JPH11277758A - Ink-jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink-jet recording apparatus which is equipped with a filter that can restrict pressure loss of ink, generation of foreign matter and can be surely fixed. SOLUTION: In an ink-jet recording apparatus including an ink-jet recording head with a plurality of nozzles for discharging ink drops, an ink feed means for feeding ink to the ink-jet recording head and a filter set in a flow passage between the head and the ink feed means, the filter has a plurality of filter holes 2 of a smaller inner diameter than a diameter of the nozzle at an area inside a flow passage of a filter main body 1 and fixation holes 4 of a larger diameter than the diameter of the filter hole 2 at a circumferential edge part of the filter main body 1 for use in fixing the filter main body 1 to a circumferential edge part of the flow passage. The filter 1 is accordingly surely fixed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus which is used in an ink jet recording head and has a filter for removing foreign matters, bubbles and the like in ink.

[0002]

2. Description of the Related Art In general, in an ink jet recording head, ink is supplied from an ink cartridge filled with ink through an ink supply needle and a flow path inserted into the ink cartridge. It is discharged from the nozzle by driving a child or the like.

In such an ink jet recording head, foreign matter present in the ink of the ink cartridge or foreign matter mixed into the ink due to, for example, attachment to an ink supply needle when the ink cartridge is attached or detached is supplied. Then, there is a problem that ejection failure occurs.
In addition, there is a problem that an ejection failure is caused by bubbles existing in the ink. Therefore, usually, a flow path of the ink between the ink cartridge and the ink jet type recording head has a plurality of fine holes and is provided with a filter for removing foreign matter and bubbles in the ink.

As this filter, a filter in which fibers are woven to form a filter hole has been used.
Foreign matter and bubbles are removed when ink passes through this filter. However, in this type of filter, the filter hole must be much smaller than the foreign matter to be removed. Therefore, since the overall aperture ratio becomes small, there is a problem that the pressure loss due to the flow of the ink is large and the ejection characteristics are deteriorated.

In order to solve this problem, there has been proposed a method of increasing the area of the filter itself or increasing the diameter of the hole through which the ink flows, thereby increasing the entire flow path area to reduce the pressure loss. .

[0006]

However, in the case of the former, there is a problem that the dimensions of the head itself become large, which leads to an increase in the length of the recording apparatus.
In the latter case, there is a problem that foreign matter and bubbles pass through the filter and cannot be sufficiently removed.

Further, when such a filter is bonded or welded to a head case made of, for example, a resin or the like, the diameter of the filter hole is small, so that sufficient bonding strength cannot be obtained, and the filter is fixed. There is a problem that variation occurs. Further, when the ink supply needle is welded to the head case by, for example, ultrasonic welding after the filter is fixed, the adhesive or resin that has entered the filter hole due to the vibration is lost and is mixed as a foreign substance into the flow path. There is a problem.

In view of such circumstances, it is an object of the present invention to provide an ink jet recording apparatus capable of reliably fixing a filter while suppressing pressure loss of ink and suppressing generation of foreign matter.

[0009]

According to a first aspect of the present invention, there is provided an ink jet recording head having a plurality of nozzles for ejecting ink droplets, and an ink for supplying ink to the ink jet recording head. An ink jet recording apparatus having a supply means and a filter in a flow path therebetween, wherein the filter has an inner diameter smaller than the nozzle diameter in a region arranged in the flow path of the filter main body. An ink jet type having a plurality of filter holes, wherein a peripheral hole of the filter body has a fixing hole for fixing the filter body to a peripheral portion of the flow path with a diameter larger than the filter hole. In the recording device.

In the first aspect, the filter is securely fixed in the flow path by the fixing hole having a diameter larger than the filter hole provided in the peripheral portion of the filter body.

According to a second aspect of the present invention, in the first aspect, the filter has a through hole substantially between a region where the filter hole is formed and a region where the fixing hole is formed. An ink jet recording apparatus is characterized in that there is a non-porous area not formed.

In the second aspect, when the filter is fixed, the flow of resin or the like into the filter hole is prevented,
The generation of foreign matter is suppressed.

According to a third aspect of the present invention, in the first or second aspect, the filter is at least one side of a region corresponding to the fixing portion provided with the fixing hole at least in a peripheral portion of the filter body. An ink-jet recording apparatus, characterized in that the surface of the ink jet recording device has a concave portion which is recessed inward in the thickness direction from another portion of the filter body.

In the third aspect, the generation of foreign matter when fixing the filter is suppressed by the step at the boundary between the concave portion and the other portion.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the filter is welded to a peripheral portion of the flow path via the fixing hole. It is in the type recording device.

According to the fourth aspect, when the filter is fixed to the peripheral portion of the flow path by welding, the molten resin is prevented from flowing into the filter hole.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on embodiments.

FIG. 1 is a plan view of a filter used in an ink jet recording apparatus according to an embodiment of the present invention, and FIG. 2 is a view showing a shape of a filter section.

As shown in the drawing, the filter 1 of the present embodiment has a filter section 3 having a plurality of filter holes 2 through which ink passes in an area corresponding to the ink flow path at the center.
And on the outer periphery of the filter outside the filter section 3,
It has a fixing portion 5 provided with a plurality of fixing holes 4 for fixing the filter. Further, between the filter portion 3 and the fixing portion 5, there is provided a non-porous portion 6 in which a through-hole is not substantially formed.

In this embodiment, the filter hole 2 provided in such a filter 1 is round, and the opening area gradually increases from the upstream side to the downstream side in the thickness direction of the filter 1. It has a shape. That is, the inner diameter d1 on the upstream side is formed to be smaller than the inner diameter d2 on the downstream side. Further, the inner diameter of the filter hole 2 is smaller than the diameter of the nozzle that discharges ink of the ink jet recording head.
While the inner diameter of the filter hole is about 1 /
2, 10 to 15 μm.

The plurality of filter holes 2 are provided such that the adjacent filter holes 2 are arranged in a regular triangular shape so that the juxtaposed directions of the filters 2 are substantially at an angle of 60 ° to each other. For example, in the present embodiment, the filter holes 2 are arranged in parallel at intervals of about 20 to 25 μm. Further, the filter holes 2 are arranged side by side so as to have a substantially hexagonal shape as a pattern of the entire filter holes 2.

The fixing holes 4 have a round cross section and are formed on the periphery of the filter 1 at substantially equal intervals. This fixing hole 4
Is desirably larger than at least the diameter of the filter hole 2 in order to securely fix the filter. For example, in this embodiment, the diameter of the filter hole is 40 to 100 μm.

Further, in the present embodiment, a non-porous portion 6, which is a region where a through hole is not substantially formed, is provided between the filter portion 3 and the fixing portion 5, as described later. The non-porous portion 6 prevents generation of foreign matter when the filter 1 and the like are bonded.

The thickness of the filter 1 is preferably larger than the diameter of the filter hole 2. For example, in this embodiment, the thickness of the filter 1 is about 20 times, which is about twice the diameter of the filter hole 2.
It is formed at 30 μm. Thereby, the filter 1
Can maintain sufficient rigidity.

As described above, by providing the filter portion 3 with the filter holes 2 having an inner diameter smaller than the nozzle diameter at a high density, in the present embodiment, the filter holes 2 with respect to the effective area in the ink flow path of the filter 1 are formed. The opening ratio, which is the ratio of the total opening area, is 30% or more.

The method for manufacturing such a filter 1 is not particularly limited. However, since the filter 1 has a large number of filter holes 2 having a small diameter, in the present embodiment, the filter 1 is formed by electroforming (electroforming). The material of the filter 1 is not particularly limited, but when the filter 1 is formed by electroforming, it is preferable to use nickel.

Here, the manufacturing process of the filter 1 of the present embodiment will be described.

First, as shown in FIG. 3 (a), a resist film 11 is formed on a substrate 10 on which an oxide film such as chromium oxide is formed on a conductive material such as stainless steel in order to improve the peeling.
To form The thickness of the resist film 11 is preferably formed to be at least larger than the thickness of the filter 1 to be manufactured. This is for easily forming the filter 1 having a desired shape as shown in the following steps.

Next, as shown in FIG. 3B, the resist film 11 is patterned according to the shape of the filter 1. That is, the resist film 20 is left in a portion corresponding to the filter hole 2 and the fixing hole 4, and the resist film 1 in other portions is left.
Remove one.

Next, as shown in FIG. 3C, the resist film 11 is removed and the filter 1 is formed on the substrate 10.
For example, a metal layer 12 such as nickel is plated to a predetermined thickness. At this time, as described above, the resist film 11
The metal layer 12 is formed thicker than the filter 1.
Is not formed more than the thickness of the resist film 11. Therefore, the filter holes 2 and the like are easily formed in a desired shape.

Thereafter, as shown in FIG. 3D, by removing all the resist film 11 and removing the resist film 11 from the substrate 10, the filter 1 having the filter holes 2 and the fixing holes 4 having desired shapes is formed. You.

As described above, the resist film 11 is
If the filter 1 is formed thicker than the thickness of the filter 1 and formed by electroforming, the filter 1 having a desired shape can be formed.
Can be easily formed. However, even if the electroforming is used, the resist film 11 can be
In the method of forming the filter 1 having the same thickness as or less than the thickness of the filter 1, as shown in FIG. 4, the metal layer 12 is plated up to the upper portion of the resist film 11, so that the filter 1 having a desired shape is formed. Is difficult. Therefore, in order to form the filter 1 of the present embodiment, it is most preferable to use the above-described manufacturing method.

The filter thus formed is incorporated in a recording unit 20 as shown in the sectional view of FIG.
The recording unit 20 includes a frame 21 that forms the recording unit 20, an ink supply needle 23 inserted into an ink supply hole 22 a of an ink cartridge 22, and a flow path that connects the ink jet recording head 30 to the ink supply needle 23. 24a.

Here, an example of an ink jet recording head used in such a recording unit will be described. FIG.
1 is a cross-sectional view illustrating an example of an ink jet recording head.

In such an ink jet recording head, for example, as shown in FIG. 6, an elastic film 33 is formed on one surface of a flow path forming substrate 32 in which a pressure generating chamber 31 is formed. On this elastic film 33, a lower electrode film 34,
The piezoelectric film 35 and the upper electrode film 36 are laminated and patterned, and the piezoelectric active section 300 is constituted for each pressure generating chamber 31. On the piezoelectric active portion 300, an insulator layer 37 having electrical insulation is formed.
7, a contact hole 37a for exposing a part of the upper electrode film 36 for connection to the lead electrode 38 is formed in a portion corresponding to each piezoelectric active portion 300. One end is connected to each upper electrode film 36 through the contact hole 37a, and the other end is connected to the lead electrode 3 extending to the connection terminal portion.
8 are formed.

On the other hand, on the other surface side of the flow path forming substrate 32,
A nozzle forming substrate 41 provided with a nozzle 41a is provided, and a nozzle communication hole 42 for communicating the nozzle 41a with the pressure generating chamber 31 is formed with a sealing plate 43 and a common ink chamber forming substrate 4.
4, the thin plate 45 and the ink chamber side plate 46 are arranged to penetrate.

A common ink chamber 47 is formed by the sealing plate 43, the common ink chamber forming substrate 44, and the thin plate 45. The common ink chamber 47 and each of the pressure generating chambers 31 are communicated with each other through an ink supply communication hole 48 formed in the sealing plate 43. An inlet 49 is formed.
An opening 46a is formed in the ink chamber side plate 46 at a portion facing the common ink chamber 47. This opening 46
The thin wall 45 of the portion a absorbs the pressure generated when the ink is ejected toward the side opposite to the nozzle 41 a, and causes the other pressure generating chambers 31 to use the unnecessary positive or negative unnecessary via the common ink chamber 47. Prevents pressure.

In such an ink jet recording head, ink is supplied from the ink inlet 49 to the common ink chamber 47 and is distributed to the pressure generating chambers 31 through the ink supply communication holes 48. Then, after the inside is filled with ink up to the nozzle 41a, a voltage is applied between the lower electrode film 34 and the upper electrode film 36 via the lead electrode 38 according to a recording signal from an external drive circuit (not shown). , Elastic membrane 3
3. By bending and deforming the lower electrode film 34 and the piezoelectric film 35, the pressure in the pressure generation chamber 31 increases, and the nozzle 41
The ink is ejected from a.

A filter 1 is provided between a head case 24 having a flow path 24a for supplying ink to such an ink jet recording head and an ink supply needle 23 inserted into the ink cartridge 22, as described later. Are fixed by heat welding (see FIG. 5). The filter 1
Needless to say, this may be fixed with, for example, an adhesive.

FIG. 7 is a diagram schematically showing a fixed portion of the filter 1.

The filter 1 is fixed between the head case 24 and the ink supply needle 23 so that the filter section 3 is located in the flow path.

That is, first, as shown in FIG. 7A, the filter 1 comprises a rib 24b provided on the peripheral portion of the flow path 24a of the head case 24, and a fixing hole 4 of the filter 1.
Are arranged to face each other. At this time, the filter section 3 having the filter hole 2 is located in a region facing the flow path 24a. Next, the ribs 24b are melted by applying heat and pressure from above the filter 1 with a heat tool (not shown), and the melted ribs 24b spread between the filter 1 and the head case 24.
Are welded to the head case 24. At this time, the molten ribs 24b simultaneously flow into the upper surface of the filter 1 via the fixing holes 4, thereby preventing the filter 1 from shifting in the surface direction.

When the filter 1 is fixed, in the present embodiment, the filter portion 3 having the filter hole 2 is connected to the flow path 24.
In FIG. 7A, it protrudes to the downstream side (FIG. 7B). Thus, the aperture ratio of the filter unit 3 in the flow path 25a is improved by increasing the effective area of the filter unit 3 in the flow path 24a.

Thereafter, as shown in FIG. 7 (b), the ink supply needle 23 is fixed to the head case 24 from above the filter 1, and the entire flow path from the ink cartridge 22 to the head 30 is formed.

In this embodiment, the ink supply needles 23
And the head case 24 are fixed by ultrasonic welding. That is, the ink supply needle 23 is connected to the head case 2
4 and apply ultrasonic waves from above. As a result, the director 23a provided in a convex shape on the joint surface of the ink supply needle 23 with the head case 24 is melted, and the ink supply needle 23 and the head case 24 are welded.

At this time, the ultrasonic wave applied to the ink supply needle 23 also gives vibration to the filter 1. For example, when the filter hole 2 is provided up to the vicinity of the fixing hole 4, as described above, when the filter 1 is fixed by heat welding, the molten resin flows into the filter hole 2 and solidifies independently. Sometimes. In this case, filter 1
When vibration or the like is generated by ultrasonic waves, the resin solidified in the filter hole 2 is lost, and enters the flow path as foreign matter. However, in the present embodiment, as shown in FIG. 8, since the non-porous portion 6 having substantially no through-hole is provided between the filter hole 2 and the fixing hole 4, the molten resin is Since the resin does not enter the filter hole 2 and exists as one lump, there is no fear that the resin will be lost even by vibrations caused by ultrasonic waves.

As described above, by providing the filter according to the present invention in the ink flow path, foreign substances, bubbles, and the like existing in the ink can be reliably removed. Further, the filter can be securely fixed, and the generation of foreign matter when the filter is fixed can be suppressed. Therefore, the ink ejection characteristics can be maintained in a good state.

In the present embodiment, the fixing holes 4 having a substantially circular cross section are provided in a line along the outer diameter of the filter 1, but the present invention is not limited to this. For example, as shown in FIG. Alternatively, the shape of the fixing hole 4A may be formed in an oval shape along the outer diameter of the filter 1. Also, for example, the fixing holes may be provided in a plurality of rows.

In this embodiment, the filter hole is formed in a tapered shape having a round cross section and a large downstream side. However, the present invention is not limited to this. For example, as shown in FIG. 2A may be formed in a hexagonal shape, or may be formed in a polygonal shape such as an octagonal shape. Further, the shape in the thickness direction may be formed in a straight shape. In any case,
Since a plurality of filter holes can be provided at high density, the ink ejection characteristics can be maintained in a good state as described above.

(Embodiment 2) FIG. 11 is a sectional view of a main part of a filter according to Embodiment 2.

In the present embodiment, as shown in FIG. 11, a concave portion 7 which is recessed in the thickness direction from other portions is formed in a region corresponding to the fixed portion 5 without providing the non-porous portion 6. This is the same as the first embodiment except for the above. Further, such a filter 1A is fixed to the head case 24 by thermal welding similarly to the first embodiment.

As described above, by providing the concave portion 7 in the filter 1, when welding the head case 24 and the filter 1, the molten rib is formed by the step between the concave portion 7 and the filter portion 3 as in the first embodiment. The flow of 24b is blocked.
Therefore, useless spreading to the surroundings can be prevented, and the resin can be prevented from entering the flow path as foreign matter.

In this embodiment, the recess 7 is provided on the side opposite to the side where the head case 24 is fixed.
However, the present invention is not limited to this. For example, as shown in FIG. In this case, the resin flowing out through the fixing hole 4 is blocked by the step between the concave portion 7 and the filter portion 3, and does not flow into the filter hole 2.

In this embodiment, the step of the concave portion 7 and the filter portion 3 prevents the molten resin from spreading to the periphery. However, a non-porous portion similar to that of the first embodiment is provided. You may. As a result, the generation of foreign matter can be more reliably prevented.

[0055]

As described above, according to the present invention,
Since the aperture ratio of the filter in the ink flow path can be improved, an increase in ink pressure loss can be suppressed. In addition, a fixing hole having a larger diameter than the filter hole is provided on the periphery of the filter, and a non-porous portion is provided between the filter hole and the fixing hole. It is possible to prevent the occasional generation of foreign matter. This produces an effect that the ink ejection characteristics of the ink jet recording head can be improved.

[Brief description of the drawings]

FIG. 1 is a plan view of a filter used in an ink jet recording apparatus according to a first embodiment of the present invention.

2A and 2B are a plan view and a cross-sectional view of the filter unit of FIG.

FIG. 3 is a view showing a process of manufacturing a filter according to the present invention.

FIG. 4 is a view showing a manufacturing process of a conventional filter.

FIG. 5 is a cross-sectional view of a recording unit having a filter according to the present invention.

FIG. 6 is a cross-sectional view illustrating an example of an ink jet recording head.

FIG. 7 is a sectional view showing a fixed portion of the filter according to the present invention.

FIG. 8 is a sectional view showing a fixed portion of the filter according to the present invention.

FIG. 9 is a plan view showing a modified example of the filter according to the present invention.

FIG. 10 is a plan view showing a modification of the filter according to the present invention.

FIG. 11 is a cross-sectional view showing a fixed portion of a filter according to Embodiment 2 of the present invention.

FIG. 12 is a sectional view showing a modification of the filter according to Embodiment 2 of the present invention.

[Description of Signs] 1 filter 2 filter hole 3 filter part 4 fixing hole 5 fixing part 6 non-hole part 7 recess

Claims (4)

[Claims] 1. An ink jet recording head having a plurality of nozzles for ejecting ink droplets, and ink supply means for supplying ink to the ink jet recording head, and a filter provided in a flow path therebetween. In the ink jet recording apparatus, the filter has a plurality of filter holes having an inner diameter smaller than the nozzle diameter in a region arranged in the flow path of the filter main body, and the filter is provided at a peripheral portion of the filter main body. An ink jet recording apparatus having a fixing hole for fixing the filter main body to a peripheral portion of the flow path with a diameter larger than the hole. 2. The method according to claim 1, wherein the filter includes:
An ink jet recording apparatus, characterized in that there is a non-porous area in which substantially no through-hole is formed between the area where the filter hole is formed and the area where the fixing hole is formed. 3. The filter according to claim 1, wherein the filter is provided on at least one side of a region corresponding to a fixing portion provided with the fixing hole in a peripheral portion of the filter main body. An ink jet recording apparatus comprising: a concave portion that is depressed inward in the thickness direction from other portions. 4. The ink jet recording apparatus according to claim 1, wherein the filter is welded to a peripheral portion of the flow path via the fixing hole.