JPH11342605A - Magnetic field driving type ink jet recording head and driving method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel magnetic field driving type ink jet recording head wherein a kind of ink is not limited and it is not necessary to generate bubbles by directly applying a heat to the ink when ejecting the ink. SOLUTION: This ink jet recording head comprises a pressure generating chamber 2003 wherein one face is sealed with a nozzle plate 2005 having ink ejecting nozzles 2004 and the other face is sealed with a magnetic plate 2007 having a first magnetic film 2006 which is deformable by a magnetic attraction force, a second magnetic film 2008 which is provided separated from the magnetic plate 2007 with a predetermined gap 2009 therebetween and is not deformable by a magnetic attraction force, and a heating resistor 2002 for applying a thermal energy to the second magnetic film 2008. The pressure generating chamber 2003 is expanded by virtue of the magnetic attraction force generated between the first and second magnetic films 2006, 2008 and is shrunk by the removing of the magnetic attraction force, thereby ejecting ink drops from the ejecting nozzles 2004.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic field driven type ink jet recording head for obtaining a discharge energy of ink droplets by deforming a pressure generating chamber by a certain field and a driving method thereof.

[0002]

2. Description of the Related Art An ink jet recording system is capable of high-speed, high-density, high-precision, high-quality recording, and is capable of colorization.
This is a recording method suitable for downsizing (US Pat. No. 47
No. 23129, U.S. Pat. No. 4,740,796). Therefore, in the world of color printers, rapid growth has been achieved in recent years.

As shown in FIG. 4, a general head used for the above-described ink jet recording has a plurality of discharge ports 100.
1, and a heating resistor 1002 for generating thermal energy to be used for ejecting ink from the heater board 1004 is provided on the heater board 1004 for each ink flow path 1003. In addition, each ink flow path 10
Reference numeral 03 denotes a grooved top plate 1007 integrally formed with a plurality of flow path walls, and a heating resistor 1 on the heater board 1004.
002 etc. are formed by joining them while aligning their relative positions with means such as image processing. Each ink flow path 1003 has an end opposite to the discharge port 1001 communicating with a common liquid chamber 1005. The common liquid chamber 1005 is connected to the common liquid chamber 1005 from an ink tank (not shown) via a supply path 1006. The supplied ink is stored. Common liquid chamber
Supplied to the ink passage 1003
To form a meniscus in the vicinity of the discharge port 1001 and hold it. At this time, by selectively driving the heating resistor 1002, the ink on the heat acting surface is rapidly heated and boiled by utilizing the generated thermal energy to generate bubbles. Discharge the ink.

Further, as described above, there has been proposed an ink jetting method which does not directly apply thermal energy to ink and does not involve the generation of bubbles. For example, many ink jet recording systems using a pressure generating element such as a piezo element as an actuator have been proposed. Although many contents have been proposed for the structure, the basic structure is almost the same, and is composed of an ink discharge nozzle, an ink flow path, an ink pressure chamber, a vibration plate to which a piezoelectric element is bonded and transmits pressure, and the like.

Specifically, for example, Japanese Patent Application Laid-Open No.
As described in Japanese Patent Publication, etching a substrate such as glass
Grooves such as ink discharge nozzles, ink flow paths, ink pressurization chambers, and ink supply paths are formed, and an organic film, a diaphragm such as a metal foil, etc. Be composed. Further, a piezoelectric element is bonded to an external position of the diaphragm, and an ink supply hole is provided in a part of the diaphragm. Electrodes are formed above and below the piezoelectric element, and when a voltage is applied to the electrodes, distortion occurs in the piezoelectric element and the diaphragm is displaced. As a result, the volume of the ink pressurizing chamber is reduced, and as a result, ink droplets are ejected from the ink nozzle onto the paper surface to perform printing.

[0006]

However, in the former ink jet recording system described in the prior art, since thermal energy is directly applied to the ink, the components of the ink change or the surface of the heater is heated by a thermochemical reaction. A problem occurs that the protective film is eroded and the life of the head is shortened. Further, due to the occurrence of bubbles, there is a problem that the heater is disconnected due to repeated cavitation at the time of defoaming, or a discharge failure occurs when bubbles are not completely defoamed and minute bubbles remain. .

In the latter method, the electrical characteristics of the piezoelectric element vary greatly with changes in humidity, and a high voltage of about 50 V is required to drive the piezoelectric element, so that a large load is applied to the power supply system of the printer. Further, there is a problem that the size of the pressure generating element cannot be reduced so much that the amount of expansion and contraction of the pressure chamber is increased to some extent, which is disadvantageous for high-density arrangement.

The present invention has been made in view of the above-mentioned problems of the conventional ink jet recording head, and has as its object the purpose of irrespective of the type of ink, and to directly apply heat energy to ink at the time of ink ejection. It is another object of the present invention to provide a novel magnetic field drive type ink jet recording head which does not need to generate bubbles. Another object of the present invention is to propose a driving method suitable for driving the ink jet recording head.

[0009]

Such a problem has been solved in the present invention as follows. In other words, the ink jet recording head according to the present invention is a magnetic head having a first magnetic film which communicates with the ink supply means and has one surface formed by a nozzle plate having an ink discharge port and the other surface elastically deformable by magnetic attraction. A pressure generating chamber sealed by a plate, a second magnetic film which is provided at a predetermined gap from the magnetic plate and cannot be deformed by magnetic attraction, and generates heat by applying heat energy to the second magnetic film A resistive element, the pressure generating chamber is expanded by a magnetic attraction between the first magnetic film and the second magnetic film, and the pressure generating chamber is contracted by removing the magnetic attractive force to form the ink discharge port. To eject ink droplets.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described based on examples with reference to the drawings. However, the present invention is not limited to the following examples, and it is sufficient that the object of the present invention can be achieved.

FIG. 1 is a schematic sectional view of an ink jet recording head according to an embodiment of the present invention. Reference numeral 200 in the figure
Reference numeral 1 denotes a heater board, and reference numeral 2002 denotes a heating resistor formed on a silicon substrate serving as the heater board 2001 by using a semiconductor process. In general, HfB, T
aN, TaSiN or the like is used.

Reference numeral 2003 denotes a pressure generating chamber which communicates with an ink supply means (not shown).
Plate 2005 having first magnetic film 20
06 is sealed by a magnetic plate 2007. Note that at least the surface of the first magnetic film 2006 that seals the pressure generating chamber 2003 is protected by a protective film 2010 such as SiN or Ta.

Reference numeral 2008 denotes an S on the heating resistor 2002
This is a second magnetic film made of a rare earth transition metal alloy film provided with a dielectric protection film such as iO or SiN interposed therebetween, and a protection film 2010 such as SiN or Ta is further provided thereon.

The second magnetic film comprises at least one or more rare earth metal elements selected from Gd, Tb and Dy elements and at least one or more rare earth metal elements selected from Fe, Co and Ni elements. The ferrimagnetic alloy film is composed of a transition metal element, is rich in a rare metal element, and has a compensation point near room temperature.

The rare earth transition metal alloy film is formed by a binary simultaneous sputtering method or the like, and a desired magnetic property can be obtained by adjusting the composition ratio of the rare earth element and the transition metal element. FIG. 2 shows the temperature dependence of the magnetic properties of the rare-earth transition metal alloy film.

Reference numeral 2009 denotes a value of 0.2 to 3.0 μm, which can be deformed enough to discharge the ink in the pressure generating chamber 2003.
m gap.

The pressure generating chamber 2003 and the gap 200
9, the first magnetic film 2 for each ink ejection port 2004;
A partition wall is provided with the magnetic plate 2007 having the 006 therebetween, and the magnetic plate 2007 is deformed with the partition wall as a fulcrum. Incidentally, the second magnetic film is formed in 2008.
Are not elastically deformable by magnetic attraction.

Next, the operation of the recording head thus configured will be described with reference to FIGS. When the operation of the recording head is stopped, that is, when the recording head is near room temperature, FIG.
As shown at point A in the figure, the magnetic moment of the rare earth metal and the magnetic moment of the transition metal are balanced in an antiparallel state, and thus have no apparent magnetization. Therefore, no magnetic attraction is induced between the first magnetic film 2006 and the second magnetic film 2008, and no deformation occurs in the pressure generation chamber 2003. During the operation of the recording head, the heating resistor 2002 corresponding to the print data is selectively driven to drive the second magnetic film 200.
8 is heated. Thereby, the second magnetic film 200
In 8, the balance between the magnetic moment of the rare earth metal and the magnetic moments of all the elements belonging to the selected group is lost, and the magnetization starts to occur rapidly as shown by the region a in FIG. Second magnetic film 20
08 generates the first magnetic film 200.
6, a magnetic attraction is induced, and the pressure generating chamber 2003 expands as shown in FIG. Thereafter, when the temperature of the second magnetic film 2008 is further increased by the heating resistor 2002, the magnetization starts to rapidly disappear as shown by a region b in FIG. The magnetization completely disappears. As a result, the magnetic attraction generated earlier is removed, so that the pressure generating chamber contracts as shown in FIG. 3B, and ink droplets are ejected from the ink ejection port 2004.

Therefore, in the ink jet recording head of the present invention, thermal energy is not directly applied to the ink at the time of the ink discharging operation, so that the component change of the ink and the damage due to the thermochemical reaction on the film surface in contact with the ink are prevented. Absent. Further, since no bubbles are generated, problems such as damage to the film surface due to the impact at the time of defoaming and remaining of minute bubbles do not occur.

[0020]

As described above, the ink jet recording head of the present invention discharges ink droplets by a change in volume of the pressure generating chamber without directly applying heat to the ink by the above-described structure. More freedom,
An ink jet recording head having excellent ejection reliability can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an ink jet recording head according to an embodiment of the present invention.

FIG. 2 is a diagram showing temperature dependence of magnetic characteristics of a second magnetic film used in an ink jet recording head according to an embodiment of the present invention.

3A and 3B are diagrams showing a method of driving an ink jet recording head according to an embodiment of the present invention, wherein FIG. 3A shows a state where a pressure expansion chamber is expanded, and FIG. 3B shows a state where the pressure expansion chamber is contracted. The state is shown.

FIG. 4 is a schematic sectional view showing a conventional example of an ink jet recording head.

[Explanation of symbols]

 2001 Heater board 2002 Heating resistor 2003 Pressure generating chamber 2004 Discharge port 2005 Nozzle plate 2006 First magnetic film 2007 Magnetic plate 2008 Second magnetic film 2009 Void 2010 Protective film

Claims (5)

[Claims] 1. One surface is sealed by a nozzle plate having an ink discharge port, and the other surface is sealed by a magnetic plate having a first magnetic film elastically deformable by magnetic attraction. A pressure generating chamber, a second magnetic film which is provided at a predetermined gap from the magnetic plate and is not deformable by magnetic attraction, and a heating resistor which applies thermal energy to the second magnetic film. A magnetic field that causes the pressure generating chamber to expand by magnetic attraction between the first and second magnetic films, and causes the pressure generating chamber to contract by removing the magnetic attractive force to discharge ink droplets from the discharge ports. Drive type ink jet recording head. 2. The method according to claim 1, wherein the second magnetic film is formed of Gd, Tb, Dy.
2. A ferrimagnetic alloy film comprising at least one or more rare earth metal elements selected from elements and at least one or more transition metal elements selected from Fe, Co, and Ni elements. Field-driven ink jet recording head. 3. The magnetic-field-driven interjet recording head according to claim 2, wherein the second magnetic film is a ferrimagnetic alloy film rich in a rare metal element. 4. A magnetic-field-driven ink jet recording head according to claim 2, wherein said second magnetic film is a ferrimagnetic alloy film having a compensation point near room temperature. 5. An ink supply means, one surface of which is sealed by a nozzle plate having an ink discharge port, and the other surface of which is sealed by a magnetic plate having a first magnetic film elastically deformable by magnetic attraction. A pressure generating chamber, a second magnetic film which is provided at a predetermined gap from the magnetic plate and is not deformable by magnetic attraction, and a heating resistor which applies thermal energy to the second magnetic film. A method of driving a magnetic field driven ink jet recording head, comprising: applying heat energy to the second magnetic film by the heating resistor to elastically deform the magnetic plate; Generating magnetic attraction between the first magnetic film and the second magnetic film by the heating resistor to restore the elastic deformation of the magnetic plate. The driving method of a magnetic field driving type ink jet recording head comprising a magnetic attraction from the step of removing between the magnetic film and 2.