JP3189532B2 - Inkjet printer - Google Patents

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 capping means.

[0002]

2. Description of the Related Art An example of a conventional ink jet printer is shown in FIGS. These are the heads 11 when not printing.
In order to prevent the nozzle 12 from drying and solidifying the ink to render printing impossible, a cap 13 covering the nozzle surface 11a is used.
Some are provided. The cap 13 separates from the head 11 during a printing operation to be in an open state, and closes the nozzle surface 11a of the head 11 to shut off the nozzle 12 from outside air during non-printing, thereby preventing drying.

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

[0004]

Among the conventional constructions, as shown in FIG. 3, in the case where the inside of the cap 13 is hollow, a small amount of ink which cannot be completely sucked by the suction means 14 remains in the cap 13. And head 1 at the time of capping
The ink may adhere to the nozzle surface 11a again, or the ink may remain in a bridge between the nozzle surface 11a and the cap 13 due to surface tension. In this case, when the cap 13 is retracted, the ink accumulated in a bridge shape falls and stains the inside of the printer.

In the case where a porous material made of polyurethane or the like, that is, a sponge-like ink absorber 16 is provided in the cap 13 as shown in FIG. 4, the sponge-like ink absorber 16 has moisture. When the ink is sucked, the volume of the ink absorber 16 increases. Then, the front surface of the ink absorber 16 expands forward from the end surface of the cap 13 (the state before expansion is indicated by a two-dot chain line). In this case, at the time of capping, since the ink absorber 13 is pressed against the nozzle surface 11a, the ink impregnated in the ink absorber 16 may seep and adhere to the nozzle surface 11a again. Further, when the capping is released, even if the end face of the cap 13 is separated from the nozzle surface 11a, the ink absorber 16 is in contact with the nozzle surface 11a to the end, and when the ink absorber 16 is separated thereafter, the front surface of the ink absorber 16 and the nozzle surface 11a are separated. During this time, ink may remain in a bridge shape due to surface tension. If the cap 13 is further retracted from this state and the ink absorber 16 separates from the nozzle surface 11a, the ink accumulated in the form of a bridge will fall and stain the inside of the printer. Further, since the sponge-like ink absorber 16 is in direct contact with the nozzle surface 11a, dirt and dust of the ink absorber 16 easily adhere to the nozzle surface 11a.

[0006] In order to prevent this, even if the ink absorber 16 expands, the ink absorber 16 does not come into contact with the nozzle surface 11a.
In consideration of the expansion rate, it is necessary to dispose the ink absorber 16 in advance so that the front surface of the ink absorber 16 is located at a position largely retreated from the end surface of the cap 13. However, when doing so, at the time when the ink absorber 16 is not yet impregnated with a large amount of ink and not much expanded, a large space is formed in the cap 13 in front of the ink absorber 16 and the case where the ink absorber 16 is not disposed. Similarly, the sucked ink is applied to the nozzle surface 1
A relatively large amount of the ink easily accumulates in the space between the ink absorbing member 1a and the front surface of the ink absorber 16, and the ink accumulated here again adheres to the nozzle surface 11a at the time of capping, etc. There is a possibility that a pool may be generated and the inside of the printer may be soiled.

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 into the inside of the printer and becoming dirty.

[0008]

In order to achieve the above object, an ink jet printer according to the first aspect of the present invention comprises:
An ink jet head having a nozzle for discharging ink, a hollow cap covering the nozzle surface of the ink jet head, and a space provided between the cap bottom surface which is close to the nozzle surface in a non-contact state and which faces the nozzle surface. And a mesh-shaped filter that is arranged to face the nozzle surface and can pass ink, and a suction unit that suctions ink in the inkjet head through a space of the cap. According to a second aspect of the present invention, in the first aspect, an ink absorber is provided in a space of the cap.

[0009]

According to the first aspect of the present invention, since a mesh filter is used, if the filter cannot be completely sucked by the suction means and remains in the cap, the mesh of the filter causes a capillary action to remove ink. It is easy to move to the space, and does not remain in the space between the nozzle surface and the filter. For this reason, it is possible to prevent the ink from re-adhering to the nozzle surface and the accumulation of the ink in a bridge shape due to the surface tension between the nozzle surface and the cap. According to the second aspect of the present invention, the expansion of the ink absorber due to the absorption of the ink is regulated by the filter, so that the ink absorber does not directly contact the nozzle surface when performing the capping operation, but is temporarily absorbed. Re-adhesion of ink to the nozzle surface can be prevented.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a main part of a first embodiment of the present invention. The ink jet head 1 has an ink flow path (not shown) formed therein, and a nozzle 1a formed at the tip thereof. And a discharge unit (not shown) (for example, a piezoelectric element)
And pressurizes the ink in the flow path to selectively discharge the ink from the nozzles. Although not shown, characters and images are formed by ink discharged onto a recording medium (such as paper) in a 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 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 fine enough to allow the ink to pass through and capture dust mixed in the ink. In order to define the position of the filter 4, a positioning projection 3c is integrally formed on the bottom surface of the cap 3. The cap 3 is moved by the driving means (not shown) to the nozzle surface 1 of the head 1.
b. That is, it is movable in the left-right direction in FIG.

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

With this configuration, at the end of the printing operation, the ink jet head 1 moves from the printing area to the home position (a position capable of facing the cap 3), and the driving means (not shown) moves the cap 3 forward. The end face 3b is brought into pressure contact with the nozzle face 1b of the head 1 so as to shut off the nozzle face 1b from the outside air. At this time, the filter 4 does not contact the nozzle surface 1b,
A space 7 is kept between the two. 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 bubbles and dust mixed in the ink are discharged from the nozzle 1a via the tube 5 and the cap 4. Almost all of the discharged ink passes through the hole 3d and reaches the suction means 6, but the ink cannot be completely sucked and the cap 3
Some ink may remain in the inside. However, since the mesh of the filter 4 generates a capillary action and the ink easily moves to the space 8, the ink hardly remains in the space 7. Therefore, even if the ink that could not be completely sucked by the suction means 6 remains in the space 8,
There is not much risk of remaining in The ink that has once passed through the filter 4 and has reached the space 8 does not return to the space 7 through the filter 4 again unless it receives an excessive impact. Further, spaces 7 and 8 in the cap 3
Is very small in volume, so that even if ink remains, it is extremely small. For this reason, there is little possibility that the ink will accumulate in the form of a bridge due to the re-adhesion of the ink to the nozzle surface 1b or the surface tension between the nozzle surface 1b and the cap 4, which is almost negligible. Therefore, the inside of the printer is not stained. Further, since the thickness of the cap is relatively thin and a member that expands due to moisture is not used, the cap end face 3b and the nozzle face 1b only need to be separated when the nozzle face 1b is opened.
Since it is not necessary to determine the distance at which the cap separates from the head in consideration of the expansion of the absorber as in the related art, the moving distance of the cap by the driving means can be small.

After the ink suction, in a state where the capping is released, for example, before the next printing, a cleaning means (not shown) cleans the nozzle surface 1b and removes the slightly attached ink and dust.

Next, a second embodiment will be described with reference to FIG. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description is omitted. In the present embodiment, the ink absorber 9 is accommodated inside the cap 3 and the filter 4 is provided on the front surface thereof. That is, the ink absorber 9 is disposed between the cap bottom surface 3a and the filter 4, and a 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 related art.

In this embodiment, when the ink suction operation is repeated in the capping state, the ink absorber 9 is gradually removed.
Begins to expand. However, if 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 comes close to 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 adhere to the nozzle surface 1b again. Further, the presence of the space 7 prevents ink from being accumulated between the cap 3 and the nozzle surface 1b due to surface tension, and prevents the ink from dripping into the printer. As in the first embodiment, the space 7 in front of the filter 4 is small, and the ink that has not been completely absorbed is absorbed by the ink absorber 9, so that the ink hardly collects in the space 7. . Further, according to this embodiment, since the ink absorber 9 impregnated with ink is present in the cap 4, the inside of the cap 4 is always kept in a humid atmosphere, and the nozzle 1a does not dry and the ejection failure occurs due to solidification of the ink. Does not occur.

The size of the ink absorber 9 and the disposition position of the filter 4 are set so that the ink absorber 9 impregnated with the ink is not pressed against the filter 4 so strongly that the ink is squeezed out. Has been adjusted.

[0018]

According to the present invention, it is possible to prevent the ink sucked through the cap from accumulating in the cap and dripping from between the nozzle surface, and to reduce the re-adhesion of the ink to the nozzle surface.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a first embodiment of an ink jet printer according to the present invention.

FIG. 2 is a sectional view of a main part of a second embodiment of the ink jet printer according to the present invention.

FIG. 3 is a sectional view of a main part of a first conventional example of an ink jet printer.

FIG. 4 is a sectional view of a main part of a second conventional example of an ink jet printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink jet head 1a Nozzle 1b Nozzle surface 3 Cap 4 Filter 6 Suction means 9 Ink absorber

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) B41J 2/165 B41J 2/18 B41J 2/185

Claims (2)

(57) [Claims] An ink-jet head having a nozzle for discharging ink; a hollow cap covering a nozzle surface of the ink-jet head; a nozzle close to a non-contact state with the nozzle surface;
A space is provided between the cap bottom surface facing the surface,
A mesh-shaped filter that is disposed to face the nozzle surface and that allows ink to pass therethrough ; and suction means that suctions ink in the inkjet head through a space of the cap. Inkjet printer. 2. An ink jet printer according to claim 1, wherein an ink absorber is provided in a space of said cap .