JPH07101069A - Ink jet printer - Google Patents

Abstract

PURPOSE:To prevent sucking ink from falling down in the interior of a printer and staining the printer by a method wherein a sucking means for sucking the ink in an ink jet head through a meshy filter, which is provided within a cap and approaches a nozzle surface under non-contact state, and the cap is provided. CONSTITUTION:By actuating a sucking means 6, the ink, mixed bubbles, dusts and the like in a head 1 are delivered through a tube 5 and a cap 3 from nozzles 1a. The delivering ink almost reaches the sucking means 6 through a hole part 3d, but is not completely sucked and sometimes left in the cap 3. However, since the ink easily moves to a space 8 due to the capillary action developed in the mesh of filter 4, ink is scarcely left within a space 7. Accordingly, the ink, which is not sucked up with the sucking means 6, is not left much within the space 7 but left with the space 8. The ink, which once passes through the filter 4 and reaches the space 8, does not return to the space 7 through the filter 4 again except on the application of a lot of impact or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer having a capping means.

[0002]

2. Description of the Related Art An example of a conventional ink jet printer is shown in FIGS. These are the head 11 when not printing.
The cap 13 that covers the nozzle surface 11a is provided in order to prevent the nozzle 12 from drying and solidifying the ink to make printing impossible.
There is one that has. The cap 13 is separated from the head 11 in an open state during a printing operation, and is in close contact with the nozzle surface 11a of the head 11 during a non-printing operation to shield the nozzle 12 from the outside air and prevent drying.

Further, in the ink jet head, a so-called purging operation of forcibly sucking and discharging the ink inside the head 11 from the nozzle 12 is performed in order to remove air and dust existing in the meniscus portion at the end of the nozzle 12. Has been. At this time, in order to suction the inside of the nozzle 12 with a negative pressure by the suction means 14, there is one in which a tube 15 or the like is connected to the cap 13 and suction is performed through this. Conventionally, such a cap 13 is not only a hollow one as shown in FIG. 3 but also a sponge inside the cap 13 as shown in FIG. 4 in order to prevent sucked ink from leaking from the inside of the cap 13. There is an ink absorber 16 such as the above.

[0004]

Among the conventional constructions, as shown in FIG. 3, in the case where the cap 13 is hollow, a small amount of ink, which cannot be completely sucked by the suction means 14, remains inside the cap 13. And head 1 when capping
There is a risk of reattachment to the first nozzle surface 11a or ink remaining in a bridge shape due to surface tension between the nozzle surface 11a and the cap 13. In this case, when the cap 13 is retracted, the ink accumulated in a bridge shape drops and stains the inside of the printer.

Further, as shown in FIG. 4, in the case where a porous material made of polyurethane or the like, that is, a sponge-like ink absorber 16 is arranged in the cap 13, the sponge-like ink absorber 16 has a moisture content. When the ink is sucked, the volume of the ink absorber 16 increases. Then, the front surface of the ink absorber 16 swells forward of the end surface of the cap 13 (the state before expansion is indicated by a chain double-dashed line). In that case, since the ink absorber 13 is pressed against the nozzle surface 11a during capping, the ink impregnated in the ink absorber 16 may seep out and redeposit on the nozzle surface 11a. Further, when capping is released, even if the end surface of the cap 13 is separated from the nozzle surface 11a, the ink absorber 16 remains in contact with the nozzle surface 11a until the end, and when the cap 13 is separated, the front surface of the ink absorber 16 and the nozzle surface 11a are separated. Ink may remain in the shape of a bridge due to surface tension. When the cap 13 is further retracted from this state and the ink absorber 16 is separated from the nozzle surface 11a, the ink accumulated in a bridge shape drops and stains the inside of the printer. Further, since the sponge-like ink absorber 16 directly contacts the nozzle surface 11a, dust and dust of the ink absorber 16 easily adhere to the nozzle surface 11a.

To prevent this, even if the ink absorber 16 expands, it does not come into contact with the nozzle surface 11a.
In consideration of the expansion rate, it is necessary to arrange in advance so that the front surface of the ink absorber 16 is at a position largely retracted from the end surface of the cap 13. However, in that case, at the time when the ink absorber 16 is not impregnated with such a large amount of ink and the ink absorber 16 does not expand so much, a large space is formed in front of the ink absorber 16 in the cap 13, which is different from the case where the ink absorber 16 is not arranged. Similarly, the ink that has been sucked into the nozzle surface 1
1a and the front surface of the ink absorber 16 are likely to accumulate in a relatively large amount, and the ink that has accumulated here reattaches to the nozzle surface 11a during capping or the like, and bridge-like ink due to surface tension as described above. There is a possibility that the inside of the printer will become dirty and stain the inside of the printer.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet printer in which the sucked ink is prevented from falling inside the printer and becoming dirty.

[0008]

The features of an ink jet printer according to the present invention include an ink jet head having nozzles for ejecting ink, a hollow cap for covering the nozzle face of the ink jet head, and a nozzle face provided inside the cap. It has a mesh-shaped filter that is in non-contact with and close to each other, and a suction unit that sucks the ink in the inkjet head through the cap.

In some cases, an ink absorber is arranged in the gap between the inner bottom surface of the cap and the filter.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a main part of the first embodiment of the present invention. The ink jet head 1 has an ink flow path (not shown), and a nozzle 1a is formed at the tip thereof. And ejection means (not shown) (eg, piezoelectric element)
With this, the ink in the flow path is pressurized to selectively eject the ink from the nozzle. Although not shown, characters and images are formed by the ink ejected onto the recording medium (paper or the like) in the print area.

A capping device 2 is provided corresponding to the ink jet head 1. The capping device 2 includes a cap 3 made of a hollow elastic body, and a mesh-shaped filter 4 made of stainless steel or the like disposed inside the cap 3 at an intermediate portion between the bottom surface 3a and the end surface 3b. The size of the mesh of the filter 4 is such that the ink can pass through and the dust mixed in the ink can be captured. A positioning projection 3c is integrally formed on the bottom surface of the cap 3 to define the position of the filter 4. The cap 3 is provided on the nozzle surface 1 of the head 1 by driving means (not shown).
It can be moved in and out of b. That is, it is movable in the left-right direction in FIG.

A hole 3d is formed on the bottom surface of the cap 3 and a connecting portion 3e is formed. And this connection 3
The tube 5 is connected to e, and the suction means 6 including a pump, which is not described in detail, is connected. Although not shown, there is a wiper-like cleaning means near the cap 3, and the nozzle surface 1b can be slid to be cleaned.

With such a construction, at the end of the printing operation, the ink jet head 1 moves from the printing area to the home position (position capable of facing the cap 3), and the cap 3 advances by the driving means (not shown), The end surface 3b is brought into pressure contact with the nozzle surface 1b of the head 1 so that the nozzle surface 1b is shielded from the outside air in a capping state. At this time, the filter 4 and the nozzle surface 1b do not contact each other,
A space 7 is maintained between the two. Further, a space 8 exists between the filter 4 and the cap bottom surface 3a. When the suction means 6 is operated in this state, the ink in the head 1 and the air bubbles and dust mixed in the ink are discharged from the nozzle 1a via the tube 5 and the cap 4. Most of the discharged ink reaches the suction means 6 after passing through the hole 3d, but it cannot be completely sucked and the cap 3
Some ink may remain inside. However, since the mesh of the filter 4 causes a capillary action and the ink easily moves to the space 8, the ink rarely remains inside the space 7. Therefore, even if the ink that cannot be completely sucked by the suction means 6 remains in the space 8,
There is not much possibility that it will remain in the. Then, the ink that has once passed through the filter 4 and reached the space 8 will not pass through the filter 4 again and return to the space 7 unless an excessive impact or the like is received. Furthermore, the spaces 7 and 8 in the cap 3
However, even if ink remains, it is extremely small. For this reason, there is little risk of ink reattachment to the nozzle surface 1b or surface tension between the nozzle surface 1b and the cap 4 that accumulates in a bridge shape, which is almost negligible. Therefore, the inside of the printer is not polluted. Further, since the cap is relatively thin and no member that expands due to water is used, it is sufficient that the cap end surface 3b and the nozzle surface 1b are separated when the nozzle surface 1b is opened.
Since it is not necessary to determine the distance that the cap separates from the head in consideration of the expansion amount of the absorber as in the conventional case, the movement distance of the cap by the driving means can be small.

After the ink is sucked, in a state where the capping is released, for example, before the next printing or the like, a cleaning means (not shown) cleans the nozzle surface 1b to remove the slightly adhered ink or dust.

Next, a second embodiment will be described with reference to FIG. The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. In the present embodiment, the ink absorber 9 is housed inside the cap 3, and the filter 4 is arranged on the front surface thereof. That is, the ink absorber 9 is arranged between the cap bottom surface 3a and the filter 4, and the space 7 exists in front of the filter 4 as in the first embodiment. As the ink absorber 9, a sponge-like member made of a porous material such as polyurethane is used as in the conventional case.

In this embodiment, when the ink sucking operation is repeated in the capping state, the ink absorber 9 gradually increases.
Is expanding. However, when the ink absorber 9 expands to some extent, it is restricted by the filter 4 and the ink absorber 9 cannot expand further forward. Therefore, even when the capping operation is performed thereafter, the ink absorber 9 does not come into direct contact with the nozzle surface 1b and approaches the nozzle surface 1b with the space 7 maintained. Therefore, there is no possibility that the ink once absorbed by the ink absorber 9 will reattach to the nozzle surface 1b. In addition, the presence of the space 7 prevents the ink from collecting between the cap 3 and the nozzle surface 1b due to the surface tension, and prevents the ink from dripping inside the printer. Further, as in the first embodiment, the space 7 in front of the filter 4 is small, and the ink that cannot be completely sucked is absorbed by the ink absorber 9, so that the ink hardly accumulates in the space 7. . Further, according to this embodiment, since the ink absorber 9 impregnated with the ink is present inside the cap 4, the inside of the cap 4 is always kept in a wet atmosphere, the nozzle 1a does not dry, and the ejection failure occurs due to solidification of the ink. Will not occur.

The size of the ink absorber 9 and the position where the filter 4 is arranged are set so that the ink absorber 9 impregnated with the ink does not come into contact with the filter 4 so strongly that the ink is squeezed out. Has been adjusted.

[0018]

According to the present invention, the ink sucked through the cap can be prevented from accumulating in the cap and dripping from between the nozzle surface and the re-adhesion of the ink to the nozzle surface.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a first embodiment of an inkjet printer according to the present invention.

FIG. 2 is a cross-sectional view of the essential parts of a second embodiment of an inkjet printer according to the present invention.

FIG. 3 is a sectional view of an essential part of a first conventional example of an inkjet printer.

FIG. 4 is a cross-sectional view of a main part of a second conventional example of an inkjet printer.

[Explanation of symbols]

 1 Inkjet head 1a Nozzle 1b Nozzle surface 3 Cap 4 Filter 6 Suction means 9 Ink absorber

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location B41J 2/175 B41J 3/04 102 Z

Claims (2)

[Claims] 1. An inkjet head having nozzles for ejecting ink, a hollow cap for covering a nozzle surface of the inkjet head, and a mesh-shaped filter provided inside the cap and in proximity to the nozzle surface in a non-contact state. An inkjet printer comprising: a suction unit configured to suction the ink in the inkjet head through the cap. 2. The ink jet printer according to claim 1, wherein an ink absorber is provided in a gap between the inner bottom surface of the cap and the filter.