JP2004114423A - Ink jet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a bubble from intruding into an ink channel by fixing an ink source and an ink supply port readily. <P>SOLUTION: In an ink jet head 1 comprising a head body 18, a spacer member 39 and a reservoir member 40, a projecting tubular member 50 is secured to the reservoir member 40. The tubular member 50 has one end being press fitted in the reservoir member 40 with the opening 52 sticking to the reservoir 44, and the other needle-like end being fixed to a coupling member 2a led out from an ink source 2 in order to supply ink from the ink source 2 through its opening (ink supply port) 51. The ink supply port 51 has a smaller outside diameter as compared with the opening 52. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an inkjet head, and more particularly, to a configuration of an ink supply port of the inkjet head.
[0002]
[Prior art]
In a conventional inkjet head, an actuator unit applies ejection energy to a pressure chamber connected to an ejection nozzle of a flow path unit, thereby ejecting ink from the ejection nozzle. The ink is stored in a reservoir of a reservoir member from an external ink supply source via an ink supply port, and is filled in each pressure chamber. Here, the ink supply source is replaced as needed.
[0003]
In addition, most of the bonding between the members (the flow path unit, the actuator unit, and the reservoir member) constituting the ink jet head is performed by an adhesive. Most of the adhesives used are thermosetting adhesives such as epoxy-based adhesives due to the types of members to be joined and the joining strength, and heat treatment is inevitably performed in the inkjet head manufacturing process. In this heat treatment, distortion or deformation occurs due to the difference in linear expansion coefficient of the members constituting the inkjet head, resulting in a defective product in which air (bubbles) enters the ink flow path of the inkjet head, The yield has been reduced.
Therefore, as described in Patent Document 1 below, as means for suppressing distortion or deformation caused by a difference in linear expansion coefficient between members constituting an ink jet head, a substrate member and a channel member having the same linear expansion coefficient are used. Techniques have been used that rely on the effects of thermal expansion, either by using or by using the same material.
[0004]
[Patent Document 1]
JP-A-6-328885
[Problems to be solved by the invention]
However, if it is not easy to mount the ink supply port and the ink supply source (or a connecting member such as a flexible tube drawn out from the ink supply source) at the time of replacing the ink supply source, the ink flow path of the ink jet head may be reduced. This causes problems such as air bubbles entering the inside.
[0006]
Further, the reservoir member and the tubular member forming the ink supply port at the tip are press-fitted and joined, but when the temperature changes in the inkjet head, there is a difference in the linear expansion coefficient between the two members. This causes a problem that distortion or deformation occurs between the cylindrical member and the reservoir member, and bubbles enter the ink flow path of the inkjet head.
[0007]
The present invention has been made in view of the above problems, and an ink jet head capable of preventing bubbles from entering an ink flow path by easily mounting an ink supply source and an ink supply port. To provide.
[0008]
[Means for Solving the Problems]
In order to solve the above problem, an ink jet head according to claim 1 includes an ink supply port to which ink is supplied from an external ink supply source, and a reservoir that stores the ink supplied from the ink supply port. And a plurality of discharge nozzles for discharging ink, a plurality of pressure chambers connected to the discharge nozzle and the reservoir, a flow path unit, and the ink in the pressure chamber fixed to the flow path unit An actuator unit for applying ejection energy, wherein a cylindrical member is fixed to the reservoir member so as to protrude, and the ink supply port is formed at a tip of the cylindrical member, and the cylindrical member is formed. The outer diameter of the tip is smaller than the outer diameter of the root of the tubular member.
[0009]
According to the first aspect, when the ink supply source (or a connecting member such as a flexible tube drawn from the ink supply source) is attached to the ink supply port, the tubular member is tapered. , Can be easily mounted.
[0010]
An ink jet head according to a second aspect is the ink jet head according to the first aspect, wherein a material of the tubular member is the same as a material of the reservoir member.
[0011]
According to the second aspect, since the material of the cylindrical member and the material of the reservoir member are the same, the coefficient of linear expansion is also the same. Therefore, when the cylindrical member is fixed by press-fitting into the hole formed in the reservoir member, both members expand and contract in the same manner even if the temperature and humidity change, so that the cylindrical member and the reservoir It is possible to maintain good contact with the member. Therefore, it is possible to prevent air bubbles from entering the ink flow path from outside via the boundary between the tubular member and the reservoir member.
[0012]
An ink jet head according to a third aspect is the ink jet head according to the second aspect, wherein the material of the cylindrical member and the reservoir member is stainless steel.
[0013]
According to the third aspect, the material of the reservoir member and the material of the cylindrical member are made of stainless steel having excellent ink resistance. Therefore, various inks can be used regardless of the type of ink. Furthermore, by employing stainless steel having excellent air blocking properties, it is possible to prevent air from passing through the reservoir member / tubular member and entering the ink flow path to form bubbles.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[0015]
First, an ink jet head according to the present embodiment will be described with reference to FIGS. FIG. 1 is a front view of an inkjet head according to one embodiment of the present invention. FIG. 2 is an enlarged side view of the inkjet head. FIG. 3 is an enlarged sectional view of the reservoir member and the cylindrical member. FIG. 4 is an exploded perspective view of the reservoir plate. FIG. 5 is a cross-sectional view of the ink jet head main body, showing an ink flow path in the flow path unit. FIG. 6 is a bottom view showing a state in which the inkjet heads are provided side by side.
[0016]
First, the structure of the inkjet head will be described. As shown in FIG. 1, the inkjet head 1 according to the present embodiment has a head main body 18, a spacer member 39, and a reservoir member 40. These members (the head body 18, the spacer member 39, and the reservoir member 40) are adhered and fixed to each other. Both ends of the reservoir member 40 are attached to appropriate members 12 provided on a printer (not shown) by screws 13.
[0017]
A cylindrical member 50 is fixed to the end of the reservoir member 40 so as to protrude, and a distal end of the cylindrical member 50 is connected to a connecting member (for example, A flexible tube 2a) is externally fitted and mounted. As shown in FIG. 3, the cylindrical member 50 has a base end (base end) press-fitted into the reservoir member 40 and an opening 52 on the base end side through an ink flow path (reservoir) 44 described later. In close contact.
The protruding end of the tubular member 50 has a reduced diameter portion 53 having a small outer diameter. Further, the end surface of the protruding end is formed obliquely (pointed), and an opening (ink supply port) 51 is formed in the end surface. Is formed.
As described above, the connecting member 2a such as a flexible tube drawn from the ink supply source 2 is fitted and mounted on the outer peripheral surface of the reduced diameter portion 53 as shown in FIG. 2 and the ink supply port 51 are connected to each other. With this configuration, the ink of the ink supply source 2 is supplied to the inside of the reservoir member 40 through the inside of the connecting member 2a and the inside of the tubular member 50. Here, as a result of the provision of the reduced diameter portion 53, the outer diameter of the ink supply port 51 is configured to be smaller than the outer diameter of the opening 52, as shown in FIG.
[0018]
As shown in FIG. 4, the reservoir member 40 has a laminated structure in which a total of three metal flat plates (reservoir plates) 41 to 43 are stacked in order from the top. In addition, an ink flow path (reservoir) 44 for guiding ink from the ink supply source 2 to the manifold flow path 30 of the head main body 18 described later is formed inside the ink flow path.
[0019]
Here, the reservoir member 40 and the tubular member 50 are formed of the same material. The material is desirably stainless steel (SUS).
[0020]
Then, as shown in FIG. 2, the inkjet head 1 is attached via a holder 15 to an appropriate member 14 provided on a printer (not shown). The holder 15 is formed in an inverted "T" shape having a vertical portion 15a and a horizontal portion 15b in a side view. The holder 15 is attached to the printer main body side with a screw 16 on the vertical portion 15a, while the horizontal portion 15b is The lower surface is configured to fix the reservoir member 40 and the head main body 18 via a spacer member 39.
[0021]
The inkjet heads 1 are provided in a row along the paper transport direction, corresponding to four color inks (magenta, yellow, blue, and black). As shown in FIG. 6, which is a view from the lower surface side, the inkjet head 1 has an elongated rectangular shape having a longitudinal direction perpendicular to the paper transport direction, and a head body 18 attached to the lower surface has A large number of minute ejection nozzles 13 for ejecting ink downward are formed side by side.
[0022]
Next, the configuration of the head body 18 of the inkjet head 1 will be described. As shown in FIG. 5, the head main body 18 is composed of a flow path unit 20 in which a number of pressure chambers 34 and discharge nozzles 13 are formed, and a plurality of trapezoidal plate-like actuator units 19 which are adhered side by side on the upper surface thereof. It is configured.
[0023]
The flow path unit 20 has a total of 9 metal flat plates 21 to 29 (cavity plate 21, base plate 22, aperture plate 23, supply plate 24, manifold plates 25, 26, 27, cover plate 28, nozzle plate 29) in order from the top. It has a laminated structure in which thin metal flat plates are laminated. The manifold channel 30 is formed so as to straddle the flat plates (manifold plates) 25 to 27 of the fifth to seventh layers counted from the top. The ink in the reservoir 44 of the reservoir member 40 is supplied to the manifold channel 30 through an inlet (not shown). A communication hole 31 is formed in the fourth layer flat plate (supply plate) 24 immediately above the fifth to seventh layer flat plates (manifold plates) 25 to 27, and the communication hole 31 is formed in the third layer flat plate (manufactured plate). It is connected to an aperture portion 32 formed on an aperture plate (23).
[0024]
The throttle section 32 communicates with one end of a pressure chamber 34 formed in the first layer flat plate (cavity plate) 21 through a communication hole 33 formed in the second layer flat plate (base plate) 22. The pressure chambers 34 are for applying pressure to the ink under the drive of the actuator unit 19, and are provided one for each of the multiple ejection nozzles 13. The other end of the pressure chamber 34 is connected to the discharge nozzle 13 formed in the ninth layer flat plate (nozzle plate) 29 through a nozzle communication hole 35 formed through the second to eighth layer flat plates. Have been.
[0025]
With the above-described configuration, ink reaches the manifold channel 30 in the channel unit 20 from the ink supply source 2 via the reservoir 44. The ink supplied from the communication hole 31 to the pressure chamber 34 via the throttle portion 32 and the communication hole 33 is applied with pressure by driving the actuator unit 19 described later, and is ejected via the nozzle communication hole 35. It reaches the nozzle 13 and is jetted.
[0026]
The above-described manifold flow path 30, pressure chamber 34, throttle section 32, communication hole 31, communication hole 33, nozzle communication hole 35, and the like are formed in the flat plates 21 to 28 by etching or laser. The discharge nozzles 13 of the nozzle plate 29 are formed by press working or laser processing.
[0027]
The actuator unit 19 includes, for example, stacking several thin piezoelectric sheets made of a lead zirconate titanate (PZT) -based ceramic material and interposing an electrode film made of a thin Ag-Pd-based metal material between the piezoelectric sheets. Thus, one active portion is formed corresponding to each of the pressure chambers 34.
[0028]
In this configuration, when a potential difference is given between the paired electrodes, the active portion is deformed so as to protrude toward the pressure chamber 34 side. As a result, the volume of the pressure chamber 34 is reduced, and a pressure for ejecting ink inside the pressure chamber 34 is obtained.
[0029]
Also, as shown in FIG. 5, one end of a flexible flat cable 17 is adhered to the upper surface of the actuator unit 19, and the flexible flat cable 17 is connected to the head body 18 as shown in FIGS. It is pulled out and is extended upward while being bent. The above-described electrodes of the actuator unit 19 are electrically connected to a driver IC (not shown) for controlling printing via a conductive wire in the flexible flat cable 17.
[0030]
As described above, according to the inkjet head 1 of the present embodiment, the outer diameter of the ink supply port 51 is configured to be smaller than the outer diameter of the opening 52.
As a result, when the connecting member 2 such as a flexible tube pulled out from the ink supply source is mounted on the ink supply port 51, the cylindrical member 50 is tapered, so that it can be easily mounted. .
[0031]
Further, since the material of the cylindrical member 50 and the material of the reservoir member 40 are the same, the coefficient of linear expansion is also the same.
As a result, when the cylindrical member 50 is fixed by press-fitting into the hole formed in the reservoir member 40, both members expand and contract in the same manner even when the temperature and humidity change, so that the cylindrical member 50 is formed. The close contact state between the member 50 and the reservoir member 40 can be favorably maintained. Therefore, it is possible to prevent air bubbles from entering the ink flow path (reservoir) 44 from outside via the boundary between the tubular member 50 and the reservoir member 40.
[0032]
As described above, the preferred embodiments of the present invention have been described, but the present invention is not limited to the above-described embodiments, and various changes can be made within the scope of the claims.
[0033]
For example, in the above-described embodiment, the ink supply port 51 is attached to the connecting member 2a such as a flexible tube drawn from the ink supply source 2 such as an ink cartridge (ink tank), but is not limited thereto. For example, it may be directly mounted on the ink supply source.
[0034]
【The invention's effect】
As described above, according to claim 1, when the ink supply source (or a connecting member such as a flexible tube drawn from the ink supply source) is attached to the ink supply port, the tubular member is connected to the cylindrical member. The tapered shape allows easy mounting.
[0035]
According to the second aspect, since the material of the cylindrical member and the material of the reservoir member are the same, the coefficient of linear expansion is also the same. Therefore, when the cylindrical member is fixed by press-fitting into the hole formed in the reservoir member, both members expand and contract in the same manner even if the temperature and humidity change, so that the cylindrical member and the reservoir It is possible to maintain good contact with the member. Therefore, it is possible to prevent air bubbles from entering the ink flow path from outside via the boundary between the tubular member and the reservoir member.
[Brief description of the drawings]
FIG. 1 is a front view of an inkjet head according to an embodiment of the present invention.
FIG. 2 is an enlarged side view of the inkjet head.
FIG. 3 is an enlarged cross-sectional view of a reservoir member and a cylindrical member.
FIG. 4 is an exploded perspective view of a reservoir plate.
FIG. 5 is a cross-sectional view of the ink jet head main body, showing an ink flow path in the flow path unit.
FIG. 6 is a bottom view showing a state in which inkjet heads are provided side by side.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 inkjet head 2 ink supply source 13 discharge nozzle 19 actuator unit 20 flow path unit 34 pressure chamber 40 reservoir member 44 reservoir (ink flow path)
50 cylindrical member 51 ink supply port

Claims (3)

A reservoir member including an ink supply port to which ink is supplied from an external ink supply source, and a reservoir that stores the ink supplied from the ink supply port;
A plurality of ejection nozzles for ejecting ink, and a plurality of pressure chambers connected to the ejection nozzle and the reservoir, a flow path unit including:
An actuator unit fixed to the flow path unit and applying ejection energy to the ink in the pressure chamber,
A cylindrical member is fixed to the reservoir member in a protruding manner, and the ink supply port is formed at a tip of the cylindrical member,
The inkjet head according to claim 1, wherein an outer diameter of the tip of the tubular member is smaller than an outer diameter of a root of the tubular member. The ink jet head according to claim 1, wherein a material of the cylindrical member is the same as a material of the reservoir member. The inkjet head according to claim 2, wherein the material of the cylindrical member and the reservoir member is stainless steel.

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