JPH0679850B2 - Nozzle clogging prevention device for ink jet recording device - Google Patents

Description

The present invention relates to a nozzle clogging prevention device in an ink jet recording apparatus.

[Conventional technology]

For example, in a charge control type ink jet recording apparatus, at the tip of the nozzle that ejects the ink flow, that is, at the orifice portion, when ink is in contact with the outside air during non-recording and drying occurs, a precipitate such as a dye is formed, and when this solidifies, the recording At times, the ejection direction of the ink is disturbed, and further, the orifice is completely closed, resulting in a state where ejection is impossible.

Therefore, in order to deal with such nozzle clogging at the time of non-recording, conventionally, a means for preventing clogging by immersing the orifice portion of the nozzle in a liquid containing water or a detergent has been proposed. .

[Problems to be solved by the invention]

However, in the above-mentioned means, the liquid containing the water or the detergent, the container having the opening for containing the liquid, the drive source for moving the nozzle portion to the installation position of the container, and the moving mechanism. Because parts etc. are necessary,
There is a problem that the configuration is complicated and expensive, and that management is time-consuming, such as the need to detect the remaining amount of liquid.

Further, in an ink jet recording apparatus in which a charging electrode is arranged at a position near the front of the nozzle and ink droplets ejected from the nozzle are charged to perform recording, the distance between the nozzle and the charging electrode is narrow. It is not possible to bring the container accommodating the nozzles close to the tip of the nozzle. Therefore, there is a demand for a nozzle clogging prevention device that can be applied to such an ink jet recording apparatus.

The present invention has been made to solve such a problem, and can prevent nozzle clogging in an ink jet recording apparatus in which a charging electrode is arranged at a position near the front of the nozzle, and has a simple structure and is inexpensive. It is also an object of the present invention to realize a nozzle clogging prevention device in an inkjet recording apparatus that is easy to manage.

[Means for solving problems]

To achieve this object, the present invention mounts a nozzle and a charging electrode arranged in front of the nozzle on a nozzle holder,
In a nozzle clogging prevention device in an ink jet recording apparatus that performs recording by charging an ink droplet that contributes to recording among ink droplets ejected from the nozzle, the nozzle is positioned in front of the nozzle. An ink passage hole provided in the holder, in which the charging electrode is arranged, a water absorbing material attached to a lower portion of the nozzle holder, the ink passage hole and the water absorbing material on the front side of the charging electrode. An ink introduction hole provided in the nozzle holder so as to tie, a connection hole provided in the nozzle holder so as to tie the ink passage hole and the water absorbing material on the rear side of the charging electrode, and one end A shutter provided on the nozzle holder so as to be vertically movable so as to be located on the front side of the nozzle holder, and a flexible member attached to one end of the shutter. A non-absorbent material and a shutter drive means, wherein the shutter drive means pushes down the shutter during non-recording of the inkjet recording apparatus to seal the front end of the ink passage hole with the flexible non-absorbent material, and Ink is ejected from a nozzle, the ink is guided to the water-absorbent material through the ink introduction hole, and water that evaporates from the water-absorbent material containing ink is connected between the nozzle and the charging electrode by the connection hole. It is characterized in that the ink is guided to the passage hole and the inside of the ink passage hole is kept in a high humidity atmosphere.

[Action]

According to the present invention having such a configuration, the shutter driving means pushes down the shutter to seal the front end of the ink passage hole with the flexible non-absorbing material while the ink jet recording apparatus is not recording, and the ink is ejected from the nozzle. Then, the ink is guided to the water absorbing material through the ink introducing hole, and the water evaporated from the water absorbing material containing the ink is guided to the ink passing hole between the nozzle and the charging electrode through the connecting hole to pass the ink. Since the inside of the hole is kept in a high-humidity atmosphere, it is possible to reliably prevent clogging of the nozzle in the inkjet recording apparatus in which the charging electrode is arranged at a position near the front of the nozzle.

〔Example〕

 Embodiments will be described below with reference to the drawings.

FIG. 2 is a perspective view showing a general structure of a head portion and its vicinity of a charge control type ink jet recording apparatus to which the present invention is applied. In FIG. 2, reference numeral 1 is an ink supply including an ink pressurizing pump and a solenoid valve described later. An apparatus 2 is a nozzle connected to the ink supply apparatus 1, 3 is an orifice of the nozzle 2,
Reference numeral 4 is a piezoelectric vibrator attached to the outer peripheral portion of the nozzle 2, 5 is a charging electrode, and the charging electrode 5 and the piezoelectric vibrator 4 are provided.
The nozzle 2 to which is attached is integrated by the nozzle holder inner 6 and is mounted and held in the nozzle holder 7. 8a and
8b is a pair of deflection electrodes, 9 is a gutter, and 10 is a recording medium.

In this configuration, the ink supply device 1 supplies the ink pressurized to a constant pressure to the nozzle 2 and ejects the ink flow 35 from the orifice 3 of the nozzle 2, at which time the piezoelectric vibrator 4 is ejected.
Oscillates the nozzle 2, which causes the ink stream 35 to regularly break up into droplets to form an ink droplet array.

Therefore, when the charging electrode 5 is arranged at the position where the ink droplet is split and a voltage is applied to the charging electrode 5 when splitting, the ink droplet is charged by electrostatic induction. The ink droplets are selectively charged according to recording information, and only the ink droplets that contribute to recording are charged, and the ink droplets that do not contribute to recording are not charged.

After that, these ink droplets reach between the deflection electrodes 8a and 8b, and the ink droplets charged here are deflected according to the charge amount, and collide with a desired position of the recording medium 10 to perform recording. On the other hand, the uncharged unnecessary ink droplets are not deflected and are collected by the gutter 9 immediately after passing between the deflection electrodes 8a and 8b. The collected ink droplets are returned to the ink supply device 1 by means not shown and used again.

The head part of the device is composed of 2-9 parts,
These are mounted on a carriage (not shown) that reciprocates parallel to the surface of the recording medium 10 in the horizontal direction, and the recording operation described above is performed along with the movement of the carriage.

FIG. 1 is a side sectional view showing a nozzle clogging prevention device according to the present invention. FIG. 1 (a) shows a recording state and FIG. 1 (b) shows a non-recording state.

In the figure, 11 is an ink passage hole provided in the nozzle holder 7 so as to be located in front of the nozzle 2, 12 is a water absorbing material attached to the lower part of the nozzle holder 7 by a cap 13, and 14 is an ink passage. An ink introducing hole is provided between the front end of the hole 11 and the water absorbing material 12, and a reference numeral 15 is a connecting hole provided between the rear end of the ink passing hole 11 and the water absorbing material 12.

Reference numeral 16 denotes a L-shaped shutter which is vertically movable on the nozzle holder 7. One end of the shutter 16 located on the front side of the nozzle holder 7 is provided with a slope 17 facing the orifice 3. A flexible non-absorbent material 18 is attached. A compression spring 19 is provided between the shutter 16 and the nozzle holder 7, and always biases the shutter 16 in a direction to push it up.

Reference numeral 20 denotes a shutter lever for operating the shutter 16, one end of which is rotatably supported by a frame (not shown) and is rotatable about the shaft 21. Reference numeral 22 is a shutter drive solenoid connected to the other end of the shutter lever 20, and this shutter drive solenoid 22 is also fixed to a frame (not shown), and 23 is the shutter lever 20.
The return spring 23 is provided between the frame (not shown) and the shutter lever 20.

In addition, this shutter lever 20 and solenoid for driving the shutter
The return spring 22 and the return spring 23 form a shutter drive means, and are provided in the home position of a carriage having a head portion.

FIG. 3 is a circuit block diagram of the present invention.
24 is a dual device power switch, 25 is a power supply, 26 is a relay,
27 is a timer, 28 is a control circuit unit, one circuit of the device power switch 24 is connected to the input of the timer 27 and the control circuit unit 28, the output of the timer 27 to the relay 26 provided in the preceding stage of the power supply 25. It is connected.

Further, the output of the home position sensor 29 is connected to the control circuit unit 28, and from this control circuit unit 28, a spacing motor drive circuit 30, a spacing motor 31, a shutter drive solenoid drive circuit 32, and a shutter drive circuit. The solenoid 22, the ink pump solenoid valve drive circuit 33, and the ink pump solenoid valve 34 are connected to each other.

Next, the operation of this embodiment will be described based on the time chart shown in FIG.

First, when the device power switch 24 is turned on, that is, when recording by the ink jet recording device, the relay 26 is held in conjunction with the device power switch 24, and the current is supplied to the power supply 25 by the two paths of the relay 26 and the device power switch 24. However, when the device power switch 24 is turned off after the end of recording, the signal is applied to the control circuit section 28, and then the spacing motor drive circuit 30 operates by the command signal from this control circuit section 28 to operate the spacing motor. 31 is driven.

The spacing motor 31 is connected to a carriage (not shown) having the above-described head portion through a connecting member such as a wire (not shown), and the spacing motor 31 drives the carriage to move to the home position. When the return operation is started and the home position is returned to, it is detected by the home position sensor 29. Then, the driving of the spacing motor 31 is stopped, and the carriage stops at the home position.

Here, the shutter drive solenoid drive circuit 32 is triggered by the detection of the home position sensor 29 to excite the shutter drive solenoid 22 shown in FIG. The other end of the shutter lever 20 is pulled down. This causes the shutter lever 20 to rotate downward about the shaft 21,
Push down the shutter 16 as shown in FIG. 1 (b). When the shutter 16 is pushed down in this way, the tip of the ink passage hole 11 of the nozzle holder 7 is sealed by the flexible non-absorbent material 18 provided on the shutter 16.

The position of the shutter at this time is the solenoid for driving the shutter.
It can be held by continuing the excitation of 22, but it may be held by providing another holding mechanism.

On the other hand, as shown in FIG. 4, the shutter drive solenoid 22
When the solenoid suction time t ₁ has elapsed, the ink pump solenoid valve drive circuit 33 is actuated by a signal from the control circuit section 28 and the ink pump solenoid valve included in the ink supply device 1 shown in FIG. The valve 34 is opened for the time t ₂ shown in FIG. 4, ink is supplied to the nozzle 2 and the ink flow 35 is ejected from the orifice 3. At this time, even if the ink pressurizing pump of the ink supply device 1 is not operated, by operating only the ink pump electromagnetic valve 34, it is possible to eject a required amount of ink described later by the effect of accumulating ink.

The operation time so far is secured by the timer 27 shown in FIG. 3, the relay 26 is held, and the power supply 25 is supplied with a current of AC100V.

After the elapse of the time set by the timer 27, the holding of the relay 26 is released, the supply of the AC 100V current to the power source 25 is cut off, and the ejection of the ink flow 35 is stopped.

The relay 26 can be implemented in the same manner even if it is replaced with a power control element made of a semiconductor such as a thyristor.

Now, as described above, the ink flow 35 ejected from the orifice 3 of the nozzle 2 collides with the slope 17 provided on the flexible non-absorbent material 18 which seals the ink passage hole 11 shown in FIG. 1 (b). Then, it falls into the ink introduction hole 14 with almost no bounce in the direction of the charging electrode 5, and is absorbed by the water absorbing material 12 held by the cap 13 under the nozzle holder 7 through the ink introduction hole 14. .

The ink ejection amount at this time is determined by the ejection time t ₂ , but is set to an amount sufficient to moisten the water absorbent material 12 in advance.

By moistening the water-absorbent material 12 with the ink in this manner, the water-absorbent material 12 evaporates from the orifice 3 to the flexible non-absorbent material 18 through the ink introduction hole 14 and the connection hole 15. The generated moisture is supplied, and the ink passage hole 11 between the nozzle 2 and the charging electrode 5 is maintained in a high humidity atmosphere by this, so that the ink does not dry on the orifice 3 of the nozzle 2 during non-recording, The clogging of 3 can be prevented.

When resuming recording, the excitation of the shutter drive solenoid 22 is stopped. As a result, the shutter lever 20 is rotated upward about the shaft 21 by the restoring force of the return spring 23 to return to the original position, and the pushing force to the shutter 16 is released, so that the shutter 16 also compresses the compression spring 19. It returns to its original position due to the restoring force. Consequently, the ink passage hole 11 is released from the hermetically closed state, and the recording operation shown in FIG.

A flexible non-absorbent material 18 attached to the shutter 16
As a material of the above, a highly elastic polymer having a small permanent set, which is obtained by coating or adhering a hydrophobic polymer Teflon or the like on the nozzle 2 side, is most suitable.

Further, in the above-described embodiment, since it is possible to increase the evaporation amount of water by heating the water-absorbing material 12, for example, a heater is provided in the vicinity of the water-absorbing material 12, and this heater is provided before shutting off the power supply 25. It may be energized to generate heat, or a heater may be energized by a battery to generate heat.

Although the above-described embodiment is applied to the head portion having one nozzle 2, it is also applicable to the head portion having a plurality of nozzles such as a color ink jet printer.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY As described above, the present invention provides an ink passage hole provided in a nozzle holder so as to be positioned in front of a nozzle, in which a charging electrode is arranged, a water absorbing material attached to a lower portion of the nozzle holder, and An ink introduction hole provided in the nozzle holder so as to connect the ink passage hole and the water absorbing material on the front side of the charging electrode, and the ink passage hole and the water absorbing material on the rear side of the charging electrode. Connecting hole provided in the nozzle holder so as to connect the shutter, a shutter vertically movable on the nozzle holder so that one end thereof is located on the front surface side of the nozzle holder, and attached to one end of the shutter. A flexible non-absorbing material and a shutter driving means are provided, and the shutter driving means pushes down the shutter when the ink jet recording apparatus is not recording, and the flexible structure is provided. While sealing the front end of the ink passage hole with a non-absorbing material, ejecting ink from the nozzle, guiding the ink to the water absorbing material through the ink introducing hole, moisture evaporated from the water absorbing material containing ink Is guided to the ink passage hole between the nozzle and the charging electrode by the connection hole, and the inside of the ink passage hole is kept in a high humidity atmosphere.

Therefore, according to this, the effect that the nozzle clogging can be surely prevented in the ink jet recording apparatus in which the charging electrode is arranged in the near position in front of the nozzle is obtained, and the water and the detergent are contained as in the conventional case. As compared with the clogging prevention means using the liquid, the structure can be simplified and the effect that the manufacturing can be performed at low cost can be obtained.

Further, in the present invention, since the ink used for recording is used to prevent clogging, there is an effect that it is not necessary to detect the remaining amount of the liquid and the like as in the conventional case, and the management becomes easy.

[Brief description of drawings]

FIG. 1 is a sectional view of a nozzle clogging prevention device according to the present invention, in which FIG. 1 (a) shows a state during recording and FIG. 1 (b) shows a state during non-recording. 2 is a perspective view showing a general structure of a head portion and its vicinity of an ink jet recording apparatus to which the present invention is applied, FIG. 3 is a circuit block diagram of the embodiment shown in FIG. 1, and FIG. It is a time chart to explain. 1 ... Ink supply device, 2 ... Nozzle, 3 ... Orifice, 4 ... Piezoelectric vibrator, 5 ... Charging electrode, 6 ... Nozzle holder inner, 7 ... Nozzle holder, 11 ... Ink passage hole, 12 ... Water-absorbent material, 14 ... Ink introduction hole, 15 ... Connection hole, 16 ... Shutter, 17 ... Slope, 18 ... Flexible non-absorbent material, 20 ... Shatter lever, 22 ... Shutter drive Solenoid, 24 …… Device power switch, 25 …… Power supply, 27
...... Timer, 28 ...... Control circuit, 34 ...... Ink pump solenoid valve

Continuation of the front page (56) Reference JP-A-57-22064 (JP, A) Actually open 51-80032 (JP, U) Actually open 57-204144 (JP, U)

Claims (1)

[Claims] 1. A nozzle and a charging electrode arranged in front of the nozzle are mounted on a nozzle holder, and among the ink droplets ejected from the nozzle, ink droplets contributing to recording are charged by the charging electrode to perform recording. In a nozzle clogging prevention device for an inkjet recording device, an ink passage hole is provided in the nozzle holder so as to be positioned in front of the nozzle, and the charging electrode is disposed in the middle, and the ink passage hole is attached to a lower portion of the nozzle holder. A water absorbing material, an ink introducing hole provided in the nozzle holder so as to connect the ink passing hole and the water absorbing material on the front side of the charging electrode, and the ink passing hole on the rear side of the charging electrode. A connecting hole provided in the nozzle holder so as to connect the hole and the water-absorbing material, and the nozzle so that one end is located on the front side of the nozzle holder. And a flexible non-absorbing material attached to one end of the shutter, and a shutter drive means. The shutter drive means causes the shutter to operate when the inkjet recording apparatus is not recording. By pressing down to seal the front end of the ink passage hole with the flexible non-absorbent material, eject the ink from the nozzle, guide the ink to the water absorbing material through the ink introduction hole, and contain the ink. In the ink jet recording apparatus, the water vaporized from the water absorbent material is guided to the ink passage hole between the nozzle and the charging electrode by the connection hole to maintain a high humidity atmosphere in the ink passage hole. Nozzle clogging prevention device.