JPH0522583B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a liquid injection device, and more specifically,
The present invention relates to a liquid ejecting device equipped with a droplet ejection recovery means.

[Prior art]

In recent years, non-impact recording methods have attracted attention because they generate extremely little noise during recording. Among them, the liquid jet recording method, which records by attaching flying droplets to a recording member, has the advantage of being able to record on plain paper without requiring any special processing such as so-called fixing, and that it is capable of high-speed recording. is attracting attention.

However, in the liquid jet recording method, droplets are ejected from a fine orifice, so if the orifice becomes clogged with foreign matter such as paper dust and the ejection of droplets stops, or if the device is not used for a long period of time, the recording liquid (liquid ) There have been cases where the solvent in the orifice evaporates and the remaining solute becomes an obstruction, stopping the ejection of droplets. Also, because the dissolved gas in the liquid is gas released from the liquid or gas that has entered due to other causes, if the liquid does not exist continuously all the way to the tip of the orifice, there will be insufficient ejection to eject droplets. In some cases, energy was not transmitted to the liquid, or even if energy was transmitted, droplets were not ejected, or ejection became unstable. Furthermore, due to these gases, a sufficient amount of liquid cannot be supplied to match the amount of liquid to be discharged, resulting in unstable discharge or non-discharge as described above.

In order to solve the above-mentioned problems, a recovery operation is generally performed by pressurizing the liquid or sucking the liquid from the orifice side to restore normal droplet ejection.
However, with the former method, when the recovery occurs or when the orifice is not clogged, the liquid overflows from the orifice and adheres to the area around the orifice, making the discharge even more unstable and causing the liquid in the liquid to overflow and adhere to the area around the orifice. There were cases where the solvent evaporated and caused clogging. In this respect, the latter method is an excellent method, but in the latter case, it is difficult to balance the suction force and the force for removing the cause of droplet non-ejection, and bubbles may be generated due to cavitation during the recovery operation.

In other words, there have been cases in which conventional recovery means have caused malfunctions or failures in droplet ejection despite operations to restore droplet ejection.

In addition, in the case of recovery by suction, if there is no liquid in the liquid chamber, when the recovery means is released from the orifice surface while the recording head side is depressurized, air flows back from the atmosphere side and the recovery operation is not performed at all. It was hot. Furthermore, if a filter is installed to prevent foreign matter in the liquid from clogging the orifice surface, if the atmosphere reaches the filter, the atmosphere (air) will enter the filter, which will seriously impede the subsequent discharge characteristics. In some cases, serious drawbacks such as:

〔the purpose〕

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a liquid ejecting device equipped with a recovery means that can control suction force with a simple mechanism. Another object of the present invention is to provide a liquid ejecting device equipped with a recovery means that ensures recovery of droplet ejection.

The present invention includes a cap for capping an orifice that discharges liquid, a suction means for suctioning the liquid from the orifice through the cap, and a suction force generated by the suction means that is greater than a predetermined value to absorb atmospheric air. Another object of the present invention is to provide a liquid ejecting device characterized by comprising: a suction force adjusting means for adjusting the suction force by introducing the suction force.

〔Example〕

Hereinafter, the present invention will be explained using the drawings.

FIG. 1 is a schematic cross-sectional view for explaining one preferred embodiment of the present invention.

In Figure 1, 1 is the main tank, 2 is the supply tube, 3 is the sub tank, 4 is the filter, and 5
is the supply pipe, 6 is the recording head, 7 is the orifice, 8
is a carriage, 9 is a suction tube, and 10 is a suction pump. 11 is a capping device, 12 is a piston, 13 is a waste liquid tube, 14 is a waste liquid reservoir, 1
5 is a valve, 16 is a spring, 17 is a packing, 18 is a suction tube, 19 is a cap, 20 is a cap moving device, 21 is a suction force adjustment device, and 22 is a suction force adjustment valve.

As shown in FIG. 1, in this embodiment, liquid is supplied from a main tank 1 containing recording liquid (liquid) to a sub-tank 3 via a supply tube 2. As shown in FIG. The liquid supplied to the sub-tank 3 is sent to the recording head 6 through a filter 4 that prevents dust, air bubbles, etc. from entering the recording head, and a supply pipe 5, where flying droplets are formed in an orifice 7 and are sent to the recording head in response to the recording signal. Recording is performed by depositing droplets on a recording member (not shown). A suction tube 9 that communicates with a suction pump 10 is in communication with the sub-tank 3 .

A capping device 11 is provided as a capping means for the orifice 7. The main parts of the capping device 11 include a cap 19 that covers the orifice 7 and a cap moving device 20 that moves the cap 19 in conjunction. Further, a suction pipe 18 communicating with the suction pump 10 is connected to the cap 19 .

A suction pump 10 for generating suction force has a piston 1
By lowering the suction tube 2, a suction force is generated, and air or liquid is suctioned from the suction tube 9 and the suction tube 18. When the piston 12 is raised by the spring 16, the sucked atmospheric air or liquid moves to the lower side of the piston 12 through the valve 15, and is collected in the waste liquid reservoir through the waste liquid tube 13.

The suction force adjustment means is a suction force adjustment valve 2 whose opening strength is adjusted by a spring as shown in FIG.
It consists of a suction force adjustment device 21 equipped with 2. In this embodiment, the suction force adjustment device 21 is connected to a suction pipe 18 that communicates with the suction pump 10 and the cap 19, and when the suction force exceeds a certain value, the suction force adjustment valve 22 is activated by the spring force. Atmospheric air is drawn into the suction force adjustment device 21 by being drawn in against the force. The suction force generated by the suction pump 10 is reduced by the atmospheric air drawn into the suction force adjustment device 21, so that it never exceeds a predetermined value.

The suction force adjustment means can be provided in the cap 19, the suction pump 10, or the suction tube 9, in addition to providing the suction force adjustment device 21 in the suction force tube 18 as in this embodiment. Further, in this embodiment, the suction adjustment valve 22 is provided in the suction adjustment device 21, but it may be provided directly in the cap 19, the suction tube 9, the suction pipe 18, and the suction pump 10.

In this embodiment, the air and liquid accumulated in the sub-tank 3 are also sucked by the suction tube 9, but if an air vent means is provided to remove the air accumulated in the sub-tank 3, the suction tube 9 can be used to The tube 9 may not be provided. Further, if the suction force is appropriate, air may be vented from the recording head side through the orifice 7 by capping means without providing an air venting means in the sub-tank 3.

The suction force adjustment valve 22 is, for example, as shown in FIGS. 2 to 5b.
Suction force adjustment means 21 shown in a schematic cross-sectional view of
Like the valve inside, a number of so-called pressure regulating valves can be advantageously used.

In both FIGS. 2 and 3, the valve 24 is in close contact with the box body 28 due to the force of the spring 25, and the valve 24 is in close contact with the box body 28.
The internal atmosphere is supplied to the suction pipe 1 connected to the communication port 23.
The liquid is sucked through a communication pipe 29 that communicates with the air. If the suction force does not exceed a certain level, that is, a pressure difference that does not deform the spring 25 occurs between the atmosphere side and the inside of the box body 28, the valve 2
4 is tightly attached to the box body 28, and the opening 26 is closed.
When a difference of more than a certain level occurs between the inside of the box 28 and the atmospheric force, the spring 25 is deformed by the valve 24. At this time, a gap is created between the valve 24 and the box body 28, and the atmosphere flows in from the opening 26. Then, the pressure inside the box body 28 approaches atmospheric pressure, so the valve 24 is moved again to the box body 28 by the force of the spring 25.
and closes the opening 26. The above operations are repeated depending on the situation while the suction force from the suction pump 10 continues.

FIG. 4a shows an example in which the suction force adjusting means is provided inside the cap 19. 4b and 4c schematically represent the operation of the valve 27 shown in FIG. 4a.

The valve 27 is made of an elastic body. In this case as well, it goes without saying that when a pressure difference above a certain level occurs, the elastic body deforms and an opening is formed.

FIG. 5a shows an example in which a part of the valve 30 is fixed to the box body 28. FIG. 5b shows a state in which the valve 30 is deformed and the box body 28 communicates with the atmosphere.
Similarly to the above-mentioned examples, the valve 30 deforms only when a certain degree of pressure difference is generated between the inside of the box body 28 and the atmosphere, and otherwise closes tightly to the box body 28 and closes the opening 26. Needless to say, there are.

Note that the pressure difference that determines the timing of opening and closing each valve is desirably set to a level below which cavitation does not occur even when liquid is sucked by the suction pump. In particular, in the case of a liquid jet recording device with multiple orifices, the valve is opened when a pressure difference that does not cause cavitation is exceeded even when liquid is sucked from only one of the orifices covered in the cap. It is preferable to determine the strength of the spring and the strength of the elastic body.

Further, it is desirable to provide packing made of an elastic material such as rubber or plastic at the portion where the valve contacts the opening provided with the valve, in order to improve the adhesion between the valve and the members surrounding the opening. It is also preferable to use a member that can serve as a packing for the member forming the valve or opening itself.

In the embodiments of the present invention, the suction pump is manual, but it may be a pump using other power means such as electric power. but,
The suction force generated tends to change depending on how the pump operates and how much force is applied when using a clogged pump. Even if the operating conditions of a manual suction pump change, it will not generate more suction force than necessary. more effective in some respects.

Further, in the embodiments of the present invention, an example is shown in which the recovery means is only a suction means, but a recovery measure for droplet ejection may be performed by using a pressurizing means at the same time as the suction means. .

When the droplet ejection recovery operation was performed using the embodiment of the present invention as shown in FIG. 1, the droplet ejection was reliably recovered and the subsequent droplet ejection was also very stable. It was hot.

〔effect〕

As explained in detail above, according to the present invention, a liquid jet device is equipped with a recovery means that can perform a reliable recovery operation that does not cause droplet failure or unstable ejection even if a recovery operation for droplet ejection is performed. Equipment is provided.

Further, according to the present invention, there is provided a liquid ejecting device that includes a recovery means that is equipped with a suction force adjustment means that has a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view for explaining one preferred embodiment of the present invention. 2 to 5 are schematic cross-sectional views showing the suction force adjusting means, respectively. 1... Main tank, 2... Supply tube, 3
...Subtank, 4...Filter, 5...Supply pipe, 6...Recording head, 7...Orifice, 8...
...carriage, 9...suction tube, 10...suction pump, 11...capping device, 12...
Piston, 13... Waste liquid tube, 14... Waste liquid reservoir, 15, 24, 27, 30... Valve, 16, 25
... Spring, 17 ... Packing, 18 ... Suction pipe, 19 ... Cap, 20 ... Cap moving device, 21 ... Suction force adjustment means, 22 ... Suction force adjustment valve, 23 ... Communication port, 26 ...Aperture, 28...
Box body, 29...Communication pipe.

Claims (1)

[Scope of Claims] 1. A cap for capping an orifice that discharges a liquid, a suction means for suctioning the liquid from the orifice through the cap, and a suction force generated by the suction means that is greater than a predetermined value. A liquid ejecting device comprising: a suction force adjusting means for adjusting the suction force by introducing atmospheric air. 2. The liquid ejecting device according to claim 1, wherein the suction force adjusting means is a valve.