Incremental printing of symbolic information – Light or beam marking apparatus or processes – With record receiver or handling means therefor
Reexamination Certificate
1998-11-06
2001-10-09
Hilten, John S. (Department: 2854)
Incremental printing of symbolic information
Light or beam marking apparatus or processes
With record receiver or handling means therefor
C347S262000, C101S481000, C101SDIG029
Reexamination Certificate
active
06300971
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an apparatus and method for handling media sheets in a photo-plotter and, more particularly, to an apparatus and method for forming fixed holes, notches or other mounting features in each media sheet and for positioning each media sheet at the exposure station of the plotter with reference to those mounting features so that the images produced on the sheet are accurately located relative to the mounting features, the mounting features later being used to mount and accurately position the media sheet and its images relative to a printing cylinder or other supporting member of a printing press.
BACKGROUND OF THE INVENTION
Internal drum plotters are typically used to optically produce images either on a media sheet for subsequent use in printing operations or during production of printed circuit boards. Conventional internal drum plotters include a concave semi-cylindrical imaging drum and a rapidly spinning projection mirror which directs a light beam from a laser or other source downwardly onto a media sheet supported by the drum and which moves the beam in raster scanning fashion over the sheet while the beam is modulated in accordance with image defining data. The directed and modulated light beam produces images on the media sheet. U.S. Pat. No. 5,619,246 entitled “Apparatus and Method of Positioning Photo Sensitive Media on an Exposure Platen” and assigned to the assignee of the present invention, is incorporated by reference herein and describes a media handling system that handles media sheets in their movement to-and-from an exposure station provided by an internal drum.
Subsequently to a media sheet being imaged, the sheet may be further processed as by a chemical developing step, if necessary, and then is used in the printing operations of a printing press. The printing process requires the imaged media sheet to include a certain arrangement of mounting features, such as holes, slots and/or notches, used both to secure the imaged media sheet to a cylinder or other supporting structure of the printing press and to accurately position the sheet relative to that structure
It is imperative that the image carried by each imaged media sheet be properly positioned on the printing press to result in a high quality final image. To ensure such proper positioning of the image, precise fixing of the image relative to the mounting features formed in the media sheet is required. The precise positioning of the image relative to the mounting features is particularly critical when the final printed product includes multiple colors. For a multiple color final product, multiple media sheets are imaged individually, with each media sheet corresponding to a particular color. Then, during the printing operation, the images of the multiple media sheets are individually applied, as color separations, to the same printed product. Even a minor registration discrepancy between the images created would result in an indistinct final product and they, therefore, need to lie in closely registered superimposition to one another. Therefore, it is critical during the imaging process to position the generated image on a media sheet precisely with respect to the mounting features used to attach and position the media sheet relative to the printing press.
It is, therefore, an object of the present invention to ensure proper placement of a media sheet at the exposure station of a media sheet imaging and handling system.
It is a more specific object of the present invention to ensure that mounting features formed within the media sheet are precisely positioned with respect to the generated image.
SUMMARY OF THE INVENTION
The invention resides in a system for photoplotting and handling media sheets having a plurality of aligning means that engage a plurality of mounting features formed in the media sheet and a plurality of drum openings formed in the drum of a photo-plotter for positioning the media sheet on the drum for subsequent imaging. Each aligning means has an engaged position and a disengaged position and includes a registration pin having extended and retracted positions, corresponding to the engaged and disengaged positions of the aligning means, respectively. In the extended position, the registration pins pass through the mounting features of the media sheet and locate and fit into the drum openings for properly positioning the media sheet on the drum. The mounting features are formed within the leading edge of the media sheet by punching means and have a centerline substantially parallel to the direction of movement of the scanning means of the photo-plotter.
One advantage of having the mounting features punched prior to the media sheet being imaged, and of positioning the media sheet on the drum utilizing the mounting features, is that greater printing accuracy and registration of color separation is achieved in the final printed product. The present invention Ensures that the media sheet is properly placed on the drum and also precisely positions the generated image relative to the mounting features.
The foregoing and other advantages of the present invention become more apparent in light of the following detailed description of the exemplary embodiments thereof, as illustrated in the accompanying drawings.
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patent: 5383001 (1995-01-01), Bosy
patent: 5488906 (1996-02-01), Iron et al.
patent: 5619246 (1997-04-01), Straayer et al.
patent: 5716048 (1998-02-01), Morrissette
patent: 5889547 (1999-03-01), Rombult et al.
patent: 6097475 (2000-08-01), Jakul et al.
Masotta John R.
Menard Alan W.
Petersen Kenneth R.
Welti Gene D.
Chau Minh H.
Gerber Systems Corporation
Hilten John S.
McCormick Paulding & Huber LLP
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