JPH0422701B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet recording device, particularly,
The present invention relates to an inkjet recording device comprising compatible output means.

An inkjet recording device has a head that generates ink droplets, and performs recording by making the ink droplets ejected from the head adhere to a recording surface. However, the ejection nozzles in the inkjet head are generally extremely minute (several
(Aperture of about 10μ to 100μ), it is prone to clogging due to drying of ink or adhesion of foreign matter such as dust. The inability to record due to such clogging of the ejection nozzles is the biggest drawback of the inkjet recording system.

Due to the above-mentioned circumstances, it is considered essential to provide a means for removing clogging of the ink jet nozzle (due to adhesion of dust or drying of ink) in an inkjet recording device. There is.

In the past, many proposals have been made as this type of clogging removal method, but during the clogging removal operation, the recording operation must be stopped, the device is too large, and a large amount of cleaning liquid is required. , has disadvantages such as insufficient cleaning effect,
None of these methods has yet reached a level where they can be put to practical use.

Therefore, in view of the actual situation regarding such inkjet recording technology, the present invention aims to provide an inkjet recording apparatus equipped with a clogging release system that guarantees good recording quality no matter what inkjet method is adopted. Make it the main purpose. In other words, the main object of the present invention is to provide an inkjet recording device that ensures stable ink droplet formation with a simple system and enables high-speed, high-quality inkjet recording.

The present invention is an inkjet recording device that achieves the above-mentioned object and is equipped with a recording head in a recordable state that discharges ink from an ejection port to record on a recording surface. Exchange means for replacing a spare recording head with the recording head, and a recovery process for replacing the spare recording head and acting on the recording head in a non-recording state to restore the recording head to a recordable state. This is an inkjet recording apparatus characterized by comprising a recovery means for performing the following steps.

The present invention will now be explained in more detail by way of examples using drawings.

An embodiment of the present invention will be explained with reference to FIGS. 1a and 1b. FIG. 1a is a front view of one embodiment of the present invention, and FIG. 1b is a cross-sectional view taken along line AA' in FIG. 1a.

In the figure, 10-1, 10-2, 10-3, 10-
4 is an inkjet head, and 11 is a head holder that holds all these heads. And heads 10-1, 10-2, 10-3, 10
-4 and holder 11 are hollow cylindrical case 1
2, and can be rotated, for example, in the direction of the arrow in the figure, about an axis (not shown). 1
3 is an inkjet head 10-1, 10-
This is a conduit that supplies ink to 2, 10-3, and 10-4, and the ink supplied from this conduit 13 is
It is distributed and supplied to each head through a branch pipe 14 in the holder 11.

In FIG. 1, the inkjet head 10-
1 is activated and ink droplets 16 are ejected toward the recording paper 15. still,
At this time, the ink droplet 16 is ejected through a small opening 12 _a provided in a part of the case 12 .

On the other hand, a recess is provided at the periphery of each head in the head holder 11, and hollow chambers 17-1 and 17- are formed between each of these recesses and the case 12.
2, 17-3, 17-4, each head 10-
The tips of Nos. 1, 10-2, 10-3, and 10-4 are in a discharged state.

In the hollow chamber 17-4, the case 12
Cleaning liquid flows in and out from the outside. In other words,
A cleaning liquid in a tank (not shown) is supplied into the hollow chamber 17-4 through a conduit _18a , forms a liquid reservoir 19, and then is discharged through another conduit _18b . In this way, the tip of the head 10-4 (where the ink jet nozzle is located) is submerged in the cleaning liquid reservoir 19,
Receives cleaning action. At this time, the cleaning liquid may be temporarily retained in the hollow chamber 17-4 and then discharged _;
7-4, it is preferable to circulate and flow through the conduit 18 _b because the cleaning effect will be higher.

In the above inkjet recording device, if
When the ink jet head 10-1 becomes clogged, move the holder 11 approximately in the direction of the arrow in the figure.
The hollow chamber 17-1 is moved to the lowest position in the figure by rotating it by 90 degrees, and the conduits 18 _a and 18 _b are connected thereto.
The head 10-1 is cleaned in the same manner as above to remove the clogging. At the same time, the already cleaned head 10-2 opens into the small opening _12a.
This head 1
0-2 allows the recording operation to be resumed immediately.

Furthermore, the embodiment according to FIGS. 1a and 1b can be modified as follows.

That is, a ventilation hole (not shown) is connected to at least one of the hollow chambers 17-2 and 17-3 in FIGS. It is also possible to remove attached dirt, etc., or dry the head wet with cleaning liquid.

Next, another embodiment of the present invention will be described with reference to FIGS. 2a and 2b. FIG. 2a is a partially cutaway front view showing a multi-head array type device;
Figure b is a cross-sectional view taken along line BB' in Figure 2a.

In the figure, there are four inkjet heads 2.
A desired number (three in the figure) of independent head holders 2 with 0, 21, 22, and 23 arranged on the same circumference.
4-1, 24-2, and 24-3 are arranged in parallel at a predetermined interval. And each holder 24-1, 2
4-2 and 24-3 are housed in the case 25, have a cylindrical shape, and are rotatably supported by a central shaft (not shown). Therefore, in each holder,
Ink jet head 20, 21, 22, 23
can be rotated, for example, sequentially in the direction of the arrow shown in the figure.

Also, a hollow chamber 26 similar to the embodiment of FIG. 1 is formed around the periphery of each head.

Among the hollow chambers 26, the cleaning liquid flows into and out of the hollow chamber at the lowest position in the figure from outside the case 25. That is, in the figure, the cleaning liquid in a tank (not shown) is supplied to the lowest hollow chamber through a conduit 27 _a , and after forming a liquid reservoir 28, another conduit 27 _b
is discharged from. In this way, the tip of the head 23 (where the ink jet nozzle is present) is immersed in the cleaning liquid reservoir 28 and receives the cleaning action. At this time, after the cleaning liquid is temporarily retained in the hollow chamber 26,
Although it may be discharged, a tank (not shown), a conduit _27a ,
The cleaning effect will be higher if the fluid is circulated through the hollow chamber 26 and the conduit _27b .

In the above inkjet recording device, if
When any of the ink jet heads 20 becomes clogged, the holders 24 (24-1, 24-1,
-2, 24-3) by about 90 degrees in the direction of the arrow in the figure, and insert the conduit 27 into the hollow chamber 26 around the head 20.
_A and 27 _b are connected and the head 20 is connected in the same manner as above.
Clean the area to remove the clogging. At the same time, the already cleaned head 21 is placed in a position aligned with the small opening 29 provided at a predetermined position in the case 25, so that the recording operation can be immediately resumed using this head 21. . Furthermore,
The embodiment according to FIGS. 2a and 2b can also be modified as follows.

That is, a cleaning liquid flow conduit (not shown) is also connected to the hollow chamber 26 around the inkjet head 21 located at the lowest position in the figure, and the area around this head 21 is also filled with cleaning liquid to perform cleaning. In addition, an opening may also be provided in the case 25 at a position corresponding to the head 22, so that this head 22 can be operated in the same manner as the head 20.

Incidentally, in FIG. 2b, reference numeral 30 indicates an ink supply pipe, and ink flowing into the ink pool 31 from this pipe is supplied to each head through a branch pipe 32.
When the apparatus of the embodiment described above has stopped for a long time and then starts recording again, the head holder must be rotated approximately 90 degrees (in the direction of the arrow in the figure) regardless of whether or not there is clogging. It is convenient to replace the head with one that has been cleaned and is on standby and restart recording, since it does not require the effort of detecting clogging.

By the way, various types of inkjet systems can be adopted for constructing the inkjet head in the above-mentioned embodiments. Incidentally, this inkjet method is roughly divided into several methods based on the method of generating ink droplets and the control method for controlling the flying direction of the generated ink droplets.

One of the typical methods is, for example,
USP 3596275 (Sweet method), USP 3298030
(Lewis and Brown method), etc., in which a flow of ink droplets with a controlled amount of charge is generated by a continuous vibration generation method, and this flow of ink droplets with a controlled amount of charge is generated at once. This method controls the flight trajectory between deflection electrodes that are applied with a similar electric field.

This method is generally abbreviated as a continuous method.

Other typical methods that can be compared with this are, for example,
This is the method (Stemme method) disclosed in USP 3747120. This method applies an electrical recording signal to a piezo vibrating element attached to an ink ejection head that has an orifice for ejecting ink, converts this electrical recording signal into mechanical vibration of the piezo vibrating element, and This is a method in which ink droplets are ejected from the orifice whenever necessary according to mechanical vibrations.

This is the so-called on-demand method. Separately, an inkjet method which is different in principle and idea from these methods has also been proposed by the applicant (ie, in Japanese Patent Application Laid-open No. 59936/1983). In short, this method applies a thermal pulse as an information signal to the ink introduced into the liquid chamber, and the ink changes its state, causing the ink to move to the previous liquid chamber according to the acting force generated. The ink is ejected into small droplets from an attached ejection port (orifice).
This is a method that allows it to fly.

Further, as the cleaning liquid, various solvents that are substantially equivalent to the ink solvent can be widely used.

As explained in detail above, according to the inkjet recording apparatus of the embodiment of the present invention, (1) recording operation and clogging removal operation can be performed simultaneously by using a plurality of inkjet heads, so that recording can be performed quickly; It is rich in sexuality.

(2) Good recording quality can be guaranteed because a clean and unclogged inkjet head is always used for recording.

(3) Since all ink jet heads are always cleaned, there are almost no malfunctions of the heads.

(4) The head cleaning efficiency is good and the amount of cleaning liquid consumed is small.

These effects can be mentioned.

As can be understood from the embodiments described above, the present invention is characterized by an exchange means that is provided with a spare recording head compatible with the recording head so as to be replaceable with the recording head, and a non-recording head that can be exchanged with the spare recording head. recovery means that performs a recovery process that acts on the recording head in a non-recording state and restores the recording head to a recordable state, so that the recording head can be replaced immediately; Since the recording head in the current state can be restored to a recordable state regardless of the recording state, high-speed recording without recording interruption can be achieved.

[Brief explanation of drawings]

FIGS. 1A and 1B and FIGS. 2A and 2B are explanatory diagrams showing embodiments of the present invention. However, FIG. 1a is a front view of one embodiment, FIG. 1b is a sectional view taken along line AA' in FIG. 1a, and FIG. 2a is a front view of another embodiment. b is a cross-sectional view taken along line BB' in FIG. 2a; In the figure, 10-1, 10-2, 10-3, 1
0-4, 20, 21, 22, 23 are ink jet heads, 11, 24-1, 24-2, 24-3
is the head holder, 12, 25 is the case, 13,
30 is an ink supply pipe, 14 and 32 are branch pipes, 17
-1, 17-2, 17-3, 17-4, 26 are hollow chambers, 18 _a , 18 _b , 27 _a , 27 _b are conduits, 1
9, 28 are cleaning liquid reservoirs, 12 _a , 29 are openings, 31
is an ink pool.

Claims (1)

[Scope of Claims] 1. In an inkjet recording apparatus equipped with a recording head that records on a recording surface by discharging ink from an ejection port in a recordable state, a preliminary recording head compatible with the recording head is connected to the recording head. and a recovery means that is exchanged with the spare recording head and performs a recovery process that acts on the recording head in a non-recording state and restores the recording head to a recordable state. An inkjet recording device comprising: 2. The recording head and the preliminary recording head are recording heads that eject ink droplets by applying a thermal pulse to the ink as an information signal to cause a change in the state of the ink. The inkjet recording device described in .