Printing – Print plate feeding or delivering
Reexamination Certificate
2002-09-23
2004-03-30
Evanisko, Leslie J. (Department: 2854)
Printing
Print plate feeding or delivering
C101S485000, C101S481000, C271S238000
Reexamination Certificate
active
06712003
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device for positioning a sheet member in a state in which the sheet member is placed on a generally flat plate, and to a device for recording an image onto a printing plate.
2. Description of the Related Art
A printing plate exposure device has been developed which exposes and records an image directly by a laser beam or the like onto a photosensitive layer on a support of a sheet-shaped printing plate such as, for example, a photo-polymer plate or a thermal plate. The photosensitive layer includes the emulsion surface of the printing plate.
In such a printing plate exposure device, the printing plate placed on a generally flat plate is, as needed, conveyed to a punching section, and is subjected to punching processing thereat. This punching processing is a processing for forming punch holes to be used for positioning the printing plate in printing processing which is a process to be carried out later. Further, the printing plate placed on the plate is conveyed to an exposure section, and exposure processing of the printing plate is carried out at the exposure section.
Here, before the punching processing in the punching section and the exposure processing in the exposure section, in order to improve the accuracy of the punching processing and the exposure processing, the printing plate must be positioned while being restrained or being held by pressure being applied thereto, in a state in which the printing plate is placed on the plate. Here, when the printing plate is restrained or held by the application of pressure, parameters, which enable the printing plate to be restrained or held by pressure such that it is difficult for the printing plate to buckle, are determined in advance by experimentation. On the basis of these parameters, the printing plate is restrained or is held by pressure being applied thereto.
The following is an example of positioning the printing plate while restraining or holding by pressure the printing plate which is in a state of being placed on a plate. Two first reference pins are provided at a side of the plate in one direction, which is the punching section side or the exposure section side of the plate. The printing plate is pushed by a first moving pin until the printing plate abuts the two first reference pins. The position of the printing plate in the one direction is thereby determined. Moreover, one second reference pin is provided at a side of the plate in another direction which is orthogonal to the aforementioned one direction. The printing plate is pushed by a second moving pin until the printing plate abuts the second reference pin. The position of the printing plate in this other direction is thereby determined.
There is also a method of positioning in which cut-outs are formed in the printing plate simultaneously with the punching processing in the punching section. With the first reference pins inserted into these cut-outs, positioning of the printing plate is carried out in the same manner as described above.
However, in such a printing plate exposure device, as described above, parameters, which make it difficult for the printing plate to buckle, are determined in advance by experimentation, and the printing plate is restrained or is held by pressure being applied thereto. Thus, there is the problem that the force of restraining the printing plate or the force of the holding by pressure of the printing plate is small, and the accuracy of positioning is unstable. The force of holding by pressure is, for example, the force of pushing the printing plate by the first moving pin and the second moving pin. The positioning accuracy being unstable means, for example, that the printing plate cannot reliably abut the first reference pins or the second reference pin. On the other hand, if the restraining force or the pressure holding force for holding the printing plate to the plate is increased, buckling deformation of the printing plate arises and the positioning accuracy deteriorates.
When cut-outs are formed in the printing plate, even if there is curving at the end surfaces of the printing plate, the printing plate can be accurately positioned. However, an expensive device for forming cut-outs is required, and the manufacturing costs thereby rise.
When two printing plate moving mechanisms are required such as in the case in which a first moving pin and a second moving pin are provided at the plate, the costs increase and the device becomes larger.
Before exposure processing at the exposure section, the printing plate is positioned in a state of being placed on the plate, and the exposure start position of the printing plate is determined. It is therefore necessary for the exposure position of the printing plate to coincide with the printing position of the printing plate determined by the punch holes.
Here, a first method for determining the exposure position of the printing plate is the following method. Simultaneously with the punching processing the punching section, cut-outs are formed in the printing plate. Insertion pins, which are fixed at the exposure section, are inserted into these cut-outs, and the printing plate is positioned. Further, on the basis of parameters set in advance for respective printing plate sizes, the exposure position of the printing plate is determined.
As a second method for determining the exposure position of the printing plate, there is a method in which end surfaces of a predetermined printing plate, which has been positioned in the exposure section by a method in which cut-outs are not formed in the printing plate, are detected optically. The exposure position of the printing plate is determined by computation from the results of detection.
However, in the above-described first method, there is the need to form cut-outs in the printing plate. Accordingly, an expensive device for forming cut-outs is required, and the device becomes expensive on the whole.
In the above-described second method, because the end surfaces of a printing plate curve slightly at each printing plate, the exposure position of the printing plate cannot be made to accurately coincide with the printing position. Thus, at the time of printing processing of the printing plate, the printing position must be made to match the exposure position by adjusting the printing position on the basis of the exposure position of the printing plate.
SUMMARY OF THE INVENTION
In view of the aforementioned, an object of the present invention is to provide a device for positioning a sheet member which can improve the accuracy of positioning a sheet member.
Another object of the present invention is to provide a device for positioning a sheet member and an image recording device which are low cost and in which, even if the end surfaces of a sheet member or a printing plate are curved, a position at which the sheet member or the printing plate is positioned by a first abutment member and a third abutment member, and a position at which the sheet member or the printing plate is positioned by a second abutment member and the third abutment member, can be made to coincide.
A first aspect of the present invention is a device for positioning a sheet member, the device comprising: a generally flat plate on which the sheet member is received; a conveying device provided so as to correspond to the sheet member received on the plate, and conveying the sheet member in the first direction; a temporary abutment member provided at a side of the plate in the first direction, and due to the sheet member, being conveyed in the first direction, the sheet member abutting the temporary abutment member at at least two points, which determines a position of the sheet member in a temporary direction; an actual abutment member provided at that side of the plate, and due to the sheet member being conveyed in the first direction after the position in the temporary direction has been determined, the sheet member abutting the actual abutment member at at least two points, which determines a
Evanisko Leslie J.
Fuji Photo Film Co. , Ltd.
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