JPH0521746B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet recording apparatus, and more particularly to a mechanism for preventing clogging of an ejection head.

The present inventor has already proposed the structure shown in FIG. 3 in Japanese Patent Application No. 56-169636.

According to FIG. 3, from the ink tank 6 to the conduit 5,
3 through the flow path of head 1 (pressure chamber, nozzle, etc.)
When discharging ink filled with ink, the suction cap 11 is brought into close contact with the nozzle end surface 2 of the head 1,
Activate the suction pump 13. By operating the suction pump 13, the ink in the head 1 and the conduit 3 is collected into the drain tank 15. Next, connect the switching valve 4 to the conduit 3.
When the conduit 7 connected to the cleaning liquid tank 10 is switched to communicate with the cleaning liquid tank 10, the cleaning liquid flows into the conduit 3 and the head 1.
The liquid is circulated to the drain tank 15 while cleaning the flow path of the liquid, and when the switching valve 4 is switched so that the conduit 3 communicates with the conduit 30 with one side open to the atmosphere, the suction pump 13 can be continuously operated. As a result, the cleaning liquid is also discharged from the head 1.

This structure prevents ink from remaining inside the head.
This prevents clogging.

The object of the present invention is to improve the above structure and prevent clogging of the ink jet head with a simpler structure.

Examples will be explained in detail below.

FIG. 1 is a diagram illustrating the principle of an embodiment of the present invention, in which numeral 1 represents an ink ejecting head and numeral 2 represents an end face of its nozzle. The head 1 performs recording by receiving recording ink from the ink tank 6, and the ink supply path for this purpose is as shown in the figure: head 1 - ink conduit 3 - switching valve 4 - ink conduit 5 - ink tank 6 Piping is done in this order.

The other conduit 7 from the switching valve 4 communicates with a cleaning liquid tank 10 that contains cleaning liquid, and a branch pipe 8 with an opening to the atmosphere is arranged in the middle of this conduit 7. 9 is this branch pipe. The opening/closing means includes a solenoid that selectively opens and closes the openings of the openings 8 and 8. A switching valve 4 connects an ink conduit 3 to the head 1, a conduit 5 to an ink tank 6, or a conduit 7 to a cleaning liquid tank 10.
It has the function of selectively communicating with. Reference numeral 11 denotes a suction cap, which is detachably attached to the nozzle end face 2. 12 is a suction cap 11 and a suction pump 1
The discharge side of the suction pump 13 reaches the drain tank 15 via the conduit 14.

Next, to explain the operation, in the normal printing state, the head 1 and the suction cap 11 are in the open state, and the switching valve 4 is in the state of communicating with the ink conduit 3 and the conduit 5 to the ink tank 6, and the ink tank 6 is connected to the ink conduit 3. When ink is supplied, printing is performed on a predetermined recording paper, and when not printing, a suction cap 11 is brought into close contact with the nozzle end face 2 of the head 1 as shown in the figure. Next, selector valve 4
is switched so that the ink conduit 3 and the conduit 7 to the cleaning liquid tank 10 are communicated with each other, the opening/closing means 9 closes the opening of the branch pipe 8, and the suction pump 13 is activated. The suction cap 11 has a space facing the nozzle on the nozzle end face 2, and when the suction pump is activated, negative pressure is created inside the suction cap 11 through the conduit 12, sucking out the ink in the head 1 and draining the cleaning liquid in the cleaning liquid tank 10. is introduced from conduit 7 into conduit 3 and further into head 1. This cleaning solution is 0.5 to 1
After approximately cc has been introduced, the opening/closing means 9 opens the branch pipe 8 and continues operating the suction pump 13. When the opening of the branch pipe 8 is closed, the cleaning liquid is introduced into the head 1 through the conduit 7, but when the opening is opened, air is introduced from this opening,
As a result, the introduced cleaning liquid is also discharged from the suction cap 11 via the suction pump 13 into the drain tank 15.

That is, the ink in the head 1 and the conduit 3 is discharged and a cleaning liquid is introduced, and this cleaning liquid is also discharged, and this state is maintained until the next printing is started.

In order to introduce about 0.5 to 1 c.c. of the above-mentioned cleaning liquid into the head 1, the amount of cleaning liquid introduced can be easily changed and set by controlling the operation of the opening/closing means 9 using a mechanical or electrical timer. It is also possible to use other power for the opening/closing means or to link it with a pump.

The principle configuration shown in Figure 1 requires three types of tanks: an ink tank, a cleaning liquid tank, and a drain ink tank, but it is difficult for the user to make these tanks separate and replace them every time the ink or cleaning liquid runs out. Therefore, as an embodiment of the tank of the present invention, we propose a tank that integrates three types of tanks as shown in FIG. 2.

In FIG. 2, reference numeral 16 denotes a tank container, and a bag-shaped ink tank 6, a cleaning liquid tank 10, and a drain ink tank 15 are built into the container 16. The tips of the three types of conduits 5, 7, and 14 to be connected are sharp in the shape of needles, and the ink tank 6 and the cleaning liquid tank 10 are communicated with the caps 17 and 18, respectively. Here, instead of a bag-like absorbent material, a sponge-like absorbent material is substituted, and the conduit 14 engages directly with this absorbent material 15. The discharged ink and cleaning liquid are absorbed by this absorbent material 15.

When the ink or cleaning liquid is used up, this tank container 16 is removed from the tips of the conduits 5, 7, and 10, and a new tank container is installed. In this way, three types of tanks can be replaced by replacing one tank container, which is the simplest operation for the user and improves reliability.

As described in FIG. 1, a branch pipe 8 is provided in the middle of the conduit 7 leading to the cleaning liquid tank 10, and an opening member 19 made of an elastic material such as rubber is attached to the opening of the branch pipe 8. 9 is composed of a solenoid 21 and an opening/closing plate 20. When the solenoid 21 is not energized, the opening/closing plate 20 is in close contact with the opening member 19 and closes the opening, and when the solenoid 21 is energized, the opening/closing plate 20 is closed.
is separate from the aperture member 19 and operates to open the aperture, performing the function described in FIG.

The present invention has the configuration shown in Fig. 1, and completely eliminates head nozzle clogging by draining the ink in the head, introducing cleaning liquid, and then discharging this cleaning liquid under preset conditions. This solves the biggest drawback regarding the reliability of the inkjet, and is very effective for its practical use.

As shown in Fig. 3, the conventional switching valve is a four-way valve, and since there are many switching operations, cleaning liquid remains in the valve when switching the valve.
This can completely eliminate the problems of the initial printout being very thin and the accumulation of air bubbles that are difficult to remove in the switching valve hole, causing clogging.

Furthermore, by using a release valve, it is possible to quickly switch between opening and shutting off to the atmosphere.

[Brief explanation of the drawing]

FIG. 1 is a principle configuration diagram showing an embodiment of the present invention.
FIG. 2 is a diagram showing an embodiment of the ink tank container of the present invention. FIG. 3 is a diagram showing the principle of the prior application of the present invention. DESCRIPTION OF SYMBOLS 1...Head, 4...Switching valve, 6...Ink tank, 9...Opening/closing means, 10...Cleaning liquid tank,
11... Suction cap, 13... Suction pump, 1
5... Drainage tank.

Claims (1)

[Scope of Claims] 1. An ink jet head having an ejection nozzle, a suction cap that selectively comes into close contact with the nozzle end face of the head, and an ink ejecting cap into the suction cap.
A drain tank connected by a conduit via a pump that operates when introducing and discharging the cleaning liquid; an ink tank containing recording ink connected to the head; In an inkjet recording device having a cleaning liquid tank containing a cleaning liquid for cleaning, a switching means provided in the middle of a pipe connecting both the ink tank and the cleaning liquid tank and the head, and a switching means and the cleaning liquid tank. A branch pipe opened to the atmosphere is provided in the middle of a conduit connecting the two, and the opening of the branch pipe is closed when ink is discharged and cleaning liquid is sucked into the head, and opened when cleaning liquid is sucked and discharged from the head. An inkjet recording device comprising an opening/closing means. 2. The inkjet recording apparatus according to claim 1, wherein the ink tank, the cleaning liquid tank, and the drain liquid tank are housed in the same container, and are configured to be detachable from the conduit.