JPH10264402A - Capping device for ink jet type recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a level of a negative pressure to be applied to all of the nozzles constant irrespective of a distance from an ink suction hole. SOLUTION: In this capping device, a cap member 2 made of an elastic material which is brought into intimate contact with a nozzle plate of a recording head having a nozzle N is installed in a frame 1 and an ink suction hole 3 that supplies a negative pressure for discharging ink from the nozzle N is provided to the cap member 2. A hole plate 4 having a plurality of holes 5, 5, 5... for treating a pressure distribution in a longitudinal direction of the cap member 2 is housed at a portion between the bottom face 2b and the opening face in the cap member 2. Size of each of holes or density in arrangement of the holes is tuned such that the negative pressure is uniformly applied to each of the nozzles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capping apparatus for sealing a nozzle opening of an ink jet recording head and applying a negative pressure to dry ink and to eliminate clogging.

[0002]

2. Description of the Related Art In an ink jet recording head, since ink in a pressure generating chamber is pressurized and ink droplets are ejected from a nozzle opening to perform recording, an ink solvent near the nozzle opening evaporates, and the inside of the recording head is reduced. When the air bubbles stagnate, ink droplet ejection failure occurs.Therefore, the recording head is sealed with a capping device, and a negative pressure is applied to the nozzle opening by a suction pump to forcibly discharge ink from the nozzle opening. It is necessary to provide a means for discharging the ink that has increased in viscosity in the vicinity of the nozzle opening or the air bubbles that have stagnated in the pressure generating chamber to the capping device.

On the other hand, in order to respond to demands for higher printing speed and higher quality of color printing, the number of nozzle openings constituting the recording head is increased, and as a result, the recording head is becoming longer. For this reason, the cap member of the capping device for sealing the recording head is inevitably lengthened,
A large imbalance occurs in the negative pressure acting due to the distance between the ink suction port communicating with the suction pump and the nozzle opening, and it becomes difficult to uniformly discharge ink from all the nozzle openings constituting the recording head. ing.

[0004]

In order to alleviate such a problem, the ink ejected in accordance with the distance from the ink suction port, for example, as disclosed in Japanese Patent Application Laid-Open No. H7-195712, is disclosed. Insert a flow regulating plate that actively changes the flow path resistance of the guiding member, or
No. 0723, the ink discharged to the cap member is quickly and reliably discharged to the outside without causing scattering, and a capping device or the like provided with an air communication hole has been proposed. All of these are intended to reliably discharge the ink of the capping device, which has become longer, to the outside.Since the negative pressure acting on the nozzle openings cannot be adjusted, the ink is uniformly discharged from all the nozzle openings. There is still a problem that the ink cannot be ejected.

The present invention has been made in view of such a problem, and an object thereof is to apply a negative pressure to a recording head to forcibly discharge ink from a nozzle opening of the recording head. It is another object of the present invention to provide a capping device for an ink jet type recording head capable of uniformly applying a negative pressure to a nozzle opening.

[0006]

According to the present invention, a cap member made of an elastic material, which is in close contact with a nozzle plate of a recording head having a nozzle opening for discharging ink, is provided on the frame. In a capping device containing an ink suction port for storing and supplying a negative pressure for discharging ink from the nozzle opening to the cap member, the cap member is provided between the bottom surface of the cap and the opening surface of the cap. A perforated plate having a plurality of through holes for adjusting the pressure distribution in the longitudinal direction of the member was accommodated, and the negative pressure acting on the nozzle opening was adjusted.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the illustrated embodiments. 1 (a) to 1 (d) show an embodiment of the present invention, in which a capping device is a butyl rubber having ink resistance and elasticity on a frame 1 serving as a mounting member to a base. Inserting a cap member 2 formed by injection molding, etc., into an ink suction port 3 communicating with an external suction pump on a bottom surface 2c substantially at the center.
Is provided.

The cap member 2 has a fold 2a formed on the upper surface thereof in close contact with the nozzle plate of the recording head, a connecting pipe portion 2b formed integrally on the outer surface of the ink suction port 3, and the frame body 1 A connecting tube 1a is formed on the bottom surface, which accommodates the tube 2b and is connected to a tube connected to the suction pump.

Reference numeral 4 denotes a perforated plate which is a feature of the present invention, and is accommodated in the cap member 2 in parallel with the bottom surface 2c of the cap so that the outer periphery of the plate is elastically contacted with the inner periphery of the cap member 2. The perforated plate 4 has through holes 5, 5, 5 mm having the same inner diameter so that the density increases in accordance with the distance from the ink suction port 3.
‥ are formed, and support portions 4a and 4b that are in contact with the bottom surface 2c of the cap member 2 are formed on the peripheral edge on the lower surface side.

The perforated plate 4 is made of a water-repellent material such that at least the surface facing the nozzle plate has ink repellency.
For example, coating polytetrafluoroethylene, polyvinylidene, polyfluorovinyl, etc.,
Eutectoid plating is performed, and the perforated plate itself is formed of a water-repellent material.

In this embodiment, when the cap member 2 is resiliently contacted with the nozzle plate of the recording head and capped, and a suction pump (not shown) is operated, the cap member 2 is placed in the space 6 between the bottom surface 2c of the cap member 2 and the perforated plate 4. Negative pressure acts,
A negative pressure also acts on the nozzle plate through the through holes 5, 5, 5 ° of the perforated plate 4.

Since the holes 5, 5, 5 ‥‥ have a density which increases with the distance from the ink supply port 3, the nozzle opening N has a constant value regardless of the distance from the ink suction port 3. The negative pressure acts to discharge ink from all the nozzle openings N at a flow rate as uniform as possible.

The ink discharged to the perforated plate 4 is
Due to the ink repellency of the surface, the perforated plate 4 hardly wets and is discharged from the ink suction port 3 to the outside through the through holes 5, 5, 5 °.

In the above embodiment, the lower surface of the perforated plate 4 is formed as a space, but a sheet 7 of a porous material having ink absorbency and air permeability as shown in FIG. 2 is inserted. Even if it does, the same effect is exerted.

In the above-described embodiment, the perforated plate 4 is supported only at the peripheral edge. However, as shown in FIG. 3A, the supporting portions 4c, 4c are also formed at the center of the back surface. 3 (b), a groove 2d is formed in the inner surface of the cap member 2 and the peripheral edge is fitted into the groove 2d as shown in FIG.
As shown in (c), the projection 2 is formed on the inner surface of the cap member 2.
e and 2f may be formed and supported by this.

Further, in the above-described embodiment, the flow path resistance is adjusted by the density of the through holes 5, but FIG.
Are formed at regular intervals, while the holes 5 ', 5', 5 ', whose inner diameters increase with the distance from the ink suction port 3, are formed. It may be formed.

Further, in the above-mentioned embodiment, the upper surface and the lower surface are communicated with each other by the through holes. However, as shown in FIG. A long hole 8 extending in parallel with the arrangement direction of the nozzle openings N;
Obviously, the same effect is obtained even if 8, 8, 8 are formed. Preferably, the width of the long hole 8 is increased according to the distance from the ink suction port 3.
The pressure acting on the nozzle opening N can be made as constant as possible regardless of the position of the nozzle opening N.

If the cap is long, it becomes very difficult to discharge the ink at a position away from the ink supply port 3 to the outside. FIGS. 6 (a) and 6 (b) are for dealing with such a problem. At a position apart from the ink suction port, an air opening port 9 selectively communicating with the atmosphere by a valve (not shown) outside the cap. Are formed.

According to this embodiment, when ink is discharged from the recording head, the air opening 9 is closed and a negative pressure is applied to the recording head. At the time when the discharge of the ink is completed, the atmosphere opening port 9 is opened, and the negative pressure of the suction pump is applied again. Then, an air flow is generated from the air opening port 9 to the ink suction port 3 to move the ink to the ink suction port 3 so that the ink can be more reliably removed.

It is desirable to arrange the ink suction port 3 and the air opening port 9 at diagonal points in the longitudinal direction as shown in FIG. Further, as shown in FIG. 6 (c), the tip 9a of the air opening 9 may be made to penetrate the perforated plate 4 so as to directly face the nozzle plate.

[0021]

As described above, in the present invention, a cap member made of an elastic material which is in close contact with a nozzle plate of a recording head having a nozzle opening for discharging ink is accommodated in a frame, and the cap member is provided with the cap member. In a capping device provided with an ink suction port for supplying a negative pressure for discharging ink from a nozzle opening, a plurality of cap members are provided with a plurality of components for adjusting a longitudinal pressure distribution of a cap member between a bottom surface of the cap and an opening surface of the cap. Since a perforated plate having through holes is accommodated, it is possible to adjust the negative pressure from a small number of ink suction ports to act equally on all nozzle openings, regardless of the length of the recording head. The ink can be uniformly discharged from the nozzle opening.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a capping device of the present invention, wherein FIG. 1A is a top view, FIG. 1B is a cross-sectional view taken along line AA, and FIG. , And FIG. 4D is a cross-sectional view taken along line CC.

FIG. 2 is a sectional view showing another embodiment of the capping device of the present invention.

FIGS. 3A to 3C are cross-sectional views showing another embodiment of the supporting form of the perforated plate.

FIG. 4 is a top view showing another embodiment of the capping device of the present invention.

FIG. 5 is a top view showing another embodiment of the capping device of the present invention.

FIGS. 6A to 6C are a cross-sectional view, a top view, and a cross-sectional view, respectively, showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Frame 2 Cap member 3 Ink suction port 4 Perforated plate 5 Through hole

Claims (12)

[Claims] 1. A cap member made of an elastic material which is in close contact with a nozzle plate of a recording head having a nozzle opening for discharging ink is housed in a frame, and a negative pressure for discharging ink from the nozzle opening is applied to the cap member. In a capping apparatus having an ink suction port for supplying, a perforated hole having a plurality of through holes for adjusting a longitudinal pressure distribution of the cap member between a bottom surface of the cap and an opening surface of the cap in the cap member. Capping device for ink-jet recording head containing plates. 2. The capping device for an ink jet recording head according to claim 1, wherein the density of the through holes increases according to the distance from the ink supply port. 3. The capping device for an ink jet recording head according to claim 1, wherein an inner diameter of the through hole increases according to a distance from the ink supply port. 4. The capping device for an ink jet type recording head according to claim 1, wherein the through hole is formed by an elongated hole extending from the vicinity of the ink supply port to an end of the cap member. 5. The capping device for an ink jet recording head according to claim 4, wherein the width of the elongated hole increases according to the distance from the ink supply port. 6. The capping device for an ink jet recording head according to claim 1, wherein at least a surface of the perforated plate facing the nozzle plate has ink repellency. 7. The capping device for an ink jet recording head according to claim 1, wherein the perforated plate has a supporting portion on the cap member side. 8. The perforated plate whose peripheral edge is fixed by a fixing portion formed on the cap member.
3. The capping device for an ink jet recording head according to claim 1. 9. The apparatus according to claim 1, wherein a porous sheet is inserted between the perforated plate and the cap member. 10. The capping device for an ink jet recording head according to claim 1, wherein the cap member has an atmosphere opening port selectively communicating with the atmosphere at a predetermined distance from the ink suction port. 11. The capping device for an ink jet recording head according to claim 10, wherein the ink suction port and the air opening port are arranged at diagonal points in the longitudinal direction of the cap member. 12. The capping device for an ink jet recording head according to claim 10, wherein the air opening is extended to a position exposed from the surface of the perforated plate.