JPS6343229B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention jets pressurized ink from a nozzle of an ink jetting head, charges the jetted ink with a charging electrode, and charges the charged ink particles with an electric field between deflection electrodes. The present invention relates to an inkjet recording device that deflects inkjet.

[Conventional technology]

In this type of inkjet recording device,
The ink ejecting head is equipped with an excitation means such as a cylindrical electrostrictive vibrator, which applies pressure vibrations of a constant frequency to the pressurized ink supplied to the head, and vibrations of a constant frequency are applied to the pressurized ink supplied to the head. The ink is ejected and is regularly separated into fine ink particles at a predetermined distance from the nozzle. A charging electrode is disposed at this separation position, and the ink particles are charged by applying a voltage pulse (charging pulse) between the ink of the head and the charging electrode at a predetermined timing with the ink droplet separation phase.

While the charged ink particles pass between a pair of opposing deflection electrodes, they are deflected by the deflection electric field between them, while the uncharged ink particles travel straight. The deflected or straight ink particles collide with the recording paper, and the straight or deflected ink particles are captured by the gutter.

[Problem to be solved by the invention]

One of the problems with this type of inkjet recording device
Among these problems are ink stains on the face plate and charging electrode of the ink ejecting head, and leaks and short circuits between the two due to the dirty ink. Ink stains are most severe immediately after ink jetting starts. The reason for this is that as the ink pressure in the head increases, the ink flight trajectory gradually extends until it reaches the gutter, but because the ink flight trajectory is short, the ink falls onto the charging electrode, head base, deflection electrode, etc. This is because residual air in the head is ejected from the nozzle together with the ink as pressurized ink is supplied to the head, and at this time, ink may be splashed at the nozzle outlet. Therefore, when a steady state of ink jetting is reached, the charging electrode may be dirty or there may be a leak between the charging electrode and the head, making it impossible to perform normal recording.

Further, even during recording, the charging electrodes and deflection electrodes may be contaminated by ink mist. However, since the distance between the nozzle plate and the charging electrode is short, and the gap between the deflection electrodes is also narrow, cleaning them is difficult, and the cleaning operation is laborious and time-consuming.

The first object of the present invention is to prevent the charging electrode from becoming dirty at the start of ink ejection, and the second object is to provide an inkjet recording apparatus in which the ink ejection head, charging electrode, and deflection electrode can be easily cleaned. It is to provide. A third object of the present invention is to provide an inkjet recording apparatus that eliminates scattered ink around the head immediately before recording starts.

[Structure of the invention]

(Means for solving the problem) In the present invention, the first support and the second support are
The former is pivotally connected to the latter in openable and closable relation, and the first support is provided with an ink ejection head, and the second support is provided with a charging electrode (first point). And the second
A suction pump is connected to the support of the first and second
An air intake port is connected to at least one surface of the second support that is stained with ink, and when the second support is opened or closed, a suction pump is driven in conjunction with the opening and closing of the second support to draw air around the head from the air intake port. It is designed to be inhaled (second point).

(Function) According to the first point, the second support can be opened with respect to the first support before ink jetting starts. In this open state, the charging electrode is separated from the ink ejection head and the ink ejected therefrom, preventing contamination of the charging electrode at the beginning of ink ejection. After the ink is flowing straight into the gutter and the ink splash has subsided, the support is closed and the charging electrode is positioned to surround the ink stream. Cleaning around the ink ejecting head can be easily performed with the second support in an open state.

Furthermore, according to the second point above, if there is ink around the suction port before closing the second support, this ink is sucked into the suction port together with the suction air, and the dirty ink around the head is removed.

In a preferred embodiment of the invention, one of the deflection electrodes is fixed to the first support and the other to the second support, in order to also simplify the cleaning of the deflection electrodes.
According to this, when the second support body is open to the first support body, the deflection electrodes are similarly opened, and cleaning of the deflection electrodes is easy. When the second support is closed relative to the first support, the deflection electrodes are opposed to each other with a narrow ink passage space between them.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

(Embodiment) FIG. 1 shows a side view of an embodiment of the present invention. 1st
In the figure, 1 is a head base which is a first support, and 2 is a head cover which is a second support. The head cover 2 has a shaft pin 1 fixed to it.
3, which is pivotally connected to the head base 1. Note that FIG. 1 shows a state in which the head cover 2 is closed with respect to the head base 1 (setting at the time of recording).

FIG. 2 shows an exploded perspective view with the shaft pin 13 removed from the head cover 2 and the head cover 2 turned over.

The configuration of this embodiment will be explained below with reference to FIGS. 1 and 2. A first adjustment table 5 is rotatably attached to the head base 1 with a shaft pin 4. 5, a long elongated hole 5a is formed along the straight line connecting it and the pin 4, and the elongated hole 5a
An eccentric pin 6 having a head having a diameter slightly smaller than the short axis of the head is inserted into the elongated hole 5a, and the eccentric leg of the eccentric pin 6 is pivotally connected to the head base 1. By rotating the eccentric pin 6, the first adjustment table 5 is rotated clockwise or counterclockwise about the shaft pin 4.

The first adjustment table 5 has a dogleg shape, and a second adjustment table 8 is pivotally attached to the vertical wall of the first adjustment table 5 with a shaft pin 7, and an ink jet head 9 is attached to the second adjustment table 8. It is fixed. A leaf spring 10 is interposed between the first adjustment table 5 and the second adjustment table 8, and this leaf spring 10 applies a clockwise rotational force to the second adjustment table 8. The second adjustment table 8 rotates counterclockwise, and by loosening the screw 11, the adjustment table 8 rotates clockwise.

The first electrode is connected to the head base 1 via the electrode stand ₁₂₁ .
A deflection electrode 13 ₁ is fixed thereto, and a gutter 14 is directly fixed thereon.

A second deflection electrode 13 2 is fixed to the head cover 2 at a position opposite to the first deflection electrode 13 ₁ via an electrode stand 12 ₂ , and between the tip of the ink ejecting head 9 and the deflection electrode 13 _{1 .} Electrode stand 14 in the upper position
is fixed, and a U-shaped charging electrode 15 and a charging detection electrode 16 are joined to this electrode stand 14.
17 ₁ and 17 ₂ are spacers for positioning charging electrodes, 18 is a limit switch for opening and closing the power supply, 19
is a windshield.

With the above configuration, when the shaft pin 13 is pivotally connected to the head base ₁ and fixed to the head cover 2, and the cover ₂ is in the closed state as shown in FIG. The deflection electrodes 13 ₁ and 13 ₂ are parallel to each other, and the charging electrode 15 and the charging detection electrode 16 are positioned to surround the ink flow axis 20 above and to the sides with the ink flow axis 20 at the center.

Before ink jetting and during cleaning, the cover 2 is preferably rotated clockwise by approximately 90° to 120° to open the cover 2 with respect to the head 1. When pressurized ink is ejected from the ink ejection head 9 and the ink flow reaches the gutter 14, the cover 2 is closed as shown in FIG. When cleaning, with the cover 2 open, clean the tip of the head 9, the top of the head base,
Clean the top surface of the first deflection electrode 13 ₁ , etc., and then clean the bottom surface of the cover 2, the U-shaped inner surfaces of the electrodes 15 and 16, the bottom surface of the second deflection electrode 13 ₂ , the inner surface of the windshield 19, etc.
Clean. These operations are extremely easy since the cover 2 is open.

Note that the limit switch 18 is provided for safety, and opens when the cover 2 is opened to cut off the charging voltage power source and the deflection voltage power source.

Next, as the head cover 2, which is the second support, is closed, the air around the head 9 is transferred to the intake port 21.
₁ , 21, ₂ , etc. will be explained.

A plurality of intake ports 21 ₁ , 21 ₂ , . . . are opened in the head base 1, which is the first support.
On the back side of the base 1, they are connected to a common channel plate 22.
It communicates with the common flow path 22a. Common flow path 22
a is connected to tube 30 ₁ , and tube 3
A tube 30 ₂ is connected to the air cylinder 0 ₁ via a check valve device 23 and a filter 24 , and the tube 30 ₂ communicates with an air cylinder 25 .
A piston 26 is inserted into the air cylinder 25, and a rack 28 is fixed to a piston rod 27 fixed to the piston 26. A pinion gear 29 fixed to the shaft pin 13 fixed to the head cover 2 is engaged with the rack 28.

With the above configuration, when the head cover 2 is rotated clockwise from the closed state shown in FIG. Piston 26 moves to the left. At this time, high pressure is applied to the tube 30 ₂ and the filter 24, but
In the check valve device 23, the ball valve 23a does not close its lower opening, so air flows into the pipe 23b.
At this time, the ink in the filter 24 and the check valve device 23 is discharged into the pipe 23b. Only a small amount of air escapes to the upper surface of the head base 1 through the suction ports 21 ₁ , 21 ₂ , etc.

When the head cover 2 is closed from the open state to the closed state shown in FIG. 1, the rack 28 is driven to the right, the piston 26 is moved to the right, and the cylinder 2
The left ventricle of No. 5 becomes negative pressure, and negative pressure (suction pressure) is applied to the tubes 30 ₂ , 30 ₁ , filter 24 and check valve device 23 . This negative pressure causes the ball valve 23a to
rises and closes the side outlet above it. As a result, the negative pressure of the cylinder 25 is directly transferred to the intake port 21 ₁ ,
In addition to the air inlets 21 ₂ and the like, air around the openings such as the intake ports 21 ₁ and 21 ₂ on the upper surface of the head base 1 is sucked in. At this time, if there is ink around them, it is also sucked in.

The intake ports 21 ₁ , 21 ₂ etc. are as shown in FIG.
They are distributed from just below the tip of the head 9 to the deflection electrode ₁₂₁ , and even if ink beads form on the surface of the first support when ink jetting starts, they will be sucked up to the filter 24 when the head cover 2 is closed. ,
No large ink beads remain on the upper surface of the head base 1. Therefore, during recording the deflection electrode 13 ₁ ,
The possibility that the charging electrode 15 and the charging detection electrode 16 will leak or short circuit is extremely reduced.

The check valve device 23 is connected to the air cylinder 25 as shown in FIG _.
If a check valve 31 is connected to the open end of the cylinder and only negative pressure is applied to the tube 30 ₂ (integrated with 30 ₁ ), when the head cover 2 is opened, the intake ports 21 ₁ and 21 ₂ No positive pressure is applied to the air inlets 21 ₁ , 21 _{2 ,} etc., and even if ink flows into the intake ports 21 1 , 21 2 , etc., the ink is not blown out temporarily, which is more preferable in terms of removing dirt from the upper surface of the head base 1.

〔Effect of the invention〕

As described above, according to the present invention, since the second support 2 can be opened and the charging electrode 15 can be retracted at the start of ink jetting, the charging electrode 15 due to ink splash can be removed.
In addition, the ink on the surface of the support between the nozzle and the deflection electrode ₁₂₁ is automatically removed through the air intake port before recording starts, and the cleaning operation is easy. No more ink beads left behind.

[Brief explanation of the drawing]

Figure 1 is a side view showing one embodiment of the present invention, Figure 2 is a side view showing one embodiment of the present invention;
The figure is an exploded perspective view. FIG. 3 is an enlarged sectional view showing a modified portion of another embodiment of the present invention.
1: Head base (first support body), 2: Head cover (second support body), 3, 4, 7: Axis pin,
5, 8: Adjustment stand, 6: Eccentric pin, 9: Ink jet head, 10: Leaf spring, 11: Adjustment screw, 12 ₁ ,
12 ₂ , 14: Electrode stand, 13: Axial pin (axis parallel to the axis perpendicular to the ink jetting direction), 13 ₁ , 13
₂ : Deflection electrode, 15: Charge electrode, 16: Charge detection electrode, 17 ₁ , 17 ₂ : Spacer, 18: Limit switch, 19: Windshield, 20: Ink flow axis, 21
₁ , 21 ₂ , ...: Intake port, 22: Common flow path plate, 22
a: common flow path, 23: check valve device, 24: filter, 25: air cylinder (suction pump),
26: Piston, 27: Piston rod, 28:
Rack, 29: Pinion gear, 30 ₁ , 30 ₂ : Tube, 31: Check valve.

Claims (1)

[Scope of Claims] 1. In an inkjet recording device comprising an inkjet head, a charging electrode that charges ink particles jetted from the inkjet head, and a deflection electrode that applies a deflection electric field to the charged ink particles: supporting the inkjet head; a first support that supports the charging electrode and is pivotally connected to the first support, and the space between the first support and the closed position is narrow and the space between the first support and the first support is wide; a second support that rotates between open positions; an air intake port provided on a surface of the support that faces the ink ejected by the ink ejection head; a suction pump for applying suction pressure to the air intake port; An inkjet recording apparatus comprising: a pump driving means for driving the suction pump to generate the suction pressure in conjunction with rotation of the second support from the open position to the closed position. 2. The second support is pivotally connected to the first support about an axis parallel to an axis perpendicular to the ink ejection direction of the ink ejection head. The inkjet recording device described above. 3 one of the deflection electrodes is attached to the first support;
The other is an inkjet recording device according to claim 1 or 2, which is mounted on a second support.