U.S. patent number 3,914,594 [Application Number 05/463,513] was granted by the patent office on 1975-10-21 for radiation lamp reflector assembly.
This patent grant is currently assigned to Sun Chemical Corporation. Invention is credited to Norman A. Helding.
United States Patent |
3,914,594 |
Helding |
October 21, 1975 |
Radiation lamp reflector assembly
Abstract
Apparatus for ultra-violet light curing of solvent-free ink by
photopolymerization. The web carrying the ink to be cured is
conveyed along a feed path. Lamps are arrayed along the feed path.
A reflector behind each lamp directs radiation toward the web. In
front of each lamp is a light absorbing shutter. When closed, the
shutter blocks radiation from impinging upon the web. When opened,
that shutter unblocks its own reflector. Means are provided for
moving the shutters from their open to their closed positions. In
one form of the invention, the lamps are arrayed along opposite
sides of the web. In this embodiment, when a shutter opens, it not
only unblocks its own reflector, but it also moves to a position
opposed to the reflector of the neighboring lamp on the other side
of the conveyor, whereby illumination from that lamp which passes
the web impinges upon the open shutter. Means are also provided for
opening the housings in which the lamps are contained and for
shutting the housings. Air duct means are also provided in the lamp
and reflector housings for cooling the lamp terminals and drawing
off ozone and heated gases in the vicinity of the lamps.
Inventors: |
Helding; Norman A. (Chicago,
IL) |
Assignee: |
Sun Chemical Corporation (New
York, NY)
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Family
ID: |
26993212 |
Appl.
No.: |
05/463,513 |
Filed: |
April 24, 1974 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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342816 |
Mar 19, 1973 |
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Current U.S.
Class: |
362/218 |
Current CPC
Class: |
F26B
3/28 (20130101) |
Current International
Class: |
F26B
3/28 (20060101); F26B 3/00 (20060101); F21V
007/00 () |
Field of
Search: |
;240/41.35,103 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Horan; John M.
Attorney, Agent or Firm: Berlow; Cynthia
Parent Case Text
This is a division of application Ser. No. 342,816 filed Mar. 19,
1973.
Claims
I claim:
1. An ultraviolet radiation lamp reflector assembly for at least
two ultraviolet radiation lamps, said assembly comprising:
a unitary, unbroken, sheet-like, reflector insert support; said
support having one surface that is defined in the form of two
neighboringly positioned, concavely shaped cylinder segments; each
said support cylinder segment being open and oriented so as to face
generally toward a common focus; said support cylinder segments
having different respective generally parallel axes;
each said support cylinder segment having outer side edges
extending along its said cylinder segments; along said outer side
edges of each said support cylinder segment are defined respective
facing support channels for supporting respective reflective
inserts one said insert for each said support cylinder segment;
a respective reflector insert inserted in each said support
cylinder segment; each said insert being shaped in the form of and
to fit into its said support cylinder segment; each said insert
being thin in its thickness dimension; each said insert having side
edges emplaced in and supported by the respective said support
channels of that said support cylinder segment; each said insert
has an exterior side that is shaped to conform to and that seats
against the interior of the respective said support cylinder
segment; each said insert having an interior side that is shaped as
a concave cylindrical segment and that extends around said axis of
the respective said support cylinder segment; each said insert
being comprised of ultraviolet light reflective material;
cooling means extending across the entire said support, thereby to
cool said support;
a respective ultraviolet radiation lamp for each said insert and
being positioned within the arc defined by the said support
cylinder segment; each said lamp being elongated and being oriented
parallel to said axis of the respective said support cylinder
segment and extending along the length thereof; each said lamp
being positioned to enable it to emit radiation toward its
respective said reflective insert and to cause the reflected
radiation to be reflected back generally toward the common focus of
said support cylinder segments.
2. The radiation lamp reflector assembly of claim 1, wherein said
cylindrical segments of said support have open opposite ends;
additional reflector elements being positioned at said cylinder
segment open ends to define closed ends for said cylinder segments
to reduce escape of stray radiation past said cylinder segment
ends.
Description
BACKGROUND OF THE INVENTION
This invention relates to apparatus for curing solvent free
materials in general and more particularly relates to means used
with printing apparatus for curing solvent-free inks. It is an
improvement over the apparatus disclosed in applications U.S. Pat.
No. 3,745,307, issued July 10, 1973 to Sandford C. Peek, et al.,
entitled "Apparatus for Curing Solvent-Free Printing Material," and
assigned to the assignee hereof; and Ser. No. 140,760, filed May 6,
1971, by Robert W. Bassemir, et al. entitled "Reflector and Cooling
Means Therefor," and assigned to the assignee hereof.
Solvent-free inks and other solvent-free coatings are finding
increased utilization in industry, particularly because use of such
material minimizes air pollution resulting from the curing of
solvent bearing inks and coatings.
High speed curing of solvent-free material is accomplished with
high-power ultra-violet radiation which is directed at the solvent
free material immediately after its application. In accordance with
the above noted patent applications, a printing apparatus is
provided, wherein ultra-violet radiation for curing the
solvent-free material is produced by a plurality of parallel,
spaced apart, elongated, radiation emitting tubes or lamps that
extend transversely to the direction of movement of the printed
material. Associated with each lamp is an elliptical reflector for
concentrating the radiation in a narrow band impinging upon the
printed material as the latter leaves the printing station of the
apparatus. The reflectors are cooled by air circulating primarily
at the rear of the reflectors, since excessive cooling on the lamp
side of a reflector might cause the lamp to cool excessively and
extinguish.
The opened sides of the elliptical reflectors are closed by end
reflectors which prevent endspill of lamp radiation and also shield
the lamp sockets from excessive heating. The free edges of the
reflector and of the end reflectors define the extent to which
radiation from each lamp spreads.
Shutter means, having reflective properties, are operable between a
closed position which blocks the outlets from the reflectors and
prevents radiation from impinging upon the printed material without
extinguishing the lamp, and an open position which opens the
outlets from the reflectors and permits radiation to impinge upon
the material.
Since the refiring time for the lamps in question is usually in the
neighborhood of 10 to 12 minutes, in order to prevent excessive
heating of the reflectors and the shutters when the shutters are
closed, the lamps are operated at reduced or standby power with
firing maintained. In these applications, air circulation keeps the
reflectors cool.
The constructions of the above noted patent application are
specifically directed to the curing of a single surface of the web
carrying the material to be cured. In addition, if the web carrying
the material is narrower than the spread of radiation from each
lamp, the radiation beyond the edge of the web undesirably impinges
upon and heats the housing holding the apparatus or other portions
of the apparatus.
SUMMARY OF THE INVENTION
In accordance with the invention, at least one lamp, and often a
plurality of lamps and the reflector associated with each lamp are
arrayed along the feed path of the web, so that solvent-free,
curable material on the web can be cured. Each lamp has a shutter.
When the shutters are closed, each shutter is in front of its
respective lamp and the open side of its respective reflector. The
shutters prevent impingement of radiation upon the web. When the
shutters open, each unblocks its respective lamp and reflector by
moving sideways and along the web feed path, thereby permitting
radiation to impinge upon the web.
In one embodiment of the invention, the lamps and their shutters
are arrayed above a single side of the web, and radiation impinges
only upon one surface of the web. Some radiation from the lamps and
reflectors does not impinge upon the web, for example, if the web
is narrower than the spread of illumination from the lamps. Arrayed
on the opposite side of the web and in the path of the expected
full extent of the spread of the illumination from the lamps and
reflectors is positioned a radiation absorbent plate, which absorbs
this radiation that has passed the web to prevent it from radiating
into the interior of the housing of the unit and damaging any of
its contents.
In accordance with another embodiment of the invention lamps and
their associated reflectors are arrayed along opposite sides of the
web so that solvent-free, curable material on both surfaces of the
web can be simultaneously cured. Preferably, the lamps and
associated reflectors alternate along opposite sides of the web.
When the shutters in this embodiment open, each moves to a position
directly opposite the lamp and the opening in a reflector on the
other side of the web. Some radiation from the latter lamp and
reflector does not impinge upon the web, for example, if the web is
narrower than the spread of illumination from that lamp. This
radiation impinges upon the open shutter now located opposite that
lamp and reflector on the other side of the web. In the preferred
arrangement, the shutters shift sideways, such that when a shutter
opens, it shifts sideways opposite the neighboring lamp.
In this arrangement, the shutters are preferably radiation
absorbent, especially the surfaces thereof which receive radiation
that has passed the web. In this manner, there is no stray
radiation to undesirably impinge upon or heat the apparatus or its
housing.
All of the lamps and reflectors on each side of the web are carried
in a respective common housing. The housing blocks stray radiation
and prevents direct viewing of the ultraviolet lamps, which would
cause obvious damage. It is desirable to gain access into the
housings to repair, adjust and clean the lamps, the reflectors and
the interiors of the housings. Therefore, an appropriate housing
separating means, e.g. an air operated piston and cylinder
arrangement, with the piston being connected with one of the
housings and the cylinder being connected with the other, is
selectively operated to move the housings apart to permit access
into each housing, and to move the housings together, to move the
housings and the lamps and reflectors into their operative
positions.
The curing apparatus in accordance with the invention provides
different degrees of curing depending upon the number of lamps and
reflectors past which the web moves. In certain applications, it is
desirable to partially cure the solvent-free curable material after
the performance of certain steps and to then completely cure this
material after completion of all of the steps. For example, in a
multi-color inking operation, radiation only partially cures the
ink for each color after that ink has been applied. Thereafter,
considerably more radiation is used to cure the entire web after
all of the colors have been applied.
For complete curing, an array of a larger number of lamps is
necessary. For partial curing, fewer lamps are needed. Certain
embodiments in accordance with the invention may employ only one
lamp and associated reflector above the respective surface of the
web to be cured.
In certain embodiments, particularly those using a small number of
lamps and reflectors, where the lamps and reflectors are carried in
a respective housing, the respective housing can be opened for the
purposes noted above by providing a hinge at one side and an
appropriate opening means, e.g. the air operated cylinder piston
combination described above, for pivoting the housings apart at
their hinge.
In yet another variation of the present invention, under a single
reflector means is positioned a cluster of a plurality, e.g. two,
lamps. The reflector means directs radiation from both of the lamps
toward the web, thereby causing the radiation from both lamps to
function as a single source of radiation. This increases the extent
of the radiation applied to a particular area of the web.
Ultraviolet radiation curing lamps generate considerable heat and
may have an operating temperature as high as 1,400.degree.F. Hot
gas and ozone develop in the vicinity of the lamps. In addition,
the lamps are supported by and are electrically connected to
terminal sockets which must be shielded from the intense heat and
radiation because the sockets would deteriorate at temperatures
greater than 600.degree.F. Protective reflectors separate the lamps
from their terminals. In addition, the terminal sockets are in an
air cooling system, which exhausts heated air and ozone from the
terminal housings. The air cooling system also exhausts heated gas
and ozone from the vicinity of the lamps. However, as noted above,
the exhaust system is not of a type which significantly cools the
lamps, since this would hinder their proper operation.
A cooling system other than blowing air is helpful to cool the
reflectors, the shutters and any plates upon which the radiation
directly impinges. Use of piped liquid coolant is preferred.
Especially with absorptive shutters and plates, such cooling is
essential.
Accordingly, it is the primary object of the present invention to
provide improved photopolymerization means to cure solvent-free
coatings.
It is another object of the invention to apply radiation to cure
solvent free materials on opposite surfaces of a web.
It is a further object of the invention to minimize the effect of
radiation which passes the web carrying the material being cured in
a photopolymerization means.
It is a further object of the invention to cool the apparatus which
is heated by radiation.
These and other objects of the present invention will become
readily apparent after reading the following description of the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic illustration of a portion of an apparatus
constructed in accordance with one embodiment of the invention,
wherein the lamp shutters are closed;
FIG. 2 is a view of the apparatus of FIG. 1, wherein the lamp
shutters are open;
FIG. 3 is a partial, cross-sectional view of the apparatus of FIG.
2 along the line and in the direction of arrows 3 in FIG. 2;
FIG. 4 is a top plan view of a single assembly of a lamp, its
reflector, and its shutter, in the open position schematically
illustrated in FIG. 2;
FIG. 5 is a side elevation view of the assembly of FIG. 4 viewed in
the direction of arrows 5 in FIG. 4;
FIG. 6 is a cross-sectional view in elevation along the line and in
the direction of arrows 6 in FIG. 5;
FIG. 7 is a schematic view of a variant of the apparatus of FIG.
2;
FIG. 8 is a schematic illustration of one alternate embodiment of
apparatus in accordance with the present invention in the condition
illustrated in FIG. 2 for the first embodiment;
FIG. 9 is a schematic view of another embodiment of apparatus in
accordance with the invention;
FIG. 10 is a top plan view of a single assembly of lamp means, its
reflector assembly, its shutter and its apparatus protecting
absorbent plate as may be used in the embodiment of FIG. 9;
FIG. 11 is a side elevation view in cross section of the assembly
of FIG. 10, viewed along the lines defined by and in the direction
indicated by arrows 11 in FIG. 10;
FIG. 12 is an end elevation view, partially in cross section, of
the assembly of FIG. 10, viewed along the lines defined by and in
the direction indicated by arrows 12 in FIG. 10;
FIG. 13 is a perspective view of a duct system used in cooling the
assembly of FIGS. 10-12; and
FIG. 14 is a schematic view of a variant of the embodiment of FIG.
7.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to FIG. 1, curing apparatus 10 operates upon a
conventional web which may be a continuous sheet on which ink is
applied or it may be by separate sheets held on a feed chain, if a
particular application requires this. The web has two significant
characteristics. First, it can receive a radiation curable ink or
the like coating on one or perhaps both sides. Second, as shown in
FIG. 3 and as described below, the web has a width between its side
edges 19 and 20, which width may be less than the width of the
spread of radiation produced by a below described lamp and
reflector assembly.
The ink or coating used on web 15 is a conventional solvent-free
radiation curable ink or material which is cured by radiation
energy through photopolymerization.
Web 15 is driven in the direction of arrow A by feed sprocket 12
and is guided by idler 13 and additional idlers (not shown). Web 15
moves along a feed path that extends between and against lower
print cylinder 17 and upper print cylinder 18.
After the curable material or ink is applied to web 15 by roller
17, 18, the web enters curing apparatus housing 22 through inlet
opening 24. After curing the web exits through outlet 26.
Within housing 22 are a plurality of radiant energy emitting
assemblies 28, 30, 32, et al. These assemblies are arrayed in an
alternating manner along opposite sides of web 15. As will be
described further below, each assembly cooperates with a
neighboring alternating assembly on the opposite side of the web.
Assembly 30 will be described, it being understood that the other
assemblies share the same characteristics, except as noted.
Assembly 30 includes elongated, tubular, ultraviolet light
producing lamp 34 and stationary, hood-like, generally elliptical,
sheet like reflector 36 positioned to the rear of lamp 34 to focus
energy near peak intensity from lamp 34, so that radiant energy is
concentrated over a short distance along the feed path for web 15.
Radiation absorbing shutter 40 has a first position at which it is
interposed between lamp 34 and reflector 36, on the one hand, and
the web 15, on the other hand, to prevent radiant energy emitted by
lamp 34 from impinging upon the web when the web is stationary or
it does not require curing and when there is no web. Further
details as to the manner of supporting and mounting the various
elements of assembly 30 with respect to each other are described
below in connection with FIGS. 4-6.
Comparing FIGS. 1 and 2, when lamp 34 is energized and it is
desired to impinge radiation upon web 15, all of the shutters 29,
31 in the top run of shutters are moved from their position in FIG.
1 to the right, in the direction of arrow B in FIG. 1, to their
second positions of FIG. 2; and all of the shutters 40, 42 in the
lower run of shutters are moved from their position in FIG. 1 to
the left, in the direction of arrow C in FIG. 1, to their second
positions of FIG. 2. Considering shutter 40 as representative, it
moves to the position opposite the position of the lamp and
reflector of assembly 28. Any radiation from assembly 28 that
passes web 15 impinges upon and is absorbed by shutter 40, thereby
preventing that radiation from heating housing 22. Similarly,
representative upper shutter 29 moves opposite assembly 30.
Referring to FIG. 3, which illustrates assembly 30 in its condition
of FIG. 2, the width of web 15 between its ends 19 and 20 is less
than the length of lamp 34 and reflector 36, whereby radiation
passes the edges 19, 20 and would impinge upon the interior of
housing 22 and undesirably heat up any apparatus therein, were it
not absorbed by the greater width of shutter 29 which has moved
opposite the open end of reflector 36 to intercept the radiation
therefrom. Shutter 29 is at least as wide as, if not wider than,
the spread of radiation from lamp 34 and reflector 36 to absorb
that radiation.
Therefore, assembly 30 relies upon two shutters in its two modes of
operation. Shutter 40 prevents any radiation from impinging upon
web 15 and shutter 29 prevents the radiation from lamp 34 from
undesirably radiating into the interior of housing 22.
When it is desired to again halt impingement of radiation upon web
15, the upper run 29, 29A of shutters are moved to the left in the
direction of arrow C in FIG. 2 and the lower run 40, 42 of shutters
are moved to the right in the direction of arrow B in FIG. 2, to
return all the shutters to their first FIG. 1 positions. This again
closes off the open end of reflector 36 and shutter 40 absorbs all
of the radiation from lamp 34.
The individual shutters may be separately shiftable. However, in
the preferred arrangement, all shutters of all assemblies move
simultaneously together. Otherwise the protection which a shutter
provides in its second position against radiation impinging into
the interior of the housing once the radiation has passed the web
will be terminated when the reflector returns to its first position
to block the radiation from its own lamp and reflector.
FIGS. 4-6 detail typical assembly 30. The various components of
assembly 30 are supported by assembly housing 46.
Elliptical reflector 36 terminates at end edges 48, 49 which extend
relatively near to shutter 40. The side ends of reflector 36 are
opened. They are closed off by end reflectors 50, 52, which are
supported on housing 46 and which include their own respective free
edges 54, 56 near shutter 40.
Lamp 34, within the confines of a reflector housing defined by
reflectors 36, 50, 52, passes through openings 55, 57 in respective
end reflectors 50, 52 to its sockets 58, 59, which are protected
against radiation from lamp 34 by the end reflectors. Openings 55,
57 are small to minimize the radiation escaping toward terminal
sockets 58, 59, but are sufficiently large to permit exhausting, by
the exhaust means described below, of heated gas and ozone
developed in the vicinity of lamp 34.
Sockets 58, 59 are carried on their own platforms 60 attached to
housing 46. Sockets 58, 59 are connected through leads 61 to a
conventional electric power source (not shown).
Shutter 40 is comprised of a flat, opaque, radiation absorbent
plate. As can be seen in FIG. 4, the dimensions of shutter 40,
particularly its width between its edges 62, 64, are greater than
the spread of illumination from lamp 34 and reflector 36, the
extent of which spread is determined by reflector 36 and end
reflectors 50, 52. Since all assemblies 28, 30, 32 et al., are
substantially the same, the width of shutter 40 is sufficient to
prevent the radiation from assembly 32 from passing shutter 40 and
radiating into housing 22 when shutter 40 is opposite assembly
32.
Housing 46 carries a pair of parallel shutter guide rails 66, 68.
At end 70 of shutter 40 are connected the rollers 72, 74 which ride
in tracks 66, 68, respectively, and determine the path of shutter
40.
Shutter drive posts 77, 78 are attached at the other edge 76 of
shutter 40 and they move the shutter between its positions.
Posts 77, 78 are connected to and driven by drive assembly 80.
There may be a separate simultaneously or correspondingly operated
drive assembly 82 on the other side of shutter 40. Assembly 80
includes pivot connection 84, which surrounds and is pivotable
about post 77. Rigidly secured to pivot connection 84 is triangular
link 86. Link 86 is also rigidly connected to pivot connection 88
that surrounds and is pivotable about pivot guide bar 90, which is
fixed in position in housing 46. An arcuate slot 92 in housing 46
guides the movement of post 77 and of pivot mount 84 from the solid
line position at the left of slot 96 in FIG. 5, at which shutter 40
is open, to the dashed phantom line position at the right of slot
96 at which the shutter 40 has moved closed across reflector
36.
Drive unit 100 comprising air cylinder 102 and postion 104 is
pivotally connected by pivot mount 106 of piston 104 to mounting
post 108 projecting from link 86. Conventional control means 110
communicates with air cylinder 102 for increasing and decreasing
the pressure therein, thereby to reciprocate piston 104 into and
out of cylinder 102, which respectively shifts shutter 40 to the
left and right in FIG. 5.
Assembly 82 would be structurally identical to assembly 80 and it
is therefore not described further.
While an individual drive unit 100 is illustrated for shutter 40
and, by implication, is proposed for each shutter of each radiation
assembly 28, 30, 32, et al., it is apparent that all of the
shutters may be conventionally mechanically interconnected, whereby
a single operating apparatus will simultaneously operate all of the
shutters connected with it.
Referring to FIGS. 1 and 4, shutter 40, which is heated by the
radiation from lamp 34 and from the lamp of assembly 32, is cooled
by cooling coil 116, which is attached in intimate contact with the
shutter. Coil 116 extends from its inlet 118, which passes through
shutter drive post 77 to its outlet 120 which passes through
shutter drive post 78. A conventional source 124 of water,
refrigerant, or the like is connected with inlet 118 to coil 116,
and the output from the outlet 120 is exhausted to waste or
recycled in a conventional manner.
Referring to FIGS. 1 and 5, reflector 36 is provided with a similar
cooling coil arrangement, comprising a coil of water or other
coolant carrying conduit 126 affixed in intimate contact with the
reflector and cooling it in the same manner as shutter 40 is
cooled. Coil 126 is charged through inlet conduit 128 which also
communicates with coolant source 124.
Referring to FIGS. 4 and 6, terminal socket 58 is supported by
platform 60 on support 46 and is within a protective housing
defined by walls 130. Through one wall 130 passes the opening 55
for reasons to be described. Similarly, terminal socket 59 is
supported within a corresponding housing defined by walls 132. An
opening 57 passes through wall 132 for reasons described below. The
housing for socket 58 communicates with an air duct 134 and the
housing for socket 59 communicates with an air duct 136. Ducts 134,
136 are in turn joined to common duct 138 which leads to exhaust
outlet 140. Exhaust outlet 140 communicates with conventional
exhaust means 142, which may be an exhaust fan, or the like.
When exhaust means 142 operates, it draws heated air and ozone from
the vicinity of lamp 34 through openings 55, 57 and through the
housings for sockets 58, 59, thereby assisting in keeping lamp 34
at the proper temperature and removing possibly dangerous and
overheated gaseous impurities. Also, air is moved past and thereby
cools sockets 58, 59. The air moving past the sockets and the gas
from the vicinity of lamp 34 is all exhausted through ducts 134,
136, duct 138 and common outlet 140 and is then released into the
atmosphere. Exhaust means 142 must exert sufficient force to draw
the air and gas out of the unit, without generating a cooling air
flow that would undesirably affect the web or undesirably cool the
lamp and make its operation ineffective. Hence, the air flow would
be quite slow. The apparatus is not tightly sealed, whereby there
is continuous air circulation in the vicinity of lamp 34 and
terminal sockets 58, 59. The exhaust means only draws out some of
the circulating air.
Turning to FIG. 1, radiation from the ultraviolet radiation lamps
can be quite dangerous if it impinges upon a person's eye. To
preclude persons from accidentally looking into apparatus 10 or
from having stray radiation impinge upon their eyes, web inlet 24
and outlet 26 are both provided with light baffles 144. Any stray
radiation which passes through inlet 24 and outlet 26 is entrapped
in the baffles.
FIG. 7 illustrates a modified arrangement of the embodiment of
FIGS. 1 and 2. All of the upper array of lamps 28, 32 are carried
in a respective support housing like support 46 illustrated in
FIGS. 4-6. The lamps and their supports are in turn supported in a
common upper support housing 145. All of the lower array of lamps,
like lamp 30, are similarly supported in a lower common support
housing 146. When a web is traveling along its feed path and the
solvent-free curable material thereon is to be cured, as shown in
FIG. 2, the lamps and their associated reflectors must be near to
the web. However, because the lamps and reflectors are enclosed
within housings which prevent radiation from escaping, access to
the lamps and reflectors for cleaning, servicing and the like is
precluded.
To permit the lamps and reflectors to be in the position of FIG. 2
when the lamps are radiating upon the web, and to also permit
separating of the lamp housings 145, 146 to enable servicing,
cleaning or the like, a lamp housing separating apparatus is
provided. In FIG. 7, this apparatus comprises a plurality of air
cylinders 147 attached to upper housing 145 and a respective piston
148 for each cylinder 147, which pistons are attached to lower
housing 146. Upon operation of air cylinder-piston arrangement 147,
148, housings 145, 146 selectively separate or move together. The
conventional means (not shown) for operating air cylinders 147
coordinate their operation so that housings 145, 146 retain
substantially the same relative orientation as they move apart and
together.
Especially in an embodiment like that in FIG. 7 where housings
separate, there will be an open seam or space between housings like
145, 146 through which radiation might leak and an operator may
inadvertently look through the openings or seams and have the
radiation impinge upon his eyes with obvious damage. Especially in
an embodiment where housings separate, but in any other
embodiments, as well, at least one of the housings is provided with
a peripheral skirt 149 which hangs down below the seam between the
housings and blocks the seam thereby to prevent any damage from
radiation within housings 145, 146.
There has just been described a first embodiment of apparatus for
curing solvent free ink or other coating material by ultraviolet or
the like radiation, using a shutter shiftable from a first
position, where it blocks radiation from one lamp, to a second
position where it absorbs radiation from another lamp, which latter
radiation impinges upon and then passes the web. In this
embodiment, the shifting of the shutters is accomplished through an
air cylinder operating upon an appropriate linkage.
FIG. 8 shows a second embodiment of curing apparatus 150, which
relies upon the same operative concept, but differs from the first
embodiment in the manner in which the movement of the shutters is
controlled. The elements in FIG. 8 which are identical to those
shown in FIGS. 1-6 are correspondingly numbered with the suffix A.
The description below will apply to the special features of the
apparatus of FIG. 8.
The interior walls of housing 22A carry upper shutter guide track
152 and lower shutter guide track 154, which respectively define
the paths of guide rollers 156, 158. Upper rollers 156 carry upper
shutter guide 160 and lower rollers 158 carry lower shutter guide
162. The positions of all the rollers with respect to their
respective shutter guides remain fixed, although the rollers do
rotate about their own axes and therefore rotate with respect to
the shutter guides. The peripheries of the rollers are in
engagement with their respective tracks. Movement of shutter guides
160, 162 rotates respective rollers 156, 158 along their tracks
152, 154 and thereby keeps the shutter guides at a constant
orientation with respect to the web and the lamp assemblies, except
that the shutter guides have shifted sideways with respect thereto.
All of the shutters on the upper run of shutters, including shutter
29A, are supported by and are located in their position by and move
together under the influence of shutter guide 160. Similarly, all
shutters on the lower run of shutters, including shutter 40A, are
supported and moved by lower shutter guide 162.
Along one side of both of guides 160 and 162 is a respective upper
toothed rack 166 and lower toothed rack 168. Both racks are in
permanent engagement with cooperatingly toothed pinion 170, which
is supported in position to be in contact with and is of a size to
be in contact with the racks. The conventional supporting means
(not shown) for pinion 170 maintain a stationary position for the
pinion with respect to housing 22A. Rotation of pinion 170 by
conventional crank means (not shown) or the like, in a clockwise
direction as viewed in FIG. 8, shifts shutter guide 160 and the
upper run of shutters to the right in the direction of arrow B and
correspondingly shifts shutter guide 162 and the lower run of
shutters to the left in the direction of arrow C, thereby moving
the shutters to one of their positions. Correspondingly, rotation
of pinion 170 counterclockwise returns the shutter guides and the
shutters to their start positions.
In all other respects besides the manner of shifting the shutters
and the manner in which the shutters are connected, the second
embodiment of FIG. 8 may be identical to the first embodiment.
The next embodiment 180 of the invention shown in FIG. 9 has
certain characteristics in common with the apparatus disclosed in
aforesaid applications Ser. No. 140,752 and 140,760. The apparatus
180 includes at least one or, as illustrate a plurality of lamp
assemblies 182, 184, with typical assembly 182 comprising lamp 186,
reflector 188 and shutter 190. The assemblies 182, 184 may be of
the type shown in FIGS. 4-6. Apparatus 180 is, in effect, one side
of apparatus 10 in FIG. 1 and is adapted to cure the solvent-free
material on only one surface of web 15.
In apparatus 180, shutters 190 shift sideways along the feed path
of web 15 from the position blocking reflectors 188 to the position
unblocking the reflectors. In this embodiment, the shutters do not
perform any function in connection with absorbing radiation which
passes beyond web 15.
To absorb radiation which passes beyond web 15 and to provide some
degree of cooling to the web as it passes beneath lamp assemblies
182, 184, panel 192 is supported in a position such that the web
will pass over panel 192 and be spaced thereabove about 1 inch. The
length of panel 192 is such that it will be under the radiation
emanating from each of the lamps and the width of the panel is such
that the spread of radiation from each of the lamps is less than
the width of panel 192, whereby regardless of size of the web,
radiation will not impinge upon the interior of the apparatus
housing.
Panel 192 is radiation absorbent and will become heated due to the
radiation impinging upon it. To keep the panel at a desired cooler
temperature, a network of coolant conduits 194 passes through the
body of panel 192. Coolant, e.g. liquid coolant, is conventionally
pumped through conduits 194.
FIGS. 10-12 illustrate yet another embodiment 200, which is a
modification of the embodiment shown schematically in FIG. 9. Web
15 moves through curing apparatus 200 in the direction of arrow A
from inlet 202 to outlet 204. Apparatus 200 includes a support
housing 206 on which the below described elements are
supported.
Within housing 200 there is only a single lamp assembly 210, which
includes the two closely spaced parallel oriented ultra-violet
radiation emitting lamps 212, 214. Lamps 212, 214 form a lamp
cluster and while two lamps are illustrated in this cluster, the
cluster may include even more lamps. Each of lamps 212, 214 are of
the same type as above described lamp 34. Each of lamps 212, 214 is
both supported in position by and electrically connected in the
manner described above for lamp 34 by means of terminal sockets
216, 218 for lamp 212 and terminal sockets 220, 222 for lamp
214.
Sockets 216, 220 are within a housing defined by housing walls 224,
226, 227. Wall 226 has openings 228, 230 therethrough respectively
for lamps 212, 214. The openings are each of a size corresponding
to and have the same purpose as above described opening 55. Sockets
218, 222 are in a corresponding housing defined by walls 232, 234,
235. Wall 234 has corresponding openings 236, 238 therethrough for
respective lamps 212, 214. Walls 227, 235 have openings
therethrough which serves as air inlets into the respective socket
housings for the below described exhaustion of air through these
housings.
Assembly 210 includes elongated, stationary, sheet like reflector
assembly 240. Reflector assembly 240 is comprised of the dual,
cylinder segment, curvature sections 242, 244 having snap in or
endwise slide in channels 246 for receiving reflector inserts 248,
250. The sections 242, 244 and their inserts 248, 250 are so shaped
and positioned with respect to lamps 212, 214 as to cause the
radiation to have a common focus upon web 15. Reflector assembly
240 is held in position on support 206 by shelves 254, which are
carried on support 206, and by position fixing screws 256 which are
joined by plates 258 to a respective wall 224, 232 of the terminal
socket housings.
In a single lamp assembly as shown in FIGS. 4-6, about 80% of the
radiant energy of lamp 34 is focused over a 2 inch length band on
web 15 in the direction of its feed path. With lamp assembly 210
and reflector assembly 240, 80% of the energy of lamps 212, 214 is
focused over a 4 inch length band on web 15. Lamp cluster assembly
210, therefore, provides intense radiation to a greater length
section of the web.
Corresponding to end reflectors 50, 52 which cooperate with main
reflector 36 to partially enclose lamp 34 within a housing in FIGS.
4-6, there are also end reflectors 262, 264 which protect terminal
sockets 216-222 from the effects of direct radiation and cooperate
with reflector assembly 240 to determine the maximum width and
length spread of the radiation.
A shutter means 270 is provided for being moved from a position,
suggested in phantom line in FIG. 11, at which it blocks radiation
from lamps 212, 214 and reflector assembly sections 242, 244 from
impinging upon web 15, to the open unblocked position illustrated
in solid line form in FIGS. 10 and 11. Shutter means 270 includes
shutter 272 which is radiation absorbent. As shown in FIGS. 10 and
11, shutter guide pin supports 274 are fixedly carried upon
apparatus support 206. Projecting outwardly from each guide pin
support 274 is a guide pin 276, which remains at the position shown
in the drawings during movement of shutter 272. Shutter 272 is
fixedly attached to and supported on support brackets 278, which
brackets each bend at 280 to join with guide pin receiving portion
282 of bracket 278. A closely fitted clearance opening 284 is
provided in each bracket portion 282, whereby the bracket portion
282 and, therefore, shutter 272 can move between its positions
illustrated in FIG. 11 along guide pin 276, which guides the
movement of shutter 272.
For moving shutter 272 between its positions illustrated in FIG.
11, a shutter moving means 290, which functions substantial in the
same manner as apparatus 102 of FIG. 4, is provided. Apparatus 290
in FIGS. 10 and 11 includes dual air cylinders 292 each operated by
conventional means (not shown), pistons 294 which are operated by
cylinders 292 and links 296, which are also secured to shutter 272,
thereby causing the movement of pistons 294 to move shutter 272 in
the desired manner.
In the embodiment of FIG. 9, when the spread of radiation is of
greater width than the width of web 15, absorbent plate 192
intercepts the radiation and prevents it from heating the interior
of the apparatus housing. In apparatus 200, radiation absorbent
means 300 is provided for this purpose. Means 300 includes
radiation absorbent plate 302, which is supported on support 206 by
brackets 303. The position of plate 302 is selected so that it will
be beneath the focused radiation of lamps 212, 214 and reflectors
242, 244, whereby plate 302 need not have great length in the
direction of the feed path of web 15. As shown in FIG. 12, the side
edges 304 of plate 302 are spaced apart to provide that plate with
a width greater than the width of the spread of illumination as
defined by end reflectors 262, 264, thereby to enable plate 302 to
intercept all of the radiation which does not impinge upon web
15.
At both inlet 202 and outlet 204 there is a respective radiation
baffle assembly 305, 306. The baffle assemblies are substantially
identical and the illustrated elements thereof are correspondingly
numbered. The baffle assemblies 305, 306 preclude radiation from
within apparatus 200 from exiting, thereby to perhaps damagingly
impinge upon the eyes of an observer. The baffle assemblies also
prevent an operator or observer from looking inside unit 200 and
thereby damaging his eyes. Baffle assembly 305 includes the
enclosing housing elements 307, 308 and internal U-shaped baffle
plates 309, 310. The internal shelves 311, 312 and the obliquely
bent shelf 313 all cooperate to reduce the exit of radiation from
within apparatus 200.
For various reasons, e.g. gaining access into apparatus 200, for
gaining access to the web, or for making an authorized, properly
safeguarded observation into the interior of apparatus 200, baffle
housing sections 307, 308 and their attached respective baffle
plates 309, 310 are hingedly connected by hinges 314 to the
exterior of support housing 206, thereby permitting baffle
assemblies 305, 306 to be pivoted out of the way.
Reflector assembly 240, shutter assembly 270 and radiation
absorbent plate assembly 300 all need to be cooled, since they are
continuously subjected to the intense radiation from lamps 212,
214. For reflector assembly 240, there is provided a liquid coolant
cooling arrangement, including the liquid carrying conduit 315,
having an inlet 316 and an outlet (not shown) and which is arranged
in a continuous circuit (not shown) of the type disclosed in FIGS.
4-6 for reflector 36.
Shutter assembly 270 is provided with a similar coolant system
having an inlet 317 communicating with a conventional source of
liquid coolant, an outlet 318 and sinusoidal coils 319 of the type
shown in FIG. 4 for shutter 40.
Similarly, absorbent plate assembly 300 has liquid coolant inlet
322, coolant outlet 324 and a sinusoidally curved conduit 326
completing the circuit for the coolant.
The source, pumping means and system which gathers the exhausted
liquid coolant for each of the three liquid coolant arrangements
just discussed, are not shown, it being understood that they are
conventional in the art.
In addition to the systems which cool those elements that are
directly impinged upon by the radiation, there is an exhaust system
for drawing ozone and heated gas away from the vicinity of lamps
212, 214 and for cooling the lamp terminal sockets.
Refer to FIGS. 10-12 which show the exhaust duct system in position
and to FIG. 13 which shows the duct system separate from the entire
system so that its elements can be observed. The socket housing
which includes walls 224, 226 communicates into closed duct 342.
Similarly, the socket housing which includes walls 232, 234
communicates into closed duct 344. Ducts 342, 344 are joined
together by joining duct 346. Duct 346 includes openings 347 which
face toward lamps 212, 214 and the suction through duct 346 tends
to cooperate in drawing heated gas and ozone from the vicinity of
lamps 212, 214. This drawings of heated gas and ozone from the
vicinity of the lamps is in addition to the drawing of the gas and
ozone through above described openings 228, 230, 236, 238.
Intermediate its length, duct 346 joins at junction conduit 348
with exhaust duct 349, which duct is attached by means (not shown)
to an appropriate conventional exhaust means (not shown). When this
exhaust means operates, it exhausts gas and ozone from the vicinity
of lamps 212, 214 through openings 348 and through aforesaid
openings 228, 230, 236, 238, and thereby causes cooling gas to move
across terminal sockets 216, 220, 218, 222 and cools them.
Additional air to cool the terminal sockets enters through the
inlets in walls 227, 235. As apparatus 200 is not sealed, the air
to be exhausted is obtained through leakage of air into the
housing.
A further variation of the apparatus shown in FIGS. 10-12 is
schematically illustrated in FIG. 14. Apparatus 350 has a single
lamp and shutter assembly 351 in the upper shell housing 352 and a
single lamp and reflector assembly 353 in the lower housing 354.
This particular embodiment could also be used in an arrangement
with two lamps in each housing, including additional lamp assembly
355 shown in phantom in the phantomed enlargement of housing 352
and additional lamp assembly 356 shown in phantom in the phantomed
enlargement of housing 354. This embodiment would be unduly
cumbersome with any larger number of lamps.
Housings 352, 354 are hinged at 358 along one of their respective
edges. At least one air cylinder-piston combination 360 is provided
for hingedly pivoting housings 352, 354 apart and together.
Cylinder 362 is attached to housing 354. Piston 364, articulated to
pivot at 365, is attached to the other housing 352. Operation of
cylinder 362 by conventional mean (not shown) selectively separates
and closes housings 352, 354.
Although the present invention has been described in connection
with a number of embodiments, many variations and modifications
will now become apparent to those skilled in the art. It is
preferred, therefore, that the present invention be limited not by
the specific disclosure herein, but only by the appended
claims.
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