JP3296035B2 - Ink absorber and ink tank using ink absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink absorber for impregnating and holding an 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 In an ink jet recording apparatus, an ink tank for supplying ink to an ink jet head is conventionally loaded with an ink absorbent made of a foam member such as urethane foam or a fiber member in which fibers such as polyester felt are entangled. It had been. Since such an ink absorber has a single opening diameter, bubbles having a diameter smaller than the opening diameter easily pass through the absorber, and the bubbles that have passed along with the ink supply reach the ink discharge nozzle, and the ink flow is reduced. There is a problem that an image defect is caused due to obstructing a road. In addition, there is a problem that the ink flow path is obstructed by fine dust caused by a part of the material forming the ink absorber coming off, thereby causing an image defect.

[0003] As means for solving this problem, conventionally, a metal filter member having a mesh structure or a fibrous material having a mesh structure is used at a portion where the ink flow path and the ink absorber are in contact with each other, so that air bubbles or air bubbles into the ink flow path are formed. Prevention of garbage contamination. However, since a filter member for preventing air bubbles or dust from being mixed is used in a narrow ink flow path, the resistance becomes a flow path resistance at the time of ink supply, which hinders ink supply. In addition, since the dust that flows with the ink supply is trapped, there is also a problem that the mesh-like structure is clogged with the passage of time, the ink flow path is closed, and the ink supply is hindered.

[0004] Further, even when the mesh-like fiber body is used so as to be in contact with at least a part of the ink absorber, the mesh-like fiber body and the ink absorber, or the mesh-like fiber body and the ink flow path tube are formed. Since an air layer is likely to be generated at the contacting interface, there is a problem that ink transferability deteriorates, adversely affects ink supply properties, and that bubbles tend to be mixed into the ink flow path when ink is reduced.

[0005] Further, the document "An Optimizer"
ion Study Of A Drop-On-De
man Ink Jet Print Head C
artridge "Eastman Kodak C
ompany (ISandT's Seventh I
international Congress 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 increases the number of parts. , The number of manufacturing processes increases,
There is a problem that leads to an increase in cost.

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 side surface of the ink tank and the side surface of the ink absorber. Therefore, there is also a problem that the negative pressure of the ink absorber increases during ink supply, bubbles are mixed into the inside of the ink absorber from a side surface in the ink tank, and bubbles enter the ink flow path to cause an image quality defect. Further, the air 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 air, and the remaining amount of the ink is still small enough to supply the ink. However, there is a problem that ink supply failure occurs.

As a means for solving this problem, a method has been conceived in which a relatively large-sized ink absorber is loaded into an ink tank and pressed sufficiently to eliminate an air layer on the side surface in the ink tank. However, there has been a problem that the loading density of the entire ink absorber increases, the capillary force for holding 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 entangled, the shape is determined by the entanglement of the fibers. However, there is a problem in that the shape is lost due to a large degree of change over time or an external pressure, and an air layer is formed at the junction with the ink supply pipe connected to the ink flow path. In addition, there is a problem that when the shape is lost, the ink holding ability or the ink supply ability is significantly reduced. Furthermore, when the ink absorber is a fibrous body, many fiber ends protrude on the surface of the ink absorber and become fluffy, so that workability when loading the ink tank and closing the ink tank is poor. There were also problems.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and an ink absorbing member for holding ink to be supplied to an ink jet head and an ink tank using the same have a problem that air bubbles are not mixed. It is an object of the present invention to provide an ink absorber which can prevent the ink flow path from being hindered by dust and obtain a good printed image, and to provide an ink tank using the same.

[0010]

According to a first aspect of the present invention, there is provided an ink absorber loaded in an ink tank for supplying ink to an ink jet head, wherein at least a portion of the surface of the ink absorber within the ink jet head is provided. 3. The invention according to claim 2, wherein the surface on the side for supplying ink to the ink flow path is heated and melted in a pressed state, and the opening diameter of the surface is reduced from the internal opening diameter. In an ink tank for supplying ink to an ink jet head, the ink is supplied to an ink flow path in the ink jet head from a surface where the opening diameter of the surface of the ink absorber according to claim 1 is smaller than the internal opening diameter. The ink absorber is housed as described above.

[0011]

According to the present invention, of the surface of the ink absorber,
At least the surface on the ink supply side of the ink jet head on the ink supply side has an opening diameter shrunk by heating and melting, so that this surface functions similarly to a filter. Can be prevented from being mixed into the water. At this time, since a metal filter member having a mesh-like structure or a fibrous body having a mesh-like 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 contracted opening diameter of the ink absorber to 20 μm or less, it is possible to prevent the passage of bubbles or dust obstructing the ink flow path of the nozzle. Further, in the case where the ink absorber is a fibrous body, fuzzing on the surface of the ink absorber can be suppressed by heating and melting, so that the workability regarding the loading of the ink absorber into the ink tank can be improved. .

[0012]

FIG. 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 molten portion, 2a, 2b
Is a molten surface, 3 is an inkjet head, 4 is an ink tank, and 5 is an air communication port. Inside the ink tank 4, the ink absorber 1 is housed. At the top of the ink tank 4, an atmosphere communication port 5 is provided, and the ink absorber 1 communicates with the atmosphere. The lower part of the ink tank 4 is connected to the inkjet head 3. In the drawing, the ink tank 4 and the ink jet head 3 are shown integrally, but they 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, and is hardened.
And the other molten surface 2a. The melting surface 2 a has an opening diameter smaller than the opening diameter of the ink absorber 1. The molten surface 2b is formed by heating and melting so that the opening diameter is smaller than that of the molten surface 2a, and may be, for example, 20 μm or less. The melting surface 2a can be constituted by the surface of the ink absorber as it is. However, in order to prevent air from entering between the side wall of the ink tank 4 and the ink absorber 1, it is preferable to use a melted surface. desirable. The ink absorber 1 can have a rectangular parallelepiped structure. Of course, such as cylindrical
Other shapes may be used. As the ink absorber, those generally used as an ink absorber, such as a porous material such as urethane foam and a fibrous member such as polyester felt, can be used.

FIG. 2 to FIG. 8 are explanatory diagrams of an example of the manufacturing process of the ink absorber 1. FIG. In each figure, (A) is a view from the front, and (B) is a view from the side. In the figure, 1 is an ink absorber, and 6 and 7 are molds. In these drawings, a manufacturing process of the rectangular parallelepiped ink absorber 1 is shown. It is also assumed that a heat source such as a heater (not shown) is on the bottom side. It is assumed that the ink absorber 1 has, for example, a polyester felt fiber structure.

FIG. 2 shows the ink absorber 1 before processing. The ink absorber at this time is made considerably 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, a constant pressure is applied from above the ink absorber 1, and heated for a certain 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 that are in contact with the heater are melted. Therefore, the volume of the surface of the ink absorber 1 shrinks, and is cured and pressed 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 of the ink absorber originally. The size of the opening on the surface depends on the density and shape of the fibers of the ink absorber, the temperature of the heater,
It is determined by the pressure at 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 again in the mold 6, and heated and melted. Similarly, in FIGS. 5 and 6, the heating and melting are performed, and the heating and melting of the four sides which are the side surfaces of the ink absorber 1 are performed. 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 ink absorber 1 is turned upside down, and the bottom surface of the ink absorber 1 is heated and melted. At this time, the heating and melting are performed by increasing the pressing pressure compared to the heating and melting on the other surface. Alternatively, the heating temperature and the heating time may be adjusted. Thereby, the ink absorber 1
Can have a smaller opening diameter than other surfaces.

FIG. 9 is a sectional view of the completed ink absorber 1. Since only the surface is melted by heating, the inside of the ink absorber 1 has the original opening diameter. Only the bottom has a smaller opening diameter than other surfaces. The ink absorber 1 thus created 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 coming from inside from entering the ink flow path in the inkjet head 3. .

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

In the ink jet cartridge as shown in FIG. 1, recording is performed by discharging ink from the ink jet head 3. At the same time as the recording, the negative pressure in the ink tank is increased by the amount of the reduced ink. If the negative pressure rises as it is, ink ejection failure will be caused. Therefore, the ink impregnated in the ink absorber 1 is sent to the ink jet head, and air is taken in from the atmosphere communication port 5. The air taken in is
The air enters the ink absorber 1 as bubbles from the opening on the surface of the ink absorber 1 that is in contact with the air communication port 5.
At this time, the diameter of the bubbles that enter the ink absorber 1 is the size of the opening diameter on the surface of the ink absorber 1.

However, the air bubbles inside the ink absorber that have entered from the air communication port side are
When the ink enters the inside of the ink flow path, ink ejection failure occurs. In order to prevent air 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 surfaces. Therefore, as shown in FIG. 10, the bubble 8 has an opening diameter d.
And is trapped by the molten 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, the molten surface 2b
There is no clogging of the ink flow path due to bubbles passing through the ink passage. For example, the opening diameter d of the fusion surface 2b can be set to 20 μm or less. This diameter is very small compared to the inner diameter of the ink flow path. For example, it is possible to forcibly remove the ink from the ink ejecting side by a maintenance operation of the ink jet recording apparatus in which the ink jet head 3 is mounted. Therefore, there is no problem that appears as a problem in image quality.

Similarly, when dusts resulting from a part of the members constituting the ink absorber 1 dropping out or dusts mixed in during production occur, and when the ink is supplied to the ink jet head 3 together with the ink supply, Since the opening diameter of the entire surface of the ink absorber 1 is reduced, the dust 9 does not go out of the ink absorber 1 as shown in FIG. Further, when the length of a part of the dust structure is smaller than the diameter of the ink flow path in the inkjet head 3 and is, for example, 20 μm or less, the dust passes through the surface of the ink absorber 1 and enters the ink flow path. However, since the ink jet head 3 can be forcibly removed from the ink ejecting 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.

In a conventional ink-jet head, a filter member or a mesh-like fibrous material having a mesh structure used between an ink absorber and an ink flow path allows bubbles or dust to pass through by the ink absorber itself. Since it can be prevented, the necessity is eliminated, 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, at least the opening diameter of the surface of the ink absorber on the side for supplying ink to the ink flow path in the ink jet head is heated and melted. By making the size smaller, it is possible to prevent bubbles from passing through the ink absorber and 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 by itself. Therefore, there is an effect that it is possible to solve the problem of the image quality defect caused by blocking the ink flow path with bubbles or dust and obstructing the ink supply.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an ink jet cartridge using an ink tank according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a part of an example of a manufacturing process of the ink absorber 1.

FIG. 3 is a diagram illustrating a part of an example of a manufacturing process of the ink absorber 1.

FIG. 4 is a diagram illustrating a part 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 diagram illustrating a part 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 an ink absorber.

[Explanation of symbols]

1 ink absorber, 2 fusion zone, 3 inkjet head, 4 ink tank, 5 atmosphere communication port, 6, 7
Mold, 8 bubbles, 9 trash.

Claims (2)

(57) [Claims] 1. An ink absorber loaded in an ink tank that supplies ink to an inkjet head, wherein at least a surface of the ink absorber on a side that supplies ink to an ink flow path in the inkjet head has An ink absorber characterized in that the ink absorber is heated and melted in a pressed state, and the opening diameter on the surface thereof is shrunk from the inner opening diameter. 2. An ink tank for supplying ink to an ink-jet head, wherein the ink has an opening diameter on the surface of the ink absorber according to claim 1 which is smaller than the inner opening diameter and flows into an ink flow path in the ink-jet head. Wherein the ink absorber is accommodated so as to supply the ink.