JP6225675B2 - Medium solution coating method and metal mask plate - Google Patents

Description

  The present invention relates to a technique for applying a medium solution for forming a dry medium used for viable count inspection.

  In the food manufacturing industry, in order to control the quality and hygiene of products, viable count tests using agar media are performed. FIG. 6 is a diagram for explaining the viable cell count test using an agar medium. As shown in FIG. 6, the viable cell count test using an agar medium is a gelled agar medium formed in a Petri dish 5a1 (glass petri dish), and after dropping a sample solution with a dropper 5a2, etc. This is a test to measure the number of viable bacteria after a certain time. The viable cell count test using an agar medium has been widely used for a long time, but it requires an agar medium with agar in the Petri dish 5a1, so it takes time to adjust the medium and is not suitable for testing many samples. there were.

  In recent years, in order to increase the efficiency of viable count testing, an increasing number of companies have introduced viable count testing using a dry medium instead of an agar medium. The dry medium means that the medium components are not gelled (dried) and applied in advance to a resin sheet or container, and the gelation proceeds at the stage where the sample solution is dropped during the viable count test. It is a culture medium which can obtain the same effect. In the viable cell count test using a dry culture medium, there is no need to adjust the culture medium at the site where the viable cell count test is performed, so that the efficiency of the viable cell count test can be greatly improved.

  Petrifilm (registered trademark) manufactured by 3M is well-known as a product already marketed in such a dry medium. FIG. 7 is a diagram for explaining the Petri film (registered trademark) 5b. As shown in FIG. 7, the Petri film (registered trademark) 5b is composed of a waterproof flat plate 5b1 (plastic-coated paper) and a cover film 5b2 that overlaps the waterproof flat plate 5b1. A dry medium is formed by applying the indicated contract and then applying a cold water soluble gel (gelling agent) and medium components on it, which is further sterilized into a product. . Such a sheet-like dry medium is also called a film medium.

  FIG. 8 is a diagram for explaining how to use Petri Film (registered trademark) 5b. When using Petrifilm (registered trademark) 5b, first, the cover film 5b2 overlaid on the flat plate 5b1 is lifted (FIG. 8 (a)), and the medium components and cold water soluble gel formed on the flat plate via the adhesive layer A predetermined amount of the sample solution is dropped onto a dry medium consisting of (Fig. 8 (b)), the cover film 5b2 is lowered (Fig. 8 (c)), and pressed by a plastic spreader 5b3 (Fig. 8 (d) )), The sample liquid is spread circularly and evenly and absorbed (FIG. 8 (e)). When the cold water soluble gel is solidified, it is stored in an incubator as it is, cultured at a predetermined temperature and time, and the number of colonies generated is counted.

  Advantages of using a film medium typified by Petrifilm (registered trademark) 5b are that it eliminates the trouble of producing the medium, saves the time of discarding the medium, and saves the space occupied in the incubator during the culture. By using the film medium for the viable cell count test, the time and materials for the viable count test can be saved significantly. In addition, since the film medium is thin, it is an important merit that it is easy to focus when observing colonies with a magnifying glass or a microscope.

  On the other hand, as a technical problem when the film medium is used for the viable cell count test, when an operator unfamiliar with the handling of the film culture medium performs the viable cell count test, when it is pressed with the spreader 5b3 from the top of the cover film 5b2, There is a problem that the gelled portion does not become a beautiful circle as in the case of using the conventional Petri dish 5a1, and a measurement error of the viable cell count occurs. In addition, the medium components outside the gelled portion pressed by the spreader 5b3 are discarded wastefully, leading to high costs.

  As a dry culture medium in which the gelled part has a beautiful circular shape and no waste of medium components, the medium part is circular from the beginning, and the medium part is surrounded by a frame having a sufficient height. A dry medium has been proposed.

  FIG. 9 is a diagram for explaining a sterile culture package disclosed in Patent Document 1, and FIG. 10 is a diagram for explaining a film medium with a pedestal disclosed in Patent Document 2.

  For example, as a dry medium having the above-described structure, in Patent Document 1, as shown in FIG. 9, a sterile culture package having a structure in which a dry medium is provided at the bottom of a cereal bottle and a sample solution is dropped onto the dry medium with an injection needle. 5c is disclosed. By using the sterile culture package 5c disclosed in Patent Document 1, a beautiful circular culture part can be obtained in the same manner as the agar medium using the Petri dish 5a1, but on the other hand, the cost is reduced by using a cereal bottle. Become high. Another problem is that it is difficult to visually count the number of colonies due to the shape of the cereal bottle.

  As a dry culture medium having the structure described above, in Patent Document 2, as shown in FIG. 10, a circular area to be a culture surface is surrounded by a convex circular pedestal 5d1 in the same form as a film culture medium. A pedestal film medium 5d is disclosed. According to the pedestal film medium 5d disclosed in Patent Document 2, it is possible to form a beautiful circular gelled portion by dropping the sample liquid into the circular pedestal 5d1 of the pedestal film medium 5d. It becomes. However, since the culture medium components are applied to the entire surface of the base of the film medium 5d with a pedestal, the medium components outside the circular pedestal 5d1 are wasted and the cost becomes high.

  In order to solve the problem of waste of medium components in the film medium 5d with a pedestal, the applicant of the present invention disclosed in Patent Document 3 that a medium liquid coating sheet, which is a sheet coated with a medium liquid (dispensing liquid in Patent Document 3). As for the manufacturing method, Patent Document 4 discloses a porous nozzle necessary for the manufacturing method disclosed in Patent Document 3, respectively.

  In the method for producing a medium solution coating sheet disclosed in Patent Document 3, a separation distance between a discharge surface of a porous nozzle composed of nozzles having a hole diameter of 0.9 mm to 1.6 mm and a substrate surface is set to 0.3 mm. -Dispensing liquid with a solid content of 20% to 50% at a rate of ~ 1.0mm is transferred to the base material surface so that the coating amount from the nozzle constituting the porous nozzle is 250g / m2 to 1050g / m2. It is a method of coating.

  FIG. 11 is a diagram for explaining the porous nozzle disclosed in Patent Document 4. As shown in FIG. The perforated nozzle 5e disclosed in Patent Document 4 is a nozzle that is required in the method for producing a medium solution coating sheet disclosed in Patent Document 3, and this perforated nozzle 5e is, as illustrated in FIG. It has a discharge surface with a bundle of thin nozzles

JP 2001-114339 A JP-T-2004-515236 JP 2013-55899 A JP 2013-51931 A

However, the following problems still remain in the method for producing a medium solution coated sheet using the porous nozzle 5e disclosed in Patent Document 4, and the mass production and production cost of the sheet coated with the medium solution remain. The situation is difficult to reduce.
(1) Since the multi-hole nozzle 5e of Patent Document 4 is a bundle of nozzles having a small diameter, clogging occurs when the solvent of the medium solution volatilizes and the viscosity of the medium solution changes. Therefore, when the dispenser stops due to chocolate stop, adjustment, break, etc., clogging occurs, and the work cannot be resumed unless the perforated nozzle 5e is thoroughly cleaned.
(2) Since the porous nozzle 5e is a precision-processed product, it is relatively expensive, and an operation method in which the porous nozzle 5e that has been clogged is replaced and disposable is not possible.

  Since these problems are caused by applying the medium solution by a dispensing method using a nozzle, screen printing (silk printing) capable of thick ink printing has been investigated as an alternative to the dispensing method using a nozzle. It was.

  Plates used for screen printing are broadly classified into two types: mesh cloth plates that are used by emulsifying areas where ink is not applied, and metal mask plates where holes are formed in areas where ink is applied. The mesh cloth plate has a problem that the emulsion used for sealing is dissolved in alcohol for diluting the medium solution and cannot be used for coating the medium solution. On the other hand, the metal mask plate does not have the same problems as the mesh cloth plate, but there is a problem that the medium solution wraps around the back of the plate during screen printing.

  Therefore, the present invention is directed to screen printing using a metal mask plate, and when the medium solution is applied onto a substrate sheet on which a protruding medium frame is formed on the surface, the medium solution is applied. It is an object of the present invention to provide a medium liquid coating method and a metal mask plate used for screen printing that can apply a medium solution in a medium frame formed on a base sheet without going around the back surface of the metal mask plate.

    According to a first aspect of the present invention for solving the above-mentioned problems, a metal mask plate used in screen printing using a base sheet having a projection-shaped medium frame formed on the surface thereof as a substrate to be printed is aligned with a position where the medium frame is formed. Forming a hole for allowing the culture medium to pass therethrough, and further forming a projection-like fitting portion that fits inside the medium frame at the back edge of the hole, and the medium frame on the surface of the base sheet A medium solution is screen-printed in a state in which the fitting portion on the back surface of the metal mask plate is fitted, and the medium solution is applied in the medium frame on the surface of the base sheet. It is a construction method.

  Furthermore, the second invention is a screen plate for use in screen printing in which a substrate sheet having a projection-shaped medium frame formed on the surface thereof is used as a printing material, the medium being aligned with the position where the medium frame is formed, It is a metal mask plate characterized by forming a hole having a protrusion-like fitting portion fitted on the inner side of the frame at the rear edge.

  According to the present invention, when screen printing is performed, the back edge of the hole portion of the metal mask plate is fitted to the fitting portion formed on the back surface of the metal mask plate and the medium frame formed on the surface of the base sheet. The fitting part formed in the part plays a role of preventing the medium solution pushed out from the hole from flowing around the back surface of the metal mask plate, and the medium solution does not flow around the back surface of the metal mask plate.

The figure explaining the culture-medium liquid coating method which concerns on this embodiment. The figure explaining the base material sheet which concerns on this embodiment. The figure explaining the metal mask plate which concerns on this embodiment. The figure explaining the process of the culture solution coating method which concerns on this embodiment. The figure explaining the base material sheet and metal mask plate in an Example. The figure explaining the viable count test using an agar medium. The figure explaining Petrifilm (trademark). The figure explaining the usage method of Petrifilm (trademark). The figure explaining the aseptic culture packaging body currently disclosed by patent document 1. FIG. The figure explaining the film culture medium with a base currently disclosed by patent document 2. FIG. The figure explaining the porous nozzle currently disclosed by patent document 4. FIG.

  From here, preferred embodiments of the present invention will be described. The following description is not intended to limit the scope of the present invention, but is provided to aid understanding.

  FIG. 1 is a diagram for explaining a medium solution coating method according to the present embodiment. The medium solution coating method according to the present embodiment is a method in which a medium solution 3 is applied to a base sheet 2 that forms a dry medium used for viable cell count inspection by screen printing using a metal mask plate 1. The metal mask plate 1 used for printing is characterized.

  FIG. 2 is a diagram illustrating the base sheet 2 according to the present embodiment. The base material sheet 2 is a rectangular sheet that is a printing material for screen printing. The base sheet 2 is required to have water resistance, and examples of materials that can be used as the base sheet 2 include plastic sheets such as polyester, polyethylene, polypropylene, polystyrene, polycarbonate, and polyvinyl chloride, and water-resistant paper. (For example, a paper laminated with a plus chip film) can be used. In addition, although there is no limitation in the thickness of the base material sheet 2, generally the thickness of the base material sheet 2 is about 50-500 micrometers.

  As illustrated in FIG. 2, the surface of the base sheet 2 according to the present embodiment is provided with a ring-shaped medium frame 20 with multiple faces (here, six faces) using a hot-melt resin. The culture medium liquid 3 is applied in the culture medium frame 20 by screen printing, and the culture medium frame 20 serves as a weir to clog the culture medium liquid 3 applied by screen printing.

  FIG. 3 is a diagram for explaining the metal mask plate 1 according to the present embodiment. The metal mask plate 1 of the present embodiment is a screen plate used by being stretched on an AL frame, and a normal metal plate used in screen printing can be used as a base material of the metal mask plate 1. In addition, the material of the normal metal plate used for screen printing is SUS or Ni, and the thickness is generally 0.03-0.2 mm.

  As illustrated in FIG. 3, the metal mask plate 1 according to the present embodiment has a circular shape that serves as an image line portion of the medium 3 in accordance with the position of the medium frame 20 formed on the base sheet 2. The hole 11 is made and the size of the hole 11 is set to be slightly smaller than the size of the medium frame 20 formed on the base sheet 2. As can be seen from the cross-section between A and B in FIG. 3, the hole 11 made in the metal mask plate 1 is a hole that penetrates the metal mask plate processed for the passage of the medium solution. .

  Further, a ring-shaped fitting portion 10 for preventing the medium solution 3 from entering the back of the metal mask plate 1 is formed on the back surface edge portion of the hole 11 made in the metal mask plate 1 using a hot melt resin. Has been. The fitting portion 10 formed on the back surface edge of the hole 11 made on the metal mask plate 1 is fitted with the inside of the medium frame 20 formed on the surface of the base sheet 2 when screen printing is performed. , It becomes a member for preventing the medium solution 3 from wrapping around the back of the metal mask plate 1. In order to fit inside the medium frame 20 formed on the surface of the base sheet 2, the outer diameter of the fitting portion 10 formed on the back surface of the metal mask plate 1 is the medium formed on the surface of the base sheet 2. It is shorter than the inner diameter of the frame 20, and the height of the fitting portion 10 formed on the back surface of the metal mask plate 1 is slightly smaller than the height of the medium frame 20 formed on the base sheet 2.

  FIG. 4 is a diagram for explaining the steps of the medium liquid coating method according to the present embodiment. As described above, when screen printing is performed using the metal mask plate 1 and the base sheet 2, the medium formed on the surface of the fitting portion 10 and the base sheet 2 formed on the back surface of the metal mask plate 1. By aligning the position of the frame 20 so that the metal mask plate 1 is on the upper side and the metal mask plate 1 and the base sheet 2 are overlapped, the fitting portion 10 and the base formed on the back surface of the metal mask plate 1 are overlapped. It fits with the culture medium frame 20 formed on the surface of the material sheet 2 (FIG. 4A).

  Next, the medium solution 3 was placed on the metal mask plate 1 and the squeegee 4a was slid to extrude the medium solution 3 from the hole 11 of the metal mask plate 1 and formed on the surface of the base sheet 2. The medium 3 is transferred into the circular medium frame 20 (FIG. 4B).

  As shown in FIG. 4B, when screen printing is performed, in order to fit the fitting portion 10 formed on the back surface of the metal mask plate 1 and the medium frame 20 formed on the surface of the base sheet 2, The ring-shaped fitting portion 10 formed at the back edge of the hole 11 of the metal mask plate 1 plays a role of blocking the culture medium 3 pushed out from the hole 11 from entering the back surface of the metal mask plate 1. , The medium solution 3 does not wrap around the back surface of the metal mask plate 1.

  After applying the medium 3 to the inside of the circular medium frame 20 formed on the surface of the base sheet 2, the surface tension effect of the medium 3 is obtained when the metal mask plate 1 is separated from the base sheet 2. As a result, the medium 3 transferred in the medium frame 20 formed on the surface of the base sheet 2 diffuses in the lateral direction (FIG. 4C), and the circular shape formed on the surface of the base sheet 2 When the culture medium 3 is blocked by the culture medium frame 20, the culture medium 3 is leveled and smoothed (FIG. 4D).

  The substrate sheet 2 coated with the medium solution 3 by the medium solution coating method according to the present embodiment is placed in a drying device (not shown), and the medium solution applied to the substrate sheet 2 by the medium solution coating method. 3 is dried. Then, the base material sheet 2 from which the medium solution 3 is dried is laminated and bonded with a cover film such as a biaxially stretched polypropylene film, and then individually cut with a cutting device (not shown) to produce a product.

  From here, the Example of the culture-medium liquid coating method which concerns on this embodiment is demonstrated. FIG. 5 is a diagram for explaining the base sheet 2a and the metal mask plate 1a in the embodiment. In FIG. 5, the inner diameter of the circular medium frame 20a formed on the surface of the base sheet 2a is 50 mm, and the height of the medium frame 20a is 0.7 mm.

  In this example, a metal mask plate 1a having a material of SUS and a thickness of 0.14 mm was used. As shown in FIG. 5, in this embodiment, the outer diameter of the ring-shaped fitting portion 10a formed on the back surface of the metal mask plate 1a is larger than the inner diameter of the medium frame 20a formed on the base sheet 2a. The inner diameter of the ring-shaped fitting portion 10a is φ46mm, and the height of the fitting portion 10a is 0.6mm. Further, in this embodiment, the diameter of the circular hole portion 11a formed in the metal mask plate 1a is φ45 mm which is smaller than the inner diameter of the circular fitting portion 10a formed on the back surface of the metal mask plate 1a. .

  The substrate sheet 2a, the metal mask plate 1a illustrated in FIG. 5 and the medium 3 (dispensing solution) disclosed by the applicant in Japanese Patent Laid-Open No. 2013-55898 are used, and the squeegee 4a is moved at a speed of 100 mm / S. When the medium was slid and screen-printed, the medium solution 3 did not wrap around the back surface of the metal mask plate 1a, and the entire surface of the medium frame 20a formed on the surface of the base sheet 2a was not affected by the surface tension effect of the medium solution 3. It was confirmed that the medium 3 could be applied. In addition, the medium 3 disclosed by the present applicant in Japanese Patent Application Laid-Open No. 2013-55898 contains 20% by mass to 40% by mass of solid content as particles, and the average particle size of the particles is preferably 90 μm or less. Is a medium 3 having a viscosity of 65 μm or less and a viscosity of 100 to 1200 cp.

DESCRIPTION OF SYMBOLS 1 Metal mask plate 10 Fitting part 11 Hole part 2 Base material sheet 20 Medium frame 3 Medium liquid 4a Squeegee 4b Aluminum frame

Claims (2)

  In a metal mask plate used for screen printing with a substrate sheet having a projection-shaped medium frame formed on the surface thereof, a hole through which a medium solution is passed is formed in accordance with the position where the medium frame is formed, Furthermore, a projection-like fitting portion that fits inside the medium frame is formed on the back surface edge of the hole, and the medium frame on the surface of the base sheet and the fitting portion on the back surface of the metal mask plate A medium liquid coating method comprising: screen-printing a medium liquid in a state of fitting the medium liquid and applying the medium liquid into the medium frame on the surface of the base sheet. A screen plate for use in screen printing with a substrate sheet having a projection-shaped medium frame formed on the surface thereof, and a projection that fits inside the medium frame in alignment with the position where the medium frame is formed A metal mask plate characterized by forming a hole having a fitting portion at the rear edge.

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