Stock material or miscellaneous articles – Structurally defined web or sheet – Discontinuous or differential coating – impregnation or bond
Reexamination Certificate
2001-03-05
2003-04-22
Kiliman, Leszek (Department: 1773)
Stock material or miscellaneous articles
Structurally defined web or sheet
Discontinuous or differential coating, impregnation or bond
C428S195100, C428S206000, C428S211100, C428S537500
Reexamination Certificate
active
06551696
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an interleaf sheet for planographic printing plates, an abutting member for planographic printing plates, and a packaging structure for planographic printing plates.
2. Description of the Related Art
In recent years, planographic printing plates such as photosensitive printing plates and thermosensitive printing plates have been widely used in plate-making methods (including electrophotographic plate-making methods) in order to facilitate automation of plate-making processes. Planographic printing plates are generally manufactured in the following manner. On a support such as a sheet-configured or coiled aluminum plate, surface treatments such as graining, anodizing, a silicate treatment, and other chemical conversion treatments are carried out alone or in appropriate combination. Subsequently, processings for applying a photosensitive layer or a thermosensitive layer onto the support and drying the layer are carried out. (Hereinafter, these layers will be collectively referred to as “applied films”, and surfaces of supports with and without an applied film formed thereon are referred to as an “image forming surface” and a “non-image forming surface”, respectively.) Then, the support with the layer applied thereon is cut into a desired size.
The planographic printing plate manufactured in this manner is subjected to plate-making processings such as exposure, development, gum coating, and the like. Subsequently, the planographic printing plate is set in a printing machine, and ink is applied onto the planographic printing plate, thereby printing characters, images, or the like on papers.
In order to protect the applied film of a planographic printing plate, sometimes a sheet of paper called an “interleaf sheet” is made to contact the image forming surface (i.e., the applied film). Particularly, in order to efficiently handle planographic printing plates, a plurality of planographic printing plates may sometimes be stacked in a thickness direction to form a stacked sheaf. In this case, the image forming surface (i.e., the applied film) is often protected by forming a stacked sheaf by, for example, alternatingly stacking the interleaf sheet described above and the planographic printing plate so that the interleaf sheet contacts the image forming surface, and by placing a protective cardboard on an end surface of the planographic printing plate in a stacking direction or placing it on every predetermined number of planographic printing plates.
However, in such a stacked sheaf, when a coefficient of static friction between the image forming surface of the planographic printing plate and the interleaf sheet or a coefficient of static friction between the interleaf sheet and the protective cardboard is small, the stacked sheaf may become disordered due to vibration or the like during transportation or the like of the stacked sheaf, or the interleaf sheet or the protective cardboard may be horizontally displaced relative to the planographic printing plate (i.e., displacement along the image forming surface of the planographic printing plate), thereby causing damage to the image forming surface.
Further, recently used are planographic printing plates of a photosensitive or thermosensitive type on which an image is formed with a laser (hereinafter referred to as a “laser exposure type”). With such laser exposure type planographic printing plates, when the protective cardboard described above is used to form a stacked sheaf, depending on the characteristics of the planographic printing plate, moisture contained in the protective cardboard may cause the applied film to deteriorate. For this reason, a protective cardboard having a moisture-proofing layer may be used as needed. Often used is a structure in which a layer of low density polyethylene (LDPE) serving as the moisture-proofing layer is adhered to a generally used protective cardboard.
However, when the stacked sheaf which is formed by using such a protective cardboard with the LDPE layer adhered thereon is handled, since the coefficient of static friction between the LDPE layer and the interleaf sheet is large relative to the coefficient of static friction between the interleaf sheet and the image forming surface of the planographic printing plate, the interleaf sheet and the protective cardboard are together displaced horizontally relative to the planographic printing plate by vibration or the like during handling. The image forming surface may be subject to damage due to this horizontal displacement.
SUMMARY OF THE INVENTION
In view of the above-described facts, it is an object of the present invention to obtain an interleaf sheet for planographic printing plates, an abutting member for planographic printing plates, and a packaging structure for planographic printing plates which can prevent horizontal displacement of an interleaf sheet for a planographic printing plate relative to an image forming surface of a planographic printing plate and can reliably prevent damage to the image forming surface.
In accordance with a first aspect of the present invention, there is provided an interleaf sheet for planographic printing plates, comprising: a planographic printing plate contacting surface which contacts an image forming surface of a planographic printing plate with an applied film formed thereon in a state in which the planographic printing plate is packaged; and an abutting member contacting surface which contacts an abutting member for planographic printing plates which is disposed at a side that is opposite to a side of the planographic printing plate contacting surface, wherein surface properties of the planographic printing plate contacting surface and the abutting member contacting surface are respectively determined so that a coefficient of static friction between the abutting member for planographic printing plates and the abutting member contacting surface is no more than a coefficient of static friction between the planographic printing plate contacting surface and the image forming surface.
In other words, in the interleaf sheet for planographic printing plates according to the first aspect, in a state in which the planographic printing plate is packaged, the planographic printing plate contacting surface contacts and thereby protects the image forming surface (i.e., the applied film) of the planographic printing plate.
Further, by the abutting member for planographic printing plates being disposed on the surface opposite to the planographic printing plate contacting surface in a state in which the planographic printing plate is packaged, the abutting member for planographic printing plates is made to contact the abutting member contacting surface.
In the interleaf sheet for planographic printing plates according to the present invention, the surface properties of the planographic printing plate contacting surface and the abutting member contacting surface are set so that the coefficient of static friction between the abutting member for planographic printing plates and the abutting member contacting surface is equal to or less than the coefficient of static friction between the planographic printing plate contacting surface and the image forming surface. For this reason, for example, when horizontal displacement between the abutting member for planographic printing plates and the planographic printing plate is caused by external force, vibration, or the like during handling or the like, the interleaf sheet for planographic printing plates is not horizontally displaced relative to the planographic printing plate. Therefore, damage otherwise caused to the image forming surface by horizontal displacement of the interleaf sheet for planographic printing plates relative to the planographic printing plate can be reliably prevented.
In accordance with a second aspect of the present invention, there is provided an abutting member for planographic printing plates which, in a state in which an interleaf sheet for planographic printing plates
Fuji Photo Film Co. , Ltd.
Kiliman Leszek
Sughrue & Mion, PLLC
LandOfFree
Interleaf sheet for planographic printing plates, abutting... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Interleaf sheet for planographic printing plates, abutting..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Interleaf sheet for planographic printing plates, abutting... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3059137