JP5082682B2 - Liquid ejector - Google Patents

Description

The present invention relates to a liquid ejecting apparatus including a liquid ejecting heads, such as ink jet recording head, in particular, by applying a pressure variation in the pressure generating chamber communicating with a nozzle, the liquid ejection for ejecting liquid in the pressure generating chamber from the nozzle Relates to the device .

  Examples of liquid ejecting heads that eject (eject) liquid droplets from nozzle openings (a type of nozzle) by causing pressure fluctuations in the liquid in the pressure generating chamber include, for example, ink jet recording apparatuses (hereinafter simply referred to as printers). Inkjet recording heads used in image recording devices (hereinafter simply referred to as recording heads), color material ejection heads used in the manufacture of color filters such as liquid crystal displays, organic EL (Electro Luminescence) displays, FEDs (surface emitting displays), etc. There are an electrode material ejecting head used for forming an electrode, a bioorganic matter ejecting head used for manufacturing a biochip (biochemical element), and the like.

  For example, in the recording head described above, a flow path unit in which a series of liquid flow paths from the reservoir to the nozzle through the pressure generation chamber are formed, or an actuator unit having a pressure generation element capable of changing the volume of the pressure generation chamber is used as a resin. It is configured to be attached to a head case made of metal. A metal nozzle plate (a kind of nozzle forming member) having a nozzle is joined to the flow path unit.

  The liquid ejected from such a recording head has a viscosity suitable for ejection, for example, approximately 4 mPa · s at room temperature, depending on the type of liquid. Since the viscosity of the liquid has a correlation with the temperature, the viscosity is higher as the temperature is lower, and the viscosity is lower as the temperature is higher. For this reason, when a recording head designed to suit the viscosity of a liquid that is normally used is placed in a low-temperature (high-temperature) environment or when a high-viscosity (low-) liquid is discharged, the liquid is heated ( A device provided with a temperature adjusting unit for cooling) has been proposed (for example, see Patent Document 1).

  This temperature control unit is arranged with a ring-shaped temperature control unit in close proximity to a part of a series of liquid flow channels up to the nozzle, and directly heats (cools) the liquid in the liquid flow channel. ing. For this reason, the portion of the liquid channel that is not close to the temperature adjusting unit cannot efficiently heat (cool) the liquid in the liquid channel to the desired temperature. That is, the recording head having such a configuration requires a long time to adjust the liquid in the liquid flow path to a desired temperature, and cannot be put to practical use. And in order to heat efficiently, it was necessary to arrange | position the liquid flow path and the temperature control part close | similar, and still long.

Japanese Patent Laid-Open No. 2001-270090

  However, if the temperature control unit is placed close to the liquid flow path and is arranged over a long length, the arrangement is limited, which may increase the size of the recording head and the shape of the recording head. There was a risk of losing the degree. Further, if the distance between the liquid flow path and the temperature adjusting unit is increased, the liquid in the liquid flow path cannot be efficiently heated (cooled).

The present invention has been made in view of such circumstances, and its purpose is to improve the reliability by efficiently adjusting the viscosity of the liquid to be discharged without impairing the degree of freedom of the head shape. The object is to provide a liquid ejecting apparatus .

In order to achieve the above object, a liquid ejecting apparatus of the present invention includes a nozzle forming member having a plurality of nozzles, and a channel unit including a channel forming substrate having a pressure generation chamber communicating with the nozzles;
A pressure generating element that applies pressure fluctuation to the pressure generating chamber;
A liquid ejecting apparatus including a liquid ejecting head including a head channel made of a resin , the housing including the pressure generating element and having a head channel for introducing a liquid into the channel unit;
The flow path unit includes an elastic plate that covers the pressure generation chamber,
A stainless steel fitting is disposed in the head case by insert molding in a state of surrounding the head flow path and in contact with the elastic plate,
The metal fitting has a housing empty part for housing a heater for heating the metal fitting,
The heater is characterized in that an outer surface of the heater is brought into contact with an inner peripheral surface of the storage empty portion in a state of being stored in the storage empty portion .

According to the above configuration, the head case has the metal fitting, the metal fitting has the storage empty portion that stores the heater that heats the metal fitting , and the heater is stored in the storage empty portion. Since the outer surface is brought into contact with the inner peripheral surface, when the heater inserted in the storage empty portion generates heat, the heat is directly conducted to the inner peripheral surface of the storage empty portion, so that the metal fitting can be efficiently heated. When the metal fitting is heated by the heater, the metal fitting having excellent heat conduction can efficiently transmit the heat of the heater, and the inside of the head case can be efficiently heated, thereby warming the liquid to be discharged. , The viscosity of the liquid can be reduced. For this reason, even when the viscosity of the liquid is not suitable for ejection, the viscosity of the liquid can be adjusted efficiently, and the reliability of the liquid ejecting head can be improved. In addition, since the metal fitting and the heater need only be connected, the heater can be disposed at a position away from the portion to be heated, and the degree of freedom of the shape of the head case can be increased as compared with the conventional case.

Also, since the head case is made of resin and the metal fittings are made of stainless steel, the head case is the same even if the metal fittings expand and contract due to heating and cooling when the linear expansion coefficients of the metal fittings and the head case are aligned. Since it expands and contracts, peeling between the two can be prevented.

Furthermore, since the metal fitting is insert-molded in the head case, the rigidity of the head case can be increased by the metal fitting. As a result, crosstalk can be suppressed. Further, swelling due to moisture absorption can also be suppressed. Furthermore, since the metal fittings are in close contact with the head case over a wide range, the heat transfer from the metal fittings to the head case is good, and thus the head case itself can be easily brought close to the temperature of the heater, and the liquid in the head case The temperature of can be adjusted efficiently.

Further, the flow path unit includes an elastic plate that covers the pressure generation chamber, and the metal fitting is in contact with the elastic plate, so that the heat of the heater is conducted to the metal fitting, and further the heat of the metal fitting is conducted to the elastic plate. Thus, the liquid in the pressure generating chamber can be indirectly heated through the elastic plate. Further, if the metal fitting to which the heater is connected is brought into contact with the elastic plate, the metal fitting does not necessarily have to be close to the pressure generating chamber, so that the degree of freedom of the arrangement position of the metal fitting is increased.

Since the metal fitting surrounds the head channel, the liquid in the head channel can be reliably heated from the outer periphery of the head channel. For this reason, the viscosity of the liquid can be adjusted more efficiently.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. In the embodiments described below, various limitations are made as preferred specific examples of the present invention. However, the scope of the present invention is not limited to the following description unless otherwise specified. However, the present invention is not limited to these embodiments. In this embodiment, an ink jet recording head (hereinafter referred to as “recording head”) will be described as an example of the liquid ejecting head.

FIG. 1 is a perspective view of an ink jet recording apparatus. First, a schematic configuration of an ink jet recording apparatus ( corresponding to a kind of liquid ejecting apparatus according to the present invention, hereinafter referred to as a printer) equipped with a recording head will be described with reference to FIG. The illustrated printer 1 is an apparatus that records an image or the like by ejecting liquid ink onto the surface of a recording medium (ejection target) 2 such as recording paper. This printer 1 includes a recording head 3 (corresponding to one type of liquid ejecting head in the present invention) for ejecting (ejecting) ink, a carriage 4 to which the recording head 3 is attached, and a carriage 4 in the main scanning direction (see FIG. 1). A carriage moving mechanism 5 for moving the recording medium 2 in the direction of arrow X and a platen roller 6 for transferring the recording medium 2 in the sub-scanning direction (a direction perpendicular to the main scanning direction; indicated by arrow Y in FIG. 1) are provided. Here, the ink is a kind of liquid of the present invention, and is stored in the ink cartridge 7 (corresponding to a kind of liquid storage part in the present invention). The ink cartridge 7 is detachably attached to the recording head 3.

  The carriage moving mechanism 5 includes a timing belt 8. The timing belt 8 is driven by a pulse motor 9 such as a DC motor. Therefore, when the pulse motor 9 is operated, the carriage 4 is guided by the guide rod 10 installed on the printer 1 and reciprocates in the main scanning direction X (width direction of the recording paper 2).

  Next, the configuration of the recording head 3 will be described. Here, FIG. 2 is a perspective view of the recording head 3 attached to the carriage 4, and FIG. 3 is an exploded perspective view of the recording head 3. The illustrated recording head 3 is schematically constituted by a cartridge base 15 (hereinafter referred to as “base”), a head case 16, a flow path unit 17, a vibrator unit 22, and the like.

  The base 15 is formed of, for example, a synthetic resin, and an ink introduction needle 19 is attached to the upper surface of the base 15 with a filter 18 interposed as shown in FIG. The ink cartridge 7 is attached to the ink introduction needle 19 attached to the base 15.

  Further, the base 15 includes a substrate mounting portion 20 formed through the center of the base 15. The board attaching part 20 accommodates a circuit board 21 inserted inside thereof. The circuit board 21 includes, for example, a drive circuit for controlling supply of a drive signal to a piezoelectric vibrator 29 described later, a connector for connection to the printer main body side, and the like. The circuit board 21 is attached to the base 15 by being inserted into the board attachment portion 20.

  The head case 16 is a casing for housing a vibrator unit 22 having a base end 27 fixed to the lower surface of the base 15 and having a piezoelectric vibrator 29 described later. FIG. 4 is a cross-sectional view of a main part in which the vibrator unit 22 is accommodated in the head case 16. For this reason, in the head case 16, an accommodation space 32 that can accommodate the transducer unit 22 is formed. The vibrator unit 22 is inserted into the housing space 32 and fixed by adhesion or the like. The flow path unit 17 is fixed to the distal end 28 of the head case 16 away from the base end 27 with an adhesive or the like.

  The flow path unit 17 is manufactured by joining and integrating with an adhesive etc. in the state which laminated | stacked the elastic board 23, the flow path formation board | substrate 24, and the nozzle plate 25. FIG.

  The nozzle plate 25 is a nozzle forming member in the present invention, and is made of, for example, a thin plate made of stainless steel, and fine nozzle openings 26 are formed in a row at a pitch corresponding to the dot formation density of the printer 1.

  The vibrator unit 22 includes a piezoelectric vibrator group 30, a fixing plate 31 to which the piezoelectric vibrator 30 is bonded, and a flexible cable (for supplying a drive signal from the circuit board 21 to the piezoelectric vibrator group 30. FC). The piezoelectric vibrator 30 of the present embodiment includes a plurality of piezoelectric vibrators 29 (corresponding to a kind of pressure generating element in the present invention) arranged in a comb shape. Each piezoelectric vibrator 29 has a fixed end joined on the fixed plate 31, and a free end protruding outside the front end surface of the fixed plate 31. That is, each piezoelectric vibrator 29 is mounted on the fixed plate 31 in a so-called cantilever state. The fixing plate 31 that supports each piezoelectric vibrator 29 is made of, for example, stainless steel having a thickness of about 1 mm. In addition to the piezoelectric vibrator, an electrostatic actuator, a magnetostrictive element, or the like can be used as the pressure generating means.

  Inside the head case 16, an accommodation empty portion 32 that can accommodate the vibrator unit 22 is formed in a state where the height direction of the head case 16 is penetrated. The vibrator unit 22 is housed and fixed in the housing space 32 by bonding the back surface of the fixing plate 31 to the inner wall surface of the case that defines the housing space 32.

  A plurality of flow path forming substrates 24 correspond to the respective nozzle openings 26 in a state in which empty portions that become common ink chambers 33, groove portions that become ink supply ports 34, and empty portions that become pressure generation chambers 35 are partitioned by partition walls. It is the formed plate-shaped member. The flow path forming substrate 24 is produced, for example, by etching a silicon wafer. The pressure generation chamber 35 is formed as an elongated chamber in a direction perpendicular to the direction in which the nozzle openings 26 are arranged (nozzle row direction). The common ink chamber 33 is connected to the ink introduction path 19 of the ink introduction needle 19 through an ink communication path 37 (corresponding to a kind of head flow path in the present invention) formed through the height direction of the head case 16. This is a chamber that communicates with an ink cartridge 7 and into which ink stored in the ink cartridge 7 is introduced. The ink introduced into the common ink chamber 33 is supplied to each pressure generating chamber 35 through the ink supply port 34.

  The elastic plate 23 is a double-structured composite plate material in which an elastic film is laminated on a metal support plate such as stainless steel. That is, the elastic plate 23 is formed of a material having a high thermal conductivity on the surface to be joined to the head case 16. The elastic plate 23 covers the pressure generation chamber 35. An island portion 36 for joining the tip of the free end of the piezoelectric vibrator 29 is formed in a portion corresponding to the pressure generating chamber 35 of the elastic plate 23, and this portion functions as a diaphragm portion. Further, the elastic plate 23 seals one opening surface of the empty portion that becomes the common ink chamber 33, and also functions as a compliance portion. Only the elastic film is used for the portion functioning as the compliance portion.

  In the recording head 3, when the piezoelectric vibrator 29 is expanded and contracted in the element longitudinal direction, the island portion 36 moves in a direction close to or away from the pressure generating chamber 35. As a result, the volume of the pressure generating chamber 35 changes, and the pressure in the ink in the pressure generating chamber 35 varies. An ink droplet (a type of droplet) is ejected from the nozzle opening 26 due to the pressure fluctuation.

  Further, in the head case 16 of the present embodiment, as shown in FIG. 5, a metal fitting 38 for applying heat to the ink in the recording head 3 and a heater 39 for heating the metal fitting 38 are provided. FIG. 5 is an exploded perspective view for explaining a metal fitting before being insert-molded in the head case 16. The heater 39 is a so-called cartridge heater that is formed in a thin cylindrical shape and has a heating element such as ceramic or heating wire sealed with a metal case. The heater 39 generates heat when a current is passed through the lead wire 39 '.

  The metal fitting 38 is made of a metal thin plate member such as stainless steel. The metal fitting 38 includes a peripheral wall 40 formed in a cylindrical shape with a rectangular shape in front view, and a partition wall 41 that isolates the inside of the peripheral wall 40. At both ends where the peripheral wall 40 and the partition wall 41 are connected to each other, a through hole 42 opened along the height direction of the peripheral wall 40 and the partition wall 41 is formed. The through hole 42 is a space that functions as an accommodation space for the heater 39. When the heater 39 is inserted, most of the outer surface of the heater 39 comes into contact with the inner peripheral surface of the through hole 42. Therefore, when the heater 39 inserted into the through hole 42 generates heat, the heat is directly conducted to the inner peripheral surface of the through hole 42 and the metal fitting 38 can be efficiently heated.

The metal fitting 38 is made of a material that is substantially equal to the linear expansion coefficient of the head case 16. That is, the linear expansion coefficient of the metal fitting 38 and the linear expansion coefficient of the head case 16 are aligned. For example, the head case 16 is a thermosetting resin having a linear expansion coefficient of approximately 10 × 10 ⁻⁶ , and the metal fitting 38 is made of SUS having a linear expansion coefficient of 12 to 13 × 10 ⁻⁶ . The material of the metal fitting 38 may be aluminum instead of SUS. In that case, the linear expansion coefficient of the head case 16 may be aligned with the linear expansion coefficient of the metal fitting 38. Thus, when the linear expansion coefficients are made uniform, even if the metal fitting 38 expands and contracts due to a temperature change, the head case 16 expands and contracts in the same manner, so that inconveniences such as peeling and deformation do not occur between them.

  In this embodiment, the metal fitting 38 is fixed to the head case 16 by insert molding the metal fitting 38 into the head case 16. Therefore, the surface of the metal fitting 38 is in close contact with the head case 16. Therefore, the heat of the metal fitting 38 is efficiently conducted to the head case 16.

  The metal fitting 38 attached to the head case 16 extends from the front end 28 of the head case 16 to the base end 27 as shown in FIG. That is, the length in the height direction of the peripheral wall 40 and the partition wall 41, that is, the metal fitting 38 is formed to be slightly shorter than the length in the height direction of the head case 16, that is, the length from the distal end 28 to the base end 27. Yes.

  Further, the peripheral wall 40 and the partition wall 41 (that is, the metal fitting 38) are arranged in a state where one end 43 located on the tip 28 side of the head case 16 is in contact with the elastic plate 23 covering the pressure generating chamber 35 as shown in FIG. Established. Therefore, the peripheral wall 40 and the partition wall 41, that is, the one end 43 of the metal fitting 38 efficiently conduct the heat from the heater 39 to the elastic plate 23. Thereby, the heat from the heater 39 is indirectly conducted to the pressure generating chamber 35 through the elastic plate 23, and as a result, the ink in the pressure generating chamber 35 is heated.

  Further, one end 43 of the peripheral wall 40 and the partition wall 41 (that is, the metal fitting 38) is disposed close to (approaching) the pressure generating chamber 35 as shown in FIG. For this reason, the path from the one end 43 of the metal fitting 38 to the pressure generating chamber 35 is short, and as a result, the ink in the pressure generating chamber 35 is efficiently heated.

  Further, as shown in FIG. 4, the peripheral wall 40 and the partition wall 41 (that is, the metal fitting 38) are fixed to the head case 16 so as to surround the entire length of the ink communication path 37 described above. Therefore, the metal fitting 38 conducts heat from the heater 39 to the entire circumference of the ink communication path 37 in the head case 16, and as a result, the ink in the ink communication path 37 is heated.

  Next, heat conduction by passing a current through the heater 39 will be described. First, when a current is passed through the heater 39, the heater 39 generates heat. The heat of the heater 39 is conducted to the metal fitting 38 through the through hole 42 of the metal fitting 38 to which the end of the heater 39 is connected. Then, the temperature of the metal fitting 38 is entirely increased by the heat conducted from the heater 39. Therefore, the peripheral wall 40 and the partition wall 41 of the metal fitting 38 can heat the ink in the ink communication path 37 by conducting the heat of the heater 39 from the entire circumference of the ink communication path 37. Further, the one end 43 of the metal fitting 38 is in contact with the elastic plate 23, whereby the ink in the pressure generating chamber 35 can be heated via the elastic plate 23. Furthermore, the one end 43 of the metal fitting 38 approaches (appears) the pressure generation chamber 35, thereby efficiently heating the pressure generation chamber 35. The ink heated in this manner is adjusted to a viscosity suitable for ejection. For this reason, the ink is ejected from the nozzle opening 26 at the designed amount and speed by the pressure fluctuation of the piezoelectric vibrator 29.

  As described above, the recording head 3 of the present embodiment fixes the metal fitting 38 in the head case 16 and connects the heater 38 that heats the metal fitting 38 to the metal fitting 38, so that when the metal fitting 38 is heated by the heater 39, The inside of the head case 16 can be efficiently heated, whereby the ejected ink can be warmed and the viscosity of the ink can be reduced. For this reason, even when the viscosity of the ink is not suitable for ejection, the viscosity of the ink can be adjusted efficiently, and the reliability of the recording head 3 can be improved. Further, since the metal fitting 38 and the heater 39 are separated, the heater 39 can be freely arranged and the degree of freedom of the shape of the head case 16 can be increased.

  Further, since the metal fitting 38 is fixed in a state where it faces the pressure generating chamber 35, the heat transfer path released from the metal fitting 38 connected to the heater 39 can be shortened, and the ink in the pressure generating chamber 35 can be efficiently heated. it can. For this reason, the viscosity of the ink can be easily adjusted by setting the temperature of the ink in the head case 16 to a temperature suitable for ejection.

  Further, the flow path unit 17 includes the elastic plate 23 that covers the pressure generation chamber 35, and the metal fitting 38 is disposed so as to contact the elastic plate 23, so that the heat of the heater 39 is transmitted from the metal fitting 38 through the elastic plate 23. Thus, the ink in the pressure generating chamber 35 can be heated. Further, if the metal fitting 38 connected to the heater 39 is brought into contact with the elastic plate 23, the metal fitting 38 does not necessarily have to be close to the pressure generating chamber 35, so that the degree of freedom of the arrangement position of the metal fitting 38 is increased.

  Further, the metal fitting 38 is insert-molded into the head case 16, whereby the rigidity of the head case 16 can be increased by the metal fitting 38. As a result, crosstalk can be suppressed. Further, swelling due to moisture absorption or the like can be suppressed. Furthermore, since the head case 16 is directly heated, the head case 16 itself can be easily brought close to the temperature of the heater 39, and the temperature of the ink in the head case 16 can be adjusted efficiently.

  In addition, since the linear expansion coefficients of the metal fitting 38 and the head case 16 are made uniform, it is possible to prevent inconveniences such as peeling or deformation due to heat expansion and contraction, and it is possible to suppress swelling due to moisture absorption and to prevent crosstalk. Can be reduced. For this reason, the reliability of the recording head 3 can be improved.

  Further, since the metal fitting 38 is fixed in a state of extending from the distal end 28 side to the proximal end 27 side of the head case 16, the rigidity in the height direction of the head case 16 can be increased. Can be reduced. For this reason, the reliability of the recording head 3 can be improved.

  Further, since the metal fitting 38 is disposed in the head case 16 so as to surround the ink communication path 37, the ink in the ink communication path 37 can be reliably heated from the outer periphery of the ink communication path 37. For this reason, the viscosity of the ink can be adjusted more efficiently.

  By the way, the present invention is not limited to the above embodiment, and various modifications can be made based on the description of the scope of claims. In the above embodiment, an example in which the metal fitting 38 is insert-molded into the head case 16 is shown. However, the present invention is not limited to this. For example, when the head case 16 is fixed to the flow path unit 17 or the piezoelectric vibrator 29, The metal fitting 38 may be attached to the head case 16 by assembling later. As a result, the metal member 38 only needs to be fixed to the head case 16.

  In the above, the printer 1 which is a kind of liquid ejecting apparatus has been described as an example, but the present invention can also be applied to other liquid ejecting apparatuses. For example, a display manufacturing apparatus that manufactures color filters such as liquid crystal displays, an electrode manufacturing apparatus that forms electrodes such as organic EL (Electro Luminescence) displays and FEDs (surface-emitting displays), and chips that manufacture biochips (biochemical elements) The present invention can also be applied to a manufacturing apparatus.

FIG. 2 is a perspective view illustrating a configuration of a printer. FIG. 3 is a perspective view illustrating a configuration of a recording head. FIG. 2 is an exploded perspective view illustrating a configuration of a recording head. 2 is a cross-sectional view illustrating an internal structure of a recording head. FIG. It is a disassembled perspective view explaining the metal fitting insert-molded to a head case.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 ... Recording head, 7 ... Ink cartridge, 16 ... Head case, 17 ... Flow path unit, 23 ... Elastic board, 24 ... Flow path formation board | substrate, 25 ... Nozzle plate, 26 ... Nozzle opening, 27 ... Base end, 28 ... Tip, 29 ... piezoelectric vibrator, 35 ... pressure generating chamber, 37 ... ink communication path, 38 ... metal fitting, 39 ... heater

Claims (1)

A flow path unit comprising a nozzle forming member having a plurality of nozzles and a flow path forming substrate having a pressure generation chamber communicating with the nozzles;
A pressure generating element that applies pressure fluctuation to the pressure generating chamber;
A liquid ejecting apparatus including a liquid ejecting head including a head channel made of a resin , the housing including the pressure generating element and having a head channel for introducing a liquid into the channel unit;
The flow path unit includes an elastic plate that covers the pressure generation chamber,
A stainless steel fitting is disposed in the head case by insert molding in a state of surrounding the head flow path and in contact with the elastic plate,
The metal fitting has a housing empty part for housing a heater for heating the metal fitting,
The liquid ejecting apparatus according to claim 1 , wherein the heater brings the outer surface of the heater into contact with the inner peripheral surface of the storage empty portion in a state of being stored in the storage empty portion .

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