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Claims  |
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What is claimed is:
1. An apparatus for developing a picture on a sheet of developing paper
from a sheet of photo-sensitive material of a type which develops said
picture upon the pressing together of said sheets of developing paper and
photo-sensitive material, said apparatus comprising:
a back-up member having a back-up surface and standby surfaces extending
from the opposite ends of said back-up surface and being raised relative
to the latter for defining guide shoulders at said ends of the back-up
surface;
means for intermittently transporting said sheets of developing paper and
photo-sensitive material in contact with each other across said back-up
surface between said guide shoulders in a predetermined direction of sheet
travel at a substantial angle to a longitudinal median of said back-up
surface;
at least one rotatable roller disposed in opposing relation to said back-up
surface and having an axis of rotation substantially at right angles to
said longitudinal median of said back-up surface;
means mounting said roller for bodily movements relative to said back-up
member toward and away from said back-up surface and parallel to the
back-up surface in directions parallel to said longitudinal median
thereof;
means for transporting said roller relative to said back-up member in said
directions parallel to said longitudinal median from one to another of
said standby surfaces while urging said roller toward said back-up surface
with said sheets of developing paper and photo-sensitive material being in
contact with each other between said roller and said back-up surface so as
to be pressed together thereby; and
control means for causing coordinate operations of said means for
intermittently transporting the sheets and said means for transporting
said roller so that said sheets are transported a predetermined
incremental distance in said direction of sheet travel while said roller
is situated on one of said standby surfaces and said sheets are at rest
while said roller is transported along said back-up surface from one to
another of said standby surfaces.
2. An apparatus according to claim 1; in which said standby surfaces are
raised relative to said back-up surface by a distance approximately equal
to the combined thicknesses of said sheets of developing paper and
photo-sensitive material.
3. An apparatus according to claim 1; in which said sheet of developing
paper is softer than said sheet of photo-sensitive material, and said
sheets are arranged between said roller and back-up surface so that said
sheet of photo-sensitive material contacts said back-up surface and said
roller contacts said sheet of developing paper in being transported from
one to another of said standby surfaces.
4. An apparatus according to claim 1; in which said back-up member and said
roller are configured so that, during said transporting of said roller
across said back-up surface from one to another of said standby surfaces,
the contact pressure between the peripheral surface of said roller and
said back-up surface is smaller at the opposite margins of said peripheral
surface than at any other portions of the latter between said margins.
5. An apparatus according to claim 4; in which at least one of said back-up
surface and said peripheral surface of said roller is shaped to diverge
relative to the other of said back-up surface and peripheral surface from
the median of said peripheral surface toward said opposite margins of the
peripheral surface.
6. An apparatus according to claim 5; in which said peripheral surface is
outwardly concave between said margins and said back-up surface is
outwardly convex and has a rectilinear generatrix extending parallel to
said directions in which said roller is transported; and in which said
outwardly concave peripheral surface has a larger radius of curvature than
said outwardly convex back-up surface.
7. An apparatus according to claim 5; in which said back-up surface is flat
and said peripheral surface is outwardly convex between said margins.
8. An apparatus according to claim 5; in which said peripheral surface of
said roller is cylindrical and has a rectilinear generatrix extending
parallel to the axis of rotation of the respective roller, and said
back-up surface is outwardly convex and has a rectilinear generatrix
extending parallel to said directions in which said roller is transported.
9. An apparatus according to claim 4; in which said peripheral surface of
said roller in cylindrical and has a rectilinear generatrix extending
parallel to the axis of rotation of the roller, said back-up surface is
flat, and said roller has opposed flanks with annular recesses therein
concentric with said axis of rotation of the roller so that the rigidity
of said roller at the opposite margins of said peripheral surface is less
than the rigidity of the roller at a median portion of said peripheral
surface intermediate said margins.
10. An apparatus according to claim 1; in which said back-up member is
cylindrical and includes non-rotatable end portions having peripheral
surfaces defining said standby surfaces, and a mid-portion between said
end portions which is of smaller diameter than the latter to define said
back-up surface and which is rotatable during said transporting of the
sheets of developing paper and photo-sensitive material.
11. An apparatus according to claim 1; in which at least one of said
back-up surface and the peripheral surface of said roller is formed with
minute concave and convex surface irregularities distributed thereover.
12. An apparatus according to claim 11; in which said photo-sensitive
material has a surface comprised of photo-sensitive microcapsules which
are selectively hardened by exposure to a light image and which contain
respective color-forming substances released for correspondingly coloring
said developing paper when said sheets are pressed together between said
roller and said back-up surface with sufficient pressure exerted at said
minute concave and convex surface irregularities to rupture the
microcapsules that have not been hardened.
13. An apparatus according to claim 12; in which said minute concave and
convex surface irregularities substantially correspond in size to a
predetermined resolution of the picture to be developed on said sheet of
developing paper.
14. An apparatus according to claim 1; further comprising a second
rotatable roller arranged in tandem in respect to the first mentioned
roller so that said first and second rollers successively press together
said sheets of developing paper and photo-sensitive material between said
rollers and said back-up surface when said rollers are transported in said
directions parallel to said longitudinal median of said back-up surface.
15. An apparatus according to claim 1; further comprising self-aligning
means for automatically attaining a desired attitude of the peripheral
surface of said roller relative to said back-up surface during said
transporting of said roller relative to the back-up member.
16. An apparatus according to claim 15; in which said self-aligning means
includes means mounting said roller for pivoting relative to said back-up
member about an axis parallel to said directions in which said roller is
transported.
17. An apparatus according to claim 15; in which said self-aligning means
includes means mounting said back-up member for pivoting about an axis
parallel to said directions in which said roller is transported.
18. An apparatus according to claim 1; in which said back-up member
includes a rotatable cylinder having a periphery forming said back-up
surface, and said means for transporting said sheets of developing paper
and photo-sensitive material includes drive means for rotating said
cylinder.
19. An apparatus according to claim 1; in which said back-up surface has
opposed margins parallel to said directions in which said roller is
transported, and said back-up surface is convex in the direction toward
said roller and has a rectilinear generatrix extending parallel to said
directions in which said roller is transported; and in which said means
for transporting said sheets includes sheet guide means disposed before
and after said back-up surface considered in respect to said direction of
sheet travel, said sheet guide means defining paths for said sheets
extending to and from said back-up surface and which converge and diverge,
respectively, in respect to a plane tangential to said back-up surface at
a region of the latter along which said roller is urged there against,
said paths being disposed between said plane and said back-up surface and
spaced from the latter at said opposed margins of the back-up surface.
20. An apparatus for developing a picture on a sheet of developing paper
from a sheet of photo-sensitive material which is more rigid than said
sheet of developing paper and of a type which develops said picture upon
the pressing together of said sheets of developing paper and
photo-sensitive material, said apparatus comprising:
means defining a back-up surface having a longitudinal median;
means for intermittently transporting said sheets of developing paper and
photo-sensitive material in contact with each other across said back-up
surface in a predetermined direction of sheet travel which is at a
substantial angle to said longitudinal median thereof, and, with said
sheet of photo-sensitive material contacting said back-up surface;
at least one rotatable roller disposed in opposing relation to said back-up
surface and having an axis of rotation substantially at right angles to
said longitudinal median of said back-up surface;
means mounting said roller for bodily movements toward and away from said
back-up surface and parallel to the back-up surface in directions parallel
to said longitudinal median thereof; and
means for transporting said roller relative to said back-up surface in said
directions parallel to said longitudinal median while urging said roller
toward said back-up surface with said sheets of developing paper and
photo-sensitive material being in contact with each other between said
roller and said back-up surface so as to be pressed together by said
roller acting on the relatively less rigid sheet of developing paper.
21. An apparatus for developing a picture on a sheet of developing paper
from a sheet of photo-sensitive material of a type which develops said
picture upon the pressing together of said sheets of developing paper and
photo-sensitive material, said apparatus comprising:
means defining a back-up surface having a longitudinal median;
means for intermittently transporting said sheets of developing paper and
photo-sensitive material in contact with each other in a predetermined
direction of sheet travel across said back-up surface;
at least one rotatable roller disposed in opposing relation to said back-up
surface and having an axis of rotation extending at right angles to said
longitudinal median;
means mounting said roller for bodily movements toward and away from said
back-up surface and parallel to the back-up surface in directions parallel
to said longitudinal median of the back-up surface; and
means for transporting said roller across said back-up surface in said
directions parallel to said longitudinal median while urging said roller
toward said back-up surface with said sheets of developing paper and
photo-sensitive material being in contact with each other between said
roller and said back-up surface so as to be pressed together thereby;
said back-up surface and said roller being configured so that, during said
transporting of said roller across said back-up surface, the contact
pressure between the peripheral surface of said roller and said back-up
surface is smaller at the opposite margins of said peripheral surface than
at any other portions of the latter between said margins.
22. An apparatus according to claim 21; in which at least one of said
back-up surface and said peripheral surface of said roller is shaped to
diverge relative to the other of said back-up surface and peripheral
surface from the median of said peripheral surface toward said opposite
margins of the peripheral surface.
23. An apparatus according to claim 22; in which said peripheral surface is
outwardly concave between said margins and said back-up surface is
outwardly convex and has a rectilinear generatrix extending parallel to
said directions in which said roller is transported; and in which said
outwardly concave peripheral surface has a larger radius of curvature than
said outwardly convex back-up surface.
24. An apparatus according to claim 22; in which said back-up surface is
flat and said peripheral surface is outwardly convex between said margins.
25. An apparatus according to claim 22; in which said peripheral surface of
said roller is cylindrical and has a rectilinear generatrix extending
parallel to the axis of rotation of the respective roller, and said
back-up surface is outwardly convex and has a rectilinear generatrix
extending parallel to said directions in which said roller is transported.
26. An apparatus according to claim 21; in which said peripheral surface of
said roller in cylindrical and has a rectilinear generatrix extending
parallel to the axis of rotation of the roller, said back-up surface is
flat, and said roller has opposed flanks with annular recesses therein
concentric with said axis of rotation of the roller so that the rigidity
of said roller at the opposite margins of said peripheral surface is less
than the rigidity of the roller at a median portion of said peripheral
surface intermediate said margins.
27. An apparatus for developing a picture on a sheet of developing paper
from a sheet of photo-sensitive material of a type which develops said
picture upon the pressing together of said sheets of developing paper and
photo-sensitive material, said apparatus comprising:
means defining a back-up surface having a longitudinal median;
means for intermittently transporting said sheets of developing paper and
photo-sensitive material in contact with each other in a predetermined
direction of sheet travel across said back-up surface at a substantial
angle to said longitudinal median;
at least one rotatable roller disposed in opposing relation to said back-up
surface and having an axis of rotation extending substantially at right
angles to said longitudinal median;
means mounting said roller for bodily movements toward and away from said
back-up surface and parallel to the back-up surface in directions parallel
to said longitudinal median thereof;
means for transporting said roller across said back-up surface in said
directions parallel to said longitudinal median while urging said roller
toward said back-up surface with said sheets of developing paper and
photo-sensitive material being in contact with each other between said
roller and said back-up surface so as to be pressed together thereby; and
at least one of said back-up surface and the peripheral surface of said
roller being formed with minute concave and convex surface irregularities
distributed thereover.
28. An apparatus according to claim 27; in which said photo-sensitive
material has a surface comprised of photo-sensitive microcapsules which
are selectively hardened by exposure to a light image and which contain
respective color-forming substances released for correspondingly coloring
said developing paper when said sheets are pressed together between said
roller and said back-up surface with sufficient pressure exerted at said
minute concave and convex surface irregularities to rupture the
microcapsules that have not been hardened.
29. An apparatus according to claim 28; in which said minute concave and
convex surface irregularities substantially correspond in size to a
predetermined resolution of the picture to be developed on said sheet of
developing paper.
30. An apparatus according to claim 27; in which said back-up surface has
an array of parallel grooves therein extending parallel to said directions
in which said roller is transported and which define said concave and
convex irregularities.
31. An apparatus according to claim 27; in which said back-up surface has
an array of pits therein defining said concave and convex irregularities.
32. An apparatus for developing a picture on a sheet of developing paper
from a sheet of photo-sensitive material of a type which develops said
picture upon the pressing together of said sheets of developing paper and
photo-sensitive material, said apparatus comprising:
a back-up cylinder defining a peripheral back-up surface with rounded edges
at the opposite ends of said back-up surface;
means for intermittently turning said cylinder and thereby transporting
said sheets of developing paper and photo-sensitive material in contact
with each other in a predetermined direction of sheet travel across said
back-up surface;
at least one rotatable roller disposed in opposing relation to said back-up
surface and having an axis of rotation extending parallel to said
predetermined direction of sheet travel;
means mounting said roller for bodily movements relative to said back-up
cylinder toward and away from said back-up surface and parallel to the
back-up surface in directions perpendicular to said predetermined
direction of sheet travel between standby positions situated beyond said
opposite ends of the back-up surface;
means for transporting said roller relative to said back-up cylinder in
said directions perpendicular to said predetermined direction of sheet
travel from one to another of said standby positions while urging each
roller toward said back-up surface with said sheets of developing paper
and photo-sensitive material being in contact with each other between said
roller and said back-up surface so as to be pressed together thereby; and
control means for causing coordinate operations of said means for
intermittently turning said cylinder and said means for transporting said
roller so that said sheets are transported a predetermined incremental
distance in said direction of sheet travel while said roller is situated
at one of said standby positions and said sheets are at rest while said
roller is transported along said back-up surface from one to another of
said standby positions and rolls smoothly over said rounded end edges in
moving between said back-up surface and said standby positions.
33. An apparatus for developing a picture on a sheet of developing paper
from a sheet of photo-sensitive material of a type which develops said
picture upon the pressing together of said sheets of developing paper and
photo-sensitive material, said apparatus comprising:
means defining a back-up surface having a longitudinal median;
means for intermittently transporting said sheets of developing paper and
photo-sensitive material in contact with each other in a predetermined
direction of sheet travel across said back-up surface at a substantial
angle to said longitudinal median;
first and second rotatable rollers arranged in tandem in opposing relation
to said back-up surface and each having an axis of rotation extending
substantially at right angles to said longitudinal median;
means mounting said rollers for bodily movements toward and away from said
back-up surface and parallel to the back-up surface in directions parallel
to said longitudinal median; and
means operative when the sheets are at rest on the back-up surface for
transporting said rollers relative to said back-up surface in said
directions parallel to said longitudinal median while urging said rollers
toward said back-up surface so that said rollers successively press
together said sheets of developing paper and photo-sensitive material
between said rollers and said back-up surface.
34. An apparatus according to claim 33; in which said means mounting said
rollers arranged in tandem includes parallel guide rods extending parallel
to said directions in which the rollers are transported, a carriage
movable along said guide rods, a single pivot pin carried by said carriage
between said first and second rollers and providing a pivot axis parallel
to the axes of said rollers, first and second support members pivotably
mounted on said single pin and extending in opposed directions from the
latter, said first and second rollers being rotatably mounted on said
first and second support members, respectively, for said movements toward
and away from said back-up surface in response to pivoting of said support
members about said pivot axis, and springs interposed between said
carriage and said support members for urging the latter in the direction
moving the respective rollers toward said back-up surface.
35. An apparatus according to claim 34; in which said guide rods have
cylindrical surfaces, and said means mounting the rollers further include
guide rolls with grooved peripheries rotatably mounted at opposite sides
of said carriage and engaging at said grooved peripheries with said
cylindrical surfaces of the guide rods under the influence of said springs
urging said rollers against said back-up surface.
36. An apparatus for developing a picture on a sheet of developing paper
from a sheet of photo-sensitive material of a type which develops said
picture upon the pressing together of said sheets of developing paper and
photo-sensitive material, said apparatus comprising:
a back-up member having a back-up surface with a longitudinal median;
means for intermittently transporting said sheets of developing paper and
photo-sensitive material in contact with each other across said back-up
surface in a predetermined direction of sheet travel at a substantial
angle to said longitudinal median;
at least one rotatable roller disposed in opposing relation to said back-up
surface and having an axis of rotation extending substantially at right
angles to said longitudinal median of said back-up surface;
means mounting said roller for bodily movements relative to said back-up
member toward and away from said back-up surface and parallel to the
back-up surface in directions parallel to said longitudinal median;
means for transporting said roller relative to said back-up surface in said
directions parallel to said longitudinal median while urging said roller
toward said back-up surface with said sheets of developing paper and
photo-sensitive material being in contact with each other between said
roller and said back-up surface so as to be pressed together thereby; and
self-aligning means for automatically attaining a desired attitude of the
peripheral surface of said roller relative to said back-up surface during
said transporting of said roller relative to the back-up member.
37. An apparatus according to claim 36; in which said self-aligning means
includes means mounting said roller for pivoting relative to said back-up
surface about an axis parallel to said directions in which said roller is
transported.
38. An apparatus according to claim 36; in which said self-aligning means
includes means mounting said back-up member for pivoting about an axis
parallel to said directions in which said roller is transported.
39. An apparatus for developing a picture on a sheet of developing paper
from a sheet of photo-sensitive material of a type which develops said
picture upon the pressing together of said sheets of developing paper and
photo-sensitive material, said apparatus comprising:
means defining an upwardly facing back-up surface having opposed parallel
margins extending longitudinally therealong, said back-up surface being
convex and having a rectilinear generatrix extending parallel with said
margins;
means for intermittently transporting said sheets of developing paper and
photo-sensitive material in contact with each other across said back-up
surface in a direction of sheet travel at a substantial angle to the
longitudinal margins of said back-up surface and including sheet guide
means disposed before and after said back-up surface considered in respect
to said direction of sheet travel, said sheet guide means defining paths
for said sheets extending to and from said back-up surface and which
converge and diverge, respectively, in respect to a plane tangential to
said back-up surface at the top of the latter, said paths being disposed
between said plane and said back-up surface and spaced from the latter at
said opposed longitudinal margins of the back-up surface;
at least one rotatable roller disposed in opposing relation to said back-up
surface and having an axis of rotation extending substantially at right
angles to said margins of said back-up surface;
means mounting said roller for bodily movements relative to said back-up
surface toward and away from said back-up surface and parallel to the
back-up surface in directions parallel to said margins; and
means for transporting said roller relative to said back-up surface in said
directions parallel to said margins while urging said roller toward said
back-up surface with said sheets of developing paper and photo-sensitive
material being in contact with each other between said roller and said
back-up surface so as to be pressed together thereby.
40. An apparatus according to claim 39; in which said roller has a
peripheral surface with rounded opposed edges.
41. An apparatus according to claim 40; in which said sheet of developing
paper is softer than said sheet of photo-sensitive material; and in which
said sheets are arranged in contact with each other with said sheet of
photo-sensitive material at the bottom to engage said back-up surface and
said sheet of developing paper at the top to be engaged by said peripheral
surface of the roller. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
1. Field Of The Invention
This invention relates generally to developing apparatus, and more
particularly is directed to an apparatus for developing an image or
picture on a sheet of developing paper from an exposed sheet of
photo-sensitive material by pressing together the sheets.
2. Description of the Prior Art
It is known, for example, as disclosed in Japanese laid-open Patent Gazette
No. 59-30537, to print or develop a color picture on a sheet of developing
paper from a sheet of photo-sensitive material having a coating of
photo-sensitive microcapsules which have been irradiated with a light
image of the picture. This known printing method employs, as the
photo-sensitive sheet, a base made of a suitable resin on which there is a
coating of uniformly distributed yellow, magenta and cyan microcapsules.
Each of the yellow, magenta and cyan microcapsules has an outer shell of a
relatively soft material in which there is sealed an optically-hardening
composition containing a respective pigment or a precursor thereof. When
the photo-sensitive microcapsules are irradiated with respective wave
lengths of light, the optically-hardening compositions therein are
selectively hardened. For example, irradiation with blue light hardens the
yellow microcapsules containing the precursor of yellow pigment,
irradiation with green light hardens the magenta microcapsules containing
the precursor of magenta pigment and irradiation with red light hardens
the cyan microcapsules containing the precursor of cyan pigment.
It will be appreciated that, when irradiating the above described sheet of
photo-sensitive material with a light image of a color picture, the light
of the color picture is suitably analyzed into the three primary colors of
red, green and blue and the sheet of photo-sensitive material is
irradiated separately with a red light image, a green light image and a
blue light image by which the cyan, magenta and yellow microcapsules,
respectively, are selectively hardened in accordance with such images.
Then, the irradiated or exposed coating of photo-sensitive microcapsules
on the sheet of photo-sensitive material is placed in contact with a sheet
of developing paper coated with or containing a developing substance, and
the contacting sheets are pressed together so as to rupture the shells of
the yellow, magenta and cyan microcapsules that were not substantially
hardened by irradiation with light of corresponding wave lengths. The
substances containing precursors of pigments are transferred from the
ruptured microcapsules to the facing surface of the sheet of developing
paper and react with the developing substances thereon for developing the
respective color pigments from the precursors thereof. Thus, the
transferred precursors of pigments from the yellow, magenta and cyan
microcapsules are developed into the respective pigments which are
suitably mixed to present a printed color picture on the sheet of
developing paper.
In a known apparatus for pressing together the sheets of developing paper
and photo-sensitive material, as indicated at a on FIG. 1, the sheet c of
the photo-sensitive material, which is desirably in the form of a long web
or film, and a sheet d of the developing paper are passed together between
a pair of vertically superposed cylindrical pressure rollers e and f
having axial lengths somewhat greater than the width of the sheets c and
d. The lower pressure roller e is rotatably mounted in a suitable support
frame (not shown) and rotated by a motor (also not shown). The upper
pressure roller is rotatably mounted in a vertically movable frame which
is pressed downward by one or more strong resilient members (not shown) so
that roller f is pressed downwardly against roller e. A frame or area of
the web or sheet c of photo-sensitive material is exposed to a light image
before being brought together with the sheet d of developing paper,
whereupon the sheets c and d are fed together between the pressure rollers
e and f. As the lower roller e is rotated, the upper roller f pressed
there-against is also rotated so that the sheet c of photo-sensitive
material and the sheet d of developing paper are moved together while
being pressed between the rollers e and f.
The apparatus a according to the prior art has the advantage of providing a
relatively high printing speed by reason of the fact that the sheets of
developing paper and photo-sensitive material are pressed together while
being continuously transported or advanced by the rotated rollers e and f.
However, in the known apparatus a, the rollers e and f act to press
together the sheets c and d simultaneously along a stripe-like area
extending across the entire width of the sheets. Therefore, in order to
provide the requisite pressure at each increment of such stripe-like area
for ensuring the rupture of those microcapsules that have not been fully
hardened, and further for ensuring the transfer of the precursors of
pigments from the ruptured microcapsules to the sheet of developing paper,
a very large force must be provided to urge the roller f toward the roller
e. For example, in order to rupture the unhardened microcapsules of the
sheet of photo-sensitive material and to ensure adequate contact of the
released pigment precursors with the developing substances on the sheet of
developing paper, it is necessary that the sheet c of photo-sensitive
material and the sheet d of developing paper be pressed together with a
pressure of 30 to 40 kg/mm.sup.2. In the case where, for example, a
picture is to be printed on a sheet of developing paper of A4 size which
has a width of 21 cm, and the rollers e and f employed for pressing
together the sheets c and d each having a diameter of 50 mm, the force
urging together the rollers has to be about 57 kg for each cm of roller
length, that is, a total force of about 1200 kg for rollers having lengths
of 21 cm. The apparatus a, in order to be capable of applying such a large
force for urging together the rollers e and f, must be massive and
requires a high-powered motor and transmission mechanism for transmitting
the torque the torque to the lower pressure roller e. As a result of the
foregoing, the apparatus a is relatively expensive and difficult to
assemble and maintain.
In order to overcome the foregoing disadvantages of the known apparatus a,
an apparatus b has been proposed which, as shown in FIG. 2, comprises a
fixed back-up member g defining an upwardly facing back-up surface g', and
a pressing member h having a spherical ball i rotatably mounted at its
lower end. The sheets c and d of photo-sensitive material and developing
paper, respectively, are brought into contact with each other and
transported intermittently across the back-up surface g' in a direction of
sheet travel that is transverse to the length of the back-up surface g'.
The pressing member h is mounted for reciprocal movements in the direction
along the back-up surface g', that is, perpendicular to the direction of
sheet travel, between terminal positions h.sub.1 and h.sub.2, shown in
dot-lines of FIG. 2, and at which the pressing member h is situated
laterally beyond the side edges of the sheets c and d. During its
movements between the terminal positions h.sub.1 the back-up surface g',
the pressing member h is urged downwardly so that the ball i exerts
pressure for urging together the sheets c and d against the back-up
surface g' progressively along a narrow pressing region extending across
the entire width of the contacting sheets c and d. The described pressing
step is effected repetitively with intervening sheet transporting steps
during each of which the sheets c and d are incrementally advanced.
Since the ball i of the pressing member h acts, at any time, against only a
very small area of the contacting sheets c and d, the requisite pressure
for ensuring the rupture of the unhardened microcapsules and the transfer
of the released pigment precursors into adequate contact with the
developing substances can be achieved with only a moderate force urging
the pressing member h toward the back-up surface g'. Thus, the apparatus b
can be relatively compact and light in weight. However, the apparatus b is
disadvantageous in that its printing speed is low because the developing
of the picture is effected by alternating the movements of the pressing
member h across the contacting sheets c and d and the intermittent
transporting of the sheets c and d of the photo-sensitive material and the
developing paper. Furthermore, as shown on FIG. 3A, the contact pressure
between the ball i of the pressing member h and the back-up surface g' is
not uniform across the width w of the pressing area, as indicated by the
pressure distribution curve j. As will be apparent from such curve j, the
contact pressure between the ball i and the back-up surface g is highest
at the center of the ball and is reduced therefrom toward the opposite
sides of the pressing area.
Therefore, the pressure urging together the sheet c of photo-sensitive
material and the sheet d of developing paper d is highest at the center of
the pressing area and is progressively reduced towards the opposite
margins of such area. Therefore, for any particular degree of exposure,
more of the microcapsules will be ruptured for releasing the respective
pigment precursors along the center of the pressing area than along the
opposite side margins thereof. Thus, the concentration of development on
the sheet d of developing paper is highest at the center of each of the
stripe-like pressing regions and is gradually reduced or diminished toward
the opposite edges of each such pressing region or area, as indicated by
the successive concentration distribution curves k on FIG. 3B. If the
sheets c and d are intermittently transported through an incremental
distance or pitch equal to the width w of the stripe-like area of contact
of the ball i with the sheet d of developing paper, the printed or
developed picture will have a striped pattern resulting from the irregular
concentration of development.
Of course, if the incremental movements of the intermittently transported
sheets c and d are reduced, for example, if each incremental movement of
the sheets c and d is made equal to about one half the width w of the
stripe-like area of contact of the ball i with the sheet d of developing
paper, the pressing member h will act on the sheets c and d along
overlapping pressing areas with the result that the developed or printed
picture will have a more uniform concentration of development on the sheet
d of developing paper, as indicated by the concentration distribution
curves k on FIG. 3C. However, such reduction of the incremental movements
of the sheets c and d will very substantially increase the printing or
developing time and thereby considerably reduce the printing speed.
In order to reduce the force that needs to be exerted for pressing together
the sheets c and d, as compared with the apparatus a of FIG. 1, while
increasing the width of the pressing area along which the sheets c and d
are pressed together during each stroke or scan across the width thereof,
as compared with the apparatus b of FIG. 2, it has been proposed, for
example, as in the pending U.S. patent application identified by Curtis,
Morris & Safford U.S. Ser. No. 248,373, and corresponding to Japanese
Patent Application No. P270758/87, filed Oct. 27, 1987 and having a common
assignee herewith, to replace the pressing member h having a rotatable
ball i for contact with the sheet d of developing paper, by a rotatable
roller 1 (FIG. 4) disposed in opposing relation to the back-up surface g'
and having an axis of rotation extending parallel to the direction of
travel of the sheets c and d across the back-up surface g'. The roller 1
has a cylindrical peripheral surface and is mounted for bodily movements
relative to the back-up member g parallel to the back-up surface g' in
directions perpendicular to the direction of intermittent sheet travel,
and during such movements of the roller 1, the latter is urged toward the
back-up surface g' with the sheets c and d of photo-sensitive material and
developing paper being in contact with each other between the roller 1 and
the back-up surface g' so as to be pressed together thereby. By reason of
the cylindrical peripheral surface of the roller 1, the width of the
stripe-like pressing area along which the sheets c and d are pressed
together sufficiently to uniformly develop the picture can be
substantially increased. Therefore, the printing or developing speed can
be increased relative to that of the apparatus b of FIG. 2.
In the apparatus of FIG. 4, during each incremental movement of the sheets
c and d, the roller 1 is moved off the contacting sheets c and d to a
standby position on the back-up surface g' at one side or the other of the
sheets c and d, as shown on FIG. 5. At the completion of each incremental
movement of the sheets c and d, the roller 1 is moved from its standby
position on the back-up surface g' at one side of the path of travel of
the sheets c and d laterally across the contacting sheets in a pressing
step to a standby position on the back-up surface g' adjacent the opposite
sides of the sheets c and d, whereupon an incremental movement of the
sheets c and d is effected in another sheet transporting step. Thus, the
sheet pressing and transporting steps are alternately performed in a
repetative manner and, due to the relatively wide area along which the
roller 1 can exert the requisite pressure against the contacted sheets c
and d during each pressing step, a sufficiently high printing or
developing speed can be realized. However, the contacting sheets c and d
have a substantial thickness and, as shown on FIG. 5, the opposite side
edges of the contacting sheets extend upwardly from the back-up surface g'
at the standby positions of the roller 1. Therefore, each time the roller
1 is rolled onto or off the contacting sheets c and d from or to,
respectively, a standby position of the roller on the back-up surface g',
the roller 1, in effect, rolls over a step and thereby generates
objectionable noise. Further, there is the likelihood that, in moving from
a standby position on the back-up surface g' onto the contacting sheets c
and d, the roller 1 will damage the side edges of the developing paper and
the photo-sensitive material, or even that the roller 1, in colliding with
the raised side edges of the sheets c and d, will have its rolling
movement halted thereby.
OBJECTS AND SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an
improved developing apparatus which avoids the above described
disadvantages of the prior art.
More specifically, it is an object of this invention to provide an
apparatus for developing a picture on a sheet of developing paper from a
sheet of photo-sensitive material by pressing together the sheets and
which permits the apparatus to be of relatively small size and low cost
while reliably achieving developing of the picture at an acceptably high
speed.
Another object of the invention is to provide a developing apparatus, as
aforesaid, which provides a uniform developing concentration.
Still another object of this invention is to provide a developing
apparatus, as aforesaid, which prevents damage to the sheets of developing
paper and photo-sensitive material, and which further avoids the
generation of objectionable noise during operation of the apparatus.
It is still another object of this invention to provide a developing
apparatus, as aforesaid, in which the sheets of developing paper and
photo-sensitive material in contact with each other are intermittently
transported in a predetermined direction of sheet travel across a back-up
surface and, during each interval when the sheets are at rest on the
back-up surface, a rotatable roller is transported along the back-up
surface at a substantial angle to the direction of sheet travel while
being urged toward the back up surface for pressing together the sheets
between the roller and back-up surface, and in which the back-up surface
has raised guide shoulders at its opposite ends for guiding the adjacent
side edges of the sheets and thereby preventing relative shifting thereof
during the pressing together of the sheets or the intermittent transport
thereof.
Still another object of this invention is to provide a developing
apparatus, as aforesaid, in which two contacting sheets, for example, of
developing paper and photo-sensitive material, respectively, which are of
different hardness or rigidity, can be transported, in contact with each,
across a curved back-up surface without being displaced relative to each
other.
Still another object of this invention is to provide a developing
apparatus, as aforesaid, in which the pressure exerted on the contacting
sheets of developing paper and photo-sensitive material between a back-up
surface and a roller transported there-across is substantially uniformly
distributed so as to achieve clear development of a picture without
irregular concentrations of the development thereof.
It is a further object of this invention to provide a developing apparatus,
as aforesaid, in which self-alignment is achieved in respect to the
back-up surface and roller between which the contacting sheets of
developing paper and photo-sensitive material are pressed together,
thereby reducing the accuracy required in the assembly and adjustment of
the respective parts.
It is a further object of this invention to provide a developing apparatus,
as aforesaid, in which a force required for pressing together the sheets
of developing paper and photo-sensitive material against a back-up surface
is minimized so as to make possible the provision of a relatively low cost
apparatus that is compact and light in weight.
It is a still further object of this invention to provide a developing
apparatus, as aforesaid, which minimizes the frictional resistance to the
intermittent transportation of the sheets of developing paper and
photo-sensitive material across a back-up surface so as to avoid irregular
movements of the sheets that adversely affect uniform development.
In accordance with an aspect of this invention, in an apparatus for
developing a picture on a sheet of developing paper from a sheet of
photo-sensitive material by pressing together the sheets, and in which the
sheets of developing paper and photo-sensitive material are intermittently
transported in contact with each other in a predetermined direction of
sheet travel across a back-up surface, and a rotatable roller disposed in
opposing relation to the back-up surface and having its axis of rotation
extending substantially at right angles to a longitudinal median of the
back-up surface is transported relative to the back-up surface in
directions parallel to the lo | | |
