JPS58179658A - Ink drop jet apparatus - Google Patents

Abstract

PURPOSE:To obtain an apparatus capable of being quickly ready for use by a construction wherein a communicating hole is made, separately from an orifice, in a partition between an ink reservoir and a ventilating chamber in order to recover almost the whole ink filled up in the ventilating chamber. CONSTITUTION:A communicating hole 13e slightly larger than an orifice 13a is formed at the position close to the periphery of a front board 13b separating an ink reservoir 13 from a ventilating chamber 14. When printing is started after a jet apparatus is unused, a switch valve 17 is operated to let a container 15a of an ink cartridge 15 communicate with the ventilating chamber 14 and allow the ink in the ventilating chamber 14 to be absorbed in the ink reservoir 13 through each of the communicating hole 13e by means of a head formed of a bag 15b and an ink jet head 1. The ink is thus recovered in the bag 15b.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ink jetting device for an inkjet printer that records patterns such as letters and figures using ink droplets.

Inkjet printers are non-impact type printers with excellent features such as low noise generation, the ability to use plain paper as a recording medium, and the ability to easily print in color. Currently, there are charge control type, electric field control type, ink mist type, and on-demand type that have been put into practical use, but colorization is extremely easy, and shading can be expressed by changing the particle size of the ink droplets. On-demand inkjet printers have been widely adopted because they have advantages such as the ability to Generally, this type of on-demand inkjet printer includes an ink reservoir with an orifice, and a ventilation chamber separated by a wall where the orifice opens, and an opening in the wall of the ventilation chamber facing the orifice. There is a so-called air flow type in which pressurized air is ejected from the orifice toward the recording paper side, and the ink droplets ejected from the orifice are sprayed onto the recording paper by an air flow from the ejection hole. However, in the case of this air flow type, the orifice opens into the air, so when the ink ejecting head is not in use, the ink moisture in the ink reservoir evaporates through the orifice, and the ink components dry and stick to the periphery of the orifice, causing the orifice to become closed. Sometimes,
When the volume of ink decreases due to evaporation of ink moisture, air is sucked into the ink pool circle, causing poor propagation of pressure waves from the diaphragm for driving ink jetting to the ink, resulting in poor ink jetting. was there.

As a means to eliminate such drawbacks, for example, when the ink jet head is not in use, the blowhole of the ventilation chamber is closed and ink is introduced from the tank into the ventilation chamber 1~, and the ventilation chamber is filled with ink. The structure maintains the entire orifice of the ink reservoir immersed in ink, prevents ink moisture from evaporating around the orifice, and eliminates clogging of the orifice and air suction into the ink reservoir. A method has already been proposed by the present applicant (Japanese Patent Application No. 112'72'i' Sho 56).

FIG. 5 is a schematic cross-sectional view showing the on-demand type and air flow type ink lh injection device in use according to the applicant's previous application, and FIG. 5 is a schematic cross-sectional view showing an ink ejecting head 50, a rotating drum 60, and 61 recording sheets wound around the rotating drum 60. Ink 1! # is connected to the head main body 51 which has a thick disc shape, and the rear side is closed by a diaphragm 52a, and the front side is closed by a diaphragm plate 52c equipped with micro holes 521 for pressure regulation. The exposed pressure chamber 52, the ink reservoir 53 formed over the outer periphery and the front of the pressure chamber 52, and the ink reservoir 53 closed by the front plate 53b having an orifice 53a on the front side, and the outer periphery and the front of the ink reservoir 53. The n1 blood 1111 formed across the fumarole 5 is located at a position facing the orifice 53a.
4a and a ventilation chamber 54 closed by a cover plate 54b. The pressure chamber 52 is filled with ink, and the ink reservoir 53 is connected to the communication path 53C1, the ink tube 53d, and the filter 53e (via the bag body 55a containing ink in the ink cartridge 55). The ink supplied from the bag body 55a is further absorbed by the ink supplied from the bag body 55a, and the ventilation chamber 54 also has a communication path 54C.

Air tube 54cl and switching valve 5 interposed in the middle
It is connected to an air pump 56 through a 4θ hole, and pressure air from the air pump 56 is introduced. Note that the air pump 56 is separately connected to a housing 55 that houses the bag body 55a of the ink cartridge 55.
b, and the air pump 56 supplies pressurized air to the housing 5.
5b to apply pressure to the ink in the bag 55a corresponding to the water head between the bag 55a and the orifice 53a. Now, when an electric signal is applied to the diaphragm 52a, the vibration of the diaphragm 52a is propagated to the diaphragm plate 52c using the ink in the pressure chamber 52 as a pressure propagation medium, and the vibration of the diaphragm plate 52c is transmitted to the ink reservoir 53. The ink is propagated as a pressure wave, and the ink is ejected as ink droplets from the orifice 53a, and is sprayed onto the recording paper 61 together with the air flow ejected from the ventilation chamber 54 through the blowhole 54a, thereby performing n recording. On the other hand, the ink consumed by recording is transferred from the bag body 55a to the ink reservoir 5 by the surface tension acting on the orifice 53a of the ink reservoir 53.
3 so that it is supplied to JL.

When not in use, as shown in FIG. While closing the lever fL by bringing it into contact with a, ? 1
4! The I control valve 54θ is set to the closed position, the ventilation chamber 54 is opened to the atmosphere, and the air pump 56 is operated to introduce pressurized air into the housing 55b, thereby introducing the ink inside the bag body 55a into the ink reservoir 53. At the same time, the diaphragm 52a is operated to supply ink from the orifice 53a to the ventilation chamber 54, and while releasing the air in the ventilation chamber 54 into the atmosphere, the ink is supplied into the ventilation chamber 54 to a height above which at least the orifice 53a is submerged. Fill it up.

In this state, the orifice 53a is submerged in the ink, so the orifice 53a will not dry out and become clogged, and even if a mechanical shock is applied, the ink pool 53 will be removed through the orifice 53ai. This eliminates inconveniences such as air being sucked into the interior.

By the way, in the above-mentioned simple ink jetting device, the ink in the ventilation chamber 54 is
(When the IQ+valve 54θ is set at the fully open position, the suction force corresponding to the water head between the orifice 53a and the test object 55a acts on the ventilation chamber 54, and the orifice 53a moves forward.)
The ink inside is sucked into the ink reservoir 53 7'15, and is collected by suction into the ink storage bag 55a. When the ink in the ventilation chamber 54 decreases and the orifice 53a is exposed, surface tension acts on the particles surrounding the orifice 53a, resulting in an equilibrium between the surface deformation and the suction force. Collection is easy. Ink collection is limited to the area from the top of the ventilation chamber 54 to the height of the orifice 53a.Ink remaining in this area can be collected from the orifice 53a and below. Therefore, the ink must be discharged, and the ink is also wasted. In addition, 1 of the above-mentioned inks! ′:! The first loss is due to the suction force due only to the height of the orifice 53a and the water head between the bag body 55a, the suction force is weak, it takes several minutes to collect the ink, and the waiting time to start printing is long. Similarly, when filling ink into the ink 54, it takes several seconds to supply the ink through the orifice 53a, and it takes 26 hours to transition from the non-use state to the use state, and from the use state to the non-use state. There were also some difficulties.

The present invention has been devised in view of the above circumstances, and its object is to provide an ink reservoir that is completely equipped with orifices in a part of a peripheral wall, and a peripheral wall that communicates with the ink reservoir through the orifice and that faces the orifice. It is equipped with a blowhole, and when in use, gas is ejected through the blowhole together with ink droplets ejected from the M:I ijd orifice, and when not in use, the orifice is filled with ink so that the orifice is immersed in the ink. In the ink droplet ejecting device, a communication hole is opened in the partition wall between the ink reservoir and the ventilation chamber at a distance from the orifice, thereby quickly discharging ink filling the ventilation chamber. To provide an ink droplet ejecting device which can recover almost the entire amount, can quickly shift from an unused state to a used state, and can save a single ink droplet.

The present invention will be explained below based on drawings showing embodiments thereof. Fig. 1 shows an ink drop ejecting device (
FIG. 2 is an enlarged sectional view of the ink jet head, and FIG.
4 is a schematic cross-sectional view showing an aspect of the apparatus of the present invention when not in use, in which 1 is an ink ejecting head, 2 is a rotating drum, and 3 is a recording paper. . The ink ejecting head l has a head main body 11, a pressure chamber 12,
It is configured with an ink reservoir 13 and a ventilation chamber 14,
The pressure chamber 12 is located in the center of the head main body 11 and has a conical shape with a diameter decreasing from the rear side to the front side, and a diaphragm 12a formed of a piezoelectric element or the like on the rear side.
The front side has a first orifice 121), the ink reservoir 13 is formed in front of the pressure chamber 12, and the front side has a front plate 13b having a second orifice 13a in the center.
Further, a ventilation chamber 14 is formed in front of the ink reservoir 13, and a second orifice 13 is formed on the 1IIi side in front of n1.
The position opposite to a is closed by a cover plate 14b having pores 14a'i5.

Ink is swirled out within the pressure chamber 12 without intervening air bubbles, and the ink reservoir 13 is connected to the bag body 15b of the ink cartridge 15 through a communication passage 13c and an ink tube 13d'i that communicate with the lower part of the ink reservoir 13. The inside of the bag is filled with ink fed from the bag body 15b,
Further, the ventilation chamber 14 is connected to an air pump 18 via a communication passage 14c, an air tube 16, and a switching valve 17 leading to the upper part of the ventilation chamber 14.
It is so that it ejects in front of it through a.

In the apparatus of the present invention, a plurality of ink reservoirs 13 and ventilation chambers 14 are arranged near the periphery of the front plate 13b, which partitions the ink reservoir 13 and the ventilation chamber 14, at equal intervals in the circumferential direction, as shown in FIGS. The communication hole 13θ is opened. Each of the flow holes 13θ has a circular shape of the same size, and its diameter is slightly larger than that of the second orifice 13a. The formation position, size, shape, etc. of this communication hole 13θ are not particularly limited.
When the vibration is propagated to the inside of the ink reservoir 13 due to the vibration of 2c, the ventilation hole], 3 e to the ventilation chamber 1
4. Set the ink reservoir at a position where it will not be ejected. In addition, the size of the communication hole 13θ is such that when vibration is propagated to the ink in the ink reservoir 13 by the diaphragm plate 12C, the vibration does not cause one drop of ink to be ejected into the ventilation chamber 14. The surface tension acting on the flow holes 3e and 3e should be made as large as possible without exceeding the ink pressure in the ink chamber 13.

The hat 4 is formed of sponge or the like, and is located at a position 1' outside one end of the rotating drum 2, that is, at a position 1' outside the ink jet head 1.
It is attached to a holder (not shown) at a position corresponding to the home position of 1, and when the ejection head l is returned to the home position with ink 1, it is moved from the position shown by the imaginary line in Fig. 4 by a detailed operating mechanism. The cover plate 1 is moved to the position shown by the solid line and comes into contact with the front surface of the ink jet head L.
The fumarole hole 14a, which opens at 4b, is closed.

5 is a diaphragm 12a, a switching valve 17. A controller for the air pump 18, which emits an electrical signal to the diaphragm 12a [to cause ink to be ejected for recording], and returns the ink ejecting head 1 to the home position so that the printing pad 4 hits the front surface of the ink ejecting head 1. Contact fumarole 14ai
When the switching valve 17 is closed, the switching valve 17 is set to the closed position τ, pressure is supplied to the ink cartridge, and the ink pressure is applied to the ink reservoir 13 through the ink passage 13d by pressing the bag body 15b and passing through the ink passage 13d to the second orifice 13a. The ink reservoir 13 is supplied so that the surface tension acting on the flow hole 13e is higher than that of the ink reservoir 13.
The ink flows into the ventilation chamber 14 through the entire ink flow hole 13e inside. Also, in synchronization with this, the control section 5 is connected to the diaphragm 12a.
The second orifice 13 gives a signal continuously for a predetermined period of time.
The ink reservoir is ejected from a to the ventilation chamber 14 (lIll).

Therefore, in the device of the present invention configured as described above,
When transitioning from the used state shown in FIG. 1 to the non-used state shown in FIG. 4, return the ink jet head 1 to its home position and open the pad 4 After closing, the switching valve 17 is set to the closed position as shown in FIG. 4, and the pump 18 is driven once to supply pressure into the housing 15a, so that the ink in the ink reservoir 13 is raised to a predetermined pressure. It flows into the ventilation chamber 14 from the flow hole J3θ against the surface tension acting on the flow hole 13e.
Ink is also supplementarily supplied into the ventilation chamber 14 from 3a. The air in the ventilation chamber 14 is discharged to the outside through the switching valve J7.The flow hole 13e has a large diameter so that ink can be quickly supplied from the ink reservoir to the ventilation chamber 14. Note that if air bubbles occur in the ink reservoir 13, when filling ink from the ink reservoir 3 into the ventilation chamber 14, the ink should flow out together with the ink into the ventilation chamber 14 through the large diameter communication hole 13θ. is also possible.

On the other hand, when starting printing from the non-use state as shown in FIG. 4, when the switching valve 17 is set to the open position as shown in FIG. 1, the housing 15a of the ink cartridge 15 and the inside of the ventilation chamber 14 The ink in the ventilation chamber 14 is sucked into the ink reservoir 13 through each communication hole 3θ by the water head between the bag body 15b and the ink jet head 1, and is collected from there into the bag body 15b. go. Flow hole 13
θ has a larger diameter than the second orifice 13a;
Therefore, the surface tension acting on the second orifice 13a
Because it is smaller than that acting on the second orifice 1
Even if 3a is exposed, suction and collection of ink continues, and the collection ends when the lowermost passage hole 13θ reaches a position where it is exposed. The communication hole 13θ located at the bottom opens near the bottom of the ventilation chamber 14, and the amount of ink remaining in the ventilation chamber 14 is extremely small, and most of the ink filling the ventilation chamber 14 is removed. All 1 will be collected. Also, the communication hole 1
Since the diameter of 3θ is large and a plurality of ink are provided, the recovery speed of ink from inside the ventilation chamber 14 becomes extremely fast, and the transition from the non-operating state to the printing start state can be quickly performed.

Furthermore, if air bubbles exist in the ventilation chamber 14, the air bubbles will float on the gas-liquid interface due to buoyancy, but will not enter the ink reservoir 13 filled with ink even if they face the ventilation hole 1361. The ink remains in the ventilation chamber 14 until suction and collection of the ink is completed, and either disappears or is ejected to the outside together with the remaining ink by jetting jets of air into the ventilation chamber 14.t'1. The Rukoto.

Note that the above-mentioned embodiment is the first embodiment. The present invention is applied to an ink jet head having a structure including a second orifice.

Although the explanation has been made regarding the lifting platform, the present invention is applicable to an ink jet head having a configuration in which a diaphragm is provided at this position instead of providing the first orifice, and the pressure in the pressure chamber 12 is propagated to the ink in the ink reservoir 13 via the diaphragm. Of course, you can do it.

As described above, in the apparatus of the present invention, the speed of supplying ink to the ventilation chamber and the recovery speed of ink from the ventilation chamber are significantly improved.
Not only does it improve work efficiency, it also has a high ink suction recovery rate, and even if air bubbles occur in the ink reservoir, they can be discharged into the ventilation chamber through the ventilation holes, maintaining stable ink jetting function. The present invention has excellent effects such as being able to

[Brief explanation of drawings]

Figure 2 is a schematic sectional view of the simple ink jetting device used in the apparatus H of the present invention, and Figure 2 is an enlarged view of the ink jetting head.
3 is a front view taken from the river-river edge of FIG. 2, FIG. 4 is a schematic sectional view showing the state when not in use, and FIG. 5 is a schematic sectional view showing the state when the conventional device is in use. FIG. 6 is a schematic cross-sectional view showing the state of the conventional device H when it is not in use. 1. Ink 1 holder 2. Rotating drum 3.
・Recording paper 4 ・Pad 5 ・Control unit 11 ・
...To ink jetting main body 12...pressure chamber],
2 a... First orifice 13... Ink reservoir 13a... Second orifice 14... Ventilation chamber
14a... Fumarole 15... Ink cartridge 1
7...Switching valve 1B...Air pump patent applicant Noboru Kono, Patent attorney representing Sanyo Kamiki Co., Ltd. Large wound Figure 1 Figure 2 Figure 5 Figure 6

Claims (1)

[Claims] 1. An ink reservoir having an orifice in a part of the peripheral wall, communicating with the ink reservoir through the orifice, and having a blowhole in the peripheral wall facing the orifice, and when in use, the ink is opened through the blowhole and the ink is ejected from the orifice. In the ink drop ejecting device, the ink drop ejecting device is provided with a ventilation chamber filled with ink so that gas is ejected together with the ink droplets, and the orifice is immersed in the ink when not in use. An ink droplet ejecting device characterized by having one or more communication holes opened at a distance from the ink droplet ejecting device.