JPH1090834A - Sheath and metallic mold for film unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film unit sheath which can surely prevent a film from falling out and to surely holds the sheath right after molding to prevent a defect in molding. SOLUTION: The sheath 1 consists of a flat plate part 1a which is covering and supporting base of the sheet film 2 and edge parts 1b, 1c, and 1d where grooves where which are holding three sides 2b, 2c, and 2d except the short side 2a of the sheet film. End parts 14 and 15 of the edge parts 1b and 1d are extended almost to the end of a rear end part 10 so that they project from the edge of an unexposed sheet film 2 while the sheet film 2 is inserted into the sheath 1, and an ultrasonic horn is pressed against this part to crush the end parts 14 and 15 and bring them into contact with the surface of the rear end part 10, closing the grooves of the end parts 14 and 15. Further, an biting means of the metallic mold is so shaped that rectangular molding marks 9 are formed at the edge parts 1b and 1d.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin film unit sheath for accommodating a sheet film to protect the film from scratches and the like, and to maintain the flatness of the sheet film, and to a mold for injection molding the same. is there.

[0002]

2. Description of the Related Art A film pack which is used by being loaded in a pack holder and which enables continuous photographing with a large camera is used.
A plurality of film units each containing a sheet of a 5 inch sheet film stored in a sheath are stored.
The sheath holds one sheet film, protects it from scratches, and maintains the flatness, and there are a conventional metal film and a resin film recently proposed by the present applicant. (JP-A-8-110569). The one made of metal is composed of a flat plate portion that supports the base surface of the sheet film in a planar shape, and an edge portion that bends four sides thereof inward to hold the edge of the sheet film. On the other hand, resin products are difficult to use because of mold problems and ease of sheet film insertion.
The edges are provided with grooves for inserting three edges of the sheet film.

[0003] In the resin sheath, since no edge is provided on one side into which the sheet film is inserted, if the sheet film is simply inserted into the sheath, the film is likely to move out of a predetermined position. . Therefore, as disclosed in the above publication, the present applicant inserts a sheet film into a sheath, and then forms a track-shaped convex portion at an end of a flat plate portion having no edge portion. Have proposed to prevent the film from coming off.
In addition, the convex portion melts the resin by, for example, pressing the heater block against the flat plate portion and heating the resin block, and raises the resin.
Has formed.

[0004] The resin sheath is injection-molded using a predetermined mold. As is well known, the mold includes a fixed mold (cavity) and a movable mold (core).
, And the movable mold is further divided into a core body and a slide core. This slide core is the sheath 3
A groove for inserting the edge of the sheet film is formed inside the surrounding edge, and the moving mold is separated from the fixed mold immediately after the sheath is formed, and then pulled out of the core body. In addition, the core body is provided with a biting means (projection) for holding the sheath when pulling out the slide core, at a position facing the edges on both sides of the sheath. As the biting means, as described in the above-mentioned publication, a method in which a molding mark has a half-moon shape on the outer surfaces of a pair of opposite edges of a sheath has been proposed.

[0005]

The above-mentioned convex portions are not always formed at a constant height due to variations in the temperature of the heater block, variations in the resin characteristics, and the like. . Further, when the resin is melted by the heater block, if the sheet film moves and approaches the heater block, there is a problem that heat fog is generated on the sheet film. Further, when the slide core is pulled out of the moving side mold, a large frictional force is generated between the surface of the slide core and the sheath immediately after molding. It has been found that the effect of holding the sheath is insufficient and molding defects frequently occur.

The present invention has been made in view of the above circumstances, and has as its object to provide a film unit sheath that can reliably prevent the film from coming off. It is another object of the present invention to provide a mold capable of reliably holding a sheath immediately after molding and preventing occurrence of molding failure.

[0007]

In order to achieve the above object, a film unit sheath according to the present invention is a film unit sheath for accommodating sheet films one by one, wherein the base surface of the sheet film is flat. A resin film unit sheath comprising: a rectangular flat plate portion supported in a shape; and a grooved edge portion formed on three sides of the flat plate portion to insert edges of the three sides of the sheet film. At least one end of a pair of opposing edges of the portion is extended so as to protrude outside the edge of the sheet film, and the extended portion is deformed to close a groove at an end of the edge. The deformation of the extension portion is performed by ultrasonic welding.

The mold of the present invention has a rectangular flat plate portion for supporting the base surface of the sheet film in a plane, and is formed on three sides of the flat plate portion to insert edges of the three sides of the sheet film. A mold for injection-molding a resin sheath having a grooved edge, comprising a fixed mold and a movable mold, the movable mold further surrounding three sides of the sheath. In a mold comprising a slide core forming a groove for inserting the edge of the sheet film inside the edge portion, and a core body provided with a biting means for holding a sheath when the slide core is pulled out, the biting means includes The shape is such that rectangular molding marks remain on the outer surfaces of a pair of opposing edges of the edges.

[0009]

In FIG. 1, a sheath 1 for a film unit of the present invention is made of, for example, polystyrene (PS).
For example, a flat plate portion 1a supporting the base surface side of a 4 × 5 inch size sheet film 2 and three sides 2b and 2c excluding the short side 2a of the sheet film 2 are formed by injection molding with a resin such as , 2d are formed with edges 1b, 1c, 1d in which a groove sandwiching each edge is formed.

The rectangular molding traces 9 formed on the edges 1b and 1d on both sides are formed by a die biting means described later. A notch 1 is provided at the rear end 10 of the sheath 1.
1 is formed. The notch 11 is used to receive the tip of the robot arm holding the sheet film 2 when the sheet film 2 is inserted into the sheath 1 and to determine the type and the front and back engraved on the short side 2 a of the sheet film 2. The notch 2e can be confirmed from both sides of the sheath 1.

The ends 14 and 15 of the edges 1 b and 1 d are formed at the ends of the rear end 10 so that the unexposed sheet film 2 is inserted into the sheath 1 and protrudes outward from the edge of the sheet film 2. As shown in FIG. 2, the ultrasonic horn 16 is crushed and brought into close contact with the surface of the rear end portion 10 as shown in FIG. The grooves 18, 19 are closed. Thus, the sheet film 2 is completely prevented from coming off. In addition, the ends 14 and 15 are spread outward by crushing. In anticipation of this degree of spread, as shown in FIG. In FIG. 4, a hatched region 20 is a portion to which the ultrasonic horn 16 is applied, and a position shown by a virtual line 21 is an end position of the end 14 after the end 14 is deformed and spread.

As shown in FIG. 4, the length D ₁ of the sheath ₁ is 129 mm and the width D ₂ is 104 mm. Width D ₃ details 10a of the rear end portion 10 which becomes narrower by the notch 11 is 5.0 mm, a width D ₄ is 3.5mm edges 1b, the rear end portion 10 from the end of the short side 2a of the sheet film 2 the distance D ₅ to the end is 2.0 mm. The distance D ₆ from the corner 23 of the region 20 to the end of the rear end 10 is 0.3 mm,
Retraction width D ₇ of the step portion 14a is 0.2 mm, the width D ₈ from the step portion 14a to the side edge of the edge 1b is 1.3m
m, the width D ₉ from the edge of the region 20 to the side edge of the edge 1b.
Is 1.7 mm, and the distance D10 from the end of the region 20 to the end of the rear end ₁₀ is 1.2 mm. The width D ₁₁ from the side end edge portions 1b to the groove 18 is 2.0 mm. Also,
The corner 23 of the region 20 is chamfered with Rα (α = 0.2 mm), and the corner 24 of the edge 1b is chamfered with Rβ (β = 0.5 mm).

In FIG. 5, a mold 30 for injection-molding the sheath 1 includes a fixed mold 31 and a movable mold 32. The movable mold 32 further includes a core body 33 and a slide core 34. I know. This slide core 34 forms a groove for inserting the edges 2b, 2c, 2d of the sheet film 2 inside the edges 1b, 1c, 1d of the sheath 1, and the movable die 32 immediately after the molding of the sheath 1. Is pulled out of the recess 33a of the core body 33 (in the direction of the arrow) after leaving the fixed side mold 31 (in the direction of the arrow).

At the time of pulling out, a large frictional force is generated between the surface 34a of the slide core 34 and the sheath 1 immediately after molding, so that the biting means 36 for holding the sheath 1
The core body 33 is provided at a position facing the edges 1 b and 1 d of the sheath 1. The biting means 36 is a quadrangular prism-shaped projection so that the sheath 1 can be firmly held in the sliding direction (the direction of the arrow) of the slide core 34. As a result, as shown in FIGS. 1, 6 and 7,
The molding trace 9 formed by the biting means 36 has a rectangular shape. Then, after the slide core 34 is pulled out of the core main body 33, the molded sheath 1 is peeled off from the core main body 33 in the direction of the arrow.

As shown in FIG. 6 and FIG.
The length of the D ₁₂ is 3.0 mm, the width D ₁₃ is 1.5 mm, the corner portion 3
8 and 39 are Rγ (γ = 0.2 mm). The depth D ₁₄ of the molding marks 9 is 0.6 mm. The thickness D ₁₅ of the edge portion 1b is 1.8 mm.

The sheath 1 is desirably molded under the conditions shown in Table 1 below, for example. The molding machine used was FE160S 36ASE type (trade name) manufactured by Nissei Plastic Industry.

[0017]

[Table 1]

The sheet film 2 is inserted into the thus formed sheath 1, and the ultrasonic horn 16 is used to insert the edges 1b, 1d.
When the end portions 14 and 15 are crushed, the sheet film 2 is securely held by the sheath 1 without falling off.

In the embodiment described above, both ends of the opposing edges are crushed. However, only one end may be crushed.

[0020]

As described above in detail, according to the film unit sheath of the present invention, at least one end of a pair of opposite edges among the edges is projected outside the edge of the sheet film. Since the extension is made and the extended portion is deformed to close the groove at the end of the edge, the film can be reliably prevented from coming off. Also, since ultrasonic welding is used to deform the extended portion, unlike in the case of heating, heat fogging does not occur on the sheet film, and the film can be prevented from coming off by a safe and reliable operation.

Further, in the mold of the present invention, since the biting means is shaped so that a rectangular molding mark remains, the holding of the sheath immediately after molding can be ensured, and the occurrence of molding defects can be completely prevented. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a sheath of the present invention.

FIG. 2 is a partial perspective view showing a state before deformation of an edge of an edge.

FIG. 3 is a partial perspective view showing a state after deformation of an edge of an edge.

FIG. 4 is a partial plan view showing dimensions near an end of an edge.

FIG. 5 is an exploded explanatory view of a mold for injection-molding a sheath.

FIG. 6 is a partial plan view of an edge showing a mark formed by the biting means.

FIG. 7 is a cross-sectional view of an edge showing a mark formed by the biting means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sheath 2 Sheet film 1a Flat plate part 1b-1d Edge 9 Forming mark 14,15 End part 18,19 Groove 30 Mold 31 Fixed side mold 32 Moving side mold 33 Core body 34 Slide core 36 Biting means

Claims (3)

[Claims] 1. A sheath for a film unit for accommodating sheet films one by one, wherein the sheath is formed on a rectangular flat plate portion for supporting a base surface of the sheet film in a plane, and on three sides of the flat plate portion. A resin film unit sheath comprising a grooved edge into which three edges of the sheet film are inserted, wherein at least one end of a pair of opposite edges of the edge is outside the edge of the sheet film. A sheath for a film unit, wherein the sheath is extended so as to protrude, and the extended portion is deformed to close a groove at an end of an edge. 2. The film unit sheath according to claim 1, wherein the extension portion is deformed by ultrasonic welding. 3. A rectangular flat plate portion for supporting a base surface of a sheet film in a planar manner, and a grooved edge formed on three sides of the flat plate portion for inserting edges of the three sides of the sheet film. A mold for injection-molding a resin sheath, comprising a fixed mold and a movable mold. The movable mold further includes a sheet film inside an edge portion surrounding three sides of the sheath. A slide core forming a groove for inserting an edge,
In a mold comprising a core body provided with a biting means for holding a sheath when the slide core is pulled out, the biting means comprises a rectangular molding mark on an outer surface of a pair of opposing edges of the edges. A mold characterized by having a shape that remains.