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Publication numberUS3914594 A
Publication typeGrant
Publication dateOct 21, 1975
Filing dateApr 24, 1974
Priority dateMar 19, 1973
Publication numberUS 3914594 A, US 3914594A, US-A-3914594, US3914594 A, US3914594A
InventorsHelding Norman A
Original AssigneeSun Chemical Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Radiation lamp reflector assembly
US 3914594 A
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.
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Description  (OCR text may contain errors)

United States Patent [191 Helding [4 1 Oct. 21, 1975 [54] RADIATION LAMP REFLECTOR ASSEMBLY [75] Inventor: Norman A. Helding, Chicago, Ill.

[73] Assignee: Sun Chemical Corporation, New

York, NY.

[22] Filed: Apr. 24, 1974 [21] Appl. No.: 463,513

Related US. Application Data [62] Division of Ser. No. 342,816, March 19, 1973.

[52] US. Cl. 240/41.35; 240/103 [51], Int. CL F21V 7/00 [58] Field of Search 240/41.35, 103

[56] References Cited UNITED STATES PATENTS 1,802,407 4/1931 Danninger et a1. 34/41 2,003,342 6/1935 Cavanaugh 240/41.35 E 2,619,583 11/1952 Baumgartner 240/103 B 2,664,282 12/1953 Mann 432/42 2,807,096 9/1957 Kullgren et al. 432/77 2,875,323 2/1959 Harling 240/103 B 3,578,965 5/1971 Tawil 240/41.35 F 3,637,983 l/l972 Nelson.... 34/49 3,642,377 2/1972 Young 355/88 3,643,342 2/1972 Tyson et al. 34/48 3,733,709 5/1973 Bassemir 34/41 Primary Examiner lohn M. Horan Attorney, Agent, or FirmCynthia Berlow [57] 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 duet 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.

2 Claims, 14 Drawing Figures Sheet 1 of 5 3,914,594

. U.S. Patent Oct. 21, 1975 US. Patent Oct.21,1975 Sheet3of5 3,914,594

US, Patent Oct. 21, 1975 Sheet40f5 3,914,594

K \V T U.S., Patent Oct.21,1975 Sheet50f5 3,914,594

RADIATION LAMP REFLECTOR ASSEMBLY This is a division of application Ser. No. 342,816 filed Mar. 19,1973.

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 US. 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 a1. 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 solventfree 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 retiring time for the lamps in question is usually in the neighborhood of 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 solventfree, 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 1,400F. 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 600F. 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 or 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; 1

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 F IG. 5;

FIG. 7- is a schematic view of a variant of the apparatus of FIG. 2; a

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 aside 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 coatingused 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 l7, 18, the web enters curing apparatus housing 22 through inlet opening 24. After curing the web exits through outlet 26.

,Within housing22 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 a 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 aredescribed 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 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 andwould 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 ofoperation. 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. I

When it is desired to again halt impingement of radiation upon web 15, the upper run 29, 29A of shutters are moved to'th'e left in the direction of arrow C in FIG. 2

and-thelowerrun40, 42 of shutters are moved to the right in'the direction of arrow B in FIG.'2, to return all 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 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 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 rigidlyconnected 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 op erating 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 persons 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 lamp30, 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 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 ofthe 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 thelike 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 l58'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 thatthe 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.

l 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 FlGS. 4-6. Apparatus 18 is, -in effect, one side of apparatus in FIG. 1 and. is adapted to cure the solvent-free material on only one surface of web 15. t

In apparatus 180, shutters 190 shift sideways along the feed path of web 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 absorbradiation which passes beyond web 15 and to provide some degree of-cooling to the web as it 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 as'sembly 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 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. 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. l0

and 1 1 includes dual air cylinders 292 each operated byconventional 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 31 l, 312 and the obliquely bent shelf 313 all cooperate to reduce the 7 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, anoutlet 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 ex- 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.

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-asa 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.

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Classifications
U.S. Classification362/218
International ClassificationF26B3/00, F26B3/28
Cooperative ClassificationF26B3/28
European ClassificationF26B3/28