the ink droplet ejection direction facing downward.

  The recording head 234 is configured by attaching liquid ejection heads 234a and 234b each having two nozzle rows to one base member, and one nozzle row of one head 234a has a black (K) droplet. The other nozzle row ejects cyan (C) droplets, the other nozzle row of the other head 234b ejects magenta (M) droplets, and the other nozzle row ejects yellow (Y) droplets. . Note that, here, a two-head configuration is used to eject four color droplets, but a liquid ejection head for each color may be provided.

  The carriage 233 is equipped with sub tanks 235a and 235b (referred to as “sub tank 235” when not distinguished) for supplying ink of each color corresponding to the nozzle rows of the recording head 234. The sub tank 235 is supplied with ink of each color from the ink cartridge 210 of each color by the supply unit 224 via the supply tube 236 of each color.

  On the other hand, as a paper feeding unit for feeding the paper 242 stacked on the paper stacking unit (pressure plate) 241 of the paper feed tray 202, a half-moon roller (feeding) that separates and feeds the paper 242 one by one from the paper stacking unit 241. A separation pad 244 made of a material having a large coefficient of friction is provided opposite to the sheet roller 243 and the sheet feeding roller 243, and the separation pad 244 is urged toward the sheet feeding roller 243 side.

  A guide 245 for guiding the paper 242, a counter roller 246, a transport guide 247, and a tip pressure roller 249 are provided to feed the paper 242 fed from the paper feeding unit to the lower side of the recording head 234. And a holding belt 251 that is a conveying means for electrostatically attracting the fed paper 242 and conveying it at a position facing the recording head 234.

  The conveyor belt 251 is an endless belt, and is configured to wrap around the conveyor roller 252 and the tension roller 253 so as to circulate in the belt conveyance direction (sub-scanning direction). In addition, a charging roller 256 that is a charging unit for charging the surface of the transport belt 251 is provided. The charging roller 256 is disposed so as to come into contact with the surface layer of the conveyor belt 251 and to rotate following the rotation of the conveyor belt 251. The transport belt 251 rotates in the belt transport direction when the transport roller 252 is rotationally driven through timing by a sub-scanning motor (not shown).

  Further, as a paper discharge unit for discharging the paper 242 recorded by the recording head 234, a separation claw 261 for separating the paper 242 from the transport belt 251, a paper discharge roller 262, and a paper discharge roller 263 are provided. A paper discharge tray 203 is provided below the paper discharge roller 262.

  A double-sided unit 271 is detachably attached to the back surface of the apparatus main body. The duplex unit 271 takes in the paper 242 returned by the reverse rotation of the transport belt 251, reverses it, and feeds it again between the counter roller 246 and the transport belt 251. The upper surface of the duplex unit 271 is a manual feed tray 272.

  Further, a maintenance / recovery mechanism 281 for maintaining and recovering the nozzle state of the recording head 234 is disposed in a non-printing area on one side in the scanning direction of the carriage 233. The maintenance / recovery mechanism 281 includes cap members (hereinafter referred to as “caps”) 282a and 282b (hereinafter referred to as “caps 282” when not distinguished) for capping each nozzle surface of the recording head 234, and nozzle surfaces. A wiper blade 283 that is a blade member for wiping the ink, and an empty discharge receiver 284 that receives liquid droplets when performing empty discharge for discharging liquid droplets that do not contribute to recording in order to discharge thickened ink. Yes.

  In addition, in the non-printing area on the other side of the carriage 233 in the scanning direction, idle ejection that receives droplets when performing idle ejection that ejects droplets that do not contribute to recording in order to discharge ink that has been thickened during recording or the like A receiver 288 is disposed, and the idle discharge receiver 288 is provided with an opening 289 along the nozzle row direction of the recording head 234 and the like.

  In this image forming apparatus configured as described above, the sheets 242 are separated and fed one by one from the sheet feeding tray 202, and the sheet 242 fed substantially vertically upward is guided by the guide 245, and is conveyed to the conveyor belt 251 and the counter. It is sandwiched between the rollers 246 and conveyed, and further, the leading end is guided by the conveying guide 247 and pressed against the conveying belt 251 by the leading end pressure roller 249, and the conveying direction is changed by approximately 90 °.

  At this time, a positive output and a negative output are alternately applied to the charging roller 256, that is, an alternating voltage is applied, and a charging voltage pattern in which the conveying belt 251 alternates, that is, in the sub-scanning direction that is the circumferential direction. , Plus and minus are alternately charged in a band shape with a predetermined width. When the sheet 242 is fed onto the conveyance belt 251 charged alternately with plus and minus, the sheet 242 is attracted to the conveyance belt 251, and the sheet 242 is conveyed in the sub scanning direction by the circumferential movement of the conveyance belt 251.

  Therefore, by driving the recording head 234 according to the image signal while moving the carriage 233, ink droplets are ejected onto the stopped paper 242 to record one line, and after the paper 242 is conveyed by a predetermined amount, Record the next line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 242 has reached the recording area, the recording operation is finished and the paper 242 is discharged onto the paper discharge tray 203.

  Thus, since the image forming apparatus includes the liquid discharge head according to the present invention as a recording head, stable droplet discharge characteristics can be obtained, and a high-quality image can be stably formed.

  In the present application, the “paper” is not limited to paper, but includes OHP, cloth, glass, a substrate, etc., and means a material to which ink droplets or other liquids can be attached. , Recording media, recording paper, recording paper, and the like. In addition, image formation, recording, printing, printing, and printing are all synonymous.

  The “image forming apparatus” means an apparatus that forms an image by discharging liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc. “Formation” means not only giving an image having a meaning such as a character or a figure to a medium but also giving an image having no meaning such as a pattern to the medium (simply causing a droplet to land on the medium). ) Also means.

  The “ink” is not limited to an ink unless otherwise specified, but includes any liquid that can form an image, such as a recording liquid, a fixing processing liquid, or a liquid. Used generically, for example, includes DNA samples, resists, pattern materials, resins, and the like.

  In addition, the “image” is not limited to a planar image, and includes an image given to a three-dimensionally formed image and an image formed by three-dimensionally modeling a solid itself.

  Further, the image forming apparatus includes both a serial type image forming apparatus and a line type image forming apparatus, unless otherwise limited.

DESCRIPTION OF SYMBOLS 1 Nozzle plate 2 Flow path plate 3 Vibration board member 4 Piezoelectric member 5 Common liquid chamber member 11 Nozzle 12 Pressure chamber 13 Fluid resistance part 14 Liquid introduction part 15 Through-hole 16 Common liquid chamber 21 1st through-hole 22 2nd through-hole 233 Carriage 234a, 234b Recording head

Claims (9)

A pressure chamber to which each of a plurality of nozzles for discharging droplets communicates;
A flow path plate that forms at least a liquid supply path having a fluid resistance section that supplies liquid to the pressure chamber on the upstream side of the pressure chamber;
The flow path plate is formed by etching a silicon substrate having a crystal plane orientation <110>,
On one surface of the flow path plate, a groove portion serving as the fluid resistance portion is formed continuously with the groove portion serving as the pressure chamber,
The liquid ejection head, wherein the groove serving as the fluid resistance portion is closed at an end opposite to the pressure chamber in a direction orthogonal to the nozzle arrangement direction. The flow path plate has a first through hole that penetrates the flow path plate in the thickness direction on the upstream side of the fluid resistance portion and forms a part of the liquid supply path.
The liquid ejecting head according to claim 1, wherein the first through hole is open to a groove portion forming the fluid resistance portion. On the other surface of the flow path plate, a liquid introduction portion that is a part of the liquid supply path is formed,
3. The liquid ejection head according to claim 1, wherein the first through hole is connected to the liquid introduction portion on the other surface side of the flow path plate.   The liquid discharge head according to claim 2, wherein the liquid introduction part opens in a tapered shape in a direction opposite to a liquid flow direction. A pressure chamber to which each of a plurality of nozzles for discharging droplets communicates;
A flow path plate that forms at least a liquid supply path having a fluid resistance section that supplies liquid to the pressure chamber on the upstream side of the pressure chamber;
The flow path plate is formed by etching a silicon substrate having a crystal plane orientation <110>,
A groove portion serving as the pressure chamber is formed on one surface of the flow path plate,
On the other surface of the flow path plate, a groove portion serving as the fluid resistance portion is formed,
The flow path plate has a first through hole and a second through hole that penetrate the flow path plate in the thickness direction and form a part of the liquid supply path,
A groove portion that forms the fluid resistance portion is provided between the first through hole and the second through hole. The groove portion that becomes the fluid resistance portion is closed at both ends in a direction orthogonal to the nozzle arrangement direction. A liquid discharge head.   6. The liquid discharge head according to claim 1, wherein a plurality of groove portions forming the fluid resistance portion are provided in a nozzle arrangement direction.   The liquid discharge head according to claim 1, wherein the groove portion forming the fluid resistance portion is provided to be offset in the nozzle arrangement direction with respect to the groove portion forming the pressure chamber. .   8. The liquid discharge head according to claim 1, wherein a connecting portion between the first through hole and the groove portion forming the fluid resistance portion is a tapered surface or a flat surface.   An image forming apparatus comprising the liquid discharge head according to claim 1.

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