JPH0747688A - Ink absorber and ink tank employing it - Google Patents

Abstract

PURPOSE:To provide an ink absorber, and an ink tank employing it, in which the ink channel is protected against blockage due to mixing of bubble or dust and a good print image can be obtained. CONSTITUTION:An ink absorber 1 impregnated with ink is contained in an ink tank 4. An atmospheric communication port 5 is made through the upper part of the ink tank 4 and the ink absorber 1 is communicating with the atmosphere. The ink tank 4 is coupled with an ink jet head 3 at the lower part thereof. The surface of the ink absorber 1 is thermally fused by means of a heater, for example, and then hardened to form fusion faces 2a, 2b. The fusion face 2b to be connected with the ink jet head 3 is formed to have smaller opening diameter than the fusion face 2a so that the bubbles and dust particles passed through the fusion face 2a is trapped and prevented from intruding into the ink jet head 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink absorber for impregnating and holding ink used when supplying ink in an ink jet recording apparatus, and an ink tank using the same.

[0002]

2. Description of the Related Art Conventionally, in an ink jet recording apparatus, an ink tank for supplying ink to an ink jet head is loaded with a foamable member such as urethane foam or an ink absorber of a fiber member in which fibers such as polyester felt are entangled with each other. It had been. Since such an ink absorber has a single opening diameter, bubbles having a diameter less than or equal to the opening diameter easily pass through the absorber, and the bubbles that have passed along with the ink supply reach the ink ejection nozzles to cause ink flow. There is a problem that an image defect is caused because the road is obstructed. In addition, there is a problem that even fine dust due to a part of the material forming the ink absorber is blocked to cause an ink defect, resulting in an image defect.

As a means for solving this problem, conventionally, a metal filter member having a mesh structure or a fibrous body having a mesh structure is used at a portion where the ink flow path and the ink absorber are in contact with each other, and bubbles or bubbles to the ink flow path are formed. It prevented the entry of dust. However, since the filter member that prevents the inclusion of air bubbles or dust is used in the narrow ink flow passage, the flow resistance of the ink is adversely affected and the ink supply is hindered. Further, since the dust that flows in along with the ink supply is trapped, there is a problem that the mesh-like structure is clogged due to a change with time, the ink flow path is blocked, and the ink supply is hindered.

Also, when a fibrous body having a mesh-like structure is used so as to contact at least a part of the ink absorber, the mesh-like fibrous body and the ink absorber, or the mesh-like fibrous body and the ink flow path tube, Since an air layer is likely to be generated at the interface in contact with each other, there are problems that the ink transferability is deteriorated, the ink supply property is adversely affected, and air bubbles are easily mixed into the ink flow path when the ink is reduced.

Further, the document "An Optimizemat"
ion Study Of A Drop-On-De
mand Ink Jet Print Head C
"Artridge" Eastman Kodak C
company (ISandT's Seventh I
international Congratulation Oct
6-11, 1991), a structure in which a nylon mesh structure is fused to the surface of the ink absorber by heat to prevent the passage of air bubbles, the number of parts is increased, and , The number of manufacturing processes accompanying it increases,
There is a problem that leads to higher costs.

On the other hand, when the conventional ink absorber is loaded in the ink tank, an air layer is formed at the interface between the inner wall of the ink tank side face and the side face of the ink absorber. Therefore, there is also a problem that the negative pressure of the ink absorber rises when ink is supplied, air bubbles are mixed into the ink absorber from the side surface in the ink tank, and the air bubbles penetrate into the ink flow path to cause an image quality defect. In addition, the atmosphere communication port of the ink tank, the air layer on the side surface inside the ink tank, and the ink flow path may be connected by the atmosphere, and the remaining amount of ink is still sufficient to supply ink. However, there is also a problem that ink supply failure occurs.

As a means for solving this problem, a method has been considered in which an ink absorber having a relatively large shape is loaded in the ink tank and pressure is applied sufficiently to eliminate the air layer on the side surface in the ink tank. However, there is a problem that the loading density of the entire ink absorber increases, the capillary force for holding the ink increases, and the ink supply capacity decreases.

When the member used as the ink absorber is a fibrous body having a structure in which fibers made of polyester or acrylonitrile are intertwined with each other, the shape is determined by the entanglement of the fibers. However, there is a problem in that the shape is deformed due to a change with time or external pressure, and an air layer is formed at a joint with the ink supply pipe connected to the ink flow path. Further, there is a problem that the ink holding ability or the ink supplying ability is significantly reduced due to the shape deformation. Further, when the ink absorber is a fibrous body, many fiber ends project on the surface of the ink absorber and become fluffy, so that workability when loading in the ink tank and covering the ink tank is poor. There was also a problem.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and in an ink absorber for holding ink to be supplied to an ink jet head and an ink tank using the same, air bubbles are mixed or It is an object of the present invention to provide an ink absorber capable of preventing an ink flow path from being hindered by the mixing of dust and obtaining a good printed image, and an ink tank using the same.

[0010]

According to the present invention, in an ink absorber loaded in an ink tank for supplying ink to an ink jet head, at least one surface of the ink absorber is heated and melted in a pressed state to open the ink absorber. It is characterized in that the caliber is contracted. Further, in the ink tank for supplying the ink to the inkjet head, the surface of the ink absorber having the opening diameter smaller than that of the other surface of the ink absorber according to claim 1 faces the ink supply path.
It is characterized in that the ink absorber is contained.

[0011]

According to the present invention, at least one of the ink absorbers is
Since the opening diameter of one surface is shrinking by heating and melting,
Since this surface functions like a filter, it is possible to prevent air bubbles or dust from entering the ink flow path. At this time, since the metallic filter member having the mesh structure or the fibrous body having the mesh structure, which has been used so far, is not required, the number of parts and the number of development steps can be reduced. By setting the opening diameter of at least part of the surface of the ink absorber to 20 μm or less, it is possible to prevent passage of bubbles or dust that obstruct the ink flow path of the nozzle. When the ink absorber is a fibrous body,
Since fluffing on the surface of the ink absorber can be suppressed by heating and melting, workability in loading the ink absorber into the ink tank can be improved.

[0012]

1 is a schematic sectional view of an ink jet cartridge using an embodiment of the ink tank of the present invention. In the figure, 1 is an ink absorber, 2 is a fusion zone, 2a, 2b
Is a melting surface, 3 is an inkjet head, 4 is an ink tank, and 5 is an atmosphere communication port. The ink absorber 1 is housed inside the ink tank 4. An atmosphere communication port 5 is provided above the ink tank 4, and the ink absorber 1 communicates with the atmosphere. The lower part of the ink tank 4 is connected to the inkjet head 3. Although the ink tank 4 and the inkjet head 3 are shown integrally in the figure, the ink tank 4 and the inkjet head 3 may be connected separately by a conduit or the like as a separate structure.

The ink absorber 1 is filled with ink. The surface of the ink absorber 1 is heated and melted by a heat source such as a heater to be hardened.
And the other melting surface 2a. The melting surface 2 a has an opening diameter smaller than that of the ink absorber 1. The melting surface 2b is formed by heating and melting so that the opening diameter is smaller than that of the melting surface 2a, and can be, for example, 20 μm or less. The melted surface 2a can be formed as a surface of the ink absorber as it is, but in order to prevent air from entering between the side wall of the ink tank 4 and the ink absorber 1, it is preferable that the melted surface 2a be a melted surface. desirable. The ink absorber 1 may have a rectangular parallelepiped structure. Of course, cylindrical shape,
Other shapes may be used. As the ink absorber, it is possible to use a porous material such as urethane foam, a fibrous member such as polyester felt, or the like which is usually used as the ink absorber.

2 to 8 are explanatory views of an example of a manufacturing process of the ink absorber 1. As shown in FIG. In each figure, (A) is a front view and (B) is a side view. In the figure, 1 is an ink absorber, and 6 and 7 are molds. In these figures, the manufacturing process of the rectangular parallelepiped ink absorber 1 is shown. A heat source such as a heater (not shown) is provided on the bottom surface side. The ink absorber 1 has, for example, a polyester felt fiber structure.

FIG. 2 shows the ink absorber 1 before processing. At this time, the ink absorber is made much larger than the volume of the ink tank. In FIG. 3, the ink absorber 1 before processing is placed in a mold 6, placed on a heater, and a constant pressure is applied from above the ink absorber 1 to heat for a certain period of time. At this time, the temperature of the heater can be set to 160 ° C. to 230 ° C. which is higher than the melting temperature of the polyester felt fiber. By this heating, only the fibers on the surface of the ink absorber 1 in contact with the heater are melted. Therefore, the volume of the surface of the ink absorber 1 shrinks, and the ink is cured and pressure-bonded on the surface. Due to the contraction of the surface of the ink absorber 1, the opening diameter can be made smaller than the opening diameter originally possessed by the ink absorber. The size of the surface opening depends on the density and shape of the ink absorber fibers, the temperature of the heater,
It is determined by the pressure with which the ink absorber is pressed against the heater.

In FIG. 4, the ink absorber 1 in the mold 6 is rotated by 90 °, put into the mold 6 again, and heated and melted. Similarly, in FIGS. 5 and 6, heating and melting are performed to heat and melt the four sides that are the side surfaces of the ink absorber 1. Next, in FIG. 7, the ink absorber 1 is put into a mold 7 having another shape,
Similarly, the upper surface of the ink absorber 1 is heated and melted.

In FIG. 8, the upper and lower sides of the ink absorber 1 are switched and the bottom surface of the ink absorber 1 is heated and melted. At this time, the pressure to be pressed is increased more than the heating and melting on the other surface to perform the heating and melting. Alternatively, the heating temperature and the heating time may be adjusted. As a result, the ink absorber 1
The bottom surface can be formed with a smaller opening diameter than the other surfaces.

FIG. 9 is a sectional view of the completed ink absorber 1. Since the portion that is melted by heating is only the surface, the inside of the ink absorber 1 has the original opening diameter. Only the bottom portion has a smaller opening diameter than the other surfaces. The ink absorber 1 created in this way is
Since the opening diameter of the surface of the ink absorber is changed without losing the original ink transferability, it is possible to prevent bubbles and dust from the inside from entering the ink flow path in the inkjet head 3. .

The operation of an ink jet cartridge having an embodiment of the ink absorber of the present invention will be described with reference to FIGS. 1 and 10. FIG. 10 is a schematic view of the vicinity of the surface of the ink absorber. In the figure, 8 is a bubble and 9 is dust. In FIG. 10, particularly, the surface of the ink absorber that is connected to the inkjet head will be described.

In the ink jet cartridge as shown in FIG. 1, recording is performed by ejecting ink from the ink jet head 3. Along with this recording, the negative pressure in the ink tank rises as much as the ink has decreased. If the negative pressure rises as it is, it causes ink ejection failure, so that the ink impregnated in the ink absorber 1 is sent to the inkjet head and air is taken in through the atmosphere communication port 5. The air taken in is
From the opening of the surface of the ink absorber 1 which is in contact with the atmosphere communication port 5, it enters the ink absorber 1 as air bubbles.
At this time, the diameter of the bubble that enters the ink absorber 1 becomes the size of the opening diameter of the surface of the ink absorber 1.

However, the air bubbles inside the ink absorber, which have entered from the atmosphere communication port side, remain as they are in the ink jet head 3.
When it enters the inside of the ink flow path, defective ink ejection occurs. In order to prevent bubbles from entering the inkjet head 3, the opening diameter of the surface of the ink absorber connected to the inkjet head 3 is made smaller than that of the other surface. Therefore, as shown in FIG. 10, the bubble 8 has an opening diameter d.
Cannot pass through and is trapped on the melting surface 2b.

Of course, bubbles smaller than the opening diameter d will pass through the melting surface 2b. For example, the opening diameter d of the melting surface 2b is made smaller than the inner diameter of the ink flow path in the ink jet head 3. By placing it, the melting surface 2b
The bubbles that have passed through do not block the ink flow path. For example, the opening diameter d of the fusion surface 2b can be 20 μm or less. This diameter is extremely smaller than the inner diameter of the ink flow path. For example, it is possible to forcibly remove the ink from the ink jet side by performing a maintenance operation of the ink jet recording apparatus equipped with the ink jet head 3. Therefore, there is no problem that appears as a problem in image quality.

Similarly, when a part of the member constituting the ink absorber 1 is dropped off or dust mixed in at the time of manufacture is generated and the ink is supplied, it is attempted to enter the ink jet head 3. Since the opening diameter of the entire surface of the ink absorber 1 is reduced, dust 9 does not go out of the ink absorber 1 as shown in FIG. In addition, when the length of a part of the structure of dust is smaller than the diameter of the ink flow path in the inkjet head 3 and is, for example, 20 μm or less, it passes through the surface of the ink absorber 1 and enters the ink flow path. However, since it can be forcibly removed from the ink jet side by the maintenance operation of the ink jet recording apparatus in which the ink jet head 3 is mounted, there is no problem that appears as an image quality problem.

Further, in the conventional ink jet head, the filter member having a mesh structure or the mesh fibrous body, which is used between the ink absorber and the ink flow path, prevents the passage of bubbles or dust by the ink absorber itself. Since it can be prevented, it is not necessary, and the number of parts and the complicated manufacturing process associated therewith can be eliminated.

[0025]

As is apparent from the above description, according to the present invention, the opening diameter of a part or the whole surface of the ink absorber is reduced by heating and melting, so that the ink passes through the ink absorber, It is possible to prevent bubbles from entering the ink flow path in the inkjet head. Further, it is possible to prevent dust deposited by the absorbing member in the ink absorber from entering the inkjet head. Therefore, there is an effect that it is possible to solve the problem of the image quality defect caused by blocking the ink supply by blocking the ink flow path with bubbles or dust.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an inkjet cartridge that uses an embodiment of the ink tank of the present invention.

FIG. 2 is a partial explanatory view of an example of a manufacturing process of the ink absorber 1.

FIG. 3 is a partial explanatory view of an example of a manufacturing process of the ink absorber 1.

FIG. 4 is a partial explanatory view of an example of a manufacturing process of the ink absorber 1.

FIG. 5 is a diagram illustrating a part of an example of a manufacturing process of the ink absorber 1.

FIG. 6 is a diagram illustrating a part of an example of a manufacturing process of the ink absorber 1.

FIG. 7 is a diagram illustrating a part of an example of a manufacturing process of the ink absorber 1.

FIG. 8 is a partial explanatory view of an example of a manufacturing process of the ink absorber 1.

FIG. 9 is a cross-sectional view of an example of a completed ink absorber.

FIG. 10 is a schematic view of the vicinity of the surface of the ink absorber.

[Explanation of symbols]

1 Ink Absorber, 2 Melting Section, 3 Inkjet Head, 4 Ink Tank, 5 Atmosphere Communication Port, 6, 7
Mold, 8 bubbles, 9 trash.

Claims (2)

[Claims] 1. An ink absorber loaded in an ink tank for supplying ink to an inkjet head, wherein at least one surface of the ink absorber is heated and melted in a pressed state to shrink the opening diameter. And ink absorber. 2. An ink tank for supplying ink to an ink jet head, wherein the ink absorbing member is configured so that a surface having an opening diameter smaller than the other surface of the ink absorbing member faces the ink supply path. An ink tank characterized by containing a body.