JP2000203060A - Ink jet recording apparatus and operation method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording apparatus capable of forming a stable meniscus after suction without leaving liquid droplets sucked into a nozzle portion and a method for operating the same. SOLUTION: A cap 2 has an absorbing member housing portion 24 and the gap forming portion 21 provided to the housing portion 24 and forming a gap between the absorbing member 3 and a nozzle portion 1a at a time of non-use of the nozzle portion 1a and, when a pressure change is generated in the cap 2 at a time of the use of the nozzle portion 1a to discharge ink to the outside of the housing portion 24 from the nozzle portion through the ink absorbing member 3, the ink absorbing member 3 is brought into contact with the nozzle portion 1a by the elastic deformation of the gap forming part 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a cap for covering a nozzle portion of an ink jet type recording head, has an ink absorber in the cap, and the cap performs storage when the nozzle portion is not used. The present invention relates to an ink jet recording apparatus configured to discharge ink when a nozzle portion is used, and an operation method in the ink jet recording apparatus.

[0002]

2. Description of the Related Art FIG. 6 shows a conventional ink-jet type capping method. Reference numeral 1001 denotes an ink jet head unit, 1001a denotes a head nozzle surface having nozzles for ejecting ink from the head, 1002 denotes a cap member that covers the head nozzle unit, and 1003 denotes a porous absorber provided inside the cap. The porous absorber 1003 is fixed by a projection of the cap member 1002a. The porous absorber 1003 is provided inside the cap 1002 so as to provide a gap A having a thickness equal to or greater than the thickness of the projection 1002a from the head nozzle surface 1001a. Reference numeral 1004 denotes a pump for generating a pressure change inside the cap, which is connected to a vent hole 1002b provided on the lower surface of the cap. Sign 1
005 is a ventilation valve for generating a pressure change inside the cap, and is connected to a ventilation hole 1002c provided on the lower surface of the cap.

Next, a method of discharging ink from the inside of the head by capping will be described. Cap 1 by capping
002 is in close contact with the head nozzle surface 1001a and is sealed from the outside air. At this time, the ventilation valve 1
005 is a closed state, and the pump 1004 is in a stopped state. Next, the pump 1004 is started and the cap 100
The internal pressure of No. 2 decreases, and ink is discharged from the inside of the head. At this time, the discharged ink is applied to the head nozzle surface 10.
01a becomes a large droplet, and the droplet is dropped or a part of the meniscus of the droplet comes into contact with the absorber 1003, so that the ink is absorbed by the absorber 1003, and then the ink is absorbed by the vent hole on the pump 1004 side. It is discharged outside through 1002b.

[0004]

Problems to be solved by the conventional method will now be described. In the above-described conventional method, a gap A exists between the head nozzle surface 1001a and the absorber 1003. For this reason, in the ink discharging process, the ink discharged from the head 1001 appears as a large droplet on the head nozzle surface 1001a, but drops, or the droplet larger than the gap A is discharged after being absorbed by the absorber 1003. However, droplets that do not fall and are smaller than the gap A remain on the head nozzle surface 1001a. Due to the residual, good formation of the ink meniscus on the head nozzle surface 1001a is prevented.

In the conventional method, after the ink is discharged by the above method by capping, ink droplets remaining on the head nozzle surface 1001a are removed by wiping. FIG. 7 shows the wiping method. After the ink is discharged by capping, ink droplets of 1008a remain on the head nozzle surface 1001a. A plate member 1006 made of an elastic material such as rubber and having a shape slightly longer than the interval B between the head nozzle surface 1001a and the elastic member fixing member 1007 is provided.
Direction, the remaining ink droplets are 100
It is removed by the plate-like member 1006 like 8b. At this time, the remaining ink droplets 100 on the head nozzle surface 1001a
8a, the amount of ink droplets 1008b when removed by wiping also increases, and the remaining ink droplets fall below the elastic plate member 1006, or the plate member 1006 is At a further distance, the remaining ink droplet 1008b scatters around and has a disadvantage such as adversely affecting the surrounding functional components.

In addition, the above-described capping method has an adverse effect even in a density modulation type ink jet system using two liquids. FIGS. 8 and 9 show a head nozzle portion of a two-liquid mixture density modulation type ink jet recording system. Symbol 100
Reference numeral 1b denotes a cross section of a head nozzle portion of a concentration modulation type ink jet system of two liquid mixture, and reference numeral 1001c denotes a head nozzle portion surface. The head nozzle portion of this system is provided with a nozzle 1010 for ink metering filled with ink, and a nozzle 1009 for discharging a droplet filled with a transparent diluent for diluting the ink. I have.

First, the ink filled in the ink liquid chamber 1013 is displaced downward in FIG. 8 by applying a voltage to the piezoelectric element 1011 a, and the ink is pushed by pressing the liquid chamber 1013. Is discharged from the fixed quantity nozzle 1010. This nozzle 1010a
Has a crescent shape shown in FIG. 9, and the ink 1015 discharged by this shape is discharged toward the discharge nozzle 1009 filled with the diluent. Next, the liquid chamber 101
When a voltage is applied to the piezoelectric element 1011b, the transparent diluting liquid 1014 filled in 2 is displaced below the piezoelectric element 1011b in FIG. Discharge nozzle 1009
Is discharged from Here, after the discharged ink 1015 is mixed with the diluting liquid 1014, the discharged ink 1015 is discharged like a droplet 1016, and lands on the recording surface as a density-modulated dot.

A problem when the above capping method is performed in this method will be described with reference to FIG. First, when the ink inside the head is discharged by the conventional capping method, as shown in FIG. 10, a gap A with an absorber 1003 installed inside a cap 1002 is formed.
And the mixed droplet 1017 remains. This mixed droplet 1
017 is a mixture of ink 1018 and transparent diluent 1019. The mixed droplet 1017 is
09 and the fixed-quantity nozzle 1010, the ink in the fixed-quantity nozzle 1010 causes the ejection nozzle 100
9, a problem arises in that the diluent in the discharge nozzle 1009 permeates into the fixed quantity nozzle and mixes with each other.

Second, after capping, the pump 1004
Causes a negative pressure change inside the cap 1002 to terminate the ink discharge, and then opens the ventilation valve 1005 to return the pressure inside the cap 1002 to atmospheric pressure.
At this time, the inside of the cap 1002 and the liquid chamber 1012 and the liquid chamber 1013 were at a pressure lower than the atmospheric pressure, but immediately after the vent valve 1005 was opened, the inside of the cap became the atmospheric pressure, and the liquid chamber 1012 and the liquid chamber 1013 is in a state of a pressure lower than the atmospheric pressure. Therefore, the droplet 1017 remaining on the nozzle surface is used to maintain the pressure balance within a range where the meniscus is broken and bubbles do not enter the nozzle.
The internal liquid chambers 1012 and 1013 of 009 and 1010 are absorbed. As a result, the droplet 10 colored with ink
Reference numeral 17 denotes a diluent liquid chamber 1012 filled with a transparent diluent mixed with a mixed liquid droplet 1017 until the pressure difference is reduced and the pressure on both sides of the meniscus is balanced, and the undiluted ink liquid Is diluted with the mixed droplet 1017. As a result of the first and second problems, the concentration in each of the liquid chambers 1012 and 1013 becomes non-uniform, and the concentration variation at the next ejection becomes significant. In view of the above, the present invention has been made to solve the above problems, and to provide an ink jet recording apparatus and an operation method in the ink jet recording apparatus which can form a stable meniscus after suction without leaving the sucked droplets in the nozzle portion. It is an object.

[0010]

According to a first aspect of the present invention, there is provided an ink jet type recording head having a cap for covering a nozzle portion of the recording head, an ink absorber in the cap, and the cap being provided with the nozzle. An ink jet recording apparatus configured to perform storage when the unit is not used and discharge the ink when the nozzle unit is used, wherein the cap is provided in the storage unit that stores the absorber, and in the storage unit. A gap forming portion for forming a gap between the absorber and the nozzle portion when the nozzle portion is not used, and causing a pressure change in the cap when the nozzle portion is used. When the ink is discharged from the nozzle portion to the outside of the storage portion through the absorber, the absorber is brought into contact with the nozzle portion by elastic deformation of the gap forming portion. An ink jet recording apparatus according to. According to the first aspect, when the nozzle portion is not used, a gap is formed between the absorber and the nozzle portion by the gap forming portion, so that the cap preserves the nozzle portion when it is not used. On the other hand, when the nozzle portion is used, the absorber is brought into contact with the nozzle portion due to the elastic deformation of the gap forming portion. Thus, if the inside of the cap is sucked and discharged, a stable meniscus can be formed after the suction without leaving the sucked droplet in the nozzle portion.

According to a second aspect of the present invention, in the ink jet recording apparatus according to the first aspect, the nozzle portion supplies the ink and a diluting liquid for diluting the ink, and the cap is provided in the container. A suction pump that operates when a pressure change is generated inside and the ink is discharged from the nozzle portion to the outside of the storage portion through the absorber is connected. According to the second aspect, when the nozzle portion is used, the absorber is in contact with the nozzle portion due to the elastic deformation of the gap forming portion. Therefore, the mixed droplets in which the ink and the diluting liquid are mixed cover the nozzle portion, and as a result, the ink is Penetrate into the diluent,
The diluent does not penetrate into the ink. As a result, density variations at the time of printing can be reduced, and printing at a stable density can be performed.

According to a third aspect of the present invention, there is provided a cap for covering a nozzle portion of an ink jet recording head, an ink absorber in the cap, and discharging of the ink when the nozzle portion is used. An ink jet recording apparatus having a configuration in which the cap is provided in the storage section for storing the absorber, and a gap is provided between the absorber and the nozzle section when the nozzle section is not used. And a gap forming portion for forming a pressure difference. When the nozzle portion is used, a pressure change is generated in the cap so that the ink is discharged from the nozzle portion to the outside of the housing portion through the absorber. In this case, the absorber may be brought into contact with the nozzle portion by elastic deformation of the gap forming portion. According to the third aspect, when the nozzle portion is not used, a gap is formed between the absorber and the nozzle portion by the gap forming portion, and when the nozzle portion is used, the absorber is brought into contact with the nozzle portion by elastic deformation of the gap forming portion. Touched. Thus, if the inside of the cap is sucked and discharged, a stable meniscus can be formed after the suction without leaving the sucked droplet in the nozzle portion.

According to a fourth aspect of the present invention, in the ink jet recording apparatus according to the third aspect, the nozzle portion supplies the ink and a diluting liquid for diluting the ink, and the cap is provided in the container. A suction pump that operates when a pressure change is generated inside and the ink is discharged from the nozzle portion to the outside of the storage portion through the absorber is connected. According to the fourth aspect, when the nozzle portion is used, the absorber is in contact with the nozzle portion due to the elastic deformation of the gap forming portion. Therefore, the mixed droplets in which the ink and the diluting liquid are mixed cover the nozzle portion, and as a result, the ink is Penetrate into the diluent,
The diluent does not penetrate into the ink. As a result, density variations at the time of printing can be reduced, and printing at a stable density can be performed.

According to a fifth aspect of the present invention, there is provided a cap for covering a nozzle portion of an ink jet recording head, an ink absorber in the cap, and the cap is stored when the nozzle portion is not used. Perform the operation method in the ink jet recording apparatus that discharges the ink when the nozzle portion is used, and when the nozzle portion is not used, a gap is formed between the absorber and the nozzle portion,
When the nozzle portion is used to generate a pressure change in the cap and discharge the ink from the nozzle portion to the outside of the storage portion through the absorber, the absorption is performed by elastic deformation of the void forming portion. An operation method in the ink jet recording apparatus, wherein a body is brought into contact with the nozzle portion. In the fifth aspect, when the nozzle portion is not used, a gap is formed between the absorber and the nozzle portion by the gap forming portion, so that the cap preserves the nozzle portion when it is not used. On the other hand, when the nozzle portion is used, the absorber is brought into contact with the nozzle portion due to the elastic deformation of the gap forming portion. Thus, if the suction and discharge are performed inside the cap, the suctioned droplets do not remain in the nozzle portion,
After the suction, a stable meniscus can be formed.

According to a sixth aspect of the present invention, in the operation method of the ink jet recording apparatus according to the fifth aspect, the nozzle unit supplies the ink and a diluting liquid for diluting the ink, The amount of elastic deformation of the void forming portion of the storage portion that stores the absorber is changed between use and use of the nozzle portion.

[0016]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Note that the embodiments described below are preferred specific examples of the present invention,
Although various technically preferable limits are given, the scope of the present invention is not limited to these modes unless otherwise specified in the following description.

1 to 5 show a preferred embodiment of the ink jet recording apparatus of the present invention. The ink jet recording apparatus 100 of FIG. 1 shows a capping state when the nozzle portion of the head is not used and the nozzle portion of the head is being stored. In contrast, FIG.
Shows a capping state when ink is discharged using the nozzle portion of the head. In FIG. 1, an inkjet recording apparatus 10
0 is a head 1, a cap 2, an absorber 3,
A suction pump 4 and a vent valve 5 for opening to the atmosphere are provided. The lower surface of the head (recording head) 1 has a nozzle portion 1a of the head. Nozzle part 1 of the head of head 1
The cap 2 is in close contact with the outer periphery of “a”. In the cap 2 there is an absorbent, preferably a porous absorbent 3
Are accommodated and arranged.

When the nozzle 1a of the head of FIG. 1 is not in use and the nozzle 1a of the head is in a capping state during storage, the nozzle 1a of the head 1 is stored to protect or protect the nozzle 1a. The cap 2 is adhered so as to surround it. In order to make such a close contact state, the cap 2 has an elastic deformation portion 21. The elastically deforming portion 21 has a function as a void forming portion when the nozzle portion 1a is not used, and is formed integrally with and protrudes from an upper portion of the housing portion 24, and has, for example, a tongue shape in cross section. . As shown in FIG. 3, the accommodating portion 24 has an arrow R in FIG.
It is almost rectangular when viewed from above. The elastic body 3 is housed and installed in the housing part 24. FIG. 3 shows such a structure of the cap 2 and the absorber 3, and the width W of the absorber 3 is set smaller than the width V inside the housing portion 24 of the cap 2. A plurality of wall-shaped convex portions 2d are formed inside the accommodating portion 24 so as to face each other. The distance between the facing wall-shaped protrusions 2d, 2d is set smaller than the width W of the absorber 3, whereby the absorber 3 is sandwiched by the plurality of wall-shaped protrusions 2d, 2d. , The absorber 3 is elastically bent and these wall-shaped projections 2
It is fixed between d. By securely fixing the absorber 3 inside the accommodation portion 24 in this manner, as shown in FIG. 2, when the capping is released from the state where the absorber 3 is in contact with the nozzle portion 1a of the head, the nozzle portion is released. This prevents the absorber 3 from sticking to the nozzle portion 1a due to the surface tension of the minute liquid remaining in 1a.

FIG. 4 shows a sectional structure of the cap 2 and the absorber 3 in FIG. 3 along the line XX. The bottom surface 2e of the cap 2 is a bottom surface on which the absorber 3 is installed, and the bottom surface 2e is set lower than the bottom surface 2f of the other portion. Pump suction hole 2 for bottom 2e
b and an air opening vent hole 2c. The pump suction hole 2b and the air vent hole 2c are also shown in FIGS. Absorber 3 is directly installed on pump suction hole 2b and open air vent hole 2c as shown in FIG. Therefore, the droplets 17 discharged from the nozzle portion 1a of the head 1 at the time of discharging the ink do not protrude outside the absorber 3, but are discharged outside through the pump suction hole 2b.

Returning to FIG. 1, in the capping state when the head is not used and the nozzle portion 1a is stored, the elastically deforming portion 21 of the cap 2 is tightly attached so as to surround the nozzle portion 1a. Moreover, the absorber 3 inside the cap 2
However, the elastically deformable portion 21 of the cap 2 is in close contact with the periphery of the nozzle portion 1a in a state having a certain gap F with the nozzle portion 1a. That is, the elastic deformation portion 21 is a gap forming portion of the cap 2. In this state, the suction pump 4 is stopped, and the vent hole 5 for opening the air inside the head 1 to the atmosphere may be closed or open. Nozzle part 1a and absorber 3
Is set to have a constant gap F, so that when the head is not used and stored, the meniscus of the ink filled in the nozzle portion 1a of the head 1 is not in contact with the absorber 3 and the nozzle The ink in the section 1a does not penetrate into the absorber and is not discharged.

Next, with reference to FIG. 2, the discharge of ink in the capping state when the head is in use and when the ink is discharged from the head 1 will be described. The discharge of the ink is performed in the following order. (1) The cap is further moved (elevated) in the H direction in FIG. 2 than in FIG. 1, and the cap 2 is more closely attached to the head 1. That is, the elastic deformation portion 21 is elastically deformed and the amount of bending is changed. FIG. 1 shows the amount of contact between the cap 2 and the head 1.
2 and G ≦ EF in FIG. 2, and the absorber 3 installed inside the cap 2 is in contact with the head nozzle portion (head nozzle surface) 1 a due to the dimension G. (2) Next, the ventilation valve 5 provided in the ventilation hole 2c for opening to the atmosphere provided on the bottom surface of the cap 2 is closed. still,
The order of (1) and (2) may be reversed. (3) When the suction pump 4 installed in the suction hole 2b provided on the bottom surface 2e of the cap 2 in FIG. 4 is driven, a pressure change occurs inside the cap 2. (4) When the pressure inside the cap 2 becomes lower than the atmospheric pressure due to the pressure change inside the cap 2, the inside of the cap 2 tries to maintain the pressure balance, and as a result, the ink is discharged from the head nozzle 1a. The ink discharged at this time is absorbed by the absorber without forming large droplets in the head nozzle portion 1a because there is no gap between the head nozzle portion 1a and the absorber 3, and the pump suction hole 2b Is more exhausted. (5) Next, the driving of the pump 4 is stopped, and
The atmosphere release valve 5 connected to c is opened. At this time, the pressure inside the cap 2 returns to the atmospheric pressure, but the pressure inside the head 1 is lower than the atmospheric pressure.
The droplet 17 attached to c attempts to enter the inside of the head nozzle 1a.

However, as described above, since the ink was discharged while the absorber 3 was in contact with the head nozzle portion 1a, the discharged droplet 17 in FIG.
And is discharged to the outside of the cap 2 and does not remain in the head nozzle portion 1a. Further, since the head nozzle portion 1a is covered with the absorber 3, the rapid pressure change generated in the vent hole 2c portion is reduced in the head nozzle portion 1a,
It is possible to reduce the phenomenon that air or droplets enter the head nozzle 1a. The procedure for stopping the operation of the pump 4 and opening the atmosphere release valve 5 may be reversed. In such an ink-jet type head 1, capping enables long-term storage when the head 1 is not used, and discharge of ink when maintaining the performance of the head 1 or when replacing the ink tank. The head 1 may be a head of a one-liquid type ink jet recording method that supplies only ink, or a head of a two-liquid mixed type density modulation type ink jet recording method.

FIG. 5 shows a preferred embodiment of the head of the two-liquid mixture density modulation type ink jet recording system. Conventionally, when ink inside the head is discharged by capping, a fixed amount of ink and a diluent are respectively discharged from a nozzle for ink quantification and a discharge nozzle filled with a transparent diluent. And head 1
Between the nozzles, the droplets discharged from both nozzles become mixed droplets and cover between the nozzles. As a result, the diluting liquid is discharged from the discharge nozzle to the ink in the quantitative nozzle, However, there is a problem that the liquid permeates into the diluent in the discharge nozzle. Further, when the inside of the cap is returned to the atmospheric pressure by opening and closing the on-off valve after discharging the ink, the mixed droplet is sucked into both nozzles, and the ink and the diluting liquid are mixed into the nozzles on the other side. There were also problems.

Therefore, the following structure is adopted in the two-liquid mixture density modulation type ink jet recording apparatus 200 shown in FIG. FIG. 5 shows a capping state when ink is discharged using the nozzle portion of the head.
In FIG. 5, the ink jet recording apparatus 200 generally includes a head 201, a cap 2, an absorber 3, a suction pump 4, a vent valve 5 for opening to the atmosphere, and the like. On the lower surface of the head (recording head) 1, a nozzle portion 1b of the head is provided.
have. The cap 2 is in close contact with the nozzle portion 1b of the head 1. In the cap 2, an absorber, preferably a porous absorber 3, is accommodated and arranged.

In a capping state when the nozzle portion 1b of the head 1 is not used and when the nozzle portion 1b of the head is stored, the nozzle portion 1b is used to store or protect the nozzle portion 1b of the head 1 (not shown). The cap 2 is adhered so as to surround the cap. In order to make such a close contact state, the cap 2 has an elastic deformation portion 21. The elastically deforming portion 21 has a function as a gap forming portion when the nozzle portion 1b is not used, and is formed integrally with and protrudes from an upper portion of the housing portion 24, and has, for example, a tongue shape in cross section. . The configuration and operation of the cap 2 and the absorber 3 are the same as those of the cap and the absorber 3 in FIGS.

The ink 18 filled in the liquid chamber 13 is
By applying a voltage to the piezoelectric element 11a, the piezoelectric element 11a is displaced downward in FIG.
Is pushed out of the nozzle 10. Similarly, the transparent diluent 19 filled in the liquid chamber 12 applies a voltage to the piezoelectric element 11b, so that the piezoelectric element 11b is displaced downward in FIG. As a result, the ink is discharged from the nozzle 9.

An ink jet recording apparatus 200 shown in FIG.
Then, the gap between the porous absorber 3 and the head 201 is eliminated, and the ink inside the head and the inside of the cap 2 are opened to the atmosphere in the contact state. When the suction pump 4 is started through the atmosphere release valve 5 by capping, and a pressure change is generated inside the cap 2 to discharge the ink inside the head 201, the fixed-side nozzle 1
0, the ink 18 is discharged, and the diluting liquid 19 is discharged from the discharge side nozzle 9. Since the head nozzle portion 1b is in contact with the absorber 3, the discharged liquid is absorbed by the absorber 3 as it is without forming droplets at the head nozzle portion 1b, and the cap 2 moves toward the suction pump 4 in the direction of the suction pump 4. Is discharged to the outside. For this reason, at the time of discharging the ink, the mixed droplet 1 of the ink 18 and the diluent 19
No connection at 7. Therefore, the diluting liquid 19 in the discharge nozzle 9 is placed in the fixed amount nozzle 10 or the fixed amount nozzle 1.
The ink 18 in 0 does not penetrate into the discharge nozzle 9 at all.

Next, the inside of the cap 2 is returned to the atmospheric pressure by opening and closing the ventilation valve 5. At this time, the inside of the cap 2 returns to the atmospheric pressure. However, since the liquid chambers 12 and 13 have a pressure lower than the atmospheric pressure, the liquid chambers 12 and 13 try to return to the atmospheric pressure. At this time, since the mixed droplet 17 connected to the discharge nozzle 9 and the fixed amount nozzle 10 does not exist, the mixed liquid droplet 17 does not penetrate into the inside of the discharge nozzle 9 and the fixed amount nozzle 10.

The effects of the embodiment of the present invention will be described. When the ink is discharged by capping, the ink sucked and discharged by the pump 4 while the absorber 3 is in contact with the head nozzle portion 1a (1b). Without remaining, a stable meniscus is likely to be formed after suction.
Even if droplets remain in the head nozzle, the droplets are in a very small amount, and a large amount of droplets adhere to the plate-like elastic body even when wiping by the plate-like elastic body after capping and ink discharge. There is nothing. For this reason, the scattering amount of the droplet after the wiping is suppressed, and the droplet is prevented from falling and penetrating into the surrounding members. In particular, the droplets used in this embodiment are effective because they often contain components that are difficult to evaporate and dry.

After the droplet is discharged by capping or suction, the air release valve 5 is opened. After the inside of the cap 2 becomes atmospheric pressure, the meniscus of the head nozzle portion 1a (1b) tries to maintain pressure balance. At this time, the porous absorber 3 functions as a pressure buffer, and the head nozzle 1a (1
The entry of air bubbles into the head nozzle without breaking the meniscus of b) can be further suppressed. In the case of the two-liquid mixing type density modulation type ink jet type head, as described above, the diluent 19 discharged from the discharge nozzle 9 and the ink 18 discharged from the fixed amount nozzle 10 when the ink is discharged by the pump 4 are used in the head nozzle section. Absorbed by the porous absorber 3 that abuts on 1b. Therefore, the ink and the diluting liquid are mixed on the head nozzle portion 1b which has been conventionally generated, and the mixed droplet 17 covers the discharging nozzle 9 and the fixed amount nozzle 10, so that the ink permeates the diluting liquid in the discharging nozzle 9, The phenomenon that the diluting liquid permeates the ink in the fixed quantity nozzle 10 is eliminated. As a result, density variations at the time of printing can be reduced, and printing at a stable density can be performed.

As described above, according to the embodiment of the present invention, in the capping method in the ink jet recording apparatus, when the head is stored by capping, a gap is provided between the absorber provided inside the cap and the head nozzle portion, and the capping is performed. The characteristic feature is that the pump suction is performed while the absorber is in contact with the head nozzle portion when the ink is discharged. Capping means for covering the head nozzle portion during non-use storage of the head, wherein the capping means has a gap between the internal absorber and the nozzle surface, and causes a pressure change inside the cap to discharge ink from the nozzle. Then, a pressure change is caused while the internal absorber is in contact with the head nozzle portion. The amount of deflection of the elastically deformable portion of the cap when the cap comes into contact with the head nozzle differs between when the head is not used and when the ink is discharged.

By the way, as the material of the cap 2 in the embodiment of the present invention, since it has the elastically deformable portion 21, it can be elastically deformed, for example, EPDM (ethylene propylene diene rubber), FKM (fluoro rubber), N
BR (nitrile rubber), CR (chloroprene rubber), I
R (isoprene rubber), IIR (butyl rubber), silicon rubber, NR (natural rubber), SBR (styrene butadiene rubber), BR (butadiene rubber) and the like. In the above rubber material, EPDM, NBR, IR, IIR, N
A cross-linking material is used for R, SBR, BR and the like, and examples of the cross-linking material include arbitrary cross-linking materials such as sulfur, organic peroxides, modified phenol resins, and metal oxides. Absorber 3
Examples of the porous body include a porous absorber such as a PVA porous body (polyvinyl alcohol), a PVF porous body (polyvinyl formal), a polyurethane porous body, a polyethylene sintered body, and a rubber sponge. May have an arbitrary diameter of several μm to several hundred μm. The porosity is also arbitrary. As the type of ink used in the inkjet recording apparatus 100,
For example, it contains water and a water-soluble organic solvent. In addition, additives such as a surfactant are added. Examples of the water-soluble organic solvent include aliphatic monohydric alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, s-butyl alcohol and t-butyl alcohol, and ethylene glycol and diethylene glycol. , Triethylene glycol, propylene glycol,
Polyhydric alcohols such as butylene glycol, glycerol, polyethylene glycol, polypropylene glycol, and thiodiglycol are exemplified. In addition, polyhydric alcohol derivatives such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, and ethylene glycol diacetate. No. The ink contains a dye and a pigment in addition to the solvent. Examples of the water-soluble dye include a water-soluble anionic dye. In addition, additives such as an antifoaming agent, a pH adjuster, and a fungicide are optionally added to the ink as needed. As the diluent, for example, water, a water-soluble organic solvent, and other additives such as a surfactant are added.
Examples of the water-soluble organic solvent include the same kind as the above-described ink.

[0033]

As described above, according to the present invention,
A stable meniscus can be formed after the suction without leaving the sucked droplet in the nozzle portion.

[Brief description of the drawings]

FIG. 1 is a view showing a preferred embodiment of an ink jet recording apparatus according to the present invention, in which a nozzle portion of a head is in a non-use state and a capping state in which the nozzle portion is stored for a long period of time and head performance is maintained.

FIG. 2 is a diagram showing a capping state when discharging ink in the ink jet recording apparatus of FIG. 1;

FIG. 3 is a plan view showing a structural example of a cap and an absorber viewed from a direction R in FIG. 1;

FIG. 4 is a sectional view of the cap and the absorber taken along line XX in FIG. 3;

FIG. 5 is a diagram showing a preferred embodiment in the case where the nozzle portion of the head is a density modulation type ink jet recording system of two liquid mixture.

FIG. 6 is a view showing a conventional ink jet recording apparatus.

FIG. 7 is a view showing a state in which ink droplets remaining in a nozzle portion of a head in the related art are eliminated.

FIG. 8 is a view showing a state of a nozzle portion in a conventional two-liquid mixture density modulation type ink jet recording system.

FIG. 9 is a view showing an example of the shapes of ink and a diluting liquid in the conventional nozzle unit of FIG. 8;

FIG. 10 is a diagram showing a state in which a mixed droplet obtained by mixing ink and a diluting liquid remains in a conventional case.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Head, 1a ... Head nozzle part (head nozzle surface), 2 ... Cap, 3 ... Absorber, 4 ...
・ Suction pump, 5 ・ ・ ・ Ventilation hole for opening to atmosphere, 10 ・ ・
-Ink jet recording device, 21 ... elastic deformation part (gap forming part), 24 ... accommodation part

Claims (6)

[Claims] An ink-jet recording head having a cap for covering a nozzle portion, an ink absorber in the cap, and the cap for storing when the nozzle portion is not used; An ink jet recording apparatus configured to discharge the ink when the unit is used, wherein the cap is provided in the storage unit that stores the absorber, and the storage unit is provided, and when the nozzle unit is not used,
A gap forming portion for forming a gap between the absorber and the nozzle portion, wherein a pressure change occurs in the cap when the nozzle portion is used to absorb the ink from the nozzle portion. The ink jet recording apparatus according to claim 1, wherein, when discharging to the outside of the storage section through the body, the absorber is brought into contact with the nozzle section by elastic deformation of the gap forming section. 2. The nozzle section supplies the ink and a diluting liquid for diluting the ink.
2. The ink jet recording apparatus according to claim 1, wherein a suction pump that operates when a pressure change is generated in the cap and the ink is discharged from the nozzle portion to the outside of the storage portion through the absorber is connected. . 3. An ink jet recording apparatus having a cap for covering a nozzle portion of an ink jet recording head, an ink absorber in the cap, and discharging the ink when the nozzle portion is used. The device, wherein the cap is provided in the storage section that stores the absorber, and is provided in the storage section, and when the nozzle section is not used,
A gap forming section for forming a gap between the absorber and the nozzle section, and when the nozzle section is used, a pressure change is generated in the cap to cause the ink to flow from the nozzle section. The ink jet recording apparatus according to claim 1, wherein, when discharging to the outside of the storage section through the absorber, the absorber is brought into contact with the nozzle due to elastic deformation of the gap forming section. 4. The nozzle section supplies the ink and a diluting liquid for diluting the ink, and the container includes:
4. The ink jet recording apparatus according to claim 3, wherein a suction pump that operates when a pressure change is generated in the cap and the ink is discharged from the nozzle section to the outside of the storage section through the absorber is connected. . 5. A cap for covering a nozzle portion of an ink jet type recording head, an ink absorber in the cap, wherein the cap performs storage when the nozzle portion is not used, A method of operating an ink jet recording apparatus that discharges the ink when the part is used, wherein a void is formed between the absorber and the nozzle part when the nozzle part is not used, and when the nozzle part is used, When a pressure change occurs in the cap and the ink is discharged from the nozzle portion to the outside of the storage portion through the absorber, the absorber is brought into contact with the nozzle portion by elastic deformation of the gap forming portion. An operation method in an ink jet recording apparatus, characterized in that: 6. The nozzle section supplies the ink and a diluting liquid for diluting the ink, and stores the absorber when the nozzle section is not used and when the nozzle section is used. The operation method according to claim 5, wherein the amount of elastic deformation of the gap forming portion of the containing portion is changed.