Photocopying – Projection printing and copying cameras – Image transferred to or from curved surface
Reexamination Certificate
1999-09-22
2003-07-29
Rutledge, D. (Department: 2851)
Photocopying
Projection printing and copying cameras
Image transferred to or from curved surface
C355S072000
Reexamination Certificate
active
06600549
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to image scanning apparatus and in particular to such apparatus comprising a profiling surface; a feed mechanism for feeding a flexible radiation sensitive record medium across the profiling surface; and a scanning system for scanning a modulated radiation beam across the record medium to expose the record medium.
DESCRIPTION OF THE PRIOR ART
A conventional internal drum imagesetter is illustrated in the schematic end view of
FIG. 5. A
drum
50
has a semi-cylindrical internal profiling surface
51
. A film
52
is mounted on the surface by attaching one end of the film to a loading carriage
53
which traverses round the drum. After the film has been loaded, it is exposed by a scanning radiation beam
54
.
The imagesetter of
FIG. 5
suffers from the problem that the film
52
will not conform precisely with the profile of the surface
51
. Therefore the loading carriage will load more than the required length of film into the imagesetter.
SUMMARY OF THE INVENTION
In accordance with a first aspect of the present invention there is provided image scanning apparatus comprising a profiling surface; a feed mechanism for feeding a flexible radiation sensitive record medium across the profiling surface; a scanning system for scanning a modulated radiation beam across the record medium to expose the record medium; and a pressurizer operable simultaneously with the feed mechanism to generate a pressure difference between opposed sides of the record medium as it is fed across the profiling surface whereby the record medium engages the profiling surface and conforms with the shape of the profiling surface.
In accordance with a second aspect of the present invention there is provided a method of loading a flexible radiation sensitive record medium into an image scanning apparatus, the method comprising feeding a flexible radiation sensitive record medium across a profiling surface; generating a pressure difference between opposed sides of the record medium as it is fed across the profiling surface whereby the record medium engages the profiling surface and conforms with the shape of the profiling surface; and scanning a modulated radiation beam across the record medium to expose the record medium.
By applying a pressure difference to the record medium during the loading operation we ensure that the record medium conforms to the profiling surface during loading, and as a result the correct length of record medium is loaded into the apparatus.
The conventional imagesetter of
FIG. 5
also suffers from the problem of dust particles—ie. dust particles can fall directly onto the film
52
and will either adhere to the film or fall down to the lower region
55
of the imagesetter. Dust particles can also collect on the surface
51
when a film is not present. The loading arrangement of the present invention enables the profiling surface to be oriented in alternative ways to reduce the problems causes by dust particles. For example the profiling surface can be oriented such that the normal to the profiling surface does not point directly upwards at any point. In addition it will be noted that the conventional imagesetter of
FIG. 5
is oriented such that the normal to the surface
51
points upwards in the range of angles 0°-90°, and 270°-360° (with gravity g pointing directly downwards at 180°). As a result the surface
51
provides a reaction force to the gravitational force of the film
52
at all points (except at the extreme edges). In contrast, the normal to the profiling surface in the present invention can point in any direction, including downwards, ie. in the range of angles 90°-270° (in which the surface provides no reaction force and the record medium is supported by the pressure difference).
In other words, compared to the orientation of
FIG. 5
, the profiling surface can be oriented on its side (or even upside down) to prevent dust from falling or collecting on the profiling surface or the record medium. Similarly, a flat-bed scanner with a planar surface can be oriented with its planar profiling surface at an angle, or even upside down.
The pressurizer may generate a vacuum on one side of the record medium. However preferably the pressurizer increases the pressure on one side of the record medium.
Typically the pressurizer comprises a pressure chamber defined by a plurality of walls including the profiling surface, and means for increasing the pressure in the pressure chamber. The use of a pressure chamber ensures a relatively uniform pressure and also reduces the power requirements.
Typically the pressure chamber has one or more openings (e.g., slots) adjacent the profiling surface. This enables gas to exit from the pressure chamber in a controlled manner. By positioning the opening(s) adjacent the profiling surface we ensure that any gas flow acts to force the record medium against the profiling surface.
The profiling surface may be planar but in a preferred embodiment the profiling surface is curved, eg semi-cylindrical.
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patent: 3561659 (1971-02-01), Anthony
patent: 4139243 (1979-02-01), Landsman
patent: 5576754 (1996-11-01), Korem
patent: 5828399 (1998-10-01), Van Aken et al.
patent: 5938187 (1999-08-01), Conlan et al.
patent: 6097475 (2000-08-01), Jakul et al.
patent: 0 096 530 (1983-12-01), None
patent: 0 126 469 (1984-11-01), None
patent: 0 551 772 (1993-07-01), None
patent: 0 722 245 (1996-07-01), None
patent: 0 734 856 (1996-10-01), None
patent: 0 818 307 (1998-01-01), None
Fujifilm Electronic Imaging Ltd.
Rutledge D.
Sughrue & Mion, PLLC
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