SCANNERS A TAMBOUR

DRUM SCANNERS

Abrégé anglais

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ABSTRACT OF THE DISCLOSURE
A roller for drum scanners is described, consisting
of a hollow cylindrical element which is arranged for
rotation at its ends and provided with suction openings
for reception of a record carrier or of an original.
The cylindrical roller element is assembled from a
plurality of individual elements which are held together
by means of a rod which may be screwed to end lid members
of the roller element and are also bonded to each other.

Revendications

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THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A roller for a drum scanner, comprising a hollow
cylindrical element which is arranged for rotation at its
ends 9 and comprising a plurality of pot-like structures
which are joined together to form a continuous outer
surface.
2. A roller for a drum scanner comprising a hollow
cylindrical element which is arranged for rotation at
its ends and comprising a number of pot-like structures
which are interfitted one within another and also bonded
together.
3. A roller for drum scanners, comprising a hollow
cylindrical element which is arranged for rotation at
its ends and comprising a plurality of rings which are
joined together at their joints by annular coupling
members and also bonded to each other.
4. A roller according to claim 3, wherein at least
one circular metal plate is transversely disposed
within the roller.
5. A roller according to claim 1, wherein the pot-like
structures are shouldered at their ends for insertion into
the next adjacent pot-like structure.
6. A roller according to claim 1, wherein the cylindrical
element has lid-like members at its ends, which may be
bolted together by means of a rod passing through the
inside of the element.
7. A roller according to claim 1, wherein the surface
of the roller is provided with suction openings which
communicate with the interior of the roller.
8. A roller according to claim 7, wherein at least one
of the pot-like structures has no holes in its surface

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and is bonded to the next structure in pressure-tight
manner.
9. A roller according to claim 3, wherein a bulkhead
which has a shape corresponding to the direction of
pressure and to the strain caused by the same, is inset
in pressure-tight manner as a complement to a base or
round plate.

Description

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1 ~ACKGROUND 0~ THE INV~NTION
The present invention relates to rollers for drum
scanners~ comp~ising a hollow cylindrical element which
is rotatably mounted at its ends.
As compared to flat bed scanners, drum scanners
comprise rapidly rotating rollers at the sc~nni n~ and
recording stations, the ori~i n~l which is to be scanned
being secured thereto at the sc~nni n~ station and the
recording carrier thereto at the recording station.
~o obtain a high operating speed on such scanners, it i~
necessary to allow the roller to rotate rapidly which
on the one hand leads to powerful centrifugal forces and
because of the original~ having the large ~ormat deæirable
nowadays renders a stable form o~ construction of the
rollers necessaryO In order that the recording carrier
may be held on the roller even at high speeds of revolution,
the roller has ~uction openings in its surface, which are
in communication with the interior which is arranged to
be connected to a vacuum pump 80 that a vacuum prevails within
the roller. If desired, clamping devices may be omit-ted, which
could lead to an undesirable imbalance at high speeds of
revolution. In view of the high precision required
during image processing, a high mechanical precision is
equally of importance regarding the geometry of the roller
surface. In the existing methods of roller production,
be it by parting off from prefabricated tubes or by
turning the rollers from the solid, comparatively high
costs and a heavy form of roller construction are the
result~
SUMMARY 0~ THE INVENTION
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1 Consequently it is an obiect of the invention to
provide a roller which fulfils the manifold requir0ments
speci~ied in respect of the same and aver-ts the dis-
advantage of the known roller. The invention accomplishes
this aim by providing a roller for a drum scanner 3
comprising a hollow cylindrical element which is arranged
for rotation at its ends, and comprises a plurality of
pot-like structures which are joined together to form a
continuous outer surface. The pot like elements may inter*it one
10 ~hanother, or they may comprise a number of rings which
are connected at their join~s by means of annular coupling
members and bonded to each other thereat. One or more
internal round metal plates assure that the round shape
is maintained. Rollers in which use is made of a combin-
ation o~ the a~oresaid structural features are al30envisagedO
~RIEF DE~CRIPTION OF THE DRAWINGS
In order that the invention may be more clearly
understood, re~erence will now be made to the accompany-
ing draw~ngs which show two embodiments thereof by wayof example and in which:-
Figure 1 shows an axial section through a ~ir~tembodiment comprising pot-like ~tructures which are
inter~itted one within the other, and
Figure 2 shows an axial sectio~ through a ~econd
embodiment comprising rings which are joined together by
mean~ of annular coupling members.
DETAI~ED DESGRIPTION OF PRE~E~RED EMBODIMENTS
Re~erring now to the drawings ~igure 1 shows a
roller 1 which is assembled from several parts in

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1 accordance with the in~ention. At the ends are situated
lids 2 and 3 which have central recesæes 21 and 31
respecti~ely, into which penetrate~ a rod 1 pas~ing along
the central longitudinal axis of the roller 1 the parts
being tightened together by mean~ of nuts 41 and 42.
The actual cylindrical roller element comprises pot-like
structure~ 5 to 10 which are inter~itted one within the
other~ a ring 18 being provided at the one extremity of
the roller to establish a closure together with the lid 1.
As apparent from the drawings, the pot-like structure~ 5
to 10 are shouldered at their ends ~o that the next element
may be pushed over the same. Upon assembling the individ-
ual elements~ the joints between them are filled with
adhesive, and the roller element is pulled together by
means of the rod 4 and the nuts 41 and 42, so that a
precisely cylindrical element is the result, ass~mi.ng that
the end~ o~ the individual element~ had been accurately
made. Suction openings 181 which have been shown only
for the element 18 in the drawing, are pro~ided in the
roller surXace to hold the material which is to be clamped,
be it the or;~;n~l or the record carrier, on the revolving
roller surface. The roller surface may be provided with
several rows of such suctio~ holes throughout its surface,
which are communication with a vacuum prev~;l; ng within
the roller.
~ igure 2 shows a si m; l ~r structure of a roller 1,
which at its ends also comprises lids 2 and 3 comparable
to Figure 15 which are also centrally recessed at 21
and 31 into which projects a rod 4 which again tightens
the separate pot-like elements together by means of the

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1 nuts 41 and 42~ However instead o~ the interfitting
pot-like structures of ~igure 1, ring elements 15, 16,
17 and 18 are provided9 which are joined together at the
inside at their joints by mean~ of annular coupling members
20, 21' and 22, and bonded to ea~h other. To increa~e
rigidity~ at least one di~c-like element is also provided
to brace the jacket o~ the cylinder and impose the round
shape. Preferably a plurality of ~uch elements is
provided, a~ shown at 23, 24, 25 and 26. In this case
too 9 it is assure~ ~hat an e~actly cylindrical element is
the result if care i~ exercised -to assure that the end
portions o~ the individual elements are machined precisely.
A~ in the case of Figure 1~ the elements are clamped
together by means o~ the lids 2 and 3, the rod 4 and the
nuts 41 and 42. To prevent ha~ing to cover large
proportions o~ the uncovered suc-tion openings upon m~k; n~
use o~ smaller ~ormats, one or more pot bases are produced
without open;nes. ~he separate compartments may be
~onnected to the vacuum pipe via valves. In the case of
large roller~ these pressure tight ba~eæ are endowed
with a shape corresponding to the ~tress in the fashion
o~ the bottom of a boiler.
The roller elements proposed in the present in~ention
are partiGularly appropriate for drum scanners in the
sphere of graphics or of other reproduction apparatus
operating with rollers for reception of originals or
r,ecord carriers.