JP2012196938A - Liquid ejecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid ejecting apparatus that can improve the liquid ejection characteristics by heating the ejected liquid to a desired temperature.SOLUTION: The liquid ejecting apparatus includes: a liquid ejection head 3 that includes a nozzle to eject the liquid droplet; and a cap member 13 that touches the liquid ejection head 3 to cover surroundings of the nozzle. The cap member 13 has a housing 41 and a heat generation part 43 provided opposing the nozzle 33 in the housing 41, and at the same time, has a heating member 42 that has a space to the area between itself and the heat generation part 43.

Description

The present invention relates to a liquid ejecting apparatus including a liquid ejecting head that ejects liquid from a nozzle opening, and more particularly, to an ink jet recording apparatus that ejects ink as a liquid.

A typical example of a liquid ejecting head that ejects droplets is an ink jet recording head that ejects ink droplets. As an ink jet recording head, for example, a nozzle plate having nozzles formed therein, a channel forming substrate on which a liquid channel including a plurality of pressure generating chambers communicating with the nozzles is formed, and one of the channel forming substrates are provided. Some have pressure generating means formed on the direction side.

The liquid ejected from such a recording head has a viscosity suitable for ejection depending on the type of the liquid. Since the viscosity of the liquid has a correlation with the temperature, there is a characteristic that the lower the temperature, the higher the viscosity, and the higher the temperature, the lower the viscosity. 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 ( Cooling). Specifically, a heating means is provided in a case provided with a flow path such as an introduction path, and the ink viscosity is lowered by heating the ink by the heating means so as to obtain good ink ejection characteristics. (For example,
Patent Document 1).

JP 2010-023257 A

However, the temperature of the ink drops before being ejected from the recording head, and the temperature of the ink at the time of ejection cannot be controlled with high accuracy, so that the desired ink ejection characteristics cannot be obtained and the print quality is degraded. There is a problem of end up.

Such a problem is not limited to an ink jet recording head that ejects ink, but also exists in a liquid ejecting head that ejects liquid other than ink.

SUMMARY An advantage of some aspects of the invention is that it provides a liquid ejecting apparatus that can improve liquid ejection characteristics by heating a liquid to be ejected to a desired temperature.

A first aspect of the present invention that achieves the above object includes: a liquid ejecting head that includes a nozzle that ejects droplets; and a cap member that contacts the liquid ejecting head so as to cover the periphery of the nozzle, The cap member includes a housing and a heating member having a heat generating portion provided in the housing so as to face the nozzle and having a space in a region between the heat generating portions. In the device.
In this aspect, since only the vicinity of the nozzle is efficiently heated by the heat generating portion provided facing the nozzle, the viscosity of the discharged liquid can be efficiently reduced, and the discharge characteristics can be improved.

Here, it is preferable that the heat generating portion is extended along a direction in which the nozzles are arranged in parallel. Thereby, the nozzle vicinity can be heated effectively.

Moreover, it is preferable that the said heat generating part is provided in the comb-tooth shape. Thereby, the heat generating part facing the nozzle and the space between them can be formed relatively easily, and the supply of current to the heat generating part is also relatively easy.

Moreover, it is preferable that the said heat_generation | fever part is columnar and is arranged in parallel along the direction in which the said nozzle is arranged in parallel. According to this, even if there is no heat generating part continuously in the nozzle direction,
The vicinity of the nozzle can be effectively heated.

Moreover, it is preferable that the said heating member is equipped with the electrode which supplies an electric current to the said heat generating part, and the said electrode is provided in the edge part of the direction where the said nozzle is arranged in parallel at the bottom part of the said housing | casing. According to this, an electric current can be supplied to the heat generating part from the electrode provided at the bottom, and a space between the heat generating parts can be greatly opened.

Moreover, it is preferable that the surface of the heat generating portion is liquid repellent. According to this, even if liquid adheres to the heat generating part, it flows down relatively easily.

Further, the housing has an opening on a surface facing the nozzle, and the cap member is
It is preferable to provide a lid member that opens and closes the opening. According to this, it is possible to prevent the heat radiation of the heat generating part and the drying of the ink when not in use.

Moreover, it is preferable that the said heat generating part is comprised with the PTC heater. According to this, the temperature of the heat generating portion can be kept at a constant temperature without providing a temperature control means.

1 is a perspective view illustrating a schematic configuration of a recording apparatus according to Embodiment 1. FIG. FIG. 3 is a cross-sectional view of a recording head of the recording apparatus according to the first embodiment. FIG. 3 is a perspective view illustrating a main part of the recording apparatus according to the first embodiment. FIG. 3 is a cross-sectional view illustrating a main part of the recording apparatus according to the first embodiment. It is a perspective view which shows an example of the heating apparatus which concerns on Embodiment 1. FIG. FIG. 3 is a cross-sectional view of a main part illustrating an example of a cross-sectional shape of a heat generating unit according to the first embodiment. It is a perspective view which shows the other example of the heating apparatus of Embodiment 1. FIG.

Hereinafter, the present invention will be described in detail based on embodiments.
<Embodiment 1>
FIG. 1 is a schematic perspective view showing an ink jet recording apparatus which is an example of the liquid ejecting apparatus of the invention. As shown in FIG. 1, the ink jet recording apparatus 1 includes an apparatus main body 2, a plurality of ink jet recording heads 3 (liquid ejecting heads), and a state in which the plurality of ink jet recording heads 3 are relatively positioned. A carriage 4 to be held, and an ink container 6 for supplying ink through an ink supply pipe 5 made of a flexible tube are provided. The ink container 6 is provided with a heating means (not shown) for heating the ink stored inside.

The carriage 4 is provided so as to be movable in the axial direction on a pair of carriage shafts 7 attached to the apparatus main body 2. A driving motor 8 is provided on one end side of the carriage shaft 7, and a driving force by the driving motor 8 is spanned between a pair of pulleys 9 and 10 provided on both end sides of the carriage shaft 7. By being transmitted to the carriage 4 through the timing belt 11, the carriage 4 on which the plurality of ink jet recording heads 3 are mounted is moved along the carriage shaft 7 (main scanning direction).

On the other hand, the apparatus main body 2 is provided with a platen 12 along the carriage shaft 7, and a recording medium S such as a recording sheet fed by a sheet feeding roller (not shown) is conveyed onto the platen 12.

Further, in the non-printing area of the ink jet recording apparatus 1, a cap member 13 that covers the ejection surface of the recording head 3 and a suction means 15 such as a vacuum pump connected to the cap member 13 via a suction tube 14 are provided. Is provided.

The cap member 13 having such a configuration is brought into contact with the ejection surface of the recording head 3 to cause the suction means 15 to perform a suction operation, thereby making the inside of the cap member 13 a negative pressure from the nozzle opening of the recording head 3. A suction operation (cleaning operation) is performed by sucking the ink in the flow path together with the bubbles. The cap member 13 of the present embodiment includes a heating unit that heats the ejection surface of the recording head 3 during non-printing, as will be described in detail later.

The cap member 13 abuts on the outer edge of the ejection surface of the recording head 3 at a desired timing to cover the ejection surface. Therefore, in this embodiment, the cap member 13 is provided to be movable in the vertical direction. ing. And the movement of the cap member 13 can be performed by moving means, such as a drive motor and an electromagnet which are not shown in figure, for example.

Here, an example of the recording head 3 will be described. FIG. 2 is a cross-sectional view of the recording head according to the first embodiment of the invention.

The recording head 3 shown in FIG. 2 is a type having a longitudinal vibration type piezoelectric element, and a flow path substrate 21.
A plurality of pressure generating chambers 22 are arranged in parallel, and both sides of the flow path substrate 21 are sealed by a nozzle plate 24 having nozzle openings 23 corresponding to the pressure generating chambers 22 and a vibration plate 25. Yes. In addition, the flow path substrate 21 is formed with a manifold 27 that communicates with each pressure generation chamber 22 via an ink supply port 26 and serves as a common ink chamber for the plurality of pressure generation chambers 22. Is connected to the ink supply pipe 5 described above.

On the other hand, on the opposite side of the diaphragm 25 from the pressure generation chamber 22, the tip of the piezoelectric actuator 28 is provided in contact with a region corresponding to each pressure generation chamber 22. These piezoelectric actuators 28 are laminated by sandwiching piezoelectric materials 29 and electrode forming materials 30 and 31 vertically in a sandwich shape, and an inactive region that does not contribute to vibration is fixed to a fixed substrate 32.

In the recording head 3 configured as described above, ink is supplied to the manifold 27 via the ink supply pipe 5 communicated with the ink storage unit 6 described above, and is distributed to each pressure generating chamber 22 via the ink supply port 26. Is done. Then, the piezoelectric actuator 28 is contracted by applying a voltage to the piezoelectric actuator 28. Accordingly, the diaphragm 25 is deformed together with the piezoelectric actuator 28 (upwardly in the drawing), the volume of the pressure generating chamber 22 is expanded, and ink is drawn into the pressure generating chamber 22. Then, after filling the inside with ink until the nozzle opening 23 is reached, the piezoelectric actuator 28 according to the recording signal from the drive circuit.
When the voltage applied to the electrode forming materials 30 and 31 is released, the piezoelectric actuator 2
8 is expanded to return to the original state.

As a result, the vibration plate 25 is also displaced to return to the original state, so that the pressure generating chamber 22 is contracted, the internal pressure is increased, and ink droplets are ejected from the nozzle opening 23. That is, in this embodiment,
A longitudinal vibration type piezoelectric actuator 28 is provided as pressure generating means for causing a pressure change in the pressure generating chamber 22.

As the pressure generating means, in addition to the longitudinal vibration type actuator device, for example, a thin film type in which electrodes and a piezoelectric material are laminated and formed by a lithography method, a pressure film formed by a method such as attaching a green sheet You may use what used the bending vibration type actuator apparatus etc., such as a type | mold. Furthermore, as pressure generation means, a heat generating element is arranged in the flow path, and droplets are discharged from the nozzle opening by bubbles generated by heat generation of the heat generating element, or static electricity is generated between the diaphragm and the electrode. Then, a device using a so-called electrostatic actuator that discharges droplets from the nozzle openings by deforming the diaphragm by electrostatic force may be used.

Next, an example of the cap member 13 will be described. 3 is a perspective view showing details of the cap member, FIG. 4 is a transverse sectional view thereof, and FIG. 5 is a perspective view showing an example of a heating device.

As shown in these drawings, the cap member 13 includes a housing 41 and a heating member 42 provided in the housing 41, and the heating member 42 is provided in parallel with the nozzle openings 23 in the housing 41. direction(
A heat generating portion 43 which is a plate-like member extending along the nozzle row direction) is provided so as to protrude. More specifically, the heat generating portion 43 includes a plurality of nozzle rows 3 (in this embodiment, five nozzle rows).
A plurality (five in the present embodiment) are provided corresponding to No. 3 and the upper edge of each heat generating portion 43 is close to the nozzle row at a predetermined interval so as to be opposed to each other at a predetermined interval. Stretched,
A space is defined between the heat generating portions 43.

An example of such a heating member 42 is shown in FIG. Each heat generating portion 43 has a longitudinal direction (nozzle row 3
A lower end portion (in three directions) is connected via an electrode member 44, and the electrode member 44 is connected to a power supply 45 that supplies current to the heat generating portion 43.

Here, the heat generating portion 43 is a so-called heater, and may be composed of a heat generating portion having electrical resistance as a whole, or has a structure in which a heater wire is embedded in the upper end portion of the heat generating portion 43. Also good. Such a heat generating portion 43 includes a temperature control means (not shown) such as a thermostat.

Further, the heat generating portion 43 is connected to the PTC (Positive Temperature Coeff).
You may comprise with the PTC heater using a characteristic: positive temperature coefficient) characteristic. In this case, it is possible to heat at a desired constant temperature by appropriately adjusting the Curie temperature of the PTC heater, so there is no need to provide a temperature control means. Here, when the heat generating portion 43 is composed of a PTC heater, the entire plate-shaped heat generating portion 43 may be composed of a ceramic material having PTC characteristics, but only the upper portion is composed of a ceramic material having PTC characteristics. May be.

In any case, the surface of the heat generating portion 43 is preferably subjected to a liquid repellent (ink repellent) process so that the ink attached to the heat generating portion 43 flows well to the bottom of the housing 41. In order to improve the ink flow, a plurality of grooves 46 for guiding the ink flow are provided on the side surface of the heat generating portion 43 of the present embodiment as shown in FIG.

Such a cap member 13 is brought into contact with the ejection surface of the recording head 3 during non-printing, so that the heat generating portion 43 disposed opposite to the nozzle row 33 of the nozzle openings 23 causes the inside of each nozzle opening 23 to be in contact. It is possible to improve the printing quality by heating the ink in the flow path to a predetermined temperature, preventing an increase in the viscosity of the ink, and obtaining good ink ejection characteristics.

Note that the cap member 13 of the present embodiment includes a lid member 47 that covers the upper opening of the housing 41 when not in use in order to prevent a temperature drop of the heat generating portion 43 during printing.

The cap member 13 can also be used for flushing and suction operations. For example, during suction, the cap member 13 is brought into contact with the ejection surface of the recording head 3 to cause the suction means 15 to perform the suction operation. A suction operation (cleaning operation) is performed by suctioning the ink in the flow path together with the air bubbles from the nozzle openings of the recording head 3 with the inside being a negative pressure.

Here, at the time of such suction operation or flushing, there may be provided a moving means capable of positioning and moving in a direction orthogonal to the nozzle row 33 at a position where the heat generating portion 43 does not face the nozzle row 33. As a result, the nozzle row 33 is opposed to the space between the heat generating portions 43, and the ink ejected from the nozzle openings 23 during the suction operation or flushing can be prevented from directly hitting the heat generating portion 43. Can be prevented from splashing.

Needless to say, a cap member for heating the nozzle row 33 and a cap member for performing a suction operation or flushing may be provided separately.

Of course, it goes without saying that such moving means need not be provided. In this case, it is preferable that the upper end surface of the heat generating portion 43 has a shape that prevents the ejected ink from directly splashing into the nozzle openings 23. Examples of such a cross-sectional shape of the heat generating portion 43 are shown in FIGS. As shown in the figure, by making the cross-sectional shape such that the central portions such as the heat generating portions 43a to 43c protrude, it is possible to prevent the ink from splashing back to the nozzle openings 23 and to further improve the ink flow. it can.

Moreover, the heat generating part 43 may not be a plate-like member, and another example is shown in FIG. In this example, the heat generating portion 43 </ b> A is configured by arranging bar-shaped members in parallel along the nozzle row 33 at a predetermined interval. Such a heat generating portion 43A also has the same effect as the heat generating portion 43. Further, the tip of the heat generating portion 43A may have a shape in which the central portion is protruded as shown in FIG. 6, thereby preventing the ink from rebounding to the nozzle opening 23 and improving the ink flow. Can be. Furthermore, instead of the plate-like member, only the upper part thereof may be a rod-like member and may be supported at both ends in the longitudinal direction.

As described above, by adopting the cap member of the present invention, only the vicinity of the nozzle row 33 of the recording head 3 is efficiently heated during printing standby, for example, the recording head 3.
Compared with the case where the whole is heated, it is possible to effectively heat only the vicinity of the nozzle opening 23 to reduce the viscosity of the ink immediately before ejection, and to prevent or improve the ejection characteristics. .

In the ink jet recording apparatus 1 described above, the ink jet recording head 3 is mounted on the carriage 4 and moves in the main scanning direction, but is not limited thereto.
For example, the present invention can also be applied to a so-called line recording apparatus in which the ink jet recording head 3 is fixed and printing is performed simply by moving the recording medium S such as paper in the sub-scanning direction.

In each of the above embodiments, an ink jet recording head has been described as an example of a liquid ejecting head, and an ink jet recording apparatus has been described as an example of a liquid ejecting apparatus. However, the present invention covers a wide range of liquid ejecting apparatuses in general. Of course, the present invention can also be applied to a liquid ejecting apparatus that ejects liquid other than ink. Other liquid ejecting heads include, for example, various recording heads used in image recording apparatuses such as printers, color material ejecting heads used for manufacturing color filters such as liquid crystal displays, organic EL displays, and FED (
Electrode material ejection head used for electrode formation for field emission display, etc., biochip
Examples thereof include bio-organic ejecting heads used for manufacturing, and the present invention can also be applied to a liquid ejecting apparatus including such a liquid ejecting head.

1 ink jet recording apparatus (liquid ejecting apparatus), 3 ink jet recording head (
Liquid ejecting head), 13 cap member, 23 nozzle opening, 41 housing, 42
Heating member, 43, 43a, 43b, 43c, 43A

Claims (8)

A liquid ejecting head including a nozzle for discharging droplets;
A cap member that contacts the liquid jet head so as to cover the periphery of the nozzle;
With
The cap member includes a casing and a heating member having a heating portion provided in the casing so as to face the nozzle and having a space in a region between the heating portions. Injection device. The liquid ejecting apparatus according to claim 1,
The liquid ejecting apparatus, wherein the heat generating portion is extended along a direction in which the nozzles are arranged in parallel. The liquid ejecting apparatus according to claim 2,
The liquid ejecting apparatus according to claim 1, wherein the heat generating portion is provided in a comb shape. The liquid ejecting apparatus according to claim 1,
The liquid ejecting apparatus according to claim 1, wherein the heat generating portions are columnar and are arranged in parallel along a direction in which the nozzles are arranged in parallel. In the liquid ejecting apparatus according to any one of claims 1 to 4,
The heating member includes an electrode for supplying a current to the heat generating part,
The liquid ejecting apparatus according to claim 1, wherein the electrode is provided at an end of the bottom of the housing in a direction in which the nozzles are arranged in parallel. In the liquid ejecting apparatus according to any one of claims 1 to 5,
A liquid ejecting apparatus, wherein a surface of the heat generating portion is liquid repellent. In the liquid ejecting apparatus according to any one of claims 1 to 6,
The housing has an opening on the surface facing the nozzle,
The liquid ejecting apparatus according to claim 1, wherein the cap member includes a lid member that opens and closes the opening. The liquid ejecting apparatus according to any one of claims 1 to 7,
The liquid ejecting apparatus according to claim 1, wherein the heat generating portion is formed of a PTC heater.

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