JP6119314B2 - Filter device - Google Patents

Description

  The present invention relates to a filter device for filtering a beverage from a raw material mixture obtained by mixing powdery raw materials such as ground coffee beans and ground tea leaves with hot water.

  Generally, beverages that extract coffee beverages and tea-based beverages from a mixture of powdered raw materials such as ground coffee beans and ground tea leaves and hot water are used in cup-type beverage vending machines and beverage dispensers. An extraction device is provided. And in order to filter the beverage extracted from the powdery raw material into hot water from the extraction basket (raw material bowl), a filter paper (through hole) is provided on a plate that uses a continuous paper filter and a plate that can be used repeatedly. Some use a so-called permanent filter.

  Conventionally, as a beverage extraction device using the former paper filter (hereinafter referred to as “paper extraction device” as appropriate), for example, one disclosed in Patent Document 1 is known. As a beverage extraction device using the latter permanent filter (hereinafter referred to as “paperless extraction device” as appropriate), for example, the one disclosed in Patent Document 2 already filed by the present applicant is known. Further, as a permanent filter, for example, a filter disclosed in Patent Document 3 already filed by the present applicant is known.

  The paper extraction device of Patent Document 1 has a cylinder whose bottom surface is open and which extracts a beverage with a raw material mixture obtained by mixing a supplied powdery raw material and hot water, and a filter block provided below the cylinder so as to freely move up and down. And a paper filter delivery mechanism for delivering a paper filter between the cylinder and the filter block.

  On the other hand, the paperless extraction device of Patent Document 2 has a cylinder similar to the above, a filter block that has a permanent filter on the upper surface, and that can be moved up and down below the cylinder, and discharges extraction residue remaining on the permanent filter. It has a scraper and so on.

  Further, the filter device of Patent Document 3 includes a filter assembly having a disk-like filter 33 (filter mesh 33a) on the upper surface of the filter block, and the filter 33 as a permanent filter is thin (for example, thickness T = 50 μm) A stainless steel plate is etched (metal corrosion) to form a large number of filtration holes 33c (for example, through holes having a hole diameter d3 = 70 μm) (see FIGS. 12 and 13).

  In general, in a paper extraction device, a beverage extracted with a raw material mixture obtained by mixing a powdery raw material and hot water in a cylinder is filtered through a paper filter, so that powders such as powder and leaves of normal size are powdered. Of course, the fine powder contained in the raw material can be removed, and there is an advantage that it is possible to provide a high-quality beverage containing almost no residue.

  On the other hand, since the paperless extraction device does not need to have a paper feeding mechanism, the entire beverage extraction device can be configured in a compact manner, and there is an advantage that the running cost can be suppressed because a paper filter is unnecessary. In addition, since there is no need to discard or replace the paper filter, there is an advantage that the operation of the beverage extraction device can be simplified for the operator.

Japanese Patent Laid-Open No. 6-259652 JP 2008-171382 A JP 2008-268997 A

  However, with conventional permanent filters, it is difficult to open fine through holes equivalent to paper filters due to the restriction of the hole diameter resulting from the processing size limit of the through holes, and the fine powder contained in the raw material is completely separated to filter the beverage. This is difficult, and since a residue remains in the filtered beverage, the beverage may have poor transparency due to the inclusion of fine powder.

In addition, beverage filtration failure due to clogging and clogging of the extraction pores in the filtration hole and beverage taste such as beverage concentration may not be maintained.
Furthermore, since the permanent filter has a through-hole formed by etching (metal corrosion) processing, the processed surface becomes a satin finish, and dirt of the beverage extract is easily attached to the lower surface (back surface) 33f of the filter 33 (see FIG. 13). The beverage taste may be deteriorated due to dirt, which has been an obstacle to the popularization of paperless extraction devices using permanent filters.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a filter device that can prevent clogging of a filtration hole by an extraction basket and maintain a beverage taste.

In order to achieve the above object, a filter device according to claim 1 of the present invention is a filter device for filtering a beverage extracted with a mixture of a powdery raw material and hot water, and on the upper surface side. In the filter device comprising a filter that separates and filters the extracted beverage by passing it through the filtration hole to the lower surface side, the filter has a plurality of dimples, A filtration hole is formed, and the filtration hole has a pore diameter of 30 μm or less and a vertical portion has a depth of 15 μm or less, and the inner surface of the hole is formed of a smooth mirror surface.

The filter device according to claim 2 of the present invention is the filter device according to claim 1 described above, wherein the filtering hole has a radiation R-cone structure whose diameter increases toward the lower surface of the filter, and a tip of the filtering hole inlet portion is formed. A knife edge is used, and the area of the lower surface is reduced .

According to invention of Claim 1, it is a filter apparatus for filtering the drink extracted with the mixture which mixed the powdery raw material and hot water, Comprising: The said drink extracted by the upper surface side is made into a lower surface through a filtration hole. In the filter device having a filter that separates and filters the extraction soot by passing it to the side, the filter has a plurality of dimples, and the filtration holes are formed in the dimples. The pore diameter is 30 μm or less and the depth of the vertical portion is 15 μm or less, and the inner surface of the hole is made of a smooth mirror surface, so that the liquid flow rate during beverage filtration is secured above a certain level, and dirt adhered to the inner surface of the hole It is possible to prevent the bridging phenomenon from occurring in the interior, and to remove the dirt adhering to the inner surface of the hole during beverage filtration, thereby maintaining the cleaning function of the inner surface of the hole. In addition, the fine powder contained in the raw material can be completely separated and the beverage can be filtered, and since no residue remains in the filtered beverage, it is possible to filter the beverage having transparency higher than that of the paper filter, The filtration time of the beverage can be stabilized. Furthermore, by finishing the inner surface of the filtration hole with a smooth mirror surface, the coffee beverage is filtered without removing the oil content of the coffee beans, so the coffee beverage contains the scent component that is removed by the paper filter. Can be filtered. In addition, the extraction soot clogged in the filtration hole collaborates with the scraper tip and the edge of the tip of the filtration hole inlet, and the shear force is applied to cut and discharge the extraction soot to block the filtration hole. While preventing, durability of a filter can be improved. In this way, it is possible to provide a filter device that can prevent clogging of the filtration hole by the extraction basket and maintain the beverage taste. Furthermore, by providing a dimple having a filtration hole inside thereof, the scraper that scrapes off the raw material extraction residue remaining on the upper surface of the filter forms a hot water film on the dimple when the upper surface of the filter slides. The sliding resistance can be reduced, the scraper sliding motor can be downsized and the scraper cost can be reduced, and a small and low cost filter device can be provided.

In addition, according to the invention of claim 2 , the filtration hole has a radiation R cone structure whose diameter increases toward the lower surface of the filter, the tip of the filtration hole inlet portion is a knife edge, and the area of the lower surface is reduced. When scraping the scraper by scraping the scraper, the extractor trapped in the filter hole (fine powder of the powder material) is extracted using the scraper tip and the knife edge of the filter hole in cooperation with the shear force. The ridge can be cut and discharged to prevent the filtration hole from being blocked. In addition, it is possible to prevent the beverage extract from adhering to and accumulating dirt, preventing the taste of the drink from being deteriorated by the dirt, maintaining the taste, and keeping it sanitary.

It is a perspective view which shows the drink extraction apparatus provided with the filter apparatus which is embodiment of this invention. It is a top view which shows (a) standby position of a filter assembly and a scraper mechanism, and (b) extraction tub discharge position, respectively. It is a perspective view which shows a filter assembly. FIG. 4 is an exploded perspective view of the filter assembly shown in FIG. 3. FIG. 4 is a partial enlarged cross-sectional view taken along line AA in FIG. 3. It is the elements on larger scale which show the filtration hole (through-hole) of a filter, (a) Top view, (b) Partial sectional view, (c) Bottom view. It is a partial expanded sectional view which shows the filtration hole (through-hole) of the filter shown in FIG. It is the elements on larger scale which show another Example of the filter hole (through-hole) of a filter, (a) Top view, (b) Partial sectional view, (c) Bottom view. It is a partial expanded sectional view which shows the filtration hole (through-hole) of the filter shown in FIG. (A) The state in which the extracted soot remains on the upper surface of the filter, (b) the state in which the extracted soot has been scraped off by the scraper, and (c) the state in which the scraper has returned to the standby position. is there. It is a figure which shows typically the state which scrapes off the extraction soot with a scraper. It is the elements on larger scale which show the filtration hole (through-hole) of the conventional filter, (a) Top view, (b) Partial sectional view, (c) Bottom view. It is a partial expanded sectional view which shows the filtration hole (through-hole) of the filter shown in FIG.

  Hereinafter, referring to the drawings, a filter device for filtering a beverage extracted by a raw material mixture obtained by mixing the powdery raw material and hot water of the present invention through a filtration hole (through hole) and separating it from an extraction basket The preferred embodiment will be described in detail. Note that the present invention is not limited to the embodiments.

  FIG. 1 shows a beverage extraction device 1 provided with a filter device 10 to which a filter 13 of the present invention is applied. The beverage extraction apparatus 1 stirs a raw material mixture obtained by mixing powdered coffee beans (hereinafter referred to as “coffee ground beans”) and hot water, extracts coffee components from the ground coffee beans into hot water, and extracts the coffee components. A cup-type beverage vending machine or a beverage dispenser (not shown) for providing regular coffee, etc. Built in.

  The beverage extraction device 1 includes a cylinder 2 for extracting coffee beverage therein, a cylinder holder 3 for detachably storing the cylinder 2 and the like. The cylinder 2 is made of plastic, for example, and is formed in a cylindrical shape extending in the vertical direction and having an upper surface and a lower surface opened. The cylinder holder 3 includes a box-shaped frame 4 for accommodating the cylinder 2 and a filter device 10 provided at a lower portion in the frame 4.

  As shown in FIG. 2, the filter device 10 is provided on a frame 4 by a slider (not shown) so as to be movable up and down, and a filter block 11 for conveying the coffee beverage in the cylinder 2 to the outside while filtering, A scraper mechanism 21 or the like is provided that is slidable in the direction and removes the extraction residue remaining on the filter block 11.

  The filter block 11 is provided so as to surround the filter assembly 12, the thin plate ring-shaped packing 16 having an outer diameter larger than that of the cylinder 2, and supports the filter assembly 12 and the packing 16. A block-like support member 17 having a passage (not shown) extending in the vertical direction is also included.

  As shown in FIGS. 3, 4, and 5, the filter assembly 12 includes a disk-shaped filter 13, a holding plate (metal plate) 14 provided below the filter 13, and the both 13 and 14 are fixed to each other. A fixed frame 15 is provided. The filter 13 is made of an extremely thin metal material, and includes a filter mesh portion 13a having an outer diameter slightly smaller than the inner diameter of the cylinder 2, and a collar portion 13b provided over the entire outer periphery of the filter mesh portion 13a. Have. The collar portion 13b protrudes laterally from the lower end of the hanging portion that hangs down from the outer peripheral portion of the filter mesh portion 13a.

  As shown in FIGS. 6 and 7, the filter mesh portion 13a is a very thin metal having a thickness T of 50 μm. The entire surface of the filter mesh portion 13a has a diameter D of 100 μm and a depth t1 of 5 to 10 μm. A large number of dimples (dimples) 13d are formed. In the center of the dimple 13d, a large number of filtration holes (through holes) 13c for filtering a beverage having a hole diameter d of 30 μm or less (for example, 20 μm) are penetrated. Since the dimple 13d has a dimple structure having a depth t1 of 5 to 10 μm, a sliding hot water film is formed on the dimple (recess) when discharging the extracted soot by the scraper 23, thereby reducing the sliding resistance of the scraper 23. Can be made.

  The filtering hole 13c has a radiation R cone structure 13g (for example, a taper enlarged shape of R = 40 μm) whose diameter increases toward the lower surface 13f while penetrating through and opening the lower surface (back surface) 13f of the filter 13. The area of 13f is made smaller than the sliding surface of the scraper 23. Thus, by making the filtering hole 13c into the radiation R cone structure 13g whose diameter increases toward the lower surface 13f, it is possible to make the tip of the hole inlet portion with respect to the dimple 13d surface of the filtering hole 13c a knife edge 13h. When the scraper 23 is slid and the extraction soot is discarded, the extraction soot (fine powder of the powder raw material) clogged in the filter hole 13c is sheared in cooperation with the tip of the scraper 23 and the knife edge 13h of the filter hole 13c. The extraction force is cut and discharged by applying a strong force to prevent the filtration hole 13c from being blocked. Furthermore, by using the radiation R cone structure 13g, the area of the lower surface 13f that is not washed by the liquid flow can be made extremely small.

  These dimples 13d, filtration holes 13c, and radiation R cone structures 13g are formed by electroforming, and the processed surfaces (filter hole inner surface and lower surface 13f) are finished to have a smooth mirror surface. Thus, the lower surface 13f can prevent the beverage extract from adhering and accumulating, and can prevent the taste of the beverage from being deteriorated due to the stain, maintain the taste, and keep it hygienic.

  The filtration hole 13c has a pore diameter d of 30 μm or less and the inner surface is finished to a smooth mirror surface, so that the liquid flow rate at the time of beverage filtration is secured above a certain level, and dirt adhered to the inner surface of the hole causes a bridging phenomenon in the hole. It can be prevented from occurring, and the dirt adhered to the inner surface of the hole can be washed away during beverage filtration, and the cleaning function of the inner surface of the hole can be maintained. If the diameter of the filtration hole is large (for example, 70 μm), the liquid flow rate at the time of beverage filtration becomes slow, so that it is difficult to wash away dirt adhering to the inner surface of the hole at the time of beverage filtration.

  By finishing the inner surface of the filtration hole 13c with a smooth mirror surface, the coffee beverage is filtered without removing the oil content of the coffee beans. Therefore, the coffee beverage containing the scent component that is removed by the paper filter is removed. Can be filtered.

  Moreover, since the filter hole 13c has a pore diameter d as small as 30 μm or less, the fine powder contained in the raw material can be completely separated and the beverage can be filtered, and no residue remains in the filtered beverage. The beverage having the above transparency can be filtered, and the filtration time of the beverage can be stabilized.

  Further, as shown in FIGS. 8 and 9, the filtration hole 13c may have a straight hole (vertical portion) 13e with a depth t2 of 15 μm or less. Thus, by making the filtration hole 13c into a straight hole 13e having a straight portion of 15 μm or less, the extraction soot (fine powder of the powder raw material) clogged in the filtration hole 13c is the edge of the tip of the scraper 23 and the inlet of the filtration hole 13c. As a result, the shearing force is exerted strongly to cut and discharge the extraction soot to prevent the filtration hole 13c from being blocked, and the durability of the filter 13 can be improved.

  The holding plate 14 has a disk-shaped support portion 14a and a fixing portion 14c having an L-shaped cross section provided over the entire outer periphery thereof. The fixing portion 14c protrudes laterally from the lower end portion of the hanging portion that hangs downward from the outer peripheral portion of the support portion 14a. Moreover, the diameter of the support part 14a is slightly smaller than the filter mesh part 13a. Moreover, the thickness of the support part 14a is set so that sufficient rigidity can be secured to maintain the shape of the support part 14a with respect to the load acting when the scraper mechanism 21 is operated. In addition, a large number of holes 14b are formed on almost the entire surface of the support portion 14a, arranged in a mesh shape, and have a much larger diameter (for example, 4 mm) than the filtration holes 13c of the filter mesh portion 13a described above. .

  The fixed frame 15 is formed in a ring shape with a side wall 15a and an upper wall 15b protruding inward from the upper end portion thereof. A holding plate 14 is fitted to the fixed frame 15 with the filter 13 interposed therebetween, and a fixing portion 14c of the holding plate 14 is press-fitted inside the side wall 15a of the fixed frame 15, thereby The collar portion 13b of the filter 13 is sandwiched between the upper wall 15b and the fixing portion 14c, and the three parties 13 to 15 are integrated. In this state, the entire upper surface of the support portion 14 a of the holding plate 14 is in contact with the filter mesh portion 13 a of the filter 13.

  Next, the scraper mechanism 21 will be described. As shown in FIG. 2, the scraper mechanism 21 is formed in a rectangular frame shape, and has a support 22 whose plane size is larger than that of the filter block 11, a scraper 23 provided integrally with the support 22, and both 22, 23. Has a drive mechanism 24 for driving. The scraper 23 is a plate-shaped member made of elastic rubber (for example, silicon rubber) or metal, and is attached to the support 22 and protrudes vertically downward. The lower end portion of the scraper 23 is formed in a tapered shape so that the width in the front-rear direction becomes narrower as it goes downward.

  The drive mechanism 24 has a rotatable drive unit 24a and a motor (not shown) connected to the drive unit 24a via a connecting shaft 24b extending in the vertical direction. The drive part 24a has an arm part 24c that extends horizontally, and an engaging convex part 24d that protrudes downward is provided at the tip of the drive part 24a. The engaging convex portion 24 d is inserted into the receiving groove 22 a of the support 22.

  Next, the operation of the above-described filter device 10 will be described. First, the filter block 11 of the filter device 10 in the standby state is lifted by being driven by the slider, and the packing 16 seals it while being in contact with the cylinder 2. Then, powdered coffee beans and hot water are supplied into the cylinder 2 from a raw material supply device and a hot water supply device (both not shown), and the coffee beverage is extracted by stirring.

  Next, an air pump (not shown) is operated and air is supplied into the cylinder 2 to pressurize the inside of the cylinder 2. Thereby, the extracted coffee drink passes through the filter hole 13c of the filter 13 to the lower surface 13f side, and is separated and filtered from the extraction basket. On the upper surface of the filter 13, the extracted coffee beverage and the separated extraction gutter G remain, and the filtered coffee beverage further passes through the hole 14 b of the holding plate 14, and passes through the filter block tube and the beverage transport tube. As can be seen, it is supplied to a cup (both not shown).

  Next, as the drive portion 24a of the drive mechanism 24 rotates 180 ° from the standby position shown in FIGS. 2A and 10A, the support 22 and the scraper 23 are moved to the engagement convex portion 24d and the receiving groove. By being pulled rearward through 22a, as shown in FIG. 2 (b) and FIG. 10 (b), it slides to the rear extraction basket discharge position.

  At that time, the scraper 23 slides backward on the upper surface of the filter 13 while preloading the filter 13 with a predetermined pressure via the arm portion 24c by the drive mechanism 24. As a result, the scraper 23 slides in close contact with the upper surface of the filter 13, and the extracted soot G remaining on the upper surface of the filter 13 is pressed and scraped off by the scraper 23 as shown in FIG. It is discharged outside through (not shown). Then, the extracted soot (fine powder of the powder raw material) clogged in the filter hole 13c cooperates with the edge of the tip of the scraper 23 and the top of the inlet of the filter hole 13c to cut the extract soot with a strong shearing force. It discharges | emits and the obstruction | occlusion of the filtration hole 13c is prevented.

  In the present embodiment, since the straight hole 13e is very shallow, such as 15 μm or less, as the scraper 23 slides, no extraction residue remains in the filtration hole 13c and is removed from the upper surface of the filter 13.

  Thereafter, when the drive unit 24a further rotates 180 °, the scraper 23 slides forward while pressing the upper surface of the filter 13, and the support 22 and the scraper 23 are moved back as shown in FIG. Return to the standby position.

As described above, according to the filter device 10 of the present embodiment, it is a filter device 10 for filtering a beverage extracted with a mixture of a powdery raw material and hot water, and extracted on the upper surface side. In the filter device including the filter 13 that separates and filters the beverage by passing the beverage to the lower surface side through the filtration hole 13c, the filter 13 includes a plurality of dimples 13d. A filtration hole 13c is formed in the filtration hole 13c. The filtration hole 13c has a pore diameter d of 30 μm or less and a vertical portion depth t2 of 15 μm or less. Having a filter 13 that separates and filters the beverage extracted on the upper surface side from the extraction basket G by passing it through the filtration hole 13c to the lower surface 13f side , Ensuring a liquid flow rate at a certain level or higher during beverage filtration, preventing dirt adhering to the inner surface of the hole from causing a bridging phenomenon in the hole, and allowing dirt attached to the inner surface of the hole to be washed away during beverage filtration. The cleaning function can be maintained. In addition, the fine powder contained in the raw material can be completely separated and the beverage can be filtered, and since no residue remains in the filtered beverage, it is possible to filter the beverage having transparency higher than that of the paper filter, The filtration time of the beverage can be stabilized. Further, the extracted soot clogged in the filter hole is cooperated with the tip of the scraper 23 and the edge of the front end of the inlet portion of the filter hole 13c, and the shear force is strongly applied to cut and discharge the extracted soot. While preventing obstruction | occlusion, durability of the filter 13 can be improved. In this way, it is possible to provide the filter device 10 that can prevent the filtration hole 13c from being blocked by the extraction basket and maintain the beverage taste.

  The scraper 23 slides on the upper surface of the filter 13 and scrapes off the raw material extraction residue G remaining on the upper surface of the filter 13, and the scraper 23 is preloaded on the upper surface of the filter 13 to press the raw material extraction residue G. When the scraper 23 is slid and the extracted soot G is discarded, the scraper 23 is in close contact with the upper surface of the filter 13 and slides, and the extract soot (fine powder of powder raw material) clogged in the filter hole 13c. In combination with the tip of the scraper 23 and the edge of the inlet of the filtration hole 13c, the shearing force is exerted strongly to cut and discharge the extraction soot, thereby preventing the filtration hole 13c from being blocked. .

  Further, in order to maintain the rigidity of the filter 13, the shape of the filter 13 is maintained by further including a holding plate 14 provided with a hole 14 b having a predetermined size on the lower surface 13 f side of the filter 13. Although the filter 13 is made of an extremely thin metal material, it is easily deformed. However, the shape of the filter 13 is maintained by the holding plate 14, and the scraper 23 is preloaded on the upper surface of the filter 13 to press the raw material extraction gutter G Even if it slides, the gap between the tip of the scraper 23 and the upper surface of the filter 13 is prevented, and the extraction soot clogged in the filtration hole 13c is removed from the tip of the scraper 23 and the inlet of the filtration hole 13c. It is possible to prevent the clogging of the filtration hole 13c by cutting and discharging in cooperation with the edge.

  Further, the filtering hole 13c has a radial R cone structure 13g whose diameter increases toward the lower surface 13f of the filter 13, the tip of the inlet portion of the filtering hole 13c is a knife edge 13h, and the area of the lower surface 13f is reduced, whereby the scraper 23 When the extraction slag G is discarded by sliding, the extraction slag (fine powder of powder raw material) clogged in the filtration hole 13c cooperates with the knife edge 13h at the tip of the scraper 23 and the inlet of the filtration hole 13c. Thus, the shearing force is exerted strongly to cut and discharge the extracted soot, thereby preventing the filtration hole 13c from being blocked. In addition, it is possible to prevent the beverage extract from adhering to and accumulating dirt, preventing the taste of the drink from being deteriorated by the dirt, maintaining the taste, and keeping it sanitary.

  Further, the upper part of the filter hole 13c has a dimple shape having a recess of 5 to 10 μm, and when the scraper 23 is pre-loaded on the upper surface of the filter 13 and slides while pressing the raw material extraction rod G, a hot water film is applied to the dimple 13d. By reducing the sliding resistance of the scraper 23 by configuring, it is possible to reduce the size of the scraper sliding motor and reduce the cost of the scraper 23, and to provide a small and low-cost filter device 10. Become.

  In addition, this invention can be implemented in various aspects, without being limited to the embodiment described above. For example, in the embodiment, the case where the present invention is applied to a filter device of a regular coffee extraction device has been described. However, the present invention can also be applied to a filter device of an extraction device that extracts tea-based beverages using tea leaves as a raw material. .

  Further, the values such as the thickness T of the filter mesh portion 13a, the diameter D and the depth T1 of the dimple 13d, the diameter d of the filtration hole 13c, and the depth t2 of the vertical portion of the straight hole 13e described in the embodiment are merely examples. It is also possible to set other appropriate values. In addition, it is possible to appropriately change the detailed configuration within the scope of the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Beverage extraction apparatus 2 Cylinder 3 Cylinder holder 4 Frame 10 Filter apparatus 11 Filter block 12 Filter assembly 13 Filter 13a Filter mesh part 13b Collar part 13c Filtration hole 13d Dimple 13e Straight hole (vertical part)
13f Lower surface 13g Radiation R cone structure 13h Knife edge 14 Holding plate (metal plate)
15 Fixed frame 21 Scraper mechanism 23 Scraper

Claims (2)

A filter device for filtering a beverage extracted with a mixture of powdered raw material and hot water, wherein the beverage extracted on the upper surface side is passed to the lower surface side through a filtration hole, In the filter device including a filter for separating and filtering, the filter has a plurality of dimples, and a filtration hole is formed in the dimple. The filtration hole has a hole diameter of 30 μm or less and has a vertical portion. A filter device, wherein the depth is 15 μm or less, and the inner surface of the hole is formed of a smooth mirror surface. 2. The filter according to claim 1, wherein the filter hole has a radial R-cone structure whose diameter increases toward the lower surface of the filter, and the tip of the filter hole inlet portion has a knife edge to reduce the area of the lower surface . Filter device.