JP2001191516A - Ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recorder having a smaller number of resonance points and a high productivity. SOLUTION: The ink jet recorder comprises a nozzle body generating ink particles by imparting an oscillation to ink ejected from a nozzle, an electrode for charging the ink particles, and an electrode for deflecting the charged ink particles wherein the nozzle body comprises an oscillator. The oscillator comprises an oscillating part having an oscillating element and a thin planar shaking part for applying an oscillation to ink.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nozzle body for generating ink particles by applying vibration to ink ejected from a nozzle, a charging electrode for charging the ink particles, and deflecting the charged ink particles. The present invention relates to an inkjet recording apparatus including a deflection electrode.

[0002]

2. Description of the Related Art A nozzle body of a conventional ink jet recording apparatus will be described.

A conventional nozzle body has a vibrating body comprising a vibrating part provided with a vibrating element and a vibrating part. The vibrating part is a rod protruding forward, and this rod is used as an ink vibrating chamber. It is configured to be inserted.

Then, the vibration of the rod is transmitted to the ink in the ink vibrating chamber, and the ink ejected from the nozzles of the nozzle body becomes particles.

[0005]

The rod-shaped body of the nozzle body vibrates in the longitudinal direction but also in the radial direction and the like. The rod-shaped body exhibiting such complicated vibration has an excitation frequency-amplitude characteristic having many resonance points as shown in FIG.

[0006] The resonance point must be separated from the excitation frequency of the ink particle generation. If the resonance point moves between the excitation frequencies due to a change in environment such as temperature, the amplitude width changes, so that the sizes of the ink particles become uneven and print quality is impaired.

In the conventional nozzle body having many resonance points, the dimensions and assembly accuracy of the components constituting the nozzle body are improved, and the voltage of the vibrating element, the ink supply pressure, and the like are adjusted to improve the quality of each product. There was no variation in the characteristics. For this reason, productivity was poor.

The present invention has been made in view of the above problems, and has as its object to provide a product having a small resonance point and good productivity.

[0009]

One of the features of the present invention is that:
A nozzle body for generating ink particles by applying vibration to the ink ejected from the nozzle, a charging electrode for charging the ink particles, and a deflecting electrode for deflecting the charged ink particles; The vibrating body is an ink jet recording apparatus having a vibrating section having a vibrating element and a vibrating section for applying vibration to ejected ink, wherein the vibrating section is formed in a thin plate shape.

As a result, the excitation frequency-amplitude characteristics relating to the vibrating section have fewer resonance points, and the productivity is improved.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

First, a description will be given with reference to FIG. 2 which schematically shows the outline of an ink jet recording apparatus.

A charging electrode 2 for charging the ink particles ejected from the nozzle and a deflection electrode 3 for deflecting the flight of the charged ink particles are provided in front of the nozzle body 1. Further, a gutter 4 is provided for collecting ink particles not used for printing. A filter 5 is provided on the ink supply side of the nozzle body 1. These are collectively referred to as a nozzle head.

The excitation source 6 supplies a high-frequency current having an excitation frequency to a vibration element (described later) of the nozzle body 1 via a lead wire. The supplied frequency is 70 kHz or 9
At 0 kHz, 70 kHz is selected in this embodiment. The recording signal source 7 applies a video signal for charging to the charging electrode 2 via a lead wire. The high voltage source 8 applies a high DC voltage to the deflection electrode 3 via a lead wire, and the charged ink particles have different deflection amounts depending on the charge amount.

The ink container 7 storing the ink 9 communicates with the nozzle body 1 via a pipe. Gutter 4
In addition, the ink container 7 communicates via the pipe. The nozzle body 1 communicates with an ink pump 11, a pressure regulating valve 12 for adjusting ink pressure, and an electromagnetic valve 13 for opening and closing a flow path. The gutter 4 is connected via a recovery pump 14, a filter 15, and a solenoid valve 16.

The path for supplying the ink 9 from the ink container 7 to the nozzle body 1 is referred to as an ink supply path 17. A path for collecting the ink 9 from the gutter 4 to the ink container 7 is referred to as an ink recovery path 18. In addition, there is an ink circulation path 20 that is connected between the filter 15 and the electromagnetic valve 16 from the middle of the nozzle body 1 via the electromagnetic valve 19.

In the printing operation, since the solenoid valve 19 is closed and the operation is performed, no ink flows through the ink circulation path 20.
The time when the solenoid valve 19 is opened is when the inside of the nozzle body 1 is washed. The ink or the cleaning liquid flows through the ink circulation path 20.

When ink is supplied from the ink container 7 to the nozzle body 1, ink particles are ejected from the nozzles of the nozzle body 1, and the ink particles are charged by the charging electrode 2, deflected by the deflecting electrode 8, and applied to the printing object. Form the print.

The ink particles are deflected according to the amount of charge charged by the charging electrode 2, so that printing can be performed. The ink particles that have not been used for printing return from the gutter 4 to the ink container 7 via the ink recovery path 18 and are used again for printing.

Next, the nozzle body 1 which is a main part of the present invention will be described with reference to FIG.

The nozzle main body 1 includes a nozzle main body base 30, an ink flow path forming member 31, a nozzle plate member 32, and a vibrating body 33. These are made of stainless steel, but may be made of hard resin or ceramic.

The nozzle body base 30 has a vibrating body housing chamber 40 formed in the center so as to be dug from the front side. An ink supply pipe 35 and an ink circulation pipe 36 are provided on the outer peripheral side.
The ink supply pipe 35 is connected to the ink supply path 17 described above, and the ink circulation pipe 36 is connected to the ink circulation path 20 described above.

The ink flow path forming member 31 has an ink vibrating chamber 42 provided at the center, an ink supply hole 43 communicating with the ink vibrating chamber 42, and an ink circulation hole 44. The ink supply hole 43 is connected to the ink supply pipe 35 via a connection pipe 45 provided so as to be fitted into the ink flow path forming member 31.
Connected to. The ink circulation hole 44 is connected to the ink circulation tube 36 via a connection tube 46 provided to be fitted into the ink flow path forming member 31.

The nozzle plate member 32 has a guide hole 50 having a truncated cone shape, a small communication hole 51, and an orifice portion 52. The orifice portion 52 has a minute hole (nozzle), and the minute hole communicates with the communication small hole 51 and the guide hole 50.

The vibrating body 33 has a vibrating part 60 and a vibrating part 61. The vibrating part 60 and the vibrating part 61 are formed integrally. The vibrating section 60 includes a piezoelectric element 62 as a vibrating element.

The vibrating section 60 has a disk-shaped support base 63 and a column 64 extending from the center of the support base 63. By inserting the donut-shaped piezoelectric element 62 into the support portion 64 to form a two-tiered structure, and tightening the piezoelectric element 62 to the support base 63 with a nut 65 screwed into a screw thread formed on the support portion 64, two The piezoelectric element 62 is attached to the vibrator 33. The piezoelectric element 62 has a terminal 67.
Is connected to the excitation source 6 via a lead wire.

The vibrating section 61 is a thin disk.
This is because the vibration part 61 is supported by the support base 63 through the constricted part 65.
Because it is connected to The constricted part 65 is the vibration part 6
This is a boundary portion between 1 and the support base 63, and is formed by cutting or pressing. Due to the constricted portion 65, the vibrating portion 61 has the shape of a thin brim that extends around. By increasing the outer diameter of the vibrating portion 61 or increasing the constriction, the thin plate-like portion can be expanded. Increasing the constriction has the advantage that the outer diameter of the vibrating part 61 can be suppressed and the nozzle body 1 can be made smaller.

The ink flow path forming member 31 and the nozzle plate member 3
2 is fixed to the nozzle main body 30 together with a fastening screw. With this fixing, the vibrating body 33 is also fastened and fixed between the nozzle body base 30 and the ink flow path forming member 31.

The ink flow path forming member 31 is provided in the vibrating section housing chamber 7.
Has zero. The inner diameter of the vibrating part storage chamber 70 is large enough to fit the vibrating part 61. Also, the vibrating section storage room 7
Numeral 0 is formed concentrically with the vibrating body storage chamber 40 of the nozzle body base 30, and the inner diameter of the vibrating part storage chamber 70 is somewhat larger. The outer peripheral portion of the vibrating section 61 is
Space color 71 between the ink flow path forming member 31 and
It is pinched through. The inner diameter of the vibrating section storage chamber 70 is larger by the thickness of the space collar 71.

The ink flow path forming member 31 has a vibrating section seal ring storage section 72. The vibrating section seal ring housing section 72 is located between the ink vibrating chamber 42 and the vibrating section housing chamber 70 and is continuous. The inner diameter of the vibrating section seal ring storage section 72 is
The diameter is smaller than the inner diameter. The space color 71
About the thickness of the plate.

The vibrating section seal ring 73 is sandwiched between the vibrating section seal ring storage section 72 and the vibrating section 61. A nozzle seal ring 80 is also provided on the joint surface between the ink flow path forming member 31 and the nozzle plate member 32. Both the seal ring 73 for the vibrating section and the seal ring 80 for the nozzle have a cross section of O-shape. Vibrating section seal ring 73,
Due to the sealing of the nozzle seal ring 80, the pressure is 2.
Even if 6 kg / cm ² of ink is supplied to the ink vibrating chamber 42, no ink leaks from the joint surface or the like.

As described above, the vibrating body 33 accommodated in the vibrating body accommodating chamber 40 has an outer peripheral portion 68 of the vibrating portion 61 having a thin disk shape.
Are held and supported.

Now, the nozzle body 1 from the ink supply pipe 40
When ink is fed into the ink vibrating chamber 42 and the vibrating body 33 is vibrated by the piezoelectric element 62, the orifice 52
The ink particles are ejected from the minute holes (nozzles). Since the ink in the ink vibrating chamber 42 is vibrated by the vibrating section 61 of the vibrating body 33, the ink jet flow from the nozzle becomes particles.

Since the vibrating portion 61 has a thin disk shape and is configured to hold the outer periphery of the vibrating portion 61, the center of the vibrating portion 61 is easily bent in the front-rear direction, and exhibits vibration swinging in the front-rear direction. It is. The vibration of the vibrating portion 61 is different from the complicated vibration which the rod-shaped body as the vibrating portion of the related art described above can swing back and forth and radially. For this reason,
It is considered that the excitation frequency-amplitude characteristic of the excitation unit 61 has an extremely small number of resonance points.

As described above, the nozzle main body 1 having a small resonance point of the vibrating section 61 is obtained. Therefore, the dimensions and assembly accuracy of the components constituting the nozzle main body can be improved, and the voltage applied to the piezoelectric element 62 and the ink vibrating can be improved. The adjustment of the ink pressure in the chamber 42 could be omitted, and the productivity was improved.

FIG. 4 shows an excitation frequency-amplitude characteristic of the excitation unit 61.

This characteristic diagram is obtained by measuring the center of the vibration section 61 facing the ink vibration chamber 42. The resonance point is shown in FIG.
In contrast to the conventional example (having a large number of resonance points) shown in (1), there is only one at a frequency of 110 kHz. The excitation frequency (70 kHz) for generating (operating) the ink particles is located sufficiently away from the resonance frequency. The amplitude is 0.1 μm. In addition, at the excitation frequency of the ink particle generation, the amplitude fluctuation with respect to the frequency change is small, so that even if the dimensions and assembly accuracy of the components constituting the nozzle body are reduced, the amplitude fluctuation hardly occurs, so that the print quality is not impaired. .

FIG. 5 shows an excitation frequency-amplitude characteristic on the nut 65 side provided in the vibrating body 33. Even when the vibrating body 33 is the same as the vibrating part 61, the vibration form is different at a place different from the vibrating part 61. It is. It is considered that the excitation frequency-amplitude characteristic with few resonance points can be obtained by using a thin disk-shaped excitation portion whose center is easily bent in the front-rear direction.

FIG. 3 shows the excitation frequency-amplitude characteristics of the vibrating section 61, and is an example in which the nozzle body is fixed with soft clay and the entire nozzle body is freely vibrated and measured. .

This is similar to the excitation frequency-amplitude characteristic of the excitation unit 61 shown in FIG. The resonance point is somewhat similar to that shown in FIG. 4 except that the resonance point moves somewhat to the lower frequency side, and the amplitude width is low and the drop point is found at two places of the high frequency and the low frequency.

There is no significant difference in the vibration of the vibrating portion 61 whether or not the outer periphery of the vibrating portion 61 is supported. Therefore, even if the clamping force for clamping the outer periphery of the vibrating portion 61 varies. It is unlikely that the vibration of the vibration unit 61 changes, and the print quality is not impaired.

Another embodiment shown in FIG. 7 will be described.

The features of this embodiment will be mainly described, and portions common to the previous embodiments will be assigned the same reference numerals and explanations thereof will be omitted.

The vibrating body 33 of the nozzle body 1 shown here
No constriction 65 is provided. The constriction 65 is not provided at the boundary between the vibration unit 61 and the support
A thin brim is formed on the outer periphery of the rim so as to expand around the rim. In this configuration, the outer diameter of the nozzle body 1 is larger than that in the configuration in which the constricted portion 65 is provided, but since the machining for forming a deeply constricted groove is not required, the vibrating body 33 is not required.
Is easy to make. Also, since there is no constricted portion 65, it is resistant to an impact load.

Another embodiment shown in FIG. 8 will be described.

The features of this embodiment will be mainly described, and portions common to the preceding embodiments will be denoted by the same reference numerals and description thereof will be omitted. In addition, dimensions have been added to main parts to grasp the size of the nozzle body 1.

The piezoelectric element 100 of this embodiment has a cylindrical shape. The vibrating part 60 of the vibrating body 33 has the support base 6 but does not have the support part 64. The end of the piezoelectric element 100 is fitted and attached to the support base 63. The ink supply pipe 35 is directly connected to the ink supply hole 43 of the ink flow path forming member 31. The illustration of the ink circulation tube 36 is omitted.

The total length L1 of the nozzle body ₁ is 21.2 mm,
Depth _{L 2} of the ink oscillating chamber 42 3.2 mm, exciting units 61
The thickness _{L 3} of is 0.5mm. At opposing the vibrating portion 61 and the ink flow path forming member 31, and a gap L ₄ which is formed in a range from the inner circumferential wall inside the cuff portion for the seal ring accommodating portion 72 is 0.05 mm. In other words, the range on the inner peripheral side of the vibrating portion seal ring 73 is
There is a slight gap between 1 and the ink flow path forming member 31.

The inner diameter _{D 1} of the vibrating body accommodating chamber 40 is 8 mm, the inner diameter _{D 2} of the constricted portion 65 2.5 mm, the outer diameter _{D 3} of the vibrating section 61 9 mm, of the vibrating portion for the seal ring accommodating portion 72 The peripheral wall diameter D ₄ is 5.8 mm, and the inner diameter D _{5 of the} ink vibrating chamber 42 is
Is 3.4 mm, inner diameter _{D 6} of the small communication hole 51 is 0.5 mm.

As described above, the vibrating section seal ring 73
And the nozzle seal ring 80 are for suppressing ink leakage from the iron joint portion.
A gap L ₄ (0.05 mm) is positively provided between the vibrating section 61 and the ink flow path forming member 31. A gap is provided so that the vibrating section 61 effectively functions as a diaphragm.

The vibrating portion 61 oscillates back and forth like a diaphragm with the sandwiched outer peripheral portion 68 as a fulcrum. The vibrating section 6 in which the vibrating section seal ring 73 vibrates even where the vibrating section seal ring 73 is in contact with the vibrating section seal ring 73.
Since the vibration is 1, no ink leakage occurs. Gap L ₄
In order to utilize the function of the vibrating section 61 as a diaphragm without providing (0.05 mm), the inner diameter of the ink vibrating chamber 42 and the outer diameter of the vibrating section 61 must be increased. The clearance L ₄ (0.
(05 mm).

The dimensions of the respective parts described above are for one embodiment, and the present invention is not limited to the dimensions alone.

[0053]

As described above, according to the present invention, it is possible to provide a product having a small resonance point and good productivity.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a nozzle body according to an embodiment of the present invention.

FIG. 2 is a schematic system diagram of an inkjet recording apparatus according to an embodiment of the present invention.

FIG. 3 is a diagram showing an excitation frequency-amplitude characteristic measured in a free state of a nozzle body according to an embodiment of the present invention.

FIG. 4 is a diagram showing an excitation frequency-amplitude characteristic of a vibrating portion of a nozzle body measured according to an embodiment of the present invention.

FIG. 5 is a diagram showing an excitation frequency-amplitude characteristic measured on a nut side of a nozzle body according to an embodiment of the present invention.

FIG. 6 is a diagram showing an excitation frequency-amplitude characteristic obtained by measuring a vibration part of a nozzle body according to a conventional example.

FIG. 7 is a longitudinal sectional view of a nozzle body according to another embodiment of the present invention.

FIG. 8 is a longitudinal sectional view of a nozzle body according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Nozzle main body, 2 ... Charging electrode, 3 ... Deflection electrode, 33 ...
Vibrating body, 60: vibrating section, 61: vibrating section.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Seiji Fujikura 1-1-1, Higashitaga-cho, Hitachi City, Ibaraki Prefecture Inside Hitachi Taga Electronics Co., Ltd. No. 1 F-term in Hitachi Taga Electronics Co., Ltd. (reference) 2C057 AF23 AG17 AG44 BF06

Claims (4)

[Claims] A nozzle body for generating ink particles by applying vibration to ink ejected from a nozzle, a charging electrode for charging the ink particles, and a deflecting electrode for deflecting the charged ink particles; The nozzle body has a vibrating body, and the vibrating body is an ink jet recording apparatus having a vibrating unit having a vibrating element and a vibrating unit for applying vibration to ejected ink, wherein the vibrating unit is formed in a thin plate shape. An ink jet recording apparatus comprising: A nozzle body for generating ink particles by applying vibration to ink ejected from the nozzle, a charging electrode for charging the ink particles, and a deflecting electrode for deflecting the charged ink particles; The nozzle body has a vibrating body, wherein the vibrating body is an ink jet recording apparatus in which a vibrating unit having a vibrating element and a vibrating unit that applies vibration to ejected ink are integrally formed, wherein the vibrating unit is An ink jet recording apparatus having a thin brim shape extending around. 3. A nozzle body for generating ink particles by applying vibration to ink ejected from a nozzle, a charging electrode for charging the ink particles, and a deflecting electrode for deflecting the charged ink particles, The nozzle body has a vibrating body, wherein the vibrating body is an ink jet recording apparatus in which a vibrating part having a vibrating element and a vibrating part for applying vibration to ejected ink are integrally formed, wherein the vibrating part and the vibrating part An ink jet recording apparatus, characterized in that a constriction for reducing the diameter of a boundary portion of the vibrating portion is provided, and the vibrating portion is formed in a thin plate shape. 4. An ink jet recording apparatus according to claim 1, wherein an outer periphery of said vibrating portion is a vibration fulcrum.