JP2009125971A - Liquid jetting head and liquid jetting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such problems that a waiting time for enabling the liquid jetting operation is needed long because it becomes effective to jet a liquid by raising a temperature of the liquid and lowering a viscosity of the liquid in the case of jetting the liquid with the high viscosity or when jetting of the liquid cannot be carried out smoothly, and because a heat capacity of a carriage is large in the case of warming the whole carriage, and that an energy required for raising the temperature becomes large to eventually cause increase of a power consumption. <P>SOLUTION: The liquid jetting head is equipped with a feeding flow channel where the liquid is stored, pressure chambers which communicate with the feeding flow channel and in which the liquid flows, and nozzles which are arranged in the pressure chambers and perform jetting of the liquid. A heater is arranged adjacently to at least one composition of the feeding flow channel, the pressure chamber and the nozzle. The heat capacity can be suppressed to be small by heating only a necessary minimum region, and the temperature of the liquid can be controlled in a short response time. Temperature control of the liquid can be carried out highly accurately. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid ejecting head and a liquid ejecting apparatus.

  2. Description of the Related Art Conventionally, there is a liquid ejecting apparatus that ejects a liquid such as a functional liquid or ink onto an object such as paper or a glass substrate to form a predetermined pattern or image. In such an apparatus, for example, a pressure chamber is provided in the middle of a flow path through which ink as a liquid flows, and pressure is applied to the ink in the pressure chamber using the electrostrictive property of the piezoelectric element, so that the end of the flow path is A liquid ejecting head that ejects ink droplets from a nozzle located is used.

  Here, when a highly viscous liquid is used, the liquid may not be smoothly ejected. In such a case, it is effective to raise the temperature of the liquid and to eject the liquid with a reduced viscosity.

  For example, as shown in Patent Document 1, a configuration is disclosed in which the entire carriage including a liquid ejecting head is heated by a heater and heat dissipation applied from the heater is suppressed using a heat insulating material.

JP 2007-144273 A

  When the entire carriage is warmed, the carriage has a large heat capacity, so that a long waiting time is required to enable the liquid ejection operation. In addition, there is a problem in that the energy required for temperature increase increases, resulting in an increase in power consumption.

  In addition, since the temperature of an apparatus having a large heat capacity is raised, the responsiveness to a temperature change is low.For example, when the liquid injection amount is changed, the liquid temperature becomes unstable, the liquid viscosity changes, and the liquid injection amount There is a problem of becoming unstable.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 In the liquid ejecting head according to this application example, the supply flow path for storing the liquid, the pressure chamber communicating with the supply flow path, the liquid flowing in, and the liquid ejection disposed in the pressure chamber. And a heater is disposed adjacent to at least one of the supply flow path, the pressure chamber, and the nozzle.

  According to this configuration, the area to be heated is smaller than in the prior art. Therefore, the heat capacity can be kept small, the liquid temperature can be controlled with a short response time, and the liquid temperature can be controlled with high accuracy.

  Application Example 2 In the liquid jet head, the liquid jet head has at least one pair of configurations of the supply flow path, the pressure chamber, and the nozzle on both sides of the heater. And

  According to the application example described above, at least a pair of configurations of a supply flow path, a pressure chamber, and a nozzle are provided at a position sandwiching the heater. Therefore, it is possible to suppress the dissipation of the amount of heat supplied from the heater, and it is possible to reduce the energy used for heating the liquid.

  Application Example 3 In the liquid jet head, a temperature detector is provided in at least one of the supply flow path, the pressure chamber, and the nozzle.

  According to the application example described above, temperature control can be performed more precisely. By controlling the electric power applied to the heater so that the signal from the temperature detector shows a constant value, the temperature of the liquid can be accurately maintained.

  Application Example 4 A liquid ejecting apparatus according to this application example includes the liquid ejecting head described above.

  According to this, since the viscosity of the liquid can be precisely controlled by precisely controlling the temperature of the liquid, the drawing quality is higher than that of a liquid ejecting apparatus equipped with a liquid ejecting head constituted by a conventional technique. It is possible to provide a liquid ejecting apparatus having the following.

(First embodiment: a liquid ejecting apparatus including independent liquid ejecting heads on both sides of a heater)
A first embodiment that embodies this embodiment will be described below. FIG. 1 shows a schematic structure of an example of a liquid ejecting apparatus including a liquid ejecting head according to the present embodiment. In addition, the blowing portion in the drawing is a schematic diagram when a carriage 20 described later is viewed from the direction of a white arrow. For convenience of explanation, the direction of the white arrow is referred to as the front direction, and the lateral direction is referred to as the left and right side directions, respectively, with the carriage 20 as a reference. In the following description, the direction of the printing paper 25 is the downward direction and the opposite direction is the upward direction.

  In this ink jet printer 10, ink cartridges 11, 12, 13, and 14 that store Y (yellow), M (magenta), C (cyan), and K (black) inks as liquids are mounted on a carriage 20. Is done. Four liquid ejecting heads 110, 120, 130, and 140 corresponding to the respective color inks are provided below the carriage 20, and ink droplets are ejected from these liquid ejecting heads to form a predetermined image on the printing paper 25. Etc. are printed.

  The carriage 20 is fixed to the carriage belt 41, and moves in the horizontal direction of the drawing (main scanning direction) along the guide 21 fixed to the frame 17 as the carriage belt 41 is driven by the carriage motor 40. At this time, in order to eject each color ink, the liquid ejecting heads 110, 120, 130, and 140 are converted into print images from nozzle rows that are formed by a plurality of nozzles that are linearly formed in a direction orthogonal to the main scanning direction. A corresponding predetermined amount of ink droplets are ejected. The printing paper 25 is supported by the platen 28 from the back side, and is moved by a predetermined amount in the vertical direction of the drawing by a paper feed roller (not shown) driven by a driving motor 26 fixed to the frame 17. In this way, an image is formed by ejecting a predetermined amount of ink droplets corresponding to the printed image over the entire printing paper 25.

  The liquid ejecting heads 110, 120, 130, and 140 will be described in detail with reference to FIGS. Since the liquid ejecting heads 110, 120, 130, and 140 all have the same structure, the liquid ejecting head 110 will be described as a representative.

  2A and 2B are schematic diagrams illustrating a schematic configuration of the liquid ejecting head 110. FIG. 2A illustrates a state viewed from above, FIG. 2B illustrates a state viewed from the right side direction, and FIG. 2C illustrates a downward direction. The state seen from is shown respectively. The configuration of the liquid jet head according to the present embodiment will be described along the ink flow path.

  First, as shown in FIG. 2A, ink supplied from an ink cartridge (not shown) flows into a supply flow path forming member 111 provided with an ink inlet 111a serving as an opening. The ink that has flowed into the supply flow path forming member 111 passes through supply flow paths (hereinafter referred to as “reservoir”) 111b and 111c formed inside, as indicated by the two-dot chain arrows in the figure. , Flows to the communication hole 113a and the communication hole 113b.

  As shown in FIG. 2B, the reservoirs 111b and 111c are formed by being surrounded by the supply flow path forming member 111, the thin film material 112, and the communication plate 113, and the communication holes 113a and 113b are opened through the communication plate 113. Has been. The ink that has flowed into the communication hole 113a flows into the pressure chambers 114a and 114b (disposed on the side facing the 114a) formed in the pressure chamber forming member 114, as shown in FIG. The ink that has flowed into the pressure chambers 114 a and 114 b is pressurized by the vibration plate 116 that is displaced by the deformation driving of the piezoelectric element 117, and is ejected as ink droplets from the nozzle 115 a formed on the nozzle plate 115. Although omitted in FIG. 2B, the ink flowing into the communication hole 113b is also pressurized in the pressure chamber formed in the pressure chamber forming member 114 on the left side which is the back side in the drawing. As shown in FIG. 2C, the ink is similarly ejected from the nozzle 115b formed on the nozzle plate 115 as ink droplets.

  The supply flow path forming member 111, the communication plate 113, the pressure chamber forming member 114, and the nozzle plate 115 are each made of a metal plate (stainless steel plate in the present embodiment), and are laminated and fixed to each other by an adhesive or welding. Yes. The thin film material 112 is made of a flexible resin thin plate (in this embodiment, PPS (polyphenylene sulfide resin)) in order to balance the vibration of ink generated in the reservoirs 111b and 111c by an ink droplet ejection operation or the like. The upper surface of the supply flow path forming member 111 is fixed by adhesion or welding.

  The diaphragm 116 is made of a ceramic plate (in this embodiment, a zirconia plate). As shown in FIG. 2B, the diaphragm 116 is formed on the left and right side wall surfaces of the communication plate 113, the pressure chamber forming member 114, and the nozzle plate 115, respectively. Bonded and fixed. Similarly, as shown in FIG. 2B, a piezoelectric element 117 for pressing the ink in the pressure chambers 114a and 114b is attached to the surface of the diaphragm 116. The piezoelectric element 117 has a width narrower than the width of the pressure chambers 114a and 114b (the horizontal direction in the drawing) and is long in the longitudinal direction (the vertical direction of the drawing) of the pressure chambers 114a and 114b. It is composed of a thin plate of a piezoelectric material having the following electrostrictive characteristics, and is configured to bend in the width direction when a voltage is applied. An electrode (not shown) is connected to the piezoelectric element 117, and a predetermined drive signal is applied to the electrode through a connection member (not shown) to bend the piezoelectric element 117. It is formed so as to pressurize the ink in the chambers 114a and 114b.

  In the liquid ejecting head 110 (see FIG. 1) of the present embodiment, the ink flow path is configured as described above. As a result, as shown in FIG. 2C, two nozzle rows of nozzles 115a and nozzles 115b arranged in a substantially straight line at a predetermined pitch interval are formed.

  The heater 150 is inserted between the nozzles 115a and 115b shifted by a half pitch, between the reservoirs 111b and 111c, and between the pressure chambers 114a and 114b, and the nozzles 115a and 115b and the pressure chambers 114a and 114b, It has a function of warming the reservoirs 111b and 111c. Since the heater 150 gives heat from both sides to the liquid ejecting head 110 (see FIG. 1), the ink can be heated with high thermal efficiency. As the heater 150, for example, a thin heater in which a stainless thin film (resistor) is sandwiched between mica plates (insulators) can be used. In this case, the heater can be formed with a thickness of about several tens of μm. Therefore, heating can be performed in a state where the liquid ejecting head 110 by inserting the heater 150 is kept small.

  Further, since only the liquid ejecting head 110 is heated, it is possible to raise the temperature in a shorter time compared to the conventional method of heating the entire carriage 20 (see FIG. 1). Further, when the ink passage amount fluctuates, for example, the temperature of the pressure chambers 114a and 114b fluctuates locally. Under this influence, the ink ejection amount is modulated and the image quality is deteriorated. However, when the temperature of the liquid ejecting head 110 is controlled locally, the heater 150 is made to follow the fluctuation of the ink passage amount. Since the temperature of the liquid ejecting head 110 can be kept constant by controlling, it is possible to suppress deterioration in image quality.

  Further, a temperature detector 151 may be disposed in the vicinity of the heater 150. The temperature detector 151 is preferably a semiconductor sensor, for example. Then, feedback control is performed to keep the output from the temperature detector 151 constant, which is preferable because a constant temperature can be maintained. Moreover, it may replace with installation of the temperature detector 151, and may control to detect the electrical resistance change of the heater 150, etc. and to maintain it at a fixed temperature. In this case, since the heater 150 and the temperature detector 151 are equivalently disposed at the same place, temperature control can be performed with high controllability. In this case, since the installation of the temperature detector 151 can be omitted, the liquid ejecting head 110 can be assembled with fewer steps. Further, by omitting the temperature detector 151, it becomes possible to have an advantage in cost.

  Further, in the present embodiment, the heater 150 is disposed over the entire area of the liquid ejecting head 110, but this may be partially disposed. In particular, when the liquid ejecting head 110 is electroformed and a metal such as nickel is used, or when semiconductor silicon is used after being processed by MEMS, the liquid ejecting head 110 has high thermal conductivity. It is possible to heat the ink without generating a large temperature distribution even if it is performed. In this case, since the flexibility of the configuration of the heater 150 occurs, the layout of the liquid ejecting head 110 can be arranged with arbitraryness.

(Second embodiment: When a liquid jet head is arranged on one side of a heater)
The second embodiment will be described below with reference to the drawings.
3A is a plan view of the liquid ejecting head 210, and FIGS. 3B and 3C are cross-sectional views of the liquid ejecting head 210, respectively. The liquid ejecting head 210 shown in FIG. 3 is flexible in order to balance the vibration of ink generated in the pressure chamber 214, the nozzle plate 215 integrated with the pressure chamber 214, and the reservoir 211 integrated with the pressure chamber 214. A thin film material 212 made of a resin thin plate, a piezoelectric element 217 for applying pressure to the pressure chamber 214 in cooperation with the thin film material 212, and a nozzle 218 drilled in the nozzle plate 215.

  The heater 150 is disposed on the side where the nozzle 218 of the liquid jet head 210 is perforated.

  The integrated pressure chamber 214, reservoir 211, and nozzle plate 215 can be formed, for example, using nickel or the like as a material and using an electroforming method.

The thin film material 212 is made of a flexible resin thin plate (in this embodiment, PPS (polyphenylene sulfide resin)) in order to balance the vibration of ink generated in the reservoir 211 by an ink droplet ejection operation or the like. It is fixed to the upper surface of 211 by adhesion or welding.
The reservoir 211 has a function of storing liquid supplied from outside (not shown).
The pressure chamber 214 is supplied with liquid from the reservoir 211 and is held in a state filled with liquid.
The nozzle plate 215 has a function of ejecting liquid onto a drawing target.
The thin film material 212 has a function of mitigating pressure fluctuations accompanying ink droplet ejection.
The piezoelectric element 217 has a function of changing the cross-sectional area of the pressure chamber 214 in cooperation with the vibration plate 216 and ejecting liquid from the nozzle plate 215.

  The heater 150 is disposed so as to avoid the nozzle 218 and heats the liquid ejecting head 210. By arranging so as to avoid the nozzles 218, it is possible to heat the inks without affecting the landing points of the ink ejected from the nozzles 218. Even in this case, it is possible to obtain the same effect as that of the first embodiment described above. Moreover, it becomes possible to perform feedback control by attaching the temperature detector 151 as in the first embodiment described above, and higher temperature controllability can be obtained. Further, the heater 150 does not necessarily have to be distributed over the entire area of the liquid jet head 210. For example, when the liquid ejecting head 210 is formed by an electroforming method or a semiconductor silicon MEMS, the liquid ejecting head 210 has high thermal conductivity, so even if partial heating is performed, the ink is heated without generating a large temperature distribution. Is possible. In this case, since the flexibility of the configuration of the heater 150 occurs, the layout of the liquid ejecting head 210 can be arranged with arbitraryness. Further, since the heater 150 can be arranged without changing the design of the liquid ejecting head 210, development elements can be suppressed. For example, by using the liquid jet head 210 having the same configuration, one can be treated as a normal head without the heater 150, and the other can be equipped with the heater 150 and supplied as a head for high viscosity ink. Thus, it is possible to provide a product having another function with a slight change.

(Third embodiment: When a heater is disposed between pressure chambers)
Hereinafter, a third embodiment will be described with reference to the drawings.
4A is a plan view of the liquid ejecting head 210, and FIGS. 4B and 4C are cross-sectional views of the liquid ejecting head 210, respectively. Since the structure of the liquid jet head 210 has the same function except that the layout of the heater 150 is different, the same number is given and the description is omitted.

  The pressure chamber 214 is formed with a gap between the pressure chamber 214 and the adjacent pressure chamber 214, and the heater 150 is sandwiched between the pressure chamber 214 and the adjacent pressure chamber 214. Further, it is formed so as to be sandwiched between adjacent nozzles 218. In this case, since the temperature control of the pressure chamber 214 can be performed with high precision, it is possible to provide the liquid ejecting head 210 that can be applied to extremely temperature-sensitive liquids such as biological samples. Even in this case, the temperature detector 151 can be provided to further increase the temperature controllability of the liquid ejecting head 210, or the temperature can be controlled using the temperature characteristics of the heater 150 (for example, the temperature dependence of the electrical resistance). It is.

(Modification)
In the above configuration, ink has been described as an example of the liquid. However, this is not intended to limit the liquid that can be handled to ink, but, for example, liquid crystal, organic EL material liquid, piezoelectric element material liquid, and ultraviolet light having high viscosity characteristics. It can also be applied to industrial applications such as effect solutions. In particular, it is possible to perform an operation suitable for an application where the temperature is deteriorated at high temperature and the viscosity is high at low temperature and the temperature should be precisely controlled.

FIG. 2 is a schematic structural diagram of a liquid ejecting apparatus including a liquid ejecting head. FIG. 3A is a schematic structural diagram illustrating a schematic configuration of a liquid ejecting head, where (a) illustrates a state viewed from above, (b) illustrates a state viewed from the right side surface direction, and (c) illustrates a state viewed from below. (A) is a plan view of the liquid ejecting head, and (b) and (c) are cross-sectional views of the liquid ejecting head. (A) is a plan view of the liquid ejecting head, and (b) and (c) are cross-sectional views of the liquid ejecting head.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Inkjet printer 11, 12, 13, 14 ... Ink cartridge, 17 ... Frame, 20 ... Carriage, 21 ... Guide, 25 ... Printing paper, 26 ... Drive motor, 28 ... Platen, 40 ... Carriage motor, 41 ... Carriage Belt, 110, 120, 130, 140 ... Liquid ejecting head, 110a ... Liquid ejecting head, 111 ... Supply flow path forming member, 111a ... Ink inlet, 111b, 111c ... Reservoir, 112 ... Thin film material, 113 ... Communication plate, 113a ... Communication hole, 113b ... Communication hole, 114 ... Pressure chamber forming member, 114a, 114b ... Pressure chamber, 115 ... Nozzle plate, 115a ... Nozzle, 115b ... Nozzle, 116 ... Vibrating plate, 117 ... Piezoelectric element, 150 ... Heating 151 ... Temperature detector 210 ... Liquid jet head 211 ... Reservoir 12 ... thin film material, 214 ... pressure chamber, 215 ... nozzle plate, 216 ... diaphragm, 217 ... piezoelectric element, 218 ... nozzle.

Claims (4)

A supply channel that stores liquid; a pressure chamber that communicates with the supply channel and into which the liquid flows; and a nozzle that is disposed in the pressure chamber and that ejects the liquid.
A liquid ejecting head, wherein a heater is disposed adjacent to at least one of the supply flow path, the pressure chamber, and the nozzle. The liquid ejecting head according to claim 1,
A liquid ejecting head having at least one pair of the supply channel, the pressure chamber, and the nozzle on both sides of the heater. The liquid ejecting head according to claim 1 or 2,
A liquid ejecting head comprising a temperature detector in at least one of the configuration of the supply channel, the pressure chamber, and the nozzle.   A liquid ejecting apparatus comprising the liquid ejecting head according to claim 1.

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