JP2005059476A - Ink feeding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink feeding device of a good deaerating efficiency by preventing a defective discharge of ink at a head section from occurring. <P>SOLUTION: This ink feeding device 100 is equipped with a main tank 10 in which an ink is stored, an ink feeding tube 20 which carries the ink, a subsidiary tank 30 which temporarily holds the ink, an ink jet head 40 which jets the ink, a deaerating device 50 which deaerates a gas in the ink, a channel switching valve 60 which switches the flowing direction of the ink, a pump 70 which feeds out the ink, and an opening/closing valve 80 which regulates the going-out/coming-in of the ink and so forth. The ink feeding tube 20 has a first ink feeding tube 21 which carries the ink from the main tank 10 to the subsidiary tank 30, a second ink feeding tube 22 which carries the ink from the subsidiary tank 30 to the ink jet head 40, and a third ink feeding tube 23 and so forth. Third ink feeding tube 23 returns the ink on the downstream side from the subsidiary tank 30 to this side of the deaerating device 50 which is provided on the first ink feeding tube 21. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ink supply apparatus that can be suitably used in an ink jet printer that performs printing by spraying fine particles of ink onto a recording medium.

  2. Description of the Related Art As a conventional technique, there is known an ink jet recording apparatus that includes a deaeration device that heats ink to a room temperature or higher and degass the ink, and does not require replenishment of deaerated ink from the outside (for example, Patent Documents). 1).

  In addition, there is known an ink jet recording apparatus that degass bubbles and dissolved gas in ink causing defective ink ejection using a circulation path (for example, Patent Document 2).

  However, according to the method of Patent Document 1, since the ink supply path is one-way, it is impossible to deaerate the ink that has once passed through the deaeration device.

  On the other hand, in the method of Patent Document 2, a circulation path is employed, and deaeration is performed by returning ink to a main tank in which ink is stored or a sub tank that temporarily holds ink. Since the ink is also returned to the main tank, it is necessary to install a deaeration device with a large amount of ink to circulate and a large capacity, resulting in a high device cost. The air could melt in the main tank and the deaeration efficiency was poor.

  In addition, since the deaeration device is arranged between the ink jet head unit and the sub tank, when the pressure of the head unit is adjusted, the pressure is lost in the deaeration device, and the pressure transmission is not successful. The problem was that the ink did not flow properly.

  Further, when left for a long time, the air is melted again in the sub tank, the effect of deaeration cannot be obtained, and discharge failure may occur.

JP 11-48493 A Japanese Patent Laid-Open No. 11-42795

  SUMMARY OF THE INVENTION An object of the present invention is to provide an ink supply device that prevents ink ejection failure in a head portion and has high deaeration efficiency.

  The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to the Example of this invention is attached | subjected and demonstrated, it is not limited to this. That is, the invention of claim 1 includes a main tank (10) in which ink is stored, a first flow path (21) for transporting ink from the main tank (10), and the first flow path (21). From the sub-tank (30) for temporarily holding the ink and adjusting the pressure of the ink, the second channel (22) for conveying the ink from the sub-tank (30), and the second channel (22) An ink supply device comprising: a head portion (40) for discharging the ink; and a deaeration device (50) provided in a part of a path from the main tank (10) to the head portion (40). The ink supply device is characterized in that a return flow path (23) for returning ink downstream from the sub tank (30) to the sub tank (30) is provided.

  According to a second aspect of the present invention, in the ink supply device according to the first aspect, the return flow path (23) returns the ink from the front of the ink discharge port of the head portion (40). An ink supply device.

  According to a third aspect of the present invention, in the ink supply device according to the first or second aspect, the deaeration device (50) is a part of an ink circulation path including the return flow path (23). An ink supply device characterized by being provided.

  According to a fourth aspect of the present invention, in the ink supply device according to any one of the first to third aspects, the deaeration device (50) includes the return flow path (23) and / or the first flow passage. The ink supply device is provided in one flow path (21).

  According to a fifth aspect of the present invention, in the ink supply device according to any one of the first to fourth aspects, the deaeration device (50) is provided in the first flow path (21). The return flow path (23) is an ink supply device that returns ink to the front of the deaeration device (50).

  According to the present invention, (1) since the return flow path for returning the ink downstream from the sub tank to the sub tank is provided, the amount of ink to be circulated for deaeration can be minimized, and the deaeration efficiency is improved. (2) Since the return flow path is provided so as to return the ink from the front of the ink discharge port of the head portion, the deaeration efficiency is further improved, and (3) one of the ink circulation paths including the return flow path Since the deaeration device is provided in the section, the deaeration efficiency is further improved. (4) Since the deaeration device is provided in the return flow path and / or the first flow path in the ink circulation path (second flow path) Since no deaeration device is provided in the head portion, pressure loss from the sub-tank to the head portion can be prevented, ink ejection failure of the head portion can be prevented, and (5) the deaeration device is connected to the first flow path. Since the ink was returned to the front of the deaeration device, the main unit Ink from click also ink from the return passage can be efficiently deaerated, there is an effect that.

  The present invention is an ink supply device for a printer that ejects ink, applies ink to a recording medium, and forms an image. This is realized by installing a deaeration device for removing the gas that is present in the ink supply system and forming a path for circulating the ink when the ink is not supplied for a long time.

  Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.

FIG. 1 is a diagram schematically showing a first embodiment of an ink supply apparatus according to the present invention, and FIG. 2 is a diagram showing the sub-tank in FIG. 1 in more detail.
The ink supply device 100 according to the first embodiment includes a main tank 10, an ink supply tube 20, a sub tank 30, an inkjet head 40, a deaeration device 50, a flow path switching valve 60, a pump 70, and an on-off valve 80. And so on.

  The main tank 10 is a pressurized container such as stainless steel or resin, and includes a compressor 11 that is a device for compressing air, a regulator 12 that is a regulator, and the like, and has a function of sending ink by compressed air. Is stored. Adjustment of the compressed air from the compressor 11 is performed using the regulator 12, and the flow rate of the ink flowing through the sub tank 30 is adjusted. When ink is allowed to flow into the sub tank 30, the measurement value of the liquid level detection sensor 31 mounted in the sub tank 30 is taken into consideration.

  The ink supply tube 20 includes a first ink supply tube 21 that transports ink from the main tank 10 to the sub tank 30, a second ink supply tube 22 that transports ink from the sub tank 30 to the inkjet head 40, and ink downstream from the sub tank 30. And a third ink supply tube 23 (return flow path) for returning to the front of the deaeration device 50 provided in the first ink supply tube 21 without returning to the main tank 10. The material is soft such as resin.

  The first ink supply tube 21 is provided with a first flow path switching valve 61, a deaeration device 50, and an on-off valve 80 in this order from the main tank 10 to the sub tank 30, and the second ink supply tube 22. The on-off valve 80 and the second flow path switching valve 62 are installed in this order from the sub tank 30 to the inkjet head 40, and the pump 70 is installed on the third ink supply tube 23.

  As shown in FIG. 2, the sub tank 30 includes a liquid level detection sensor 31 for measuring the height of the ink liquid level, a filter 32 for preventing contaminants such as dust, a jack 33 for adjusting the head height, and the like. And temporarily holds the ink from the first ink supply tube 21, adjusts the pressure of the ink transported to the inkjet head 40, and keeps the pressure constant. Further, the sub tank 30 has a smaller capacity than the main tank 10 and uses a hard material that is not immersed in ink such as stainless steel or resin. Do. Further, the sub tank 30 has a small hole on the upper surface in order to adjust the amount of air inside, and the hole is covered with a filter 32.

  The ink jet head 40 is a head portion of an ink jet printer that performs printing by spraying fine ink particles onto a recording medium. Here, the ink jet printer is a printer used in the field of patterning apparatuses, industrial ink jet printers premised on mass use, color filters for which ejection stability is desired, and the field of fine patterning for organic EL.

  The deaeration device 50 is a device that removes the gas dissolved in the ink, and employs a method in which the ink is passed through a hollow fiber having gas permeability and vacuumed by a vacuum pump from the outside of the hollow fiber. ing.

  The flow path switching valve 60 includes a first flow path switching valve 61 and a second flow path switching valve 62, and is a three-way valve that switches the direction of ink flow.

  The pump 70 is a tube pump that sends out ink by squeezing the tube.

  The on-off valve 80 is a valve that controls the amount of ink supplied from the main tank 10 by opening and closing thereof, and is installed in the vicinity of the entrance / exit of the sub-tank 30. When the ink is transported from the main tank 10 to the sub-tank 30, This is a valve for preventing the ink supply pressure to the inkjet head 40 from fluctuating.

Next, the ink flow according to the first embodiment will be described.
When printing is performed by ejecting ink from the head portion, first, the first flow path switching valve 61 is set in the direction in which the ink flows from the main tank 10 to the sub tank 30 and the second flow path switching valve 62 is set in the sub tank. The flow direction is switched from 30 to the inkjet head 40.

  Next, the ink level in the sub tank 30 is measured by measuring the level of the ink level in the sub tank 30 using the liquid level detection sensor 31, and when the ink level is low, The compressor 11 and the regulator 12 of the main tank 10 are operated to convey ink to the sub tank 30. The ink is transported from the main tank 10 to the sub tank 30 after the on-off valve 80 attached to the second ink supply tube 22 is closed in order to prevent ink leakage from the inkjet head 40 due to pressure fluctuation.

  Finally, the ink in the sub tank 30 is transported to the inkjet head 40 via the second ink supply tube 22 and discharged onto the recording medium.

On the other hand, when degassing ink, first, the ink flows through the first flow path switching valve 61 in the direction in which the ink flows from the third ink tube 23 to the degassing device 50, and the second flow path switching valve 62 is filled with the sub tank. The direction is switched from 30 to the third ink supply tube 23. Thus, a circulation path is formed in which the sub tank 30, the second flow path switching valve 62, the third ink supply tube 23, the first flow path switching valve 61, and the deaeration device 50 are circulated in this order and returned to the sub tank 30 again. .
Next, the ink is deaerated by the deaeration device 50 by operating the pump 70 to circulate the ink in the circulation path.

  As described above, according to the first embodiment, the circulation path for returning the ink to the main tank 10 without returning the ink to the sub tank 30 is formed. Therefore, the deaeration can be performed with the minimum necessary ink circulation. The capacity of the air device 50 can be minimized, and degassing can be performed reliably even with a small degassing device.

  In addition, when the use of the inkjet 40 is stopped for a long time, in the conventional type without a circulation path, the ink that is between the degassing device 50 is ejected from the inkjet head 40 and the use is started after the degassed ink is filled. However, since the ink was circulated by using the circulation path to enable deaeration, the ink was not wasted.

  Further, since the deaeration device 50 is provided in the first ink supply tube 21 on the circulation path (not provided in the second ink supply tube 22), the pressure when the ink jet head 40 ejects ink from the sub tank 30 is reduced. Loss of ink was eliminated, and ink ejection failure in the inkjet head 40 could be prevented.

  Furthermore, since the ink is returned to the front of the deaeration device 50 provided in the first ink supply tube 21, the ink from the main tank 10 and the ink from the third ink supply tube 23 can be deaerated at the same place. As a result, work efficiency has improved.

FIG. 3 is a diagram schematically illustrating an ink supply device according to a second embodiment of the present invention.
In addition, the part which fulfill | performs the same function as Example 1 mentioned above attaches | subjects the same code | symbol or the code | symbol unified at the end, and abbreviate | omits duplication description and drawing suitably.
The ink supply device according to the second embodiment is different from the ink supply device 100 according to the first embodiment in that the second flow path switching valve 62A is provided inside the ink jet head 40 and from before the ink discharge port of the ink jet head 40. The third ink supply tube 23A is disposed so as to return the ink.

  As described above, according to the second embodiment, when the ink is circulated and deaerated, the ink between the inkjet head 40 and the second flow path switching valve 62 that cannot be circulated in the first embodiment is also included. Since the ink could be circulated, the ink degassing efficiency was improved.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and changes are possible, and these are also within the equivalent scope of the present invention.
(1) FIG. 4 is a diagram schematically showing a modification of the sub-tank shown in FIG. In each embodiment described above, the sub-tank 30 has been described as an example using a hard material. However, for example, as shown in FIG. 4, a bag-like pack (soft container) such as a retort pack may be used. In this case, the pressure of the supplied ink is adjusted by adjusting the height of the pack, and the remaining amount of ink in the sub tank 30A is measured by measuring the thickness of the pack and converting the remaining amount of ink. 31A is used, and the increase or decrease of the ink amount is adjusted by the swelling of the bag. In this way, since air can be further prevented from being mixed in, the deaeration state of the ink can be maintained for a long time, and the ink does not have to be frequently flowed to the circulation path, so that the working efficiency is improved.

(2) FIG. 5 is a diagram schematically showing another modification of the sub-tank shown in FIG. In each of the embodiments described above, the pressure adjustment of the sub-tank 30 has been described as an example in which the jack 33 is moved up and down. For example, as shown in FIG. 5, a vacuum generator 34B, a vacuum regulator 35B, and the like are provided. The sub tank 30B may be used. In this way, the space of the jack 33 can be eliminated, and the jack 33 does not have to be moved up and down, so that the operation is simplified and the entry of air can be further prevented.

(3) In each embodiment described above, the deaeration device 50 has been described as being installed in the first ink supply tube 21 on the circulation path. However, if it is on the circulation path, the second ink supply tube 22 is provided. Or in the third ink supply tube 23 or on the path from the main tank 10 to the inkjet head 40. Further, although the deaeration device 50 has been described as a method of removing gas in the ink by evacuation, a method of removing the gas in the ink by bringing the ultrasonic source into contact with the ink may be used.

(4) In each of the above-described embodiments, the example in which the ink downstream from the sub tank 30 is returned to the first ink supply tube 21 has been described. However, the ink may be returned directly to the sub tank 30.

(5) In each of the embodiments described above, the ink supply tube 20 has been described as being soft, such as resin, but it may be hard, such as stainless steel.

It is a figure which shows typically Example 1 of the ink supply apparatus by this invention. It is the figure which showed the subtank in FIG. 1 in detail. It is a figure which shows typically Example 2 of the ink supply apparatus by this invention. It is a figure which shows typically the modification of the subtank shown in FIG. It is a figure which shows typically the other modification of the subtank shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Main tank 11 Compressor 12 Regulator 20 Ink supply tube 21 First ink supply tube 22 Second ink supply tube 23 Third ink supply tube 30 Sub tank 31 Liquid level detection sensor 32 Filter 33 Jack 40 Inkjet head 50 Deaerator 60 Flow path Switching valve 61 First flow path switching valve 62 Second flow path switching valve 70 Pump 80 On-off valve 100 Ink supply device

Claims (5)

A main tank where ink is stored,
A first flow path for transporting ink from the main tank;
A sub tank for temporarily holding ink from the first flow path and adjusting the pressure of the ink;
A second flow path for transporting ink from the sub tank;
A head portion for discharging ink from the second flow path;
A deaeration device provided in a part of a path from the main tank to the head part;
An ink supply device comprising:
A return flow path is provided for returning ink downstream from the sub tank to the sub tank;
An ink supply device. The ink supply device according to claim 1,
The return flow path returns ink from the front of the ink discharge port of the head unit,
An ink supply device. In the ink supply device according to claim 1 or 2,
The deaeration device is provided in a part of a circulation path of the ink including the return flow path;
An ink supply device. The ink supply device according to any one of claims 1 to 3, wherein:
The deaeration device is provided in the return flow path and / or the first flow path;
An ink supply device. In the ink supply device according to any one of claims 1 to 4,
The deaeration device is provided in the first flow path,
The return flow path returns ink to the front of the deaeration device;
An ink supply device.

Images