U.S. patent number 3,894,343 [Application Number 05/454,402] was granted by the patent office on 1975-07-15 for ink curing and drying apparatus.
This patent grant is currently assigned to Thermogenics of New York. Invention is credited to Ralph L. Foster, Robert W. Pray.
United States Patent |
3,894,343 |
Pray , et al. |
July 15, 1975 |
Ink curing and drying apparatus
Abstract
Curing and drying apparatus for printing inks which includes a
housing having openings for passing a printed web therethrough and
lamp assemblies each including a shell, a reflector, and an
ultraviolet light lamp or radiator for focusing radiation onto said
web. Blowers are coupled to said housing for feeding air about the
back side of said reflectors and about the sockets for the lamps to
remove excess heat and means are provided for protecting said lamps
from said cooling air to prevent lowering the temperature and
therefor the efficiency of the lamps. The lamp assemblies are
rotatable to and from an operating position and when out of the
operating position the radiation is directed into cooled radiation
absorbing chambers which permit the lamps to remain energized
without damaging the web should movement of the latter be
temporarily stopped because of the need for stopping the associated
printing press.
Inventors: |
Pray; Robert W. (East
Northport, NY), Foster; Ralph L. (Darien, CT) |
Assignee: |
Thermogenics of New York
(Byram, CT)
|
Family
ID: |
26949733 |
Appl.
No.: |
05/454,402 |
Filed: |
March 25, 1974 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
263250 |
Jun 15, 1972 |
3829982 |
|
|
|
Current U.S.
Class: |
34/278; 392/417;
219/388; 392/424 |
Current CPC
Class: |
F26B
3/28 (20130101); B41F 23/0409 (20130101); H05B
3/0066 (20130101) |
Current International
Class: |
B41F
23/00 (20060101); B41F 23/04 (20060101); F26B
3/28 (20060101); F26B 3/00 (20060101); H05B
3/00 (20060101); F26b 003/30 () |
Field of
Search: |
;34/1,4,39,41,43,44,48,49,151,152 ;219/348,354,388 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Camby; John J.
Assistant Examiner: Schwartz; Larry I.
Parent Case Text
This application is a division of Ser. No. 263,250 filed June 15,
1972, now U.S. Pat. No. 3,829,982.
Claims
What is claimed is:
1. Ink curing apparatus comprising a housing having openings for
feeding a web therethrough, an ultra-violet lamp assembly rotatably
supported within said housing and positioned transversely of said
web, said assembly including an elongated shell having an opening
extending longitudinally thereof, an elongated reflector and
ultra-violet lamp within said shell, said lamp and reflector being
positioned within said housing to direct radiation through said
opening, said lamp being of cylindrical configuration having neck
portions extending therefrom and terminals on said neck portions,
sockets carried on each end of said assembly for engaging said
terminals, transverse plates within said shell each having an
opening therein, said plates being positioned with said necks
extending through the plate openings and means carried by said
plates and sealing said plate opening about said neck portions
whereby said neck portions and sockets can be air cooled without
cooling said lamps.
Description
This invention relates to ink drying and curing apparatus for
printing presses and more specifically to a novel and improved
ultraviolet ink drying system useful among other things for offset
presses of both single color and multi-color types.
With the development of printing inks and other coatings which may
be rapidly cured and dried by relatively high intensity ultraviolet
radiation, apparatus for the production of high intensity
ultraviolet radiation has been suggested utilizing, among other
devices, high intensity mercury lamps. While mercury lamps which
utilize a high intensity arc to evaporate mercury within a sealed
envelope have been found most effective for generating ultraviolet
light, they present certain problems, particularly when used in
connection with printing presses. One of the basic difficulties is
encountered in stopping a press since the ultraviolet radiation
will immediately burn the web which is normally paper or other
similar material that is readily damaged by excessive radiation.
While the use of shutters and partitions have been suggested, they
have not been found particularly effective to prevent damage to the
printed web since the lamps must continue to be energized at least
to 50 percent of their intensity if the web is to be halted only
momentarily. This is necessary since five to ten minutes are
required to restart a lamp once the arc has been extinguished.
Furthermore, shutters and partitions will absorb substantial energy
so that the time during which the shutters would be effective
before reradiating heat of sufficient magnitude to burn the printed
web is materially limited.
This invention overcomes the difficulties heretofore encountered
and provides a novel and improved device particularly adaptable for
use in rapidly curing and drying printing inks and wherein the
printed web may be stopped for an indefinite period while the
ultraviolet lamps are energized and without adversely affecting the
lamps or web in any way.
Another object of the invention resides in the provision of novel
and improved curing and drying apparatus for continuously moving
printed and coated webs embodying means for irradiating the web and
for rapidly terminating the irradiation should the web be stopped
without deenergizing the source of radiation.
Still another object of the invention resides in the provision of
novel and improved irradiating apparatus utilizing high intensity
lamps for curing and drying printed and coated surfaces and which
includes energy absorbing chambers for receiving and dissipating
radiant energy of said lamps when it is desired to terminate
irradiation of the printed or coated surfaces without deenergizing
the lamps.
A further object of the invention resides in the provision of novel
and improved ink drying and curing apparatus embodying high
intensity ultraviolet lamps and reflectors and air cooling means
for cooling both the reflectors and the electrical connectors for
the lamps without permitting circulation of air over the lamp
envelopes.
A still further object of the invention resides in the provision of
a novel and improved ultraviolet radiator for drying and curing
printing inks and coatings.
The objects of the invention are attained by the provision of a
housing having elongated cylindrical tubes or shells rotatably
disposed therein. A longitudinal portion of each tube is open to
receive a reflector and an ultraviolet energy source and the
housing has openings to permit a web to be treated to pass
therethrough. The cylindrical tubes are rotatable from one position
to direct radiation onto the web and to another position wherein
the open portion of each tube is closed by an energy absorbing
chamber. The housing and tubes have openings for the circulation of
air through the housing, through the tubes and about the
reflectors, and about the energy absorbing chambers to cool the
housing, tubes, chambers and lamp terminals while, at the same
time, permitting the energy sources to remain at a normal operating
temperature.
The above and other objects and advantages of the invention will be
more clearly understood from the following description and
accompanying drawings forming part of this application.
In the Drawings:
FIG. 1 is a side elevational view with parts broken away of one
embodiment of drying and curing apparatus in accordance with the
invention,
FIGS. 2 and 3 are cross-sectional views of FIG. 1 taken along the
lines 2--2 and 3--3 thereof,
FIG. 4 is a view similar to FIG. 3 with the cylindrical tubes or
shells rotated away from the web being treated,
FIG. 5 is a cross-sectional view of FIG. 1 taken along the line
5--5 thereof and with parts broken away, and
FIG. 6 is a cross-sectional view of FIG. 5 taken along the line
6--6 thereof.
Referring now to the drawings, the drying apparatus is enclosed
within a housing generally denoted by the numeral 10 having a web
inlet 11 and a web outlet 12. The web is denoted by the numeral 13
and moves vertically through the housing. As will become apparent,
the housing 10 may be positioned so that the web traverses the
housing horizontally or at any angle of inclination.
In the instant embodiment of the invention, four ultraviolet lamp
assemblies generally denoted by the numerals 14, 15, 16 and 17 are
utilized for simultaneously curing ink on each side of the web
though it is evident that any desired number of lamps on one or
both sides may be employed depending on the speed of the web and
whether one or both sides are to be treated.
The lamp assemblies 14 through 17 are supported by transverse
partitions 18 and 19 disposed within the housing 10 and spaced
apart a distance slightly greater than the width of the web. The
partitions 18 and 19 each include four openings, 21 through 25 in
partition 18 and 21' through 25' in partition 19, for rotatably
supporting the lamp assemblies on each side of the web 13. More
specifically, the lamp assemblies which are generally of tubular
configuration are arranged with the assemblies 14 and 15 on the
left side of the web 13 is viewed in FIGS. 3 and 4, while the
assemblies 16 and 17 are on the right side of the web and displaced
upwardly therefrom so that radiation from two opposing lamp
assemblies is not directed simultaneously on the same portion of
the web. Inasmuch as the four lamp assemblies are identical in
structure and mounted in a similar manner, only one lamp assembly
will be described.
The lamp assembly 14 includes a tubular shell 26 which extends
through the openings 21 and 21' in the partitions 18 and 19
respectively. The shell is rotatably sealed in the openings by
light-tight rings 27 and 28 of a suitable high temperature plastic
or metal. As will be described, each lamp assembly is rotatable
through an angle of 90.degree. and, accordingly, suitable means are
provided to limit rotation as well as longitudinal displacement.
The shell 26 has a longitudinal opening 29 of substantial arcuate
width and a length slightly greater than the width of the web. A
curved reflector 30 of suitable hypobolic or other curvature is
disposed within the shell 26 and with the edges of the reflector
coincident with the edges of the longitudinal opening 29. The ends
of the reflector are closed by annular plates 31 and 32 having
openings 31' and 32' respectively communicating with the back side
of the reflector.
The ends of the shell 26 are closed by plates 33 and 34 each of
which carry electrical sockets 35 and 36 respectively for the
ultraviolet radiation lamp 37. The sockets are positioned in such a
manner that the lamp 37 will be disposed in proper relationship to
the reflector in order to focus the radiation on the web with a
beam width at the point of impingement preferably being of the
order of one quarter inch. The shell is further provided with an
elongated opening 38 and the ends of the shells which extend
through the partitions 18 and 19 are provided with openings 19 and
40. The plates 33 and 34 on the ends of the shells 26 are removably
secured in position to facilitate servicing and maintenance.
Because of the high intensity radiation emitted by the lamps 37 and
the concentration of the radiation on an exceedingly narrow strip
across the web, the web will be quickly burned should the press
speed be materially decreased or the press be stopped for any
reason whatsoever. While the lamps can be deenergized, even
momentary deenergization would require at least 5 to 10 minutes for
restarting with the result that substantial press-time would be
lost. To avoid deenergization of the lamps 37 should the press
speed be reduced, a suitable control signal is applied to the
terminal 41 which is fed to an electrically operated valve 42 and
to switching means 43. The switching means 43 is supplied via
conductors 44 with a normal operating voltage for the lamps 37 and
a low operating voltage, and the conductors 45 are connected to the
lamps 37. The actual electrical connections have been omitted in
order to avoid unnecessary complication of the drawings. When the
press speed is reduced to approximately 25 percent of its normal
speed, switching means 43 is actuated to switch the lamps 37 to the
low voltage source which functions to operate the lamps at
approximately one-half of the normal power output. Under these
conditions, since the web 13 continues to move through the dryer
10, the intensity of the radiation from the lamps 37 is
insufficient to damage the web but will effect curing of the ink on
the printed web.
If the printing press is completely stopped or its speed falls
below 25 percent of its normal speed, the control signal 41 will
operate the electrically operated valve 42 and thereby actuate a
pneumatically operated control 46 which effects rotation of the
shells 26 from the positions shown in FIG. 3 to the positions shown
in FIG. 4 so that the radiation emitted by the lamps 37 is directed
into energy absorbing chambers 47. The pneumatically operated
device 46 is carried by the partition 18 and has a shaft 48 pivoted
at 49 to a piston disposed within the cylinder 50 and the lower end
of the shaft 49 slidably engages a cooperating opening in a fixed
support 51 also carried by the partition 18. The end plates 33 of
the shells 26 each carry a stud 52 fixedly secured thereto. Each
stud 52 engages a bracket or dog 53 fixed to the shaft 48 and
having a slot 54 slidably engaging pin 52. With the piston in the
retracted position as shown in FIG. 2, the reflectors in the shells
are directed toward the web 13 as shown in FIG. 3. When air
pressure is applied to the upper conduit 55 of the pneumatic device
46 and the lower conduit 56 is vented to the air by reason of the
operation of the electrically operated valve 42, the shaft 48 will
move downwardly to rotate the shells 26 to the position shown in
FIG. 4. At the same time, the control 43 reduces the intensity of
the lamps 37 to approximately 50 percent of their normal operating
power. Immediately upon restarting the press and its attainment of
a speed in excess of 25 percent of its normal speed, the shells 26
are rotated to the position shown in FIG. 3 and normal voltage is
applied to the lamps.
The energy absorbing chambers 47 are generally identical in
structure and extend between and are supported by the partitions 18
and 19. Each chamber includes a bottom wall 57 and upwardly
extending side walls 58 and 59. The upper edges of the side walls
58 and 59 are positioned as close as possible to the associated
shell 26 so that the light and air leakage from the chambers 47
will be maintained at a minimum. To further minimize the leakage of
air from those portions of the housing 10 surrounding the lamp
assemblies 14 through 17 into the space between the lamp assemblies
and the web, each leg 59 carries an elongated strip of flexible
material 60 which rides against the outer surface of the associated
shell 26. In addition, the legs 58 of the energy absorbing chambers
47 associated with the lamp assemblies 14 and 16 each carry a
downwardly and outwardly extending bracket 61, each of which
carries a piece of flexible material 62 on the outer end thereof
which bears against the surface of the underlying lamp assemblies
15 and 17, as the case may be. The leg 58 of the energy absorbing
chamber associated with the lamp assembly 15 has a downwardly
extending wall 63 and the energy absorbing chamber 47 associated
with the lamp assembly 17 has a similar wall 64 extending
downwardly from the leg 58. The walls 63 and 64 are in closely
spaced relationship and provide just sufficient clearance for the
web 13 so that the latter will not touch the partitions 63 and 64
during normal operation of the associated press. The lower edges of
the walls 63 and 64 are coincident with an elongated opening 65 in
the bottom end of the housing 10 through which the web 13 enters
the housing.
Light and air leakage above the lamp assemblies is prevented by
walls or baffles 66, 67, 68 and 69. The baffle 66 is supported
between the partitions 18 and 19 and has a flexible strip 70
extending throughout its length and bearing against the shell 26 of
the lamp assembly 14. A wall or baffle 68 is hinged at 71 to the
upper edge of the wall 66 and is movable from an operating position
as shown in FIG. 3 to an open position as shown in FIG. 4. The open
and closed positions are controlled by a spring 72. Similarly, the
wall or baffle 67 also extends between the partitions 18 and 19 and
has a flexible member 73 bearing against the outer surface of the
shell 26 forming part of the lamp assembly 16. The wall or baffle
69 is pivoted at 74 to the upper edge of the wall 67 and is movable
from an operating position as shown in FIG. 3 to an open position
as shown in FIG. 4 under the control of a spring 75. The upper ends
of the baffles 68 and 69 are curved inwardly at 68' and 69'
respectively to form an exceedingly narrow gap through which the
web 13 may emerge from the housing 10. This procedure greatly
minimizes light leakage from the housing 10 and it is important
that such leakage be minimized because the radiation is high
tensity ultraviolet light which has serious adverse effects on the
human eye. To facilitate threading of the web through the housing
however, the baffles 68 and 69 can be moved to the open position
shown in FIG. 4.
Inasmuch as substantial heat is developed within the housing 10, a
novel and improved system is provided for both removing the heat
from the housing and for cooling the reflectors 30. The cooling
system includes a pair of centrifugal or other suitable motor
operated blowers 76 and 76'. The blowers are secured to the rear
wall 77 of the housing 10 and are coupled by conduits 78 and 79 to
openings 80 and 81 so that air from the blowers 76 and 76' is
discharged into the spaces surrounding the lamp assemblies and
bounded by the partitions 18 and 19. Exhaust conduit 82 as shown in
FIG. 1 is also secured to an aligned with a cooperating opening in
the rear wall 77 of the housing 10. The conduit 82 therefore
communicates with the space 84 between the housing end wall 77 and
the partition 18. The space 84 and the space 85 in the forward end
of the housing between the partition 19 and the housing front wall
86 are coupled by conduits 87 and 88 extending between and
supported by partitions 18 and 19.
With the foregoing arrangement, air from the blowers 76 and 76' is
fed through the conduits 78 and 79 into the spaces between the
partitions 18 and 19 and the outer sides of the lamp assemblies 14
and 15 on one side of the web 13 and the outer sides of the lamp
assemblies 16 and 17 on the other side of the web 13. In the case
of the lamp assemblies 14 and 15, the air enters the slots or
openings 38 as shown in FIG. 1 and travels in both directions over
the back sides of the reflectors 30. Part of the air passes through
the openings 31' in the plates 31 and is discharged through
openings 39 and into the chamber 84. The remainder of the air flows
through openings 32' in the plates 32 and is discharged through
openings 40 into the chamber 85. The same air flow occurs in
connection with the lamp assemblies 16 and 17. The air flowing into
chamber 85 passes through conduits 87 and 88 into chamber 84 and
all of the air in chamber 84 is exhausted through the conduit
82.
As pointed out above, it is important that the air does not contact
and cool the envelopes of the lamps 37. This is accomplished by the
structure previously described and shown in FIGS. 3 and 4. The air
is directed through the openings 31' and 32' in plates 31 and 32
for the purpose of cooling the narrow neck portions 37' of the
lamps 37 as well as the sockets 35 and 36 as may be observed more
clearly in FIG. 5. Inasmuch as electrical connectors are secured to
the neck portions 37', the openings 90 and 91 in the plates 31 and
32 must have a diameter larger than the electrical connectors which
engage the sockets 35 and 36. To prevent air from flowing about the
lamps 37, the opening 90 and 91 are closed by split rings 93 of a
high temperature insulating material held in position by suitable
brackets 94. In this way effective cooling of the lamp necks 37'
and the sockets 35 and 36 is accomplished and the cooling air
cannot flow over and about the lamps 37 which would adversely
affect the operation thereof.
The split rings 93 as well as the sealing strips 60, 62, 70 and 73
are preferably formed of a flexible high temperature material. One
such material that has been found effective for this purpose is
asbestos impregnated with a tetrafluoroethylene resin generally
known in the trade as Teflon. Other suitable materials may of
course be employed provided however that they will enable the
attainment of a good air seal.
While only one embodiment of the invention has been illustrated and
described, it is understood that alterations, modifications and
changes may be made without departing from the true scope and
spirit thereof as defined by the appended claims.
* * * * *