JPS61189943A - Ink jet recording apparatus - Google Patents

Abstract

PURPOSE:To secure good printing quality by preventing dust or air bubbles from flowing into an ink flow channel, by providing a filter having a linear open diameter between the ink supply channel and ink tank of a head. CONSTITUTION:A filter consists of a mesh part 2 formed by electroforming and having shaped opening parts provided with parallel side intervals of about 10mum or less, a fixing part 3 provided with opening parts each having larger diameter and locating holes 4a, 4b and the mesh part 2 is constituted of filter apertures 5 each having an oval shape wherein the interval d1 of each parallel side is 10mum or less and the length d2 thereof in the longitudinal direction is 100mum or less. As mentioned above, if the parallel side interval d1 of each filter aperture 5 of the mesh part 2 is 10mum or less, air bubbles with a diameter of 10mum or less passing through the filter aperture 5 are dissolved prior to reaching a pressure chamber. In order to generate no clogging due to dust, it is desirable to set the parallel side interval of the filter aperture to a diameter range from 4-10mum.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an inkjet recording device.The present invention particularly relates to an on-demand type inkjet recording device that prevents dust from entering the head, air bubbles from entering the head, and the like.

<Prior art> Ink-on-demand type inkjet heads have drawbacks such as deterioration of print quality or inability to print if dirt or air bubbles enter the ink flow path. Although a method using a filter is known, as described in Japanese Patent No. 150027, etc., the only known methods for arranging the filter are pressing it with rubber or adhering it with an adhesive.

<Problems to be Solved by the Invention> An object of the present invention is to prevent dust, air bubbles, etc. from flowing into the ink flow path, and to ensure good print quality.

Another object of the present invention is to easily install a filter that prevents harmful substances from entering.

Means for Solving the Problems> The inkjet recording apparatus of the present invention is an ink-on-demand type inkjet recording apparatus, and the inkjet recording apparatus is an ink-on-demand type inkjet recording apparatus.

This filter is equipped with a filter having a linear aperture diameter of approximately 104 m or less between opposing sides.

<Example> The inkjet recording apparatus of the present invention will be explained in detail below based on one drawing. In the following explanation, the filter portion will be explained in detail, and the explanation of other portions will be omitted.

Figure 1 shows the configuration of filter 1, which is an oval made of nickel or the like by electroforming, and the distance between parallel sides is about 10 A.
It consists of a mesh part 2 with an opening of m or less, a fixing part 8 having an opening with a larger hole diameter, and five positioning holes 4α, 46, one of which is an oval hole. Figure 2 (c) and (
In b), the mesh part 2 is.

The filter hole 5 is composed of an oval shape with an interval d1 of parallel sides of 114 m or less and a length d2 of the longitudinal direction of the filter hole 5 of 100 μm or less, and the fixing part 8 has a fixing hole 6α with a diameter of 800 Atn.
It is made up of. Moreover, as shown in FIG. 2(b), the fixing hole 6(b) of the fixing part 3 may be in the form of a slit.

The ellipses are aligned in the direction of gravity so that air bubbles can easily rise in the ink.

FIG. 8(α) shows a method of making the filter 1 using electric railway, in which 8 ft of resist is formed on the electrode 7.

A nickel layer is formed to a thickness of approximately lOμ. When the formed filter 1 is peeled off from the electrode 7 and the resist 8 is removed, the filter 1 often warps as shown in FIG. 8(b) due to the effects of stress and the like when peeled off from the electrode 7.

FIG. 4 shows the configuration of an inkjet head used in the apparatus of the present invention.

A nozzle, a pressure chamber (both not shown), and a supply path 4 are formed in the shape of a groove on the head substrate 4, and an ink flow path is formed by pasting together a vibrating plate. Further, the ink tank 31 is constructed by welding the tank wall 301jt to the head substrate n, and the filter lt- is disposed between the ink tank 31 and the supply path 4. These head boards
The diaphragm array and the tank wall are made of plastic such as Polysal 7on or ABS, and are assembled using an organic solvent that dissolves plastic for adhesion.

The fixing part 8 of the filter 1 is sandwiched between the filter retainer A 20 and the fixing surfaces A24 and B25 of the filter retainer B 21 (in FIG. 4, the filter retainer B 2 is shown for convenience).
a) The filter holder A20 and the filter holder E 21 are made of the same plastic as the head substrate I, and an organic solvent is poured between the fixing surface A24 and the fixing surface B25 that sandwich the fixing part 8. .

The fixing part 3 of the filter 1 is as shown in FIG. 2 (b).

Since the large fixing hole 6 is thick and the thickness of the filter 1 is about 10 μm, the fixing surface A24 and the fixing part B25 are welded through the fixing hole 6 completely, and the filter l is held by the filter holder A20 and the filter holder B 21. Fixed.

By welding the filter holder A20i to the head substrate n, the filter 1 was placed between the ink tank 31 and the supply path 4.

The role of the filter l is to prevent dust and air bubbles from flowing into the ink flow path system. Generally, if the dust is smaller than the nozzle, it will fly out from the nozzle along with the ink. If it is a filter for dirt on the fist, the diameter of the hole may be slightly smaller than the nozzle diameter, and the diameter of the hole may be about 1 μm.However, when air bubbles flow into the pressure chamber, they absorb pressure changes, making printing impossible. In particular, microbubbles try to rise due to buoyancy, but are subject to the force of viscous resistance, and are known to float in water without rising. Also, due to the influence of surface tension, they can dissolve even in saturated aqueous solutions. It is known that a bubble with a diameter of IO μm dissolves in a saturated aqueous solution in about 1.5 seconds. Further, it takes 5 seconds for a bubble with a diameter of 15 μm to fill, and 10 seconds for a bubble with a diameter of 15 μm.

Normally, bubbles in ink take on a spherical shape due to surface tension. Therefore, the distance d between the parallel sides of the filter holes 5 of the mesh part 2
If 1 is 10 μm and t34 is lower, air bubbles having a diameter of 113 μm or less passing through the filter holes 5 will be dissolved before reaching the pressure chamber.

In addition, if the filter hole 5 is too small, it will quickly become clogged with dust, etc., increase the flow path resistance, and cause a shortage of ink supply.
It has been found that it is desirable that the distance between the parallel sides is within a diameter of 4 μm to a diameter of 10 μm IJ.

In addition, since it is welded to the fixing surface A 24 and the fixing surface B 25 through the fixing hole 6 of the fixing part 8, if it is too small, welding will not be possible, and if it is too large, the strength of the filter l itself will be insufficient, and the fixing hole 6 will be welded. The pore size is 800 μm in diameter, 8 degrees, and the opening ratio is 30 ~
70chi is good.

When making the filter 1, the resist 8 may not be peeled off sufficiently, and if the resist surface 9 is placed on the ink tank 31 side when the filter 1 is placed, the ink tank may be removed during initial use. The resist 8 is peeled off little by little within 31 to form a colloid with the ink contents,
Colloidal molecules larger than the filter pores 5 may be created. Since this causes clogging, the filter l is arranged so that the resist surface 9 is placed on the fourth side of the supply path, and the stripped resist 8
The ink will be ejected from the nozzle along with the ink, and the filter l will warp as shown in Figure 3(b).
As shown in FIG. 4, the resist surface 9 is attached to the west side of the supply path (positioning holes 4α, 4bVC, positioning pins ρα, 22b are easy to insert and easy to handle.

In addition, in the present invention, the parallel side spacing of the filter is approximately 10μ.
mK also includes 114 m and 12 μm. However, 12 μm
The above 5, for example, 15 μm are not included.

<Effects of the Invention> As explained above, by making the mesh part 2 and the fixing part 3 integrally by casting, it is possible to eliminate dust.

A filter for removing air bubbles can be disposed between the supply path 4 and the ink tank 31, which prevents missing dots and even the inability to print.

Since the fixing part 3 and the mesh part 2 are made integrally, they can be fixed with high positional accuracy. Furthermore, the size of the filter holes 5 can be made uniform compared to a filter made by weaving fibers or the like.

Further, by arranging the resist surface 9 on the supply path side, initial clogging of the filter holes 5 can be prevented, and the filter 1 can be easily handled.

As shown in the cross-sectional view of filter 1 in FIG. 8, 11! ,
When made by casting, the thickness can be reduced to about 10 μm, and fluid resistance can be reduced. Furthermore, by making the filter holes 5 by electroforming, even if the minimum diameter part is 10 μm in diameter, the adjacent part does not have a uniform shape in the thickness direction, but quickly widens, and the flow path resistance of the filter 1 is reduced. It is small and has little effect on the ink flow path system.Nickel, which is the material for electroforming, has a very good wetting ratio, so the filter holes 5 are blocked by air bubbles that block the flow of ink, resulting in a shortage of ink supply. This is not the case, and the ink supply is also excellent.

When making a filter, it is possible to form many identical mask patterns at the same time, and it also has the advantage that pores with various shapes and sizes can be formed.

Furthermore, compared to conventionally considered filters with circular holes or holes in a similar shape, the aperture ratio can be increased while maintaining strength, so fluid resistance can be reduced. Moreover, the 6th
As shown in the figure, even if a bubble adheres to a hole, at least one end is open, so ink can easily flow in, and even if pressure is applied, the bubble with a diameter above the parallel side spacing ds IJ This has the advantage of not entering the pressure chamber.

The shape of the opening may be an ellipse, a rectangle, etc. in addition to an ellipse, but it may be any shape as long as it maintains the strength and aperture ratio of the filter and satisfies the following conditions. A circle with a diameter of 10 μm as shown in Figure 7? No matter where on the hole pattern you draw, there is always an overlapping portion (the shaded area in FIG. 7).

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a filter used in the inkjet recording apparatus of the present invention, FIG. 2 (α) (b) is a partially enlarged view of the first factor filter, and FIG. FIG. 3(6) is a cross-sectional view of the finished filter in FIG. 3(α), FIG. FIG. 4 is an enlarged configuration diagram of the filter fixing part in FIG. 4; FIG. 6 and FIG. 7 are explanatory diagrams of the non-invention. l...Filter 2Φ mesh part 311/Fixed part
5. Filter hole 6. Fixing hole 8. Resist 9
@φ resist [1 [i a)...filter holder A21
--Filter holder B 22α, 22b@e Positioning pin α, 24b...Guide hole A...Fixing surface A25...
Fixed surface B27--Head board 29--Supply path 31--Ink tank 32--Air bubbles or more

Claims (1)

[Claims] An ink-on-demand type inkjet recording device, characterized in that the inkjet recording device is provided with a filter having a linear opening diameter with an interval between opposing sides of about 10 μm or less between an ink supply path of a head and an ink tank. .