JPH11227225A - Ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recorder capable of effectively discharging waste ink which is absorbed to be held by an ink absorbing member. SOLUTION: In an ink jet recorder 1, waste ink discharged from a nozzle 17 on an ink jet head 2 is absorbed by an ink absorbing member 30 disposed inside a recess section 21 of a cap 3. The ink absorbing member 30 comprises a first absorber section 31 having large gaps disposed at a side of an opening portion of the recess section 21 and a second absorber section 32 having small gaps disposed at a side of a bottom portion having a communicating hole 22 connected to a pump 4. As the waste ink absorbed by the second absorber section 32 moves to the first absorber to be concentrically held thereby, the pump 4 effectively sucks and discharges the waste ink which is absorbed and held by the ink absorbing member 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ink jet recording apparatus such as an ink jet printer. In particular, the present invention relates to a mechanism for discharging ink or the like having increased viscosity from an ink nozzle of an inkjet head.

[0002]

2. Description of the Related Art An ink jet recording apparatus provided with an ink jet head for discharging ink droplets from ink nozzles in accordance with recording contents is used in printers, facsimile machines and the like. In this ink jet recording apparatus, air bubbles may accumulate in the nozzles, or the ink may dry in the nozzles, and the nozzles may be clogged by the ink having increased viscosity. All of these phenomena cause a reduction in print quality. For this reason, the inkjet recording apparatus is provided with a mechanism for periodically cleaning the inkjet head in order to solve these problems.

That is, an ink jet recording apparatus includes:
A cap having a recess forming a suction chamber between the nozzle forming surface and the nozzle forming surface while covering the nozzle forming surface of the ink jet head; a porous ink absorbing member disposed in the recess of the cap; And a suction means such as a pump capable of sucking ink that is absorbed and held by the ink absorbing member.

Therefore, in the ink jet recording apparatus, if the suction means is operated while the nozzle forming surface of the ink jet head is covered with the cap at the time of turning on the power or at the start of printing, bubbles generated in the nozzles and ink paths may be generated. Of ink can be discharged into the cap. Also, the ink having increased viscosity in the nozzle can be discharged into the cap by performing the preliminary ejection operation. The ink discharged to the cap in this manner is absorbed and held by the ink absorbing member arranged in the concave portion of the cap, and the ink held here periodically performs an operation called idle suction for operating the suction means. The ink is sucked and discharged from the inside of the cap, and collected in the discharged ink reservoir.

[0005]

However, even if the ink held in the ink absorbing member in the cap is discharged from the cap by idle suction, the suction force of the pump only acts on the vicinity of the communication hole. There is a problem in that the ink located at a portion distant from the communication hole cannot be sufficiently discharged. For this reason, the ink holding ability of the ink absorbing member cannot be sufficiently restored,
It is necessary to reduce the amount of ink ejected from the nozzles during the preliminary ejection operation, or to frequently perform the idle suction operation. Here, if the amount of ink ejected from the nozzles during the preliminary ejection operation is reduced, the effect of discharging the thickened ink is diminished, and if the idle suction operation is performed frequently, the load on the suction means increases and the durability thereof is deteriorated. , And the printing speed is delayed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet recording apparatus capable of efficiently discharging the ink absorbed and held by an ink absorbing member by an idle suction operation.

[0007]

In order to solve the above-mentioned problems, suction is performed between an ink jet head for discharging ink droplets from a nozzle and the nozzle forming surface of the outer ink jet head while covering the nozzle forming surface. A cap having a concave portion forming a chamber, a porous ink absorbing member disposed in the concave portion of the cap, and ink that is communicated with the concave portion of the cap and absorbed and held by the ink absorbing member. In the ink jet recording apparatus having a suction unit capable of sucking the ink, the size of the gap in the ink absorbing member is partially different.

In the ink jet recording apparatus of the present invention, the ink discharged from the nozzle by the preliminary discharge operation or the like
The ink is absorbed and held by the ink absorbing member by capillary force (capillary attraction). Here, the size of the gap is partially different in the ink absorbing member, and the capillary force is large in the small portion of the gap. Therefore, due to the difference in capillary force between the large gap portion and the small gap portion, the ink absorbed in the large gap portion also moves toward the small gap portion and concentrates. Therefore, the ink held by the ink absorbing member is merely kept in such a manner that the suction force of the suction means effectively acts on the portion of the ink absorbing member where the ink is concentrated (the portion where the gap is small). Can be efficiently discharged. Accordingly, a large amount of ink can be sucked and discharged from the ink absorbing member by one idle suction operation, so that the ink holding ability of the ink absorbing member can be sufficiently restored. Therefore, the number of times of performing empty suction can be reduced, so that the load on the suction means such as a pump is reduced, and deterioration of the suction means can be prevented. Further, since the number of times of idle suction can be reduced, the printing speed can be improved.

In the present invention, among the ink absorbing members,
In order for the suction force of the suction means to effectively act on the portion where the ink is concentrated (the portion with a small gap),
In order to allow the suction means to communicate with the concave portion of the cap, a portion where the gap of the ink absorbing member is small may be arranged near a communication hole formed in the cap.

For example, when the communication hole is formed in the bottom of the concave portion of the cap, the ink absorbing member includes a first absorber portion having a small gap on the bottom side of the concave portion, and What has the 2nd absorber part which has a bigger gap than the 1st absorber part on the opening side of the said recessed part should just be employ | adopted. Further, when the communication hole is formed at the bottom of the recess of the cap, the ink absorbing member has a small gap from the position covering the communication hole at the bottom of the recess to the opening side of the recess. An opening of the recess from a bottom side of the recess so that a second absorber having a larger gap than the first absorber is adjacent to the first absorber; It is also possible to employ one that is arranged up to the section side. When such an ink absorbing member is employed, the ink discharged from the nozzle is first absorbed by the second absorber portion having a large gap on the side of the opening of the concave portion, and is absorbed by the second absorber portion. Due to the difference in capillary force between the second absorber portion and the first absorber portion, the first ink near the communication hole from the second absorber portion is removed.
It moves toward the absorber part of. For this reason, the ink in the cap concentrates near the communication hole in the ink absorbing member, so that the ink can be efficiently discharged by idle suction.

Further, when the communication hole is formed at the bottom of the recess of the cap, the communication hole formed at the bottom of the recess and the communication hole at the bottom of the recess are formed in the cap. A first protrusion that protrudes from the vicinity toward the opening side of the concave portion and a first protrusion that protrudes from the inner side surface of the concave portion on the opening side and holds the ink absorbing member between the first protrusion portion and the bottom portion of the concave portion. 2 and the ink absorbing member has flexibility, and
It is also possible to adopt a device having a small portion of the gap by being partially crushed by the first protrusion. With such a configuration, the peripheral portion of the first protrusion of the ink absorbing member is crushed and deformed, so that a small portion is formed near the communication hole. For this reason, the ink discharged from the nozzle is first absorbed by the large portion of the void on the side of the opening of the concave portion,
The ink absorbed by the large portion of the gap moves toward the vicinity of the communication hole due to the difference in capillary force between this portion and the small portion of the gap. For this reason, the ink in the cap is concentrated near the communication hole in the ink absorbing member, so that the ink can be efficiently discharged by idle suction.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an ink jet recording apparatus to which the present invention is applied will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of the ink jet recording apparatus 1. As shown in the figure, an ink jet recording apparatus 1 includes an ink jet head 2, a cap 3 capable of covering a nozzle forming surface 2a of the ink jet head 2, and an ink discharged from the ink jet head 2 inside the cap 3. Porous ink absorbing member capable of absorbing and holding (not shown)
And a pump 4 as suction means capable of sucking and discharging ink absorbed and held by the ink absorbing member from the inside of the cap 3.

The ink jet head 2 includes a carriage 5
And prints characters, images, and the like on the recording paper 7 held on the platen 6 while reciprocating in the scanning direction with the movement of the carriage 5. The ink jet head 2 is connected via an ink supply tube 8 to an ink tank 9 in which ink is stored. The cap 3 is connected to the pump 4 via the discharge tube 10, and the pump 4 can guide the discharged ink discharged inside the cap 3 via the discharge tube 10 to the discharged ink reservoir 11.

In such an ink-jet recording apparatus 1, when starting printing, the ink-jet head 2 moves to the position of the cap 3 and stops. It covers the nozzle forming surface 2a.

FIG. 2 shows a state in which the cap 4 covers the nozzle forming surface 2a of the ink jet head 2, and FIG. 3 shows the structure of the ink absorbing member in detail. The configuration of the cap 3 and the configuration of the inkjet head 2 will be described in more detail with reference to these drawings.

The ink jet head 2 has a plurality of nozzles 17 capable of discharging ink droplets according to the recorded contents. These nozzles 17 are open on the nozzle forming surface 2 a (front surface) of the inkjet head 2.

The cap 3 has an ink jet head 2
On the side opposite to the nozzle forming surface 2a,
Is formed between the nozzle forming surface 2a and the nozzle forming surface 2a. This recess 2
A communication hole 22 communicating with the discharge tube 10 is formed in the bottom 21 a of the first unit 21, and the inside of the concave portion 21 communicates with the pump 4. A porous ink absorbing member 30 is disposed inside the concave portion 21 of the cap 3.

The cap 3 is movable in a direction indicated by an arrow A in FIG. 2, and is used for filling the ink-jet head 2 with ink, performing preliminary ejection, or causing ejection failure.
When it becomes necessary to suck ink from inside the nozzle 17, it moves to the side of the ink jet head 2, comes into close contact with the nozzle forming surface 2 a, and forms an airtight suction chamber 25 between the nozzle forming surface 2 a of the ink jet head 2. (See FIG. 3).

When the pump 4 operates in this state, the ink in the nozzle 17 and the air bubbles generated in the nozzle 17 are sucked, and the discharged ink and the like are discharged into the recess 21 of the cap 3. In addition, not only the ink in the nozzle 17 but also the ink attached to the nozzle forming surface 2 a of the inkjet head 2 is sucked and discharged into the recess 21 of the cap 3. The discharged ink discharged into the concave portion 21 is absorbed and held by the capillary force of the porous ink absorbing member 30 disposed therein.

In the ink jet recording apparatus 1, a preliminary ink ejection operation is also performed in order to discharge the ink that has dried and increased in viscosity in the nozzle to the outside of the nozzle 17. Also when this operation is performed, the cap 3 covers the nozzle forming surface 2a of the inkjet head 2, and the thickened ink in the nozzle 17 is discharged into the concave portion 21 of the cap 3 and absorbed by the ink absorbing member 30. Is done.

In the ink jet recording apparatus 1, an idle suction operation of sucking the ink absorbed and held by the ink absorbing member 30 by the pump 4 and collecting the ink in the discharged ink reservoir 11 (the cap 3 is communicated with the atmosphere, The operation of sucking the ink accumulated in the cap 3 by the pump 4 without sucking the ink in 17 is performed. The ink absorbed and held by the ink absorbing member 30 is discharged to the discharged ink reservoir 11 by this idle suction operation, and the ink absorbing member 30
The ability to absorb and retain the ink is restored.

In the present embodiment, the ink absorbing member 30 in the cap 3 is made of a flexible material having a flat plate shape, and has a first absorber portion 31 having a small gap and a larger portion than the first absorber portion 31. Second absorber portion 3 having voids
2 has a two-layer structure. First absorber part 3
1 is thinner than the second absorber portion 32 and is located on the bottom side of the concave portion 21 of the cap 3. Therefore, the communication hole 22 is covered with the first absorber portion 31 on the bottom side of the concave portion 21 of the cap 3. The second absorber portion 32 is located on the opening side of the concave portion 21 and first receives the ink discharged from the nozzle 17.

In the ink jet recording apparatus 1 configured as described above, when the power is turned on or when printing is started, the nozzle 1
The cap 2 removes bubbles generated in the ink 7 and ink in the ink path.
When the ink is discharged inside, the discharged ink discharged from the nozzle 17 and the like is first absorbed by the second absorber portion 32 having a large gap. Here, the first absorber portion 3 having a small air gap is used.
1 has a large capillary force, and the second absorber portion 32 having a large void has a smaller capillary force than the first absorber portion 31. Due to such a difference in capillary force, the discharged ink absorbed and held in the second absorber portion 32 moves toward the first absorber portion 31 as shown by an arrow B in FIG. . As a result, the discharged ink concentrates on the bottom 21 of the recess 21 near the communication hole 22 with the pump 4. The area where the discharged ink is concentrated is the cap 3
Of the concave portion 21 where the suction force of the pump 4 acts most strongly. Therefore, when the idle suction operation is performed,
Since the suction force of the pump 4 effectively acts on the discharged ink that is concentrated and absorbed and held in the first absorber portion 31, the discharged ink is efficiently suctioned and discharged from the cap 3 and discharged. The ink is collected in the ink reservoir 11. Therefore, since a large amount of waste ink can be removed from the ink absorbing member 30 by one idle suction, the ability of the ink absorbing member 30 to suck and hold ink can be effectively restored. For this reason, since the load applied to the pump 4 can be reduced because the idle suction operation does not need to be performed frequently, the deterioration of the pump 4 can be prevented, and the standby time during the idle suction operation can be reduced. Since it can be shortened, there is an effect that the printing speed can be improved. In addition, in the ink absorbing member 30, the ink is intensively absorbed and held by the first absorbing portion 31, so that the surface of the second absorbing portion 32 (the surface of the ink absorbing member 30) is always 17
Etc. are in a state where they can easily receive ink discharged from such devices.

(Other Embodiments) The ink absorbing member 30 is not limited to the above-described two-layer structure. FIG. 4 shows a configuration of a different ink absorbing member. The ink absorbing member 30a shown in FIG.
A first absorber portion 31a having a small air gap and disposed from a position covering the communication hole 22 formed at the bottom of the concave portion 21 of the cap 3 to the opening side of the concave portion 21; The second absorber portion 3 disposed from the bottom side of the recess 21 to the opening side of the recess 21 so as to be adjacent to the first absorber portion 31a with a gap larger than 31a.
2a. Here, the first and second absorber portions 31a and 32a are formed to have the same thickness, but the volume of the second absorber portion 32a is larger than that of the first absorber portion 31a.

Even in such an ink absorbing member 30a, the discharged ink discharged from the nozzle 17 and the like is first absorbed by the second absorber portion 32a having a large gap. Here, the first absorber portion 31a having a small gap has a large capillary force, and the second absorber portion 32a having a large gap has a small capillary force as compared with the first absorber portion 31a. Due to such a difference in capillary force, the discharged ink absorbed and held in the second absorber portion 32a moves toward the first absorber portion 31a as shown by an arrow C in FIG. . Therefore, the discharged ink can be concentrated in the vicinity of the communication hole 22 with the pump 4, so that the pump 4 efficiently sucks and discharges the discharged ink absorbed and held in the ink absorber 30a during idle suction. Can be collected in the discharged ink reservoir 11. Therefore, the ink absorbing member 3
0a can effectively restore the ability to suck and hold ink, and reduce the number of times the idle suction operation is performed. For this reason, since the load applied to the pump 4 can be reduced because the idle suction operation does not need to be performed frequently, the pump 4
Can be prevented, and the standby time during the idle suction operation can be reduced, so that the effect of improving the printing speed can be achieved. In addition, in the ink absorbing member 30a, the ink is intensively absorbed and held by the first absorber portion 31a, so that the surface of the second absorber portion 32a always keeps the ink discharged from the nozzle 17 or the like. It is in an acceptable state.

FIG. 5 shows a porous ink absorbing member 30 having a uniform thickness and a substantially uniform void size.
An example is shown in which the first ink absorber portion having a small air gap is formed near the communication hole 22 using b. The ink absorbing members 30 and 30a described with reference to FIGS.
Need not necessarily be formed from a flexible material.
Is formed of a flexible material. As shown in FIG. 5, the cap 3 includes a plurality of first protrusions 26 protruding from a peripheral portion (near portion) of the communication hole 22 at the bottom 21 a of the recess 21 toward the opening side of the recess 21. A plurality of second protrusions 27 projecting horizontally from the inner side surface 21b on the opening side of the recess 21 and holding the ink absorbing member 30b between the recess 21 and the bottom 21a of the recess 21 are provided. First protrusion 2
6 rises almost vertically from the peripheral portion of the communication hole 22. Here, the length from the bottom 21a of the recess 21 to the second protrusion 27 is substantially equal to the thickness of the ink absorbing member 30b. Therefore, the second protrusion 27 and the bottom 21
a, the ink absorbing member 30b is arranged so as to be pushed into the second protrusion 2a.
7 does not come off the cap 3. In addition, a portion of the ink absorbing member 30b that covers the communication hole 22 is crushed by the first protrusion 26, and the gap is reduced. That is, the portion is the first absorber portion 31
b. In addition, the portion other than the first absorber portion 31b becomes a second absorber portion 32b having a larger gap than the first absorber portion 31b.

Accordingly, as in the case of using the ink absorbing members 30 and 30a described with reference to FIG. 3 or FIG. 4, the discharged ink discharged from the nozzle 17 and the like firstly has a second space having a large gap. It is absorbed by the absorber portion 32b. Here, the first absorber portion 31b having a small gap has a large capillary force, and the second absorber portion 32b having a large gap has a small capillary force as compared with the first absorber portion 31b. Due to such a difference in capillary force, the discharged ink absorbed and held in the second absorber portion 32b moves toward the first absorber portion 31b as shown by an arrow D in FIG. . Therefore, the discharged ink can be concentrated in the vicinity of the communication hole 22 with the pump 4, so that the pump 4 efficiently sucks and discharges the discharged ink absorbed and held in the ink absorber 30b during idle suction. Can be collected in the discharged ink reservoir 11. Therefore, the ink absorbing member 3
0b can effectively restore the ability to suck and hold ink, and reduce the number of idle suction operations. For this reason, since the load applied to the pump 4 can be reduced because the idle suction operation does not need to be performed frequently, the pump 4
Can be prevented, and the standby time during the idle suction operation can be reduced, so that the effect of improving the printing speed can be achieved. Moreover, in the ink absorbing member 30b, the ink is intensively absorbed and held by the first absorber portion 31b, so that the surface of the second absorber portion 32b always keeps the ink discharged from the nozzle 17 or the like. It will be easy to accept.

[0028]

As described above, in the ink jet recording apparatus according to the present invention, the size of the voids of the porous ink absorbing member disposed inside the cap is partially changed, so that the large voids and the voids are removed. The ink discharged from the nozzle by the preliminary ejection operation or the like is intensively absorbed and held in a desired portion by a difference in capillary force between the small portion and the small portion. Therefore, the ink absorbing member is held by the ink absorbing member only by making the suction force of the suction means such as the pump most act on the portion where the ink is concentrated (the portion with a small gap). Ink can be efficiently sucked and discharged. Therefore, a large amount of ink can be sucked and discharged from the ink absorbing member by one idle suction operation, so that the ability to suck and hold the ink can be effectively recovered, and the idle suction operation is frequently performed. No need. Therefore, the load applied to the pump can be reduced, so that the deterioration of the pump can be prevented, and the waiting time during the idle suction operation can be shortened, thereby improving the printing speed. Play.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an ink jet recording apparatus to which the present invention is applied.

FIG. 2 is a cross-sectional view showing a configuration of a cap in detail.

FIG. 3 is a cross-sectional view illustrating a configuration of an ink absorbing member in detail.

FIG. 4 is a cross-sectional view illustrating a different configuration example of the ink absorbing member.

FIG. 5 is a sectional view showing still another configuration example of the cap and the ink absorbing member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink jet recording apparatus 2 Ink jet head 2a Nozzle formation surface 3 Cap 4 Pump 17 Nozzle 21 Concave part 21a Bottom part 21b Inner peripheral side surface 22 Communication hole 25 Suction chamber 26 First projection part 27 Second projection part 30, 30a, 30b Ink absorption Member 31, 31a, 31b First absorber part 32, 32a, 32b Second absorber part

Claims (5)

[Claims] An ink jet head for ejecting ink droplets from a nozzle; a cap having a concave portion forming a suction chamber between the ink jet head and the nozzle forming surface while covering the nozzle forming surface; An ink jet recording apparatus comprising: a porous ink absorbing member disposed in the concave portion; and suction means communicating with the inside of the concave portion of the cap and capable of sucking ink absorbed and held by the ink absorbing member. 3. The ink jet recording apparatus according to claim 1, wherein the ink absorbing member partially differs in the size of a gap. 2. The cap according to claim 1, wherein the cap has a communication hole in the recess for the suction means to communicate with, and the ink absorbing member has a portion having a small gap near the communication hole. An ink jet recording apparatus. 3. The cap according to claim 2, wherein the cap includes the communication hole at a bottom of the concave portion, and the ink absorbing member includes a first absorbent portion having a small gap disposed at a bottom side of the concave portion. An ink jet recording apparatus comprising: a second absorber portion disposed on the opening side of the concave portion with a gap larger than the first absorber portion. 4. The cap according to claim 2, wherein the cap includes the communication hole at a bottom of the recess, and the ink absorbing member extends from a position covering the communication hole at a bottom of the recess to an opening side of the recess. A first absorber portion having a small gap disposed therein, and an opening side of the recess from the bottom side of the recess so as to be adjacent to the first absorber portion with a gap larger than the first absorber portion. An ink-jet recording apparatus, comprising: a second absorber portion arranged up to the second absorber portion. 5. The cap according to claim 2, wherein the cap projects from the communication hole formed at the bottom of the recess and a portion of the bottom of the recess near the communication hole at the bottom of the recess toward the opening of the recess. A first protruding portion, and a second protruding portion protruding from an inner side surface of the concave portion on the opening side and holding the ink absorbing member between the concave portion and the bottom of the concave portion; Flexible, and the first
An ink jet recording apparatus comprising a small portion of the gap by being partially crushed by the projection.