U.S. patent number 3,830,419 [Application Number 05/391,334] was granted by the patent office on 1974-08-20 for tapered roller transport mechanism for web of photographic materials and the like.
This patent grant is currently assigned to Pako Corporation. Invention is credited to Conrad E. Lee.
United States Patent |
3,830,419 |
Lee |
August 20, 1974 |
TAPERED ROLLER TRANSPORT MECHANISM FOR WEB OF PHOTOGRAPHIC
MATERIALS AND THE LIKE
Abstract
The tapered rollers of this web transport mechanism are
specifically constructed and arranged to apply driving force to
only the marginal edge portions of the web being transported to
minimize the possibility of scratching and pressure marking of the
central image-bearing sensitized surface of the web and also
maintain frictional driving contact without close fitting tolerance
between each pair of rollers. The mechanism includes a plurality of
pairs of oppositely tapered rollers having opposed surfaces spaced
apart a distance slightly greater than the thickness of the web to
be transported, the rollers of adjacent pairs being oppositely
tapered and arranged to alternately offset the marginal edge
portions of the web path defined thereby and produce a zigzag,
twisting action on the web to cause the frictional driving pressure
to be exerted only on the marginal edge portions of said web and
also permit a spacing wider than the web thickness be maintained
between each pair of rollers.
Inventors: |
Lee; Conrad E. (Mound, MN) |
Assignee: |
Pako Corporation (Minneapolis,
MN)
|
Family
ID: |
23546186 |
Appl.
No.: |
05/391,334 |
Filed: |
August 24, 1973 |
Current U.S.
Class: |
226/184;
226/189 |
Current CPC
Class: |
G03D
3/132 (20130101); B65H 23/26 (20130101); B65H
20/02 (20130101); B65H 2404/147 (20130101) |
Current International
Class: |
B65H
20/02 (20060101); B65H 23/04 (20060101); B65H
23/26 (20060101); G03D 3/13 (20060101); G03d
003/12 () |
Field of
Search: |
;226/118,184,189,17,15
;95/94R,89A |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Schacher; Richard A.
Attorney, Agent or Firm: Adams; John W.
Claims
What is claimed is:
1. A transport mechanism for elongated webs of sheet material
comprising
a roller supporting structure,
a plurality of pairs of tapered transport rollers mounted on said
structure, the spacing between the rollers of each pair being
greater than the thickness of the web being transported,
the taper of each roller being opposite to its adjacent rollers and
said rollers being oriented to produce a zigzag path for the
marginal edge portions of a web of material being transported
through said rollers, and
means for driving said rollers to produce the movement of such web
through the spacing between the respective pairs along the desired
web path.
2. The structure set forth in claim 1 wherein the axes of rotation
of the rollers are parallel and define the center line of desired
web path therebetween.
3. The structure set forth in claim 2 and said web path having a
number of U-shaped loops with an even number of pairs of rollers
disposed at the closed curved portion of each loop.
4. The structure set forth in claim 2 and the number of pairs of
rollers for all of the respective conditions encountered along the
web path being an even number to avoid any tendency of the tapered
rollers to move the web off the center line of its desired
path.
5. The structure set forth in claim 1 and a number of liquid
confining tanks through which the web is transported and a pair of
soft yieldable squeegee rollers at the exit end of each tank to
remove substantially all of the liquid from the web surfaces.
6. The structure set forth in claim 1 and adjacent pairs of rollers
being oriented to produce a web path center portion through which a
substantial central image-bearing area of the web is free from
contact with said rollers, the web diagonally transversing the
width of the space between each pair of rollers with the marginal
edge portion of one side of the web in frictional driving contact
with a larger portion of one of said rollers and the marginal edge
portion of the other side of the web in frictional driving contact
with a larger portion of the other roller of each pair.
Description
It has constantly been a problem to provide a transport mechanism
for photographic web materials such as film and print paper, to
prevent surface scratching and pressure marking of the relatively
soft photographic surface being processed by the particular
processing equipment through which the transport mechanism carries
the web.
It is an object of the present invention to provide a transport
mechanism for photographic equipment which is particularly designed
to produce roller contact pressure along only the marginal edge
portions of the web of photographic material being transported.
It is another object of the present invention to provide a web
transport mechanism including pairs of oppositely tapered rollers
spaced apart a distance greater than the thickness of the web being
transported and mounted on opposed parallel axes which define the
center line of the web path therebetween for simplicity of
manufacture and application of driving motion to the rollers, the
edges of the web path through adjacent pairs of rollers being
offset to produce a zigzag, twisting motion of the web about said
center line and thus exert driving pressure on only the marginal
edge portions of said web and eliminate roller contact with the
central principal image-bearing area of the web.
These and other objects and advantages of this invention will more
fully appear in the following description made in connection with
the accompanying drawings in which like reference characters refer
to similar parts throughout the several views, and, in which:
FIG. 1 is a side elevational view of the transport mechanism with
the oscillating plate removed;
FIG. 2 is an end elevation of the transport mechanism taken
substantially along the line 2--2 of FIG. 1;
FIG. 3 is a fragmentary horizontal sectional view taken
substantially along the line 3--3 of FIG. 2; and,
FIG. 4 is a fragmentary vertical sectional view taken substantially
along the line 4--4 of FIG. 2.
The photographic processor which embodies this invention is best
shown in FIG. 1 and includes an outer housing or casing designated
by the letter C. The particular processor illustrated includes four
separate processing tanks respectively designated by the numerals
10, 11, 12 and 13. Tanks 10, 11 and 12 each contain a different
liquid used in the processing system and tank 13 defines a drying
chamber. The transport mechansim includes a pair of side panels or
plates respectively designated by the numerals 14 and 15.
The transport mechanism includes a plurality of pairs of tapered
rollers 16. Each roller is mounted for rotation between the plates
14 and 15 on suitable supporting shafts 17 respectively rotating on
axes 17a.
Any suitable means for imparting rotary driving motion to the
rollers 17 may be provided such as the DRIVING MECHANISM FOR A
ROLLER TRANSPORTING DEVICE disclosed in my U.S. Pat. No. 3,608,807.
This mechanism includes a single oscillating plate (not shown
herein) to which a plurality of driving pins 18b are fixed. One
shaft 17 of each pair of rollers has a crank arm 18a fixed in
radially outstanding relation thereto and these crank arms 18a are
respectively engaged by the crank pins 18b which in turn are driven
by said oscillating plate in the manner set forth in said prior
patent. Instead of the two oscillating plates 40 and 42 disclosed
in said patent, the present mechanism includes only one such plate
which is designed to drive only one of each pair of rollers. In the
mechanism disclosed herein, the other roller in each pair is driven
by a pair of meshed gears 19 respectively fixed to the ends of the
shafts 17 opposite to the ends to which the crank arms 18a are
fixed. This is best shown in FIGS. 2 and 3.
As best shown in FIG. 1 the axes of adjacent pairs of rollers are
oriented in such a manner to define a continuous web path through
the processing tanks 10, 11, 12 and 13. A plurality of rollers 16
are provided which are tapered from one end to the other and the
opposed surfaces thereof are spaced apart a distance greater than
the thickness of a web W of material to be transported. The
direction of taper of one roller in each pair is opposite to the
direction of taper of the other roller in that pair as best shown
in FIG. 3. The direction of taper of each pair of rollers is
opposite to the direction of taper of adjacent pairs of rollers.
The web of photographic material W is best shown in FIGS. 3 and 4
which illustrate the zigzag path followed by the marginal edge
portions of the web W through the roller train and the photographic
processing tanks.
The alternating of the direction of taper of adjacent rollers not
only produces the zigzag path of the web as described but also
maintains the web in transversely centered relationship along the
center line of its desired web path. We have found that an even
number of pairs of transport rollers at the curved ends of each
loop of the web path serves to maintain the web W in this centered
relationship as it passes around the curved portion of the path. It
seems to be important that an even number of pairs of rollers are
provided for carrying the web through each of the various
conditions encountered along the web path to avoid any tendency to
cause the web to travel off the center line of the path.
Since the spacing between the rollers of each pair is wider than
the thickness of the web being transferred it has been found to be
desirable to provide a pair of squeegee rollers 20 at the top of
the exit portion of the path in each liquid confining tank. These
squeegee rollers 20 are in surface contact and are positioned above
the liquid level of each of the liquid tanks, 10, 11 and 12. They
are of soft yieldable material and are positioned to press against
both sides of the web to "squeegee off" substantially all of the
liquid from the surface of the web W as it is transported out of
each tank.
It will be seen that the opposite orientation of adjacent rollers
produces an offset of both marginal edge portions of the web thus
causing a tensioning of edge portions to provide maximum drive
pressure therealong and eliminate the driving contact pressure on
the central image-bearing areas of the web. The requirement for
close tolerances of the spacing between each pair of rollers 17 has
also been eliminated.
It will, of course, be understood that various changes may be made
in the form, details, arrangement and proportions of the parts
without departing from the scope of this invention as set forth in
the appended claims.
* * * * *