JP2003165218A - Ink jet print head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable high temperature ink jet print head in which variation in ink ejection characteristics is reduced. <P>SOLUTION: A heater comprising a first temperature sensor is disposed in a housing provided with a common ink channel for supplying ink to a restrictor, a heater comprising a second temperature sensor is provided on a multilayer piezoelectric element fixing plate for generating a pressure variation in a pressure chamber by applying an electric signal, and a section for controlling the temperature of respective heaters is provided. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to office and industrial inkjet printheads.

[0002]

2. Description of the Related Art It is generally known that conventional inkjet printheads are provided with a heater on a housing or a fixing member for fixing the inkjet printhead to heat components constituting the inkjet printhead by heat conduction. Has been.

[0003]

With the above-mentioned structure, when using solid ink, for example, a heater or an ink jet in which the ink jet print head is attached to a housing at about 120 ° C. which is a temperature above the melting point of the solid ink. It is necessary to provide a heater on a fixing member that fixes the print head and heat the inkjet print head by heat conduction. Further, since the diaphragm plate provided with the diaphragm is joined to the housing and has a small thickness, the expansion and contraction of the housing is dominant in the expansion and contraction due to the temperature difference. Further, since the laminated piezoelectric element is also bonded to the laminated piezoelectric element fixing plate in a comb shape, the expansion and contraction of the laminated piezoelectric element fixing plate is dominant in the expansion and contraction due to the temperature difference.

When heated by the heater or the like with the above-mentioned structure, only the housing becomes high in temperature earlier,
Due to the fact that it is difficult to conduct heat to the laminated piezoelectric element fixing plate, the heat radiation of the laminated piezoelectric element fixing plate is large, and the laminated piezoelectric element fixing plate does not rise to a predetermined temperature, a temperature difference occurs between the housing and the laminated piezoelectric element fixing plate. Strain occurs at the bonding position of the laminated piezoelectric element that is bonded to the diaphragm plate having the vibration plate bonded to the plate and the laminated piezoelectric element fixing plate. Therefore, it affects the displacement amount of the laminated piezoelectric element and the vibration plate when the voltage is applied to the laminated piezoelectric element, and as a result, it is reflected in the variation of the ink ejection characteristics. In particular, in a long head having a large number of nozzles and a long length per one row, distortion occurs in the vibration plate or the laminated piezoelectric element due to the temperature difference, and the ink ejection characteristics become unstable. In particular, this defect occurs in the nozzles at the extreme outermost ends, which not only deteriorates the printing quality, but also adversely affects the life characteristics such as damage of the laminated piezoelectric element and the diaphragm and peeling of the adhesive in the worst case.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a highly reliable high temperature ink jet print head in which variations in ink ejection characteristics are reduced.

[0006]

At least one of a chamber plate having a plurality of pressure chambers for accumulating ink, a laminated piezoelectric element for generating pressure fluctuations in the pressure chambers by application of an electric signal, and a wall surface of the pressure chambers. A diaphragm plate, which is a vibrating plate forming a portion and connected to the laminated piezoelectric element with an adhesive, a laminated piezoelectric element fixing plate having the laminated piezoelectric element end fixed, and an electric signal to the laminated piezoelectric element. A flexible cable for feeding, a restrictor plate having a restrictor forming a flow path for supplying ink to the pressure chamber, a housing provided with a common ink flow path for supplying ink to the restrictor, and the pressure An ink jet print head composed of an orifice plate having a plurality of nozzles for ejecting ink droplets from a chamber A heater having a first temperature detecting sensor is provided in the housing, a heater having a second temperature detecting sensor is provided in the laminated piezoelectric element fixing plate, and the temperature of each heater is controlled. It is characterized by having a section.

The orifice plate, the chamber plate, the restrictor plate, the diaphragm plate, the support plate, the laminated piezoelectric element fixing plate, and the housing are made of stainless steel.

Further, it is characterized in that the timing of turning on / off each of the heaters is performed first from the one having a larger heat capacity of the housing or the laminated piezoelectric element fixing plate.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on Examples.

FIG. 1 is a perspective view for explaining a component structure of an ink jet head showing an embodiment of the present invention, and FIG. 2 is a sectional view showing its assembled state. In FIGS. 1 and 2, 2 is an orifice plate in which a plurality of nozzles 1 are formed, 4 is a chamber plate in which a pressure chamber 3 is formed, 6 is a common ink supply passage 12 and the pressure chamber 3 are connected to each other, and the pressure chamber 3
3 is a restrictor plate in which a restrictor 5 that controls the amount of ink flowing into the restrictor plate is formed. 9 is a laminated piezoelectric element 15
Is a diaphragm plate for removing dust and the like in the ink flowing into the restrictor 5 from the common ink passage 12 and the vibration plate 7 for efficiently transmitting the pressure of the nozzle to the pressure chamber. Innumerable fine holes smaller than the hole diameter of 1 are formed. When the vibration plate 7 and the laminated piezoelectric element 15 are fixed with the adhesive 22,
The support plate is formed with a frame 10 that defines that the adhesive protruding from the bonding portion spreads on the diaphragm 7.
Reference numeral 15 is a laminated piezoelectric element fixing plate for fixing the laminated piezoelectric element 15. Reference numeral 13 is a housing having a common ink passage 12. The orifice plate 2, the chamber plate 4, the restrictor plate 6, the diaphragm plate 9, and the support plate 11 are sequentially aligned with the reference holes 20 of the housing 13 by aligning an adhesive or the like with reference to the reference hole 21 of the housing 13. An appropriate amount is applied, the flow path forming member is overlaid and pressure-bonded. Reference numeral 16 is a heater equipped with a first temperature sensor. The heater 16 is joined to the housing 13 with good heat conduction. Further, 17 is a heater equipped with a second temperature sensor, and the heater 17 is bonded to the laminated piezoelectric element fixing plate 15 with good thermal conductivity. Reference numeral 18 denotes a heater control unit for controlling the temperature of the heater 16 having the first temperature sensor and the heater 17 having the second temperature sensor. Reference numeral 19 is a flexible cable for sending an electric signal to the laminated piezoelectric element. Reference numeral 23 is a sealing agent that prevents ink from entering the laminated piezoelectric element 15.

When the ink jet print head having the above structure is heated, the temperature of the heater 16 having the first temperature sensor and the temperature of the heater 17 having the second temperature sensor are controlled by the heater control section 17, It is possible to heat the housing 13 and the laminated piezoelectric element fixing plate 15 so that there is no temperature difference. For example, when the housing 13 and the laminated piezoelectric element fixing plate 15 are made of materials having different thermal expansion coefficients, by controlling the temperature of the housing 13 and the laminated piezoelectric element fixing plate 15 at a predetermined temperature, the housing 13 and the laminated piezoelectric element fixing plate 15 are laminated. Piezoelectric element fixing plate 1
5, it is possible to suppress the generation of strain, and strain is generated at the bonding position of the diaphragm plate 9 having the vibration plate 7 bonded to the housing 13 and the laminated piezoelectric element 14 bonded to the laminated piezoelectric element fixing plate 15. do not do. Therefore, the displacement amount of the laminated piezoelectric element 14 and the vibration plate 7 when the voltage is applied to the laminated piezoelectric element 14 becomes stable, and as a result, the variation in the ink ejection characteristics is reduced. In particular, even in a long head having a large number of nozzles and having a long length per one row, the vibration plate 7 or the laminated piezoelectric element 14 due to the temperature difference.
No distortion occurs in the ink and the ink ejection characteristics are stable. Furthermore, since the strain generated in the laminated piezoelectric element 14 and the vibration plate 7 is reduced, the life characteristics such as breakage and peeling of the adhesive are also improved.

Further, the orifice plate 2, the chamber plate 4, the restrictor plate 6, the diaphragm plate 9, the support plate 11, the housing 13,
By using a stainless material as the material of the laminated piezoelectric element fixing plate 15 in terms of workability and ink corrosion resistance, all components have the same thermal expansion coefficient, so that distortion does not occur and better ink ejection characteristics are obtained. To be Further, since no strain occurs in the room temperature and high temperature heat cycles or the adhesive agent that joins the components, the life characteristics are also improved.

Further, the timing of turning on / off each of the heaters is performed by the housing 13 in which the heaters 16 and 17 are attached or the laminated piezoelectric element fixing plate 15 having the larger heat capacity first.
3 and a heater ON / on the laminated piezoelectric element fixing plate 15.
It is possible to reduce the temperature difference at the time of OFF and reduce the strain with respect to the adhesive agent that joins the component parts, and it is possible to improve the life characteristics.

By adopting the configuration described above, it becomes possible to provide a highly reliable ink jet print head for high temperature in which variations in ink ejection characteristics are reduced.

[0015]

According to the present invention, the heater and the laminated piezoelectric element fixing plate are provided with heaters each having a temperature detecting sensor, and a control unit for controlling the temperature of the heater is provided, so that the dispersion of ink ejection characteristics is improved. It is possible to provide a highly reliable inkjet print head for high temperature, in which the temperature is reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration of an inkjet printhead showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an assembled state of an inkjet printhead showing an embodiment of the present invention.

[Explanation of symbols]

1 is a nozzle, 2 is an orifice plate, 3 is a pressure chamber, 4
Is a chamber plate, 5 is a restrictor, 6 is a restrictor plate, 7 is a diaphragm, 8 is a filter part, 9 is a diaphragm plate, 10 is a frame, 11 is a support plate, 12 is a common ink passage, 13 is a housing, 14 Is a laminated piezoelectric element, 15 is a laminated piezoelectric element fixing plate, 16 is a heater having a first temperature detecting sensor, 17 is a heater having a second temperature detecting sensor, 18 is a heater controller, 1
9 is a flexible cable, 20 is a reference hole, 21 is a reference hole of the housing, 22 is an adhesive, and 23 is a sealing agent.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroshi Shoji             Hitachiko, 1060 Takeda, Hitachinaka City, Ibaraki Prefecture             Machine Co., Ltd. (72) Inventor Hajime Terachi             Hitachiko, 1060 Takeda, Hitachinaka City, Ibaraki Prefecture             Machine Co., Ltd. F-term (reference) 2C057 AF65 AF71 AG12 AG47 AG55                       AG99 AH15 AK01 AL25 AL40                       AM40 AN01 AQ06 BA03 BA14

Claims (3)

[Claims] 1. A chamber plate having a plurality of pressure chambers for storing ink, a laminated piezoelectric element for generating pressure fluctuations in the pressure chambers by applying an electric signal, and at least a part of a wall surface of the pressure chambers. Diaphragm plate which is a vibration plate connected to the laminated piezoelectric element with an adhesive, a laminated piezoelectric element fixing plate to which an end of the laminated piezoelectric element is fixed, and a flexible structure for transmitting an electric signal to the laminated piezoelectric element. Ink droplets from the pressure chamber, a cable, a restrictor plate having a restrictor forming a flow path for supplying ink to the pressure chamber, a housing provided with a common ink flow path for supplying ink to the restrictor, In an inkjet printhead including an orifice plate having a plurality of nozzles for discharging Is provided with a heater having a first temperature detecting sensor, a heater having a second temperature detecting sensor is provided on the laminated piezoelectric element fixing plate, and a controller for controlling the temperature of each heater is provided. Inkjet print head characterized by 2. The orifice plate, the chamber plate, the restrictor plate, the diaphragm plate, the support plate, the laminated piezoelectric element fixing plate, and the housing are made of stainless steel, respectively. 1. The inkjet printhead according to 1. 3. The ink jet print head according to claim 1, wherein the heaters are turned on / off at the timing of the one having a larger heat capacity of the housing or the laminated piezoelectric element fixing plate. .