JPH11133550A - Light shielding cover for instant film pack and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light shielding cover for an instant film pack and its production by which the consumption of a battery for driving an ejection mechanism is reduced by decreasing ejection resistance. SOLUTION: A drawing guide 52 is arranged so that its edge 52a may interrupt the tangent of a developing roller 50b passing through an ejection port. When the edge 6a of the light shielding cover 6 projects from the ejection port by specified length, it abuts on the edge 52a of the guide 52, goes toward a developing roller 50a and is fed to space between the rollers 50a and 50b through the roller 50b. Since the cover 6 is displaced in an arched state in a thickness direction with the guide 52 as fulcrum, pressing force to press the cover 6 to the guide 52 is generated and becomes the ejection resistance. However, since the cover 6 is made thinner than the conventional one so as to drastically enhance flexibility, not only the pressing force but also the ejection resistance are weak, whereby driving torque to drive the rollers 50a and 50b becomes small and the consumption of the battery is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-shielding cover for an instant film pack which is displaced in a thickness direction and is discharged while receiving a resistance, and a method of manufacturing the same.

[0002]

2. Description of the Related Art There is known an instant film pack (hereinafter, referred to as a film pack) which is used by being loaded into an instant camera. This film pack is, as described in, for example, JP-A-7-209814, a rectangular, mono-sheet type self-developing processing type in a box-shaped hard plastic light-shielding container (hard case). There is a type in which a plurality of film units (hereinafter, referred to as film units) are stacked and stored. This film unit is effective in capturing a developing solution pod in which a developing solution is sealed at one opposite edge of a photosensitive sheet having a photosensitive layer and a light receiving layer, and capturing an excess developing solution at the other edge. This is provided with a trap section for allowing the sheet to be handled as one sheet until the end.

[0003] In the hard case of the film pack,
An exposure opening and a slit-like discharge opening for discharging the exposed film unit are formed therein, and a thin plate-shaped light shielding cover made of a hard plastic for shielding the exposure opening is formed in the uppermost layer. The film unit is placed on the exposure surface of the film unit.

In the above-described film pack, a pressure plate is housed between the lowermost film unit and the bottom plate of the hard case, and the pressure plate presses the film unit against the exposure opening side. There is a type in which a film unit is protruded from an opening provided in a bottom plate of a case, and the film unit is pressed against the exposure opening side by the pushing member.

When this film pack is loaded into a film loading chamber of an instant camera (hereinafter referred to as a camera) and then a shutter button is depressed, a well-known claw mechanism incorporated in the camera body in preparation for photographing opens a light shielding cover. Scrape out of the case. After the upper end of the light-shielding cover scraped out of the case is fed between the rotating developing rollers, the light-shielding cover is moved out of the camera from the outlet provided on the upper surface of the camera body by the rotation of the developing roller. Is discharged. When the light-shielding cover is discharged, the uppermost film unit is pushed up and set in the exposure opening.

[0006] Each time one picture is taken, the claw mechanism scrapes the exposed film unit out of the case. The scraped-out film unit is similarly nipped by the developing roller and sent toward the take-out port. At that time, the developing solution is spread on the exposure surface of the film unit by the developing roller, and the developing process is performed. Further, the film unit of the next layer is pushed up to the uppermost layer and set in the exposure opening.

In such a film pack, the light-shielding cover is displaced in the thickness direction to receive a resistance while preventing the light-shielding cover from jumping out of the discharge port by the impact and exposing the internal film unit to light. There is a type in which the light-shielding cover is prevented from inadvertently jumping out of the discharge port even if a slight impact is received by discharging the light from the discharge port.

Further, paying attention to the fact that, when the film unit is displaced in the thickness direction at the time of development and the passage of the developing solution is compressed in the thickness direction, the distribution of the developing solution is useful, and the film unit is displaced in the thickness direction. A camera having a passage for discharging is considered.

[0009]

In each of the above-described film packs and cameras, the light-shielding cover is discharged while being displaced in the thickness direction. The light shielding cover is, for example, 0.
Since it has a thickness of 7 mm, a large resistance is applied when the light shielding cover is discharged. Since the claw mechanism and the developing roller are driven with a driving force exceeding this resistance, there is a problem that the consumption of the driving battery increases. In addition, since the light-shielding cover has a large discharge resistance, the light-shielding cover may not be discharged.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a light-shielding cover for an instant film pack, which has reduced discharge resistance at the time of discharge to prevent discharge mistakes and reduced battery consumption, and a method of manufacturing the same. The aim is to provide a method.

[0011]

In order to achieve the above object, in the light-shielding cover for an instant film pack according to the present invention, the light-shielding cover has a thickness of 0.45 to 0.6 mm.
And the material is polystyrene to which carbon black is added in the range of 0.4 to 0.8%.

In the method for manufacturing a light-shielding cover for an instant film pack according to the present invention, of the mold for injection-molding the light-shielding cover, a tip of a protruding pin provided on a fixed mold is provided so as to protrude into the mold. When the movable mold is separated from the movable mold, the projecting pin is cut into the light-shielding cover during the injection molding, so that the movable mold cannot be removed from the light-shielding cover. The trace of the protruding pin integrally formed on the light-shielding cover at the time of injection molding is provided outside a region facing the exposure opening of the light-shielding cover.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 7 showing the structure of an instant film pack (hereinafter referred to as a film pack) according to the present invention, a film pack 1 has a plurality of film units 3 laminated in a resin case 2. The case 2 includes a case body 2a and a bottom plate 2b. Although the number of the film units 3 loaded in the film pack 1 is usually about ten, the number of the film units 3 is small in order to avoid complicating the drawing.

The front plate 4 of the case body 2a is formed with an exposure opening 4a for determining an exposure range for the film unit 3. The exposure opening 4a is shielded from light by a plate-shaped light-shielding cover 6 that is overlaid on the uppermost film unit 3 when not in use. A notch 4b into which a well-known claw member is inserted is provided in the exposure opening 4a.

The upper plate 7 of the case body 2a is provided with a slit-shaped outlet 7a for discharging the film unit 3 after photographing. The light-shielding cover 6 as well as the film unit 3 is discharged from the discharge port 7a. A light-shielding seal 14 (not shown in FIG. 7; see FIG. 4) that is bent by the light-shielding cover 6 that is discharged is attached to the outlet 7a.

The bottom plate 2b has two pins 8b at the center.
, Two long holes 9 are formed so as to sandwich the pin 8b, and a push-up member 8a is formed between the two pins 8b. The long hole 9 is used to connect the film unit 3 to the exposure opening side 4.
It serves as an entrance when the push-up member 15 on the camera side that presses toward the a side enters the film pack 1. A strong light-shielding sheet 10 having a hole 10a through which the pin 8b penetrates, a bent portion 10b bent upward, and a long hole 10c through which the push-up member 8a penetrates is formed on the bottom plate 2b from the inside. It is attached and blocks the long hole 9 to shield light.

The light-shielding sheet 10 has its center portion attached to the bottom plate 2b and its peripheral portion weakly sealed to the bottom plate 2b by an adhesive when the pins 8b are crushed and caulked. The weak seal is easily peeled off when pressed by the push-up member 15 from the long hole 9. Further, a thin plastic plate 11 for reinforcement is attached inside the light-shielding sheet 10, and even if the weak seal of the light-shielding sheet 10 is peeled off by an impact or the like before being mounted on the camera, the light-shielding sheet 10 is loosened. To prevent light from leaking from the long hole 9. The push-up member 8a on the film unit 3 side penetrating the long hole 10c contacts the center of the light-shielding sheet 11, and presses the center of the film unit 3 toward the exposure opening side 4a.

When the film pack 1 is not in use, a light-shielding cover 6 is accommodated above the film unit 3 to close the exposure opening 4a, thereby shielding the film unit 3 from light. When the light-shielding cover 6 is pressed in this state, a gap is generated between the light-shielding cover 6 and the exposure opening 4a, and external light may enter from the gap to expose the film unit 3. In order to prevent this, arcuate ribs 12 extending in the longitudinal direction of the film pack 1 are provided on both side edges of the bottom plate 2b. The rib 12 comes into contact with the back surface of the film unit 3 and pushes up to the exposure opening 4a. As described above, the thickness of the film unit 3, the rib 12 and the push-up member 8
Since the light-shielding cover 6 is slightly pushed down by the height a, the gap formed between the light-shielding cover 6 and the exposure opening 4a is very small. Even if the gap is formed, external light that has entered the case goes to the outside of the rib 12, so that The film unit 3 is not accidentally exposed.

The push-up member 15 is attached to the back cover 1 of the camera.
The same number as the long holes 9 is provided at a position corresponding to the long holes 9 inside 6. When the back cover 16 is closed after the film pack 1 is loaded into the film loading chamber of the camera, the push-up member 15 enters the case 2 through the long hole 9 and pushes up the film unit 3 toward the exposure opening 4a by a spring. .

The film unit 3 is a self-developing type. As is well known, a photosensitive sheet 3a having a photosensitive layer and a light receiving layer, a developing solution pod 3b enclosing a developing solution, and a trap portion 3c for capturing and hardening excess developing solution are unitized. It is a rectangular mono-sheet type that can be handled as one sheet until the end.

In FIG. 5, the light-shielding cover 6 is viewed from the exposure opening 4a side. The light-shielding cover 6 has a rectangular plate shape having substantially the same size as the film unit 3 so as to cover almost the entire surface of the film unit 3. And a projection 2 on the upper end 6a side.
1 to 26 are integrally formed. These projections 21 to 26
Of the projections 2 on the side to which the force is applied by the claw member
Only 1 has a wider width than the others, and the portion extended in the horizontal direction has a surface 21 a substantially perpendicular to the plate surface of the light shielding cover 6.

A strip-shaped light-shielding film 28 is attached to the rear end grip 6b with which the claw member is engaged. The light-shielding film 28 shields the notch 4b into which the claw member enters from the inside. Reference numeral 27 indicates a gate cut mark formed during injection molding. A gate cut mark 27 is provided on the exposure opening 4a side to prevent the film unit 3 from being caught or damaged by the gate cut mark 27 beforehand.

In FIG. 6 where the pack body 2 is viewed from the inside, protrusions 31 to 36 are formed on the inner wall of the front plate portion 4 facing the light shielding cover 6. Among them, the light shielding cover 6
Only the projection 32 corresponding to the projection 21 has a shape different from the other, the edge side of the front plate portion 4 is extended in the lateral direction, and has a surface 32a engaged with the surface 21a of the projection 21. (See FIG. 4). The ends of the projections 31 to 36 on the side of the exposure opening 4a are inclined, and when the light shielding cover 6 is discharged, the projections 22 to
Over 25.

The light-shielding cover 6 is made thinner than before in order to obtain high flexibility, and is made of high-impact polystyrene to which carbon black has been added.
When the concentration of carbon black increases, the strength becomes insufficient, and when the concentration of carbon black decreases, the light-shielding properties become insufficient. In addition, when the thickness of the light-shielding cover 6 is increased, the flexibility is insufficient, and when the thickness is reduced, molding failure is likely to occur.
In consideration of strength, light-shielding property, flexibility, moldability, and the like, the thickness of the light-shielding cover 6 is set to a range of 0.45 to 0.6 mm, and the addition amount of carbon black is set to a range of 0.4 to 0.8%. And

FIG. 4 showing the film pack 1 before use.
In (A), before using the film pack 1, the light-shielding cover 6 closes the exposure opening 4a in a light-tight manner.
The first surface 21a and the surface 32a of the projection 32 are engaged.
In order for the light-shielding cover 6 to come out of the outlet 7a, the surface 32a is required.
The light-shielding cover 6 is displaced toward the film unit 3 along, and the projection 21 must ride over the projection 31 (see FIG. 4B). At this time, since the light shielding cover 6 has to compress the film unit 3 in the thickness direction, a large resistance force is applied to the light shielding cover 6 by this reaction. Thus, even if the film pack 1 receives an impact such as dropping before use, the light shielding cover 6 is inadvertently discharged.
a is prevented from being discharged.

In FIGS. 1 and 4, the developing roller 50b of a pair of well-known developing rollers 50a and 50b provided inside the camera is arranged such that the discharge port 7a of the film pack 1 is located on the tangent line. The driving force of the driving motor is transmitted to the shaft, and the shaft is rotated at a fixed position. The developing roller 50a provided as a pair with the developing roller 50b is provided so as to be displaceable in the thickness direction of the film unit 3, and is urged by the spring 51 toward the developing roller 50b.

In the film unit 3, the developing solution is pushed out and developed from the developing solution pod 3b when passing between the developing rollers 50a and 50b. At that time, the flow of the developing solution is controlled. If so, the developing solution can be evenly distributed over the entire screen. Attention is paid to the fact that the flow of the developing solution can be controlled by displacing the film processing unit 3 in the thickness direction to compress the passage of the developing solution at the time of unfolding. And constitutes a passage for discharging the film unit 3 while displacing it in the thickness direction.

The developing rollers 50a and 50b start rotating almost simultaneously with the operation of the claw mechanism. When the upper end 3d of the film unit 3 is fed out from the discharge port 7a for a predetermined length by the claw mechanism, the film unit 3 comes into contact with the leading end 52a of the sword guide 52. Since the leading end 52a is inclined toward the developing roller 50b, the film unit 3 is sent to the developing roller 50b while gently curving while rubbing the non-exposure surface against the leading end 52a. When the leading end 3d of the film unit 3 contacts the outer peripheral surface of the developing roller 50b, the film unit 3
As the developing roller 50b rotates, the developing roller 50a is gently curved toward the opposite side toward the developing roller 50a.
Sent between 0b. The film unit 3 is ejected from the take-out opening of the camera while passing between the developing rollers 50a and 50b while being displaced in the thickness direction in a bow shape with the sword guide 52 as a fulcrum.

When passing through the developing rollers 50a and 50b, the developing liquid pod 3b is pressed by the developing roller 50a, and the developing liquid is pushed out of the developing pod 3b. The film unit 3 is displaced in the thickness direction in an arc shape. Therefore, the passage of the developing solution is compressed, and the developing solution can be developed while controlling the flow rate. The surplus developing solution is captured by the trap portion and hardened. While the film unit 3 is sandwiched between the developing rollers 50a and 50b, a constant tension is applied to the film unit 3, so that the film unit 3 is stably fed. Further, since the sword guide 52 comes into contact with the anti-exposure surface of the film unit 3, the quality is not deteriorated.

After the film pack 1 has been loaded into the film loading chamber of the camera, when the shutter button is depressed in preparation for photographing, the claw mechanism enters the notch 4b, and the rear end corner of the light shielding cover 6 via the light shielding film 28. 6b. When the claw mechanism starts to scrape out the light-shielding cover 6 toward the discharge port 7a, the light-shielding cover 6 receives a resistance force when the projection 21 gets over the projection 32, but is thinner than before so as to increase flexibility. Elastic deformation while protrusion 2
1 smoothly gets over the projection 32. Therefore, the driving torque of the motor for driving the claw mechanism can be reduced, and the consumption of the battery for driving the motor can be reduced.

Subsequently, the upper end 6 of the light shielding cover 6
When a pushes and bends the light-shielding seal 14 and projects a predetermined length from the discharge port 7a, the light-shielding cover 6 comes into contact with the tip 52a of the sword guide 52, and the light-shielding cover 6 moves the exposure opening 4a toward the tip 52a.
While being rubbed, the paper is sent to the developing roller 50b while gently curving. The leading end 6a of the light shielding cover 6 is
When the light-shielding cover 6 comes into contact with the outer peripheral surface of the developing roller 50b, the light-shielding cover 6 is gradually curved to the opposite side toward the developing roller 50a according to the rotation of the developing roller 50b and is sent between the developing rollers 50a and 50b. The light-shielding cover 6 is displaced in the thickness direction with the stiffener guide 52 as a fulcrum, and
a and 50b, are conveyed toward the outlet of the camera, and are discharged out of the camera. As a result, the uppermost film unit 3 is set in the exposure opening 4a, and the preparation for photographing is completed.

Since the light-shielding cover 6 is displaced in the thickness direction in an arc shape, a repulsive force is generated and the tip 52 of the sword guide 52 is formed.
a is pressed against the light-shielding cover 6, and this becomes the resistance at the time of discharging. The light-shielding cover 6 was thinner than the conventional one, so that the repulsive force was small and the resistance was small. Therefore, even if the driving torque of the motor for rotating the developing rollers 50a and 50b is small, the light shielding cover 6 can be reliably discharged. Therefore, the developing rollers 50a, 50b
The consumption of the battery for driving the motor for rotating the motor is reduced as compared with the related art.

Further, since the above-mentioned light shielding cover 6 is thinner than the conventional one, it is necessary to devise a manufacturing method. In FIG. 3 showing the fixed mold and FIG. 2 showing a part of the mold among the molds for injection molding of the light shielding cover 6, the fixed mold 40 has protrusion pins 41 ( Two (two in FIG. 2) are provided so as to be movable forward and backward in the direction in which the movable mold 42 is removed. A recess 41 a is provided at the tip of the protruding pin 41. The recess 41 a has a depth of 0.02 to 0.4 depending on the thickness of the light-shielding seal 14.
mm. The tip of the protruding pin 41 protrudes into the fixed mold 40 during the injection molding of the light shielding cover 6.
Injection molding is performed with a depth of 2 to 0.4 mm.

In the case of injection molding using the above-mentioned mold, first, a molten resin is poured into a mold in which the fixed mold 40 and the movable mold 42 are combined, and after a lapse of a predetermined time, the movable mold 4 is moved from the fixed mold 40 to the movable mold 4.
Pull 2 apart. The movable mold 42 is provided with a gate (not shown) and a mold for molding the projections 21 to 26 (a mold 42a for molding the projection 21 in FIG. 2). Since the eight protruding pins 41 projecting from the inner surface are injected into the light shielding cover 6, the light shielding cover 6 can be prevented from being taken by the movable mold 42 when the movable mold 42 is separated. Movable type 4
Only 2 are pulled apart. Thereafter, the protruding pin 41 further projects into the fixed mold 40, and the light shielding cover 6 is separated from the fixed mold 40 and removed.

Also, by the injection molding described above, the protrusion pins 41 are provided on the film unit 3 side of the light shielding cover 6.
Mark of the protruding pin 41 at a position corresponding to each of
A protrusion pin mark 45) is provided. The portion of the light-shielding cover 6 where the protrusion pin traces 45 are provided is so thin that the light-shielding property is insufficient as it is.
Is provided outside a region surrounded by a one-dot chain line 46 corresponding to the exposure opening 4a, and since this portion is hidden by the case 2a, there is no practical problem.

[0036]

As described above, the light-shielding cover for an instant film pack according to the present invention is constituted by an injection-molded product having a thickness in the range of 0.45 to 0.6 mm to reduce the resistance at the time of discharge. Therefore, the consumption of the battery for driving the claw member can be reduced as compared with the related art. Further, by setting the material of the light shielding cover to polystyrene to which carbon black is added in a range of 0.4 to 0.8%, sufficient light shielding properties can be secured while maintaining sufficient strength and excellent moldability. .

In the method for manufacturing a light-shielding cover for an instant film pack according to the present invention, of the mold for injection-molding the light-shielding cover, the tip of a protruding pin provided on a fixed mold is provided so as to protrude into the mold. In the above injection molding, the protruding pins are cut into the light-shielding cover so that the light-shielding cover is prevented from being removed when the movable mold is separated, so that the above-described light-shielding cover can be injection-molded with high quality. In addition, since the protrusion pin marks are provided outside the area facing the exposure opening of the light-shielding cover so as to be hidden by the front plate portion, the portions where the protrusion pin marks are provided are thin and the light shielding property is insufficient. It is also practical.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a state in which a light shielding cover of the present invention is discharged by a developing roller.

FIG. 2 is an explanatory diagram showing a main part of a mold of a light shielding cover.

FIG. 3 is an explanatory view showing the inside of a fixed mold among dies.

FIG. 4 is an explanatory diagram showing when an instant film pack using the light-shielding cover of the present invention is not used, and when shifting to a shooting preparation state.

FIG. 5 is an explanatory diagram of the light shielding cover as viewed from the film unit side.

FIG. 6 is an explanatory diagram of the case viewed from the inside.

FIG. 7 is an exploded perspective view showing the configuration of the instant film pack.

[Description of Signs] 1 Film pack 2 Pack body 6 Light shielding cover 21, 32 Projection 27 Gate cut mark 40 Fixed type 41 Projection pin 42 Movable type 45 Projection pin mark 50a, 50b Deployment roller 52 Sigoki guide

Claims (3)

[Claims] 1. A case in which a front plate portion in which an exposure opening is formed and an upper plate portion in which a slit-shaped discharge port for discharging an exposed film unit are formed at a substantially right angle, and a case laminated inside the case. A self-developing process type film unit to be stored therein, and a plate-shaped light-shielding cover which is sandwiched between the self-developing type film unit and the front plate portion, closes the exposure opening light-tightly, and is discharged from the discharge opening. In the light-shielding cover for an instant film pack, the light-shielding cover is made of an injection molded product having a thickness of 0.45 to 0.6 mm, and carbon black is added in a material of 0.4 to 0.8%. A light-shielding cover for an instant film pack, which is made of polystyrene. 2. A case in which a front plate portion in which an exposure opening is formed and an upper plate portion in which a slit-shaped discharge port for discharging an exposed film unit are formed at substantially right angles, and a case laminated inside the case. A self-developing process type film unit to be stored therein, and a plate-shaped light-shielding cover which is sandwiched between the self-developing type film unit and the front plate portion, closes the exposure opening light-tightly, and is discharged from the discharge opening. In the method for manufacturing a light-shielding cover for an instant film pack, of the mold for injection-molding the light-shielding cover, a tip of a protruding pin provided on a fixed mold is provided to protrude into the mold, and the protrusion pin is provided during injection molding of the light-shielding cover. The light shielding cover for an instant film pack is characterized in that the light shielding cover is not taken off by the movable type when the movable type is separated by making the light shielding cover bite. Method of manufacturing over. 3. The instant film pack according to claim 2, wherein the marks of the protrusion pins integrally formed with the light shielding cover during injection molding are provided outside a region facing the exposure opening of the light shielding cover. Manufacturing method of light shielding cover.