JPH03158246A - Deaeration device for ink jet printer - Google Patents

Abstract

PURPOSE:To remove bubbles in an ink quickly by a method wherein at the time of removal of bubbles, the upstream side and by-pass side of an ink passage are communicated through a 3-way valve, and at the same time, a pump is started; and at the time of recording, the upstream side and downstream side of the ink passage are communicated through the 3-way valve, and at the same time, the pump is stopped. CONSTITUTION:At the time of removal of bubbles, an upstream side 5a and a by-pass 6 side of an ink passage are communicated through a 3-way valve 3, and at the same time, a pump 4 is started. As the result, an ink flows while circulating a closed passage which consists of an ink container 1, an ink passage 5 and the by-pass 6, and bubbles which contained in the ink disperse in the atmosphere through fine pores on a tube 7. At the same time, a small quantity of the ink is absorbed by an ink absorbing material 8. At the time of recording, through the 3-way valve which is turned by 90 deg. to the right, the upstream side 5a and a downstream side 5b of the ink passage are communicated, and at the same time, the pump 4 is stopped. By this method, bubbles which are contained in an ink are completely and quickly removed, and a favorable printing quality can be maintained.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an inkjet recording head, an ink channel connecting an ink container, and a degassing device for an inkjet printer that is installed in the ink container and removes air bubbles contained in the ink in the ink channel and the ink container. [Conventional technology]

FIG. 4 is a diagram showing the connection between an ink container and a recording head in a conventional inkjet printer. In FIG. 4, ink is constantly supplied to the recording head 2 from an ink container 1 connected to the recording head 2 via an ink flow path 9.
Continuous recording for long periods of time becomes possible.

[Question B that the invention attempts to solve]

As explained above, in the conventional technology, ink from the ink container 1 simply passes through the ink flow path 9 to the recording head 2.
Therefore, if air bubbles get mixed into the ink flow path 9 for some reason, the normal functioning of the recording head 2 will be inhibited. For example, when replenishing ink to the ink container 1 or replacing the ink container 1 itself, if a large amount of air bubbles get mixed in, the ink will not be ejected from the nozzles (not shown) of the recording head 2, and printing will be interrupted. It becomes impossible or incomplete, resulting in malfunction or deterioration of print quality. Generally, the nozzles of the recording head 2 are exposed to air from outside,
When a blockage occurs due to infiltration of dust or dried ink residue, a suction device (bumping device) is used to suck out the clog from the nozzle opening. Removal is performed. If, in addition to this blockage, a large amount of air bubbles are mixed in as described above, it will be extremely difficult or impossible to suction and remove them using the normal capacity of the suction device, making maintenance work difficult and making it necessary to use a large suction device. This can lead to maintenance problems, such as the need for The fact that the recording head 2 is inherently susceptible to clogging due to air bubbles and dust mixed into the ink at its nozzles and other locations will be explained below with reference to the drawings. Note that this recording head 2 is the same as that used in the embodiments of the present invention described later. Conventionally, a method of recording by ejecting ink from fine nozzle holes and depositing it on a recording medium such as paper is known as an inkjet recording method, and one of the methods is an on-demand type inkjet recording head. This type of recording head is used for boat fishing, as shown in Fig. 2, which is a plan view, and Fig. 3, which is a side sectional view. Nozzle 22.
Injection channel 23. Ink pressurization chamber 25. After laminating and integrating the temporary cavity 21 in which the ink supply path 26 and the ink reservoir 27 are formed and the diaphragm 29, the ink pressurizing chamber 25 is
A piezoelectric element 3 as an electromechanical transducer is placed at a position facing the
0 is attached. In such a configuration, when a voltage as an electric signal is applied to the piezoelectric element 30, the diaphragm 29 moves into the ink pressurizing chamber 25.
is displaced inward to rapidly reduce its volume, and ink corresponding to that volume is ejected from the ink nozzle 22,
These become ink droplets that are spotted on the recording paper and printed. The object of this invention is to solve the problems of the conventional technology, to completely and quickly remove air bubbles contained in the ink in the ink flow path and ink container, and to improve the print quality and maintainability of inkjet printers. An object of the present invention is to provide a degassing device for an inkjet printer that improves the performance of inkjet printers.

[Means to solve the problem]

In order to solve this problem, a degassing device for an Ink Geno I printer according to the present invention is installed in an ink jet recording head, an ink flow path between an ink container, and the ink container. A device for removing air bubbles contained in ink, comprising: a tube made of porous fluororesin provided as at least a part of the ink flow path and the bypass of the ink container; and an ink absorption tube provided in contact with the outer peripheral surface of the tube. a pump inserted into the bypass; a pump installed at a connection point between the bypass and the ink flow path, and an upstream side of the ink flow path with this connection point as a reference, and a pump inserted into the bypass; and a three-way valve capable of selectively communicating with the three-way valve, the upstream side of the ink flow path and the bypass side communicate with each other via the three-way valve when removing air bubbles, and the pump is activated, and when recording, the three-way side communicates with the bypass side. The upstream side and the downstream side of the ink flow path communicate with each other via the valve, and the pump is floated.

[For use]

When removing air bubbles, that is, degassing, the upstream side of the ink flow path and the bypass side communicate with each other via the three-way valve, and the pump is activated, so ink flows between the ink container and the ink flow path between the ink container and the three-way valve. The ink flows through a closed flow path consisting of a bypass and a bypass, and during this time bubbles contained in the ink are dissipated from the outer peripheral surface of the tube, and some of the ink that flows out at that time is absorbed by the ink absorbing material. During recording, the upstream and downstream sides of the ink flow path communicate with each other via the three-way valve and the pump is stopped, so ink from the ink container flows to the inkjet recording head via the ink flow path.

【Example】

An embodiment of a degassing device for an inkjet printer according to the present invention will be described with reference to FIG. 1, which is a configuration diagram thereof. In FIG. 1, 1 is an ink container, 2 is a recording head,
This is the same as the conventional example shown in FIG. 3 is a three-way valve as a flow path switching means, and 4 is a pump. An ink flow path 5 that connects the ink container 1 and the recording head 2 includes an ink flow path 5a on the upstream side (ink flow path 5a of the ink container 1 to 7) and an ink flow path on the downstream side (recording head 2 side) with respect to the three-way valve 3. A bypass 6 is provided in parallel to the ink container 1 and the ink flow path 5.
is provided. That is, one end of the bypass 6 is connected to the ink container 1, and the other end is connected to the three-way valve 3. Further, the bypass 6 includes a tube 7 in at least a portion thereof, and the pump 4 is inserted therein. An ink absorbing material 8 is provided in contact with the outer peripheral surface of the tube 7 . The tube 7 is made of porous fluororesin and is installed in a zigzag shape to increase the surface area.The tube 7 has a high water repellency of the porous fluororesin, so that the liquid inside, that is, the ink, is Although it is difficult to pass through, the bubbles contained in it are easy to pass through.Tube 8 is made by Sumitomo Electric, pore diameter: 1.08 m, porosity 260%, outer diameter: 2 mm, inner diameter: 11 II [Il, total length: approx. 50-1. The operation of the embodiment is as follows. When removing bubbles, that is, degassing, the ink flow is controlled via the three-way valve 3, which takes the position shown in FIG. The upstream side 5a of the path and the side of the bypass 6 are communicated with each other, and the pump 4 is activated.As a result, ink circulates through the closed flow path consisting of the ink container 1, the ink flow path 5a, and the bypass 6. During this time, air bubbles contained in the ink pass through the fine holes of the tube 7 and dissipate into the atmosphere from the outer circumferential surface, and some of the ink that flows out at that time is absorbed by the ink absorbing material 8.The tube 7 zigzags. This formation improves the space efficiency for the dissipation of air bubbles contained in the ink into the atmosphere. During recording, the air bubbles contained in the ink are dissipated into the atmosphere through the three-way valve 3, which is rotated by 90 degrees to the right from the position shown in FIG. , upstream side 5 of the ink flow path
A and the downstream side 5b are communicated with each other, and the pump 4 is stopped. As a result, the ink inside the ink container 1 and the ink flow path 5 is deaerated and flows to the recording head 2 in a bubble-free state. Although not shown in FIG. 1, a filter is provided near the connection point between the ink container 1 and the tube 7 to remove minute foreign matter that may be contained in the ink that has passed through the tube 7. Can be configured. τ Effects of the Invention] According to the present invention, there are the following superior effects compared to conventional techniques. (1) Even if a large amount of air bubbles get mixed into the ink flow path and ink container due to ink container replacement or other causes, these air bubbles are completely and quickly removed, so it is possible to print immediately. , good print quality is maintained. (2) In relation to the previous item, maintainability can be improved in that the frequency of nozzle cleaning is reduced and the nozzle suction pumping device can be downsized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment according to the present invention, FIG. 2 is a plan view of a common recording nozzle in the embodiment or a conventional inkjet printer, FIG. 3 is a side sectional view thereof, and FIG. The figure is a diagram illustrating the connection between an ink container and a recording head in a conventional inkjet printer. Description of symbols 1: Ink container, 2: Recording head, 3: Three-way valve, 4: Pump, 5.5a, 5b: Ink channel, 6: Bypass, 7: Tube, 8: Ink absorbing material. Ryo 4th figure high 3rd figure

Claims (1)

[Claims] 1) In an ink jet recording head, an ink channel between an ink container, and a device installed in the ink container to remove air bubbles contained in the ink in the ink channel and the ink container, a bypass of the ink channel and the ink container is provided. A tube made of a porous fluororesin provided at least in part; an ink absorbing material provided in contact with the outer peripheral surface of the tube; a pump inserted in the bypass; a connection between the bypass and the ink flow path; a three-way valve provided at a connection point and capable of selectively communicating the upstream side of the ink flow path with the connection point as a reference with the downstream side or the bypass side; The upstream side of the ink flow path and the bypass side communicate with each other via the ink flow path, and the pump is activated,
A degassing device for an inkjet printer, characterized in that during recording, the upstream side and downstream side of the ink flow path communicate with each other via the three-way valve, and the pump is stopped.