Special receptacle or package – For plate or sheet – Fragile or sensitive
Reexamination Certificate
2000-08-30
2003-04-15
Gehman, Bryon P. (Department: 3629)
Special receptacle or package
For plate or sheet
Fragile or sensitive
C206S524600, C378S182000
Reexamination Certificate
active
06547075
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a packaging structure of planographic printing plates and an internal packaging material for the planographic printing plates. More specifically, the present invention relates to a packaging structure of planographic printing plates, which can block the planographic printing plates from light from the exterior and can protect the plates from an external force, and to an internal packaging material for the planographic printing plates, which can block the planographic printing plates from light from the exterior and can internally package the plates.
2. Description of the Related Art
In electrophotographic plate making methods in recent years, in order to facilitate automation of plate making processes, planographic printing plates such as photosensitive printing plates or thermosensitive printing plates have been widely used. The photosensitive printing plates have high photosensitivity, and thus, even if the plates are exposed to a slight amount of light within a visible light wavelength band, a change is caused in photosensitive layers thereof. Therefore, the photosensitive printing plates need to be blocked from light. Similarly, in the thermosensitive printing plates, thermosensitive layers thereof may be deteriorated by thermal energy of light striking thereon, or a sensitivity change may be caused by a reaction progress. Therefore, it is preferable that the thermosensitive printing plates are appropriately blocked from light. Further, if the photosensitive or thermosensitive printing plates are subjected to rapid changes in humidity and temperature, there is a drawback in that, for example, dewing is caused in the photosensitive or thermosensitive layers thereof and the layers are thereby deteriorated. Therefore, these printing plates need to be kept free from moisture.
Accordingly, from the time when the planographic printing plates are manufactured to the time when the plates are loaded into an automatic plate making machine or the like, the planographic printing plates are packaged in an internal packaging paper which has a light-blocking property and a moisture-proofing property (i.e., the property of keeping the plates packaged therein free from moisture). As the internal packaging paper, for example, an aluminum kraft paper, in which low density polyethylene is melted and applied at a thickness of about 13 &mgr;m on a kraft paper, and then aluminum foil having a thickness of about 6 &mgr;m is further adhered thereon, is used. A stack of products (a stack of the planographic printing plates) are packaged in this aluminum kraft paper, and thereafter, portions (so-called ear portions and top surface portions) of the aluminum kraft paper are fastened by an adhesive tape or other fastening means. Further, as the internal packaging paper, a paper in which low density polyethylene is adhered at a thickness of about 10-70 &mgr;m on the aluminum foil of this aluminum kraft paper, or a paper in which black polyethylene film is further adhered at a thickness of about 70 &mgr;m on this low density polyethylene so as to increase the light-blocking property and the moisture-proofing property, is also used.
However, this aluminum kraft paper cannot be recycled once it has been used, and since it becomes necessary to dispose of the paper by dumping it as industrial waste, or by incineration or the like, the disposal requires a high expense.
On the other hand, a light-blocking and moisture-proofing paper which has the required light-blocking and moisture-proofing properties without the aluminum foil adhered thereon, has been suggested (see Japanese Patent Application Laid-Open (JP-A) No. 9-111697). However, this light-blocking and moisture-proofing paper becomes expensive, because a light-blocking layer and a moisture-proofing layer must be provided on the surface thereof.
Moreover, each of the photosensitive printing plates and the thermosensitive printing plates is formed in a single thin plate, and thus, if there is a blemish or deformation in a corner, an edge, an interior or the like thereof, problems are easily caused. For example, an image may be unclear when the plate has been developed after light-exposure or the plate has been developed with heat, or ink may not be uniform when the image has been printed.
Therefore, in order to prevent such blemishes or deformations, a corrugated cardboard box, which protects the planographic printing plates from an external force and packages the plates, has been suggested (see Japanese Patent Application Laid-Open (JP-A) No. 10-16946).
As shown in
FIG. 10
, in a corrugated cardboard box
50
, triangular tube-shaped bodies
54
are formed by bending two opposite sides of a bottom surface panel
52
, and thereby the perpendicularity of the bottom surface panel
52
to side surface panels
56
and to facing panels
58
is strongly maintained. In this way, the corrugated cardboard box
50
is structured so as not to lose its shape due to the weight of its contents.
However, in this corrugated cardboard box
50
, light comes inside from the vicinities of the triangular tube-shaped bodies
54
, fastened portions of the corrugated cardboard, and the like. Accordingly, when the planographic printing plates are contained in the corrugated cardboard box
50
, there is the danger that so-called accidental exposure (light fog) can occur in the planographic printing plates.
SUMMARY OF THE INVENTION
In consideration of the above facts, it is an object of the present invention to obtain a packaging structure of planographic printing plates, which can reliably protect the planographic printing plates from an external force, which can block the plates from light and keep the plates free from moisture, and which can be disposed of easily and inexpensively; and an internal packaging material for the planographic printing plates, which can reliably block the planographic printing plates from light.
A first aspect of the present invention is a packaging structure of planographic printing plates, the structure comprising: an internal packaging material, which is made from a material having a light transmittance of predetermined value or lower, and which internally packages the planographic printing plates; and an external packaging material, which externally packages the planographic printing plates that have been internally packaged in the internal packaging material, and which has a higher rigidity than the internal packaging material.
Namely, the planographic printing plates, which have been internally packaged in the internal packaging material, are externally packaged in the external packaging material which has a higher rigidity than the internal packaging material. Therefore, the planographic printing plates are protected from an external force, and thus, the plates are not deformed or blemished.
The external packaging material can block the planographic printing plates from light and keep the plates free from moisture to some extent by itself. As a result, in a state of being externally packaged in the external packaging material, only a minuscule amount of light enters through very small gaps in the external packaging material to the interior thereof.
Because the planographic printing plates are internally packaged in the internal packaging material which is structured of a material having a light transmittance of a predetermined value or lower, even if there is such light-leakage, the light does not reach the planographic printing plates, and thus, changes in the photosensitive or thermosensitive layers of the planographic printing plates are prevented.
Further, even if there is a large change in humidity outside the external packaging material, a change in humidity in the interior of the external packaging material is small, because the external packaging material functions as a buffer. In the interior of the internal packaging material, a small change in humidity in the interior of the external packaging material is further buffered. Therefore, problems resul
Fuji Photo Film Co. , Ltd.
Gehman Bryon P.
LandOfFree
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