JPH10278262A - Ink-jet recording head and method for correcting diameter of ink drop of ink-jet recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct unevenness in dot diameter of ink drops discharged from a plurality of nozzles, by constituting a part or the whole of individual wirings set corresponding to the plurality of nozzles and connected to an ink discharge driving element of a resistor material. SOLUTION: A piezoelectric member 31 as an ink discharge driving element which corresponds to a cavity having nozzles connected at an end part is fixed by a laminate piezoelectric member of laminated metallic electrode layers between a diaphragm and a substrate. One end is connected to a common electrode 44 and the other end is connected to individual electrodes 46. When the individual electrodes 46 are partly formed of a resistor material 48 of a sintered material and the substrate is formed of silicon carbide, the substrate itself can be used as the resistor material 48. The silicon carbide corrects as a varistor material a waveform of an impressed voltage. Therefore, the piezoelectric member 31 when driven with the corrected voltage reduces unevenness in fly speed of ink drops and the individual electrodes 46 can change the impressed voltage at an image signal circuit connected thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head for recording an image by ejecting ink droplets from a plurality of nozzles in accordance with an image signal and attaching the ink to a recording medium such as recording paper. The present invention relates to an ink jet recording head for correcting variations in the diameter of ink droplets ejected from nozzles, and a method for correcting the ink droplet diameter of the ink jet recording head.

[0002]

2. Description of the Related Art Conventionally, there has been known an ink jet recording head which discharges ink droplets from a plurality of nozzles and records an image by ink dots formed by attaching the ink droplets to a recording medium. In this type of ink jet recording head, the gradation of an image formed is adjusted by controlling the diameter of an ink droplet. Further, in order to form a good image, it is necessary to correct variations in the diameter of ink droplets ejected from a plurality of nozzles. 2. Description of the Related Art Increasing the assembling accuracy of parts and controlling a control circuit of an ink jet recording head after assembling are performed.

[0003]

However, there is a limit to increasing the processing accuracy of the components constituting the ink jet recording head and the assembly accuracy of the components, and when the variation of the ink droplet diameter is wide, There is a problem that it is not possible to control the control circuit after assembly to correct the variation in the ink droplet diameter.

[0004]

SUMMARY OF THE INVENTION Accordingly, an ink jet recording head according to the present invention has been made to solve the above problems, and is an ink jet recording head having a plurality of nozzles. A part or all of the individual wirings connected to the corresponding ink ejection drive elements are made of a resistor material.

Further, in the ink droplet diameter correcting method for an ink jet recording head according to the present invention, an ink jet recording head having a plurality of nozzles, wherein an ink ejection driving element provided corresponding to each of the plurality of nozzles is provided. Part or all of the individual wirings to be connected are made of a resistor material, and the resistance value of the resistor is adjusted by changing the volume of the resistor material to adjust the diameter of ink droplets ejected from a plurality of nozzles. Is characterized by correcting the variation of

Further, in the ink droplet diameter correcting method for an ink jet recording head according to the present invention, an ink jet recording head having a plurality of nozzles, wherein the ink ejection driving elements provided respectively corresponding to the plurality of nozzles are provided. Part or all of the individual wirings to be connected are made of a resistor material that can be vaporized or removed with excitation light energy, and the resistor material is irradiated with excitation light energy to reduce its volume, thereby reducing the resistance value. Is adjusted to correct variations in diameter of ink droplets ejected from a plurality of nozzles.

[0007]

According to the ink jet recording head and the method for correcting the ink droplet diameter of the ink jet recording head according to the present invention, a part of each individual wiring connected to the ink discharging drive element provided corresponding to each of the plurality of nozzles. Or, since all are made of a resistor material, by adjusting the resistance value of the resistor material, it is possible to correct variations in dot diameter of ink droplets ejected from a plurality of nozzles,
Further, the correction of the above-mentioned variation is not affected by the processing accuracy of the components constituting the inkjet recording head, the assembly accuracy of the components, and the ink droplet diameter correcting ability of the control circuit.

Further, in the ink droplet diameter correction method for an ink jet recording head, the resistance value is changed by reducing the volume of the resistor material by irradiating excitation light energy to vaporize or remove a part of the resistor material. Variations in dot diameter of ink droplets can be easily corrected.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a part of a printer 3 having an ink jet recording head 1 according to the present invention. The printer 3 includes a feeding mechanism 7 for feeding the paper 5 in the sub-scanning direction (y direction) and a moving mechanism 9 for moving the carriage 11 in the main scanning direction (x direction). Inkjet recording head 1
Is provided so as to move in the main scanning direction (x direction) by being attached to the carriage 11.

The ink jet recording head 1 has an ink jet recording head section 21 as shown in FIG. This inkjet recording head unit 21 has a total of 20
Are provided in two rows of ten nozzles 23 in the sub-scanning direction y, and the top plate 27, the partition wall 29, the vibration plate 30, and the substrate 3
3 are superposed in this order to be integrally formed. The top plate 27 is made of ceramic, synthetic resin, metal, or the like. As shown in FIGS. 3 to 5, the surface facing the partition wall 29 is finely processed by a method such as electroforming or photolithography to form a plurality of groove-shaped concave portions. Are formed. A partition wall 29 made of a thin film of metal, synthetic resin, or the like is adhered to the recess forming surface of the top plate 27 so as to cover the plurality of recesses. This partition 29
In each of the concave portions covered with the ink, an ink cavity 37 containing the ink 35, an ink supply chamber 41 containing the replenishing ink 39, and an ink inlet 43 communicating the ink cavity 37 with the ink supply chamber 41 are formed. Have been.

The nozzle 23 is formed so as to communicate with the end of each cavity 37. As shown in FIG. 4, each of the ink cavities 3 opposed to each other with the center line 45 interposed therebetween.
Reference numeral 7 denotes a long groove extending along the facing direction, and is formed side by side in the sub-scanning direction y. Further, the ink supply chamber 39 is formed on the opposite side of the center line 45 with the ink cavity 37 interposed therebetween, and is connected to an ink tank (not shown) via an ink supply port 46.

The vibration plate 30 is divided by forming a vertical groove 47 and a horizontal groove 49 by dicing, and a piezoelectric member (ink ejection driving element) 31 corresponding to each ink cavity 37 and a piezoelectric member adjacent thereto are formed. The partition wall 51 is divided into a partition wall 51 located between the partition walls 31 and a peripheral wall 53 surrounding the partition wall 51.

The piezoelectric member 31 is a well-known laminated piezoelectric member formed by laminating a plurality of thin film piezoelectric sheets alternately sandwiching metal electrode layers, and includes a partition wall 29 and an alumina ceramic (Al ₂ O ₃ ) substrate. 33.
As shown in FIGS. 6 and 7, the piezoelectric member 31 has one end connected to the common electrode 44 and the other end connected to the individual electrode 46. Each piezoelectric member 31 has a common electrode 4 at a high temperature.
Polarization is performed by applying a high voltage between the electrode 4 and the individual electrode 46.

Part of each individual electrode 46 is formed of a resistor material 48 made of a sintered material. This resistor material 48 is made of a resin (carbon black particles:
The maximum particle size of 0.2 μm) is dispersed at 5% by weight, and is formed into a length of 1 mm, a width of 100 μm, and a thickness of 5 μm. You. The substrate 33 is not limited to alumina ceramics, but may be metal, synthetic resin, or the like. Also, the substrate 3
By forming the substrate 3 from silicon carbide (Sic), the substrate itself can be used as the resistor material 48. In this case, the silicon carbide acts as a varistor material, and the waveform of the applied voltage is corrected to a substantially trapezoidal waveform without overshoot and undershoot. By driving with the voltage having the above waveform, the piezoelectric member 31 can reduce the variation in the flying speed of the ink droplet. Further, in order to correct the waveform of the applied voltage, a silicon carbide film may be formed on the substrate 33 other than silicon carbide, and this film may be used as the resistor material 48.

The resistor material 48 is patterned to form a portion of each individual electrode 46,
The entirety of each individual electrode 46 may be formed, or may be formed in a band shape so as to be orthogonal to each individual electrode 46 without patterning (so-called solid coating), and shared by each individual electrode 46 to reduce cost. You may make it go down. In this case, it is necessary to adjust the resistor material 48 to a high resistance value of about 1 MΩ to prevent interference between the individual electrodes 46.

The resistor material 48 is vaporized or removed by, for example, irradiating a YAG or excimer laser beam to reduce its volume (trimming process).
What is necessary is just to be able to adjust the resistance value of itself. Therefore, the resin constituting the resistor material 48 is not limited to carbon black particles, and can be replaced with a known resin material such as an epoxy cured resin or an acrylic resin. Similarly, the resistor material 48 is not limited to nichrome, but may be any material that can be trimmed with YAG or excimer laser light. For example, a material obtained by sintering manganese (Mn), aluminum (Al), or the like, or It may be a thin film formed by vapor deposition, such as silicon nitride (SiN), tantalum oxide (TaO), aluminum nitride (AlN), and tungsten oxide (WO ₃ ).

The common electrode 44 of each piezoelectric member 31 is connected to the ground, and the individual electrode 46 is connected to an image signal control circuit (not shown). Can be changed. The piezoelectric member 31
Is not limited to a laminated piezoelectric member, and a single-layer type may be used.

In the printer 3 having the above structure, the ink jet recording head 2 of the ink jet recording head 1
1, ink is supplied from an ink tank (not shown) through respective ink supply ports 46, and an ink supply chamber 39 is provided.
And the ink is stored in the ink cavity 37 of the inkjet recording head unit 21 through the ink inlet 43.

In this state, by applying a voltage to the piezoelectric member 31 from the image signal control circuit, the piezoelectric member 31 is instantaneously deformed and the partition wall 29 is pushed toward the ink cavity 37, and the ink 35 in the ink cavity 37 is removed. Is pressed to eject ink droplets through the nozzle 23 or the nozzle 24 and adhere to the paper 5.

At this time, a desired image is formed by feeding the paper 5 set in the feed mechanism 7 in the sub-scanning direction y and moving the ink jet recording head 1 in the main scanning direction x by the moving mechanism 9.

The piezoelectric member 3 is controlled by an image signal control circuit.
When the voltage applied to 1 is changed, the amount of deformation of the piezoelectric member 31 increases or decreases, and based on this, the pressure acting on the ink 35 changes, so that the diameter of the ink droplet to be ejected can be changed.

Next, a method for correcting variations in the diameter of ink droplets ejected from the twenty nozzles 23 formed in the ink jet recording head unit 21 will be described. The vertical and horizontal axes of the table shown in FIG.
The nozzle numbers corresponding to the zero nozzles 23 are shown. The width indicated by a solid line indicates the ink droplet diameter before the variation correction in each nozzle 23 (No. 1 to No. 20), and the width indicated by the dotted line indicates the ink droplet diameter after the variation correction. I have. Note that the ink droplet diameter shown here is the value when a 300-character ink dot is printed by applying a trapezoidal waveform pulse voltage (see FIG. 9) having a frequency of 4 KHz and 20 V to the piezoelectric member 31 corresponding to each nozzle 23. This refers to the diameter of the ink dot. However, in this case, the piezoelectric member 31 uses a laminated PZT material formed by laminating 20 layers each having a thickness of 23 μm.

In the method of correcting the variation of the ink droplet diameter according to the present invention, first, the nozzle 23 having the smallest resistance value among the resistor material 48 corresponding to each nozzle 23 and exhibiting a desired variation width. Select In the present embodiment, as shown in the upper part of the table shown in FIG. 10, since the resistance values of the respective resistor materials 48 corresponding to the nozzles 1 to 20 are all 108Ω, the desired variation width (± 3 μm in the present embodiment)
Select Therefore, among the widths indicated by the solid lines in FIG. 8, the No. 5 nozzle having a variation width of ± 3 μm is selected, and the variation width of the other nozzles is corrected based on this width. If there is no nozzle 23 showing the desired variation width, the nozzle 23 showing the smallest variation is selected, and correction is performed including this.

The specific content of the correction work is to disassemble the ink jet recording head unit 21 after the variation has been measured, and as shown in FIG.
A laser 57 emitted from the nozzle 23 is irradiated on the resistor material 48 corresponding to each nozzle 23 to perform a trimming process. As a result, as shown in FIG. 12, a vaporized or removed portion 49 is formed in a part of the resistor material 48 to reduce the volume, increase the resistance value of the resistor material 48, and reduce the flying ability of the ink droplet. Then, the width of the variation of the ink droplet diameter is narrowed to perform the correction. After the trimming process, the ink jet recording head unit 21 is assembled again to perform printing, and the ink dot diameter is measured to determine whether or not the variation has been corrected.

As a result of the trimming process, as shown in the lower part of the table shown in FIG.
The resistance value of the resistor material 48 corresponding to the fifth nozzle 23 can be increased, and as shown by the dotted line in FIG. Corrected to equal width.

As is clear from the above description, in the ink jet recording head 1 according to the present invention, the resistor material 48 is used.
By changing the resistance value, the variation in the diameter of ink droplets ejected from the plurality of nozzles 23 can be corrected. Therefore, with respect to correcting the above-mentioned variation, the top plate 27 and the partition 2 constituting the ink jet recording head 1
9, the processing accuracy of the diaphragm 30 and the substrate 33, the assembling accuracy of these components, and the ability of the image signal control circuit to correct the ink droplet diameter are not affected.

Further, by irradiating the excitation light energy to vaporize or remove a part of the resistor material 48, the volume of the resistor material 48 can be reduced and its resistance value can be changed. Correction can be performed easily.

[Brief description of the drawings]

FIG. 1 is a partial perspective view of a printer including an inkjet recording head according to the present invention.

FIG. 2 is a partially enlarged perspective view of an inkjet recording head.

FIG. 3 is a front view of the inkjet recording head unit.

FIG. 4 is a sectional view taken along line II-II of FIG.

FIG. 5 is a sectional view taken along line III-III in FIG. 4;

6 is a sectional view taken along line VI-VI of FIG.

FIG. 7 is a sectional view taken along line VV of FIG. 6;

FIG. 8 is a table showing the relationship between each nozzle and the variation width of the ink droplet diameter.

FIG. 9 is an explanatory diagram of a trapezoidal waveform pulse voltage.

FIG. 10 is a table showing resistance values of a resistor material corresponding to each nozzle before and after a trimming process.

FIG. 11 is an explanatory diagram showing a trimming process.

FIG. 12 is a plan view of a trimmed resistor material.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Ink-jet recording head, 3 ... Printer, 21 ...
Ink jet recording head section, 23 nozzle, 31 piezoelectric member, 46 individual electrode, 48 resistor material.

Claims (3)

[Claims] 1. An ink jet recording head having a plurality of nozzles, wherein a part or all of each individual wiring connected to an ink discharge drive element provided corresponding to each of the plurality of nozzles is formed of a resistor material. An ink jet recording head comprising: 2. An ink jet recording head having a plurality of nozzles, wherein a part or all of each individual wiring connected to an ink discharge drive element provided corresponding to each of the plurality of nozzles is made of a resistor material. Wherein the resistance value of the resistor is adjusted by changing the volume of the resistor material to correct the variation in the diameter of ink droplets ejected from a plurality of nozzles. Drop diameter correction method. 3. An ink jet recording head having a plurality of nozzles, wherein a part or all of each individual wiring connected to an ink ejection drive element provided corresponding to each of the plurality of nozzles is provided with excitation light. A resistor material that can be vaporized or removed with energy, and the resistor material is irradiated with excitation light energy to reduce the volume, thereby adjusting the resistance value to adjust the diameter of ink droplets ejected from a plurality of nozzles. A method for correcting an ink droplet diameter of an ink jet recording head, comprising correcting variations.