JPS59199254A - Liquid jet recording apparatus - Google Patents

Abstract

PURPOSE:To perform the restoration in the emission of liquid droplets with certainty and to attain to prolong the life of a porous body, by providing a control means for controlling suction force by introducing the atmosphere when suction force for sucking the liquid in a cap reaches a predetermined value or more. CONSTITUTION:A sensor 20 detects a position to stop a carriage 5 while a duct 27 is moved toward the carriage 5 to respectively bring porous bodies 22-25 into close contact with the orifice surface of each head. In the next step, suction force is generated by a suction means 29 to suck the liquid or gas absorbed with each porous body. In this case, when suction force large enough to result in non- emission of liquid droplets acts on the interior of a cap 21, a suction force control means 37 acts to introduce the atmosphere into a suction pipe 28. Because suction force is lowered by this mechanism, the generation of a non-emission cause is prevented and, when the suction force acting on the interior of the cap 21 is lowered, the introduction of the atmosphere is stopped. Thereafter, the suction means 29 is stopped and the duct 27 is separated from the carriage 5. By this mechanism, the life of each porous body is prolonged and, therefore, it is unnecessary to exchange each porous body over a long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid jet recording apparatus, and more particularly to a liquid jet recording apparatus equipped with droplet ejection recovery means.

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 performs recording by depositing flying droplets on a recording member, has the advantage that recording can be performed on plain paper without the need for special processing such as so-called fixing, and high-speed recording is also possible. is attracting attention.

However, since the liquid jet recording method ejects droplets through a minute orifice, there is a possibility that the orifice may become clogged with foreign matter such as paper dust and stop ejecting the droplets, and if the device is not used for a long period of time, the recording liquid may As the solvent in the (liquid) evaporates, the solute remaining in or near the orifice may become an obstruction and stop ejection of droplets. In addition, due to the gas generated when dissolved gas in the liquid is released from the liquid, or the gas that enters due to other reasons, the liquid exists continuously from the liquid reservoir storing the liquid to the orifice. There were times when it disappeared. In that case,
There were 11 cases in which the energy required to eject a droplet from an orifice was not transmitted to the liquid, or even if it was transmitted, the droplet was not ejected, or the ejection became unstable.

Furthermore, if unnecessary gas is present, the liquid may not be supplied in proportion to the amount of liquid discharged due to the presence of unnecessary gas.

Among the above, in liquid jet recording devices, non-ejection of droplets due to clogging of the orifice or the liquid flow path communicating with the orifice is an important problem, and many proposals have been made to counter this problem. There is.

Furthermore, as mentioned above, there can be various causes of clogging, and countermeasures are required depending on the cause. One possible cause of such non-ejection is an increase in ejection resistance due to thickening of the ink due to evaporation of low-boiling point substances in the ink near the ink ejection holes.

In such a case, as a countermeasure, it is effective to bring a porous body into close contact with the ink ejection hole and to absorb the thickened ink into the porous body. However, in such a method, the absorbed ink saturates the porous body, requiring frequent replacement of the porous body.

In addition, depending on the increase in the viscosity of the liquid or the evaporation of the solvent, the S-rich oR14b upper layer 5-hole discharge recovery method is an excellent preventive measure to make it difficult to cause liquid non-discharge and as a countermeasure against minor clogging. However, in some cases, it was not possible to eliminate the cause of severe clogging or severe non-discharge, such as when a large number of cis bodies filled with foreign matter got into the liquid flow path. .

As a means to eliminate such severe causes of ejection failure, the orifice surface of the recording head is capped with a cap, and the inside of the cap is suctioned using a suction means that generates suction force, and the foreign matter is sucked out along with the liquid from the orifice. There is a known method for eliminating the cause of non-ejection by sucking out the gas. However, in this case, it is difficult to balance the suction force and the force for removing the cause of droplet non-ejection, and air bubbles may be generated due to cavitation during the recovery operation.

In other words, even though operations have been carried out to restore droplet ejection, if the cause of droplet ejection failure or failure occurs, or if the sucked out liquid remains near the orifice and the droplet Conventional recovery means sometimes make the discharge unstable.

In addition, in the case of recovery by suction, if there is no liquid in the liquid chamber, and when the recovery means is released from the oriSwiss surface while the recording head side is depressurized, air flows back from the atmosphere side and the recovery operation is not performed at all. was there. 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 and affect the subsequent discharge characteristics. In some cases, serious drawbacks such as injury may also occur.

〔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 jet recording device equipped with a recovery means that can control suction force with a simple mechanism. Moreover, the present invention
Another object of the present invention is to provide a liquid jet recording apparatus equipped with a recovery means that ensures recovery of droplet discharge.

Still another object of the present invention is to provide a liquid jet recording apparatus that achieves a long life of the porous body as described above and is equipped with a highly reliable droplet ejection recovery means.

The present invention provides a recording head that performs recording by forming flying droplets across an orifice, and a capping means that caps the orifice surface with a cap having a porous body that contacts the orifice surface and absorbs the liquid. The ejection recording device includes a suction means for suctioning the liquid in the cap, and a suction force adjustment that adjusts the suction force by introducing atmospheric air when the suction force generated by the suction means exceeds a predetermined value. Another object of the present invention is to provide a liquid jet recording device provided with means.

The above-mentioned recording head may be one suitable for use in a liquid jet recording apparatus, but preferably includes an orifice for forming flying droplets, a liquid flow path communicating with the orifice,
An energy generator that generates energy used to form the flying droplets is used.

〔Example〕

The present invention will be explained below using preferred embodiments.

FIG. 1 is a schematic perspective partial view for explaining the liquid jet recording apparatus of the present invention. As shown in FIG. 1, in this embodiment, a carriage drive belt 7 is placed on a recording paper sheet that is moved in the sub-scanning direction (direction of arrow A) on a platen 2 by a paper feed sheet roller 3 and a pinch roller 4. Droplets are ejected from multi-nozzle head units 9 to 12 (hereinafter referred to as heads) fixed via a head aligner 8 to a carriage 5 that is moved in the main scanning direction (in the direction of arrow B) along a guide shaft 6. This is an example of performing ejection recording according to an input signal. The heads 9 to 12 each have a liquid chamber 13.
Each of the liquid chambers 13 is connected to ink pipes 15 to 18, which communicate with ink tanks (not shown) through coverrs 14, respectively. Further, seven reciprocal wiring lines 19 are connected to each of the heads 9 to 12, and electrical signals for ejecting droplets are inputted thereto.

22 to 25 are porous bodies held by a cap 21 which is also a porous body holder, and fixed to a duct 27 via an elastic support 26. A suction pipe 28 whose one end is connected to a suction means 29 for generating suction force is connected to the duct 27. Also, the duct 27
It is fixed to a substrate 30 that holds the. Suction pipe 2
In addition, the duct 2 is equipped with a suction force adjustment means 37.
7 is movable together with the porous bodies 22 to 25 in the direction of arrow C shown in FIG.

The recovery operation in this embodiment is performed as follows. First of all, carriage 5 is set/? The carriage 5 is stopped by detecting the $ that has come to a predetermined position Mv by -23, and the duct 27 is moved to the 10,000-point position of the 1000-yield 5, thereby forming porous bodies 22 to 25 on the orifice surface of each -\d, respectively. Make it a dense layer.

Next, the suction means 29 is operated to generate suction force, and the liquid air absorbed by the porous body is suctioned. At this time, the cap 21 receives a suction force that is strong enough to cause droplet failure to be ejected as described above.
In this embodiment, the suction force adjusting means 37 attached to the suction pipe 28 operates to introduce atmospheric air into the suction pipe 28. Then, the suction force is reduced due to the introduction of atmospheric air, and the occurrence of causes of non-ejection is prevented. When the suction force acting within the cap 21 decreases due to the introduction of the atmosphere, the introduction of the atmosphere is stopped. This operation of the opening attraction force adjusting means 37 under which the attraction force is applied is repeated.

Thereafter, the operation of the suction means 29 is stopped and the duct 27 is separated from the carriage 5. That is, the cap 21 is attached to the head 9.
to 12.

In this embodiment, recovery of droplet ejection is performed as described above.

Taking the head 9 shown in FIG. 1 as an example, an example of the recovery means in the liquid jet recording apparatus of the present invention will be described in detail with reference to FIG. 2. What is shown in FIG. 2 is a schematic cross-sectional partial view when the head 9 is undergoing a recovery operation. The numbers indicated by lead lines in FIG. 2 are the same as those shown in FIG. 1.

As shown in FIG. 2, a waste liquid reservoir 33 is formed in the camp 21 that holds the porous body 22.Also, at least the suction means side of the part where the porous body 22 and the cap 21 come into contact has a porous hole. The mass body 22 is moved in the direction of arrow C shown in FIG. 1 by pushing a fixed cam follower 36 provided with a hole 32 so as to apply a suction force to the mass body 22. As a result, the porous body 22 is pressed against the head 9. At this time, the elastic support 26 is slightly compressed to apply an appropriate pressing force to the porous body 22. The porous body 22 is in close contact with the orifice surface of the head 9 and absorbs the liquid near the orifice.

By operating the suction means in this state, the porous body 2
Negative pressure is created on the back side of 2. The liquid absorbed by the porous body 22 is guided to the back side through the continuous foam pores of the porous body 22, and the liquid saturated on the back side is stored in the waste liquid reservoir 33. The suction force adjusting means 37 repeats the operation described in FIG. 1 while the suction force is being generated.

Figures 3 and 6 (b) are schematic cross-sectional views showing preferred embodiments of the suction force adjusting means in the present invention. In FIG. 3 and FIG. 6(b), 101 is a valve body, 102 is a suction pipe, and 103 is an elastic body.

The valve bodies 101 shown in FIGS. 5 to 6(b) each have elastic force themselves, and also function as the elastic body 103 shown in FIGS. 3 and 4.

Each valve body 101 in FIGS. 3 to 6(b) is moved to the suction pipe 102 by the suction force within the suction pipe 102.
The suction pipe 102 is pulled into the pipe to communicate between the atmosphere and the inside of the suction pipe 102. The elastic body is appropriately selected to have such a force that it operates when a predetermined suction force is generated within the suction pipe 102.

Note that FIG. 6(b) shows the state when the valve body 101 shown in FIG. 6(a) is introducing atmospheric air.

Although FIG. 1 shows a liquid jet recording apparatus having a plurality of heads, there are four heads as shown in the figure.
It does not have to be a single number, it can be a larger number or a smaller number, and of course it can be a singular number. However, if there are multiple heads, in order to make the porous material evenly adhere to each head, or to prevent the ink of each head from mixing, a holder and an elastic support should be attached to each head. It is preferable to make each one independent.

Further, although the elastic support is not necessarily required, it is preferable to provide it in order to effectively transmit the suction force generated by the suction means to the porous body or to improve the adhesion between the porous body and the head.

It is preferable that the porous body is a continuously foamed elastic body and made of a material that is easily compatible with liquid. It is also preferable that the porous body has appropriate elasticity.

The elastic support is preferably a closed-cell type with little air circulation, such as a so-called rubber material with appropriate softness.

Although FIG. 2 shows an example in which an eccentric cam is used as a method for moving the duct 31, it is of course possible to move the duct 31 in many other ways besides the eccentric cam.

Further, the recovery operation may be performed when the carriage reaches the home position without providing a mechanism for stopping the carriage at a predetermined position.

Although the suction force adjusting means is provided in the suction pipe in this embodiment, it is of course not necessary to provide it here. It may be provided between the suction means that generates suction force and the cap. That is, it is sufficient that the suction means is attached at a location where the suction force generated can be adjusted with sufficient response.

〔effect〕

As explained above in detail, according to the present invention, the life of the porous body that absorbs liquid is significantly extended, so it is not necessary to replace the porous body over a much longer period than in the past. The physical management and financial burden will be greatly reduced. or,
By setting the suction force generated by the suction means to an appropriate level, a small amount of liquid can be sucked into the orifice, which not only removes liquid adhering to the vicinity of the orifice but also eliminates clogging in the liquid flow path. I can do it. Furthermore, unlike conventional devices equipped with a means to remove clogging by suction, the porous body absorbs excess liquid, so there is no possibility of liquid adhering to the vicinity of the orifice and resulting in unstable discharge.

That is, since the liquid jet recording apparatus of the present invention is equipped with a very excellent droplet ejection recovery means, it can always perform excellent recording even when used for a long period of time.

[Brief explanation of the drawing]

1 and 2 are diagrams for explaining preferred embodiments of the present invention, respectively, with FIG. 1 being a schematic perspective view and FIG. 2 being a schematic cross-sectional view. 3 to 6 are cross-sectional views showing preferred embodiments of the suction force adjusting means used in the liquid jet recording apparatus of the present invention. 1... Recording paper 2... Platen 3... Paper feed 90
- roller 4...pinch roller -5.1. Carriage 6
... Guide shaft 7 ... Carriage drive belt 8 ...
・Head aligner-9, 10, 11, 12...Head 13...Liquid chamber 14...Coupler 15.16,1
7.18... Ink pipe 19... Flexible wiring 20... Sensor 21... Cap 22,
23, 24.25...Porous body 26...Elastic support 27...Duct 28.102...Suction pipe 29...Suction means 30...Substrate 31...
Shaft 32... Hole 33... Waste liquid reservoir 34... Frame body 35... Eccentric cam 36... Cam follower 3
7... Suction force adjustment means 101... Valve body 103...
・Elastic body

Claims (1)

[Claims] A recording head that performs recording by ejecting liquid from an orifice to form flying droplets, and a capping means that caps the orifice surface with a cap having a porous body that contacts the orifice surface and absorbs the liquid. In the liquid jet recording device, a suction means for suctioning the liquid in the cap, and a suction force for adjusting the suction force by introducing atmospheric air when the suction force generated by the suction means exceeds a predetermined value. A liquid jet recording device characterized by being provided with an adjustment means.