KR20070022002A - Uv curing for ink jet printer - Google Patents

Abstract

Printing a product, article or other article 402 at printing station 406 and improving the application of UV light at curing station 400 to a UV photoinitiator in a UV curable ink applied to the product, article or other article at printing station A method and apparatus for printing, the method comprising: printing a UV curable ink onto an article, article or other article from a printing station to a printing head; Providing or including a set of UV-LED arrays 408 of UV-LED chips at a curing station, and causing relative movement between the set of UV-LED arrays and the printed product, article or other article, or It includes a mechanism for.

UV curing, UV photoinitiator, printing station, curing station

Description

Thin Curing for Inkjet Printers {UV CURING FOR INK JET PRINTER}

The present invention relates to a method and apparatus for using emitted ultraviolet (UV) light to cure ink on a product, article or other article, wherein the ink binds monomers in the ink upon exposure to UV light. UV photoinitiators to convert to solidify the monomer material.

Until now, UV light emitting diode (LED) arrays have been proposed to cure inks, coatings or adhesives. Thick polymers require longer wavelengths to cure. Surface hardening requires shorter wavelengths.

Colored coatings cure better at wavelengths different from the absorption wavelength of the pigment. The same is true for the wavelength absorbing properties of resins and additives in inks, coatings or adhesives.

Accordingly, it would be desirable to provide improved UV methods and apparatus for ink jet printers and other printers.

There is provided an improved method and curing apparatus for inkjet printers and other printers that are economical, effective, convenient and efficient to use.

As described in more detail below, the methods and apparatus or apparatus of the present invention provide a technique for applying UV light emitted from a UV-LED onto a newly printed product, article or other article to cure the ink of the printing and Provide structure.

Since the intensity of light emitted by the UV-LED chip is affected or reduced as the temperature of the UV-LED chip increases, one embodiment of the present invention includes heat dissipation fins on the substrate on which the chip is mounted. To provide a cooling system and a device to blow cooling air through the fins to maintain the temperature of the UV-LED chip within a predetermined range or generally constant.

In addition, the temperature of the substrate or the intensity of the emitted light can be measured and used to adjust the current or voltage to a fan that blows cooling air onto the substrate, whereby cooling of the substrate when the chip is about to reduce brightness To maintain a constant temperature of the substrate, thereby generally maintaining a constant luminous intensity.

Furthermore, "forward voltage matching techniques", V _F , are used to provide an LED chip string or row (chip selection). Here, the current generated by the chip varies between only about 5% and about 10%, thereby minimizing "current hogging".

The distance between the light source and the product, article, ink, coating, adhesive, or other article that is emitted by the light affects the light intensity. However, if UV curable products, articles, inks, coatings, adhesives or other objects are too close to the UV-LED array, a uniform radiation pattern will not be obtained. The preferred distance between the UV-LED chip arrays is thus the distance that provides a uniform pattern of light from the light emitted from the UV-LED chip at 50% of the power output of the UV-LED chip. This distance is defined as the viewing cone angle of 2θ _1/2 .

As other UV wavelength emitting diodes become available, a wide range of UV light can be applied to cure devices and appliances.

Further, in order to obtain a larger wavelength change, a UV-LED chip array may be placed after other light sources, such as one or more fluorescent lamps, with phosphors selected to increase the light wavelength increase. For example, Osram Sylvania, Inc., of Danvers, Mass., Provides Type 2011C fluorescent lamps emitting 351 nm, Type 2052 emitting 371 nm, Type 2092 emitting 433 nm and Type 2162 emitting 420 nm.

It is thought that large junction UV-LED chips (more than 400 microns on one side) can also be used because they emit UV light at higher light densities.

Furthermore, the spatial offset between adjacent columns of 1 / X can be provided to the array of UV-LED chips, where X is equal to the number of columns.

According to the teachings of the present invention, a product, article, ink, coating agent, adhesive or other article is printed at a printing station and cured to a UV photoinitiator in a UV curable ink applied to the product, article, coating agent, or other article at the printing station. A method and UV curing apparatus are provided for improving UV light application at a station. This may include printing a UV curable ink using a printing head on a product, article, ink, coating agent, adhesive or other article at a printing station; Providing or including a set of UV-LED arrays of UV-LED chips at a curing station, and causing relative movement between the UV-LED array set and the printed product, article, ink, coating, adhesive, or other article It includes.

Further details of the invention are provided in the following claims and the appended claims relating to the accompanying drawings.

1 is a top plan view of a prior art UV LED chip assembly including a cathode and an anode pad.

FIG. 2 is a top plan view of a basic block or substrate design in which anodes and cathodes may be mounted on or above empty in accordance with the teachings of the present invention.

3 is a front view of one array of UV LED assemblies in which the columns of the UV LED assembly are arranged in the array such that the cross rows of the UV LED assemblies in one row are staggered with the UV LED assemblies in adjacent rows in accordance with the teachings of the present invention.

FIG. 4 is a front view of three arrays of panels, each having six rows of UV LED assemblies shown in FIG. 3 in accordance with the teachings of the present invention, abutting one side edge of the panel to move, reciprocate or move the panel in the X direction; The first eccentric cam moves in contact with the spring at the opposite edge and the panel moves in the Y direction, thereby causing all the arrays to move in the orbital, circular, or elliptical path when the first and second cams are rotated. A second eccentric cam is shown schematically, operating in contact with a spring bearing the upper edge and the lower edge of the panel.

5 is a schematic block diagram of a web made of, or carrying, a product, article, or other article to be UV cured. Here, a product, article having an UV photoinitiator as each product, article or other item moves past an array of UV LED assemblies while an oxygen-free, heavier than air gas is injected from a gas tube disposed near the top of the web's path of travel. Alternatively, the web may be burned on a roller to move in a generally vertical path past a panel of the array of UV LED assemblies shown in FIG. 4 so that other objects can be cured.

6 is a block diagram of a web made of or carrying a product, article or other article to be UV cured. Here, each product, article or other article with a UV photoinitiator is moved as each product, article or other article moves past the array of UV LED assemblies while oxygen-free gas is injected from a gas tube located near the bottom of the web's path of travel. In order to be curable, the web is burned on a roller to move in a generally vertical path past a panel of the array of UV LED assemblies shown in FIG. 4.

FIG. 7 is a plan view of another method of placing a UV LED assembly in at least three rows in which the space between the UV LED assemblies of each row is increased to establish a three stage stagger of the UV LED assembly.

8 is a top view of a staggered array (UV LED array) of UV LED assemblies emitting UV light at different wavelengths.

9 is a plan view of one die array of four rows of LED chips.

10 is a partially enlarged view of the array shown in FIG. 9.

FIG. 11 is an arrangement or line of a set of arrays shown in FIG. 9 and two long fluorescent lamps arranged next to the lines of the array.

FIG. 12 is a side view of a UV LED array mounted on a porcelain coated substrate alternately mounted on an aluminum heat sink comprising heat dissipation fins.

FIG. 13 is a side perspective view of the UV LED array shown in FIG. 12, showing the passage through the heat sink for the passage of the power supply conductor to the UV LED array.

FIG. 14 is a view similar to FIG. 5 except that the UV LED array shown in FIGS. 12 and 13 with four heat sinks mounted adjacent to the moving web of the product, cooling to the heat dissipation fins of the heat sink; Shows four fans for applying air.

FIG. 15 is a plan view of four UV LED arrays of the type shown in FIG. 11 covered with a sheet of glass or plastic material to protect the LED array from splatters.

FIG. 16 is a fragmentary cross-sectional view of the UV LED array shown in FIG. 15 showing a product positioned over a glass or plastic protective layer and showing a nitrogen gas layer between the product and the glass or plastic protective layer.

17 is a top plan view of a printing and curing station where a product is printed and then placed on a support or conveyor and a UV-LED array is passed over the printed product or the conveyor is moved under the UV-LED array to cure the print. to be.

18 is a top plan view of a conveyor for carrying printed compact discs down a UV-LED array.

FIG. 19 is a top plan view of a turntable carrying a compact disc, which is first indexed to move the compact disc below a spaced apart print head at which printing of the compact disc occurs and newly refreshed to cure the print. A second index is followed that moves the printed compact disk past the spaced UV-LED array.

20 shows a current in a variable speed cooling fan that measures light intensity with an optical sensor to increase cooling as the UV-LED chip of the UV-LED assembly heats up and then blows on the heat sink based on the detected light intensity. Or to maintain a generally constant luminous intensity from a UV-LED assembly mounted on a substrate with a heat sink, which can maintain a generally constant temperature resulting in a generally constant light output from the UV-LED chip by adjusting the voltage. Block diagram of the system.

Figure 21 measures the temperature of the heat sink on a substrate that also mounts a UV-LED assembly with a heat / temperature sensor mounted on the heat sink to increase cooling as the UV-LED chip of the assembly heats up. A system for maintaining a generally constant luminous intensity, similar to FIG. 20, which can maintain a generally constant temperature resulting in a generally constant light output from a UV-LED chip by adjusting the current or voltage to the fan based on the sensed temperature. Is a block diagram of.

22 is an elevation view of a printing and curing station constructed in accordance with the teachings of the present invention.

FIG. 23 is a top plan view of the printing and curing station of FIG. 22.

24 is a top plan view of a modified printing curing station that includes a heating station defined by a heat sink.

Detailed description of preferred embodiments and best practices for carrying out the invention is described herein.

Referring now to the drawings in more detail, a conventional ultraviolet light emitting diode (UV LED) assembly 10 comprising an anode 14 mounted with a chip 16 comprising a cathode pad 12 and a UV LED chip 16. ) Is shown in FIG. 1. Each cathode pad 12 (FIG. 1) is connected to a wire conductor as each anode 14 is.

Referring now to FIG. 2, a base with a first array 21 of UV LED assemblies 10, i.e., a pad 12 and an anode 14, providing a plurality of UV LED chips 16. A building block 20 is shown. The basic blocks are designed to be paired with similar basic blocks to form a group 22 of arrays 21, 23 and 25 as shown in FIGS. 3 and 4. In this way, several blocks 20 can be fastened to coincide with each other and arranged in a pattern on the panel 28 (FIG. 4) (eg, like a tile on the floor).

As shown in FIG. 3, the UV LED assembly 10 in each array 21, 23 and 25 is spaced apart from the first lower row 36 of the UV LED assembly 10 at regular intervals. The UV LED assemblies 10 are then arranged in a staggered manner so as to be positioned above the space between the UV LED assemblies in the first row in adjacent second rows 38. In the same way, the next upper row 40 of the UV LED assembly 10 is staggered and the UV LED array 21 is provided with a total of twenty staggered rows as shown in FIG. 3.

Also, as shown in FIG. 3, the beginning of the first UV LED assembly of the bottom row 36 in the first array 21 is the last UV LED assembly (at the end of the bottom row 42 of the second lower left array 23). 10) to align with the end.

Then, the start of the first UV LED assembly 10 of the top row 44 in the first array 21 coincides with the end of the last UV LED assembly of the top row 46 in the second lower left array 23. To be aligned. Next, the end of the last UV LED assembly of the bottom row 36 in the first array 21 is aligned with the beginning of the first UV LED assembly of the bottom row 48 in the third lower right array 25. Finally, the end of the last UV LED assembly of the top row 44 in the first array 21 is the first UV LED assembly of the top row 49 in the third lower right array 25 as shown in FIG. 3. 10) to align with the beginning.

As optimally shown in FIG. 4, the UV light from each UV LED assembly 10 can be placed and staggered at intervals corresponding to adjacent rows in the array as well as placed and staggered at intervals corresponding to the columns of other arrays. The three arrays 21, 23 and 25 can be arranged in a staggered manner over the panel 28 so that they are arranged. Although not shown, more than three arrays 21, 23 and 25 may be provided, such as six arrays.

In addition, the mechanism shown in FIG. 4, preferably the eccentric cams 50 and 52, move, move or reciprocate the panel 28 in the X direction, up and down in the Y direction, as in an orbital sander. It can be provided to make. The first x-axis eccentric cam 50 is mounted to rotate about the shaft 54 and has a spring 58, such as a helical tension spring, arranged to operate in contact with the other side edge 60 of the panel 28. It operates in contact with one side edge 56 of panel 28.

Next, the second y-axis eccentric cam 52 (FIG. 4) is mounted to rotate on the shaft 64, such that a spring 68, such as a helical tension spring, is arranged to operate in contact with the lower edge 70 of the panel 28. Opposing operation of the upper edge 66 of the panel 28.

Rotation of each shaft 54 and 64 (FIG. 4) by a mover, such as a variable speed motor (not shown), can cause the panel 28 to move in a trajectory, annular, circular, or elliptical path generally. . This means that each row of UVs in each array 21, 23 and 25 mounted on panel 28 to emit the UV light emitted and apply the UV light uniformly to the product, article or other article to be cured This results in orbital movement of the LED assembly 10. This divergence of UV light also minimizes or eliminates the occurrence of so-called "hot spots" of UV light.

As shown in FIG. 5, a schematic block diagram of a UV curing device, assembly, mechanism or apparatus constructed in accordance with the teachings of the present invention is shown. The panels 28 of the UV LED arrays 21, 23 and 25 are here generally arranged vertically and very close to the movement of the conveyor belt comprising the web 74-the web 74 is a UV LED array. The rollers 76, 78 and 80 will be burned so as to move straight and vertically in close proximity to the panels of (21, 23 and 25). For this purpose, at least one of the rollers 76, 78 and / or 80 of the conveyor may be a drive roller.

UV curable products, articles or other articles, such as labels disposed on or within the web 74 (FIG. 5), may have one or more UV curable inks, coatings and / or adhesives between the plastic cover layer and the label. The UV curable ink, coating and / or adhesive may comprise a UV photoinitiator that will polymerize monomers in the UV curable ink, coating or adhesive when subjected to UV light within a predetermined UV wavelength range.

The UV curable inks, coatings and / or adhesives are preferably disposed on the side of the web 74 (FIG. 5) facing the panel 28 closest. Preferably, the UV LED assembly has a viewing cone angle, 2θ _{1 /} , in proximity to the ink, coating or adhesive, wherein the light cone emanating from the UV-LED chip is at least 50% of the chip's optical power output. Should not be closer than ₂ . The effect of UV emitted light disappears exponentially with increasing distance to the product, article or other UV curable article being treated.

Preferably, the shafts 50 and 52, such as to cause orbital movement of the panel 28 and the UV LED assembly as the web 74 comprising the article, article or other UV curable article moves past the panel 28, 4) is rotated. Such movement also minimizes "hot spots" or "cold spots" and provides uniform sweeping, distribution and application of UV light from the UV LED assembly 10.

A block schematic of the assembly or appliance shown in FIG. 5 is provided to minimize exposure to oxygen to inhibit UV curing of a product, article or other object during curing. A gas tube 84 providing an upper gas injection is provided with an oxygen-free gas, eg carbon dioxide, that is heavier than air near the upper end 86 of the downward travel path, indicated by the arrow 88 of the web 74. It is provided on the assembly and the instrument for injection. Accordingly, the gas is provided between the panel 28 and the web 74 to provide an oxygen free region between the UV LED assembly 10 on the panel 28 and the web 74 including the UV curable product, article or other article to be cured. It can flow downward in the space between.

The wiper blades 90 (FIG. 5) providing the lower papermaking unit store and compress the gas in the space between the orbiting UV LED arrays 21, 23 and 25 (FIG. 4) and the moving web 74 (FIG. 5). And may be disposed adjacent the lower edge 70 of the panel 28 to collect and / or cover. Preferably the wiper blade 90 is secured to the lower edge 70 of the panel 28 and has an outer edge 92 disposed to be attracted to the moving web 74. In this way, the injected gas can be restrained from exiting the curing zone.

FIG. 6 shows that the moving web 74 rides around the rollers 94, 96 and 98, at least one of which may be a drive roller, as in the UV curing apparatus, assembly and apparatus shown in FIG. A web 74 having a UV curable product, article or other article thereon as shown by an arrow 100 past a panel 28 mounted with an array of UV LED assemblies 21, 23 and 25, FIG. 4. A block schematic diagram of a UV curing device, assembly, mechanism or appliance configured to move upwards as well.

In the device, assembly or instrument shown in FIG. 6, an oxygen free gas, such as helium, which is lighter than air, inert in the space between the orbiting panel 28 (FIG. 4) and the moving web 74 (FIG. 6). A gas tube 104 is provided near the lower end 106 of the movement path 100 of the web 74 to provide a lower gas injection to inject the gas. This provides an oxygen free region that enhances and facilitates curing of the UV photoinitiator in the UV curable product, article or other article carried by the web 74.

As in the UV curing apparatus, assembly and apparatus shown in FIG. 5, injection into the curing zone between the orbiting panel 28 (FIG. 4) and the moving web 74 (FIG. 6) minimizes the outflow of gas lighter than air. A wiper blade 108 is provided which provides the upper papermaking portion 108 near the upper edge 68 of the panel 28 as shown in FIG. 6 to store, compress, collect and / or cover the gas. In addition, the wiper blades 108 (FIG. 6) may be arranged to be secured to the upper edge 68 and attracted to the web 74.

In order to prevent overheating of the UV LED assembly 10, ie to control the heat generated by the UV LED assembly 10, the power supplied to the UV LED assembly is activated at a relatively high frequency, periodically or sequentially. And can be deactivated. That can be turned on and off. In addition, the duty cycle of the on-off cycle can be changed to adjust the UV light intensity.

FIG. 7 shows another way in which a UV LED assembly, i. E. LED chip 16, can be placed to achieve the same uniformity as shown in FIGS. 2 and 3. This is to use three rows to get uniformity. That is, the LED chips 16 are arranged at intervals of X in the first row 112, and the next row 114 and row 2 start at an interval 1/3 X from the start of the first row 112 and the next row ( 116, column 3 allows to start at interval 2/3 X from the start of the first column 112 or at interval 1/3 X from the start of the second column 114.

It can be understood that the spacing X coincides with the width of the UV LED assembly 10 such as 1, 2, 3, 4, 5, etc. to provide the desired stagger of light rays from the UV LED assembly 10. Preferably x is equal to the number of columns.

In addition, when the UV curable ink, coating or adhesive is deposited on the UV LED assembly, a clear, transparent protective sheet or layer of plastic material may be placed over the arrays 21, 23 and 25 to protect the UV LED assembly 10. have. The protective sheet or layer is then periodically cleaned or replaced.

The array 220 shown in FIG. 8 shows six staggered rows 201-206 of the UV LED assembly 216. This array 220 is similar to the array shown in FIG. However, the individual UV LED assemblies 216 in the array have different wavelengths in order to apply UV light with different wavelength emission, which is more effective for curing inks, coatings and adhesives that contain UV photoinitiators and have different thicknesses. effective.

The UV light emitted from an LED or fluorescent lamp is over a range of wavelengths, often called the Spectral Energy Distribution, which has a peak at one wavelength, for example 370 nm.

The UV LED assemblies can be arranged in any, mixed fashion or in continuous rows. For example, in row 201 the first UV-LED assembly 216A emits light at 390 nm, the next UV-LED assembly 216B emits UV light at 370 nm, and the next UV LED assembly 216C at 415 nm. UV light can be emitted and this pattern is repeated throughout the heat. The next column 202 and the following columns 203-206 may have the same pattern or different patterns.

Alternatively, all UV LED assemblies 216 in row 201 emit at 390 nm, all UV LED assemblies 216 in row 202 emit at 370 nm, and all UV LED assemblies in row 203. 216 may emit at 415 nm, and this pattern may be repeated in the remaining columns 204-206. In addition, the pattern or order, for example, 370nm, 390nm and 415nm can be changed.

Another variant may be any mixture of UV LED assemblies that emit at 415 nm, 390 nm and 370 nm or other wavelengths, such as UV wavelength emitting diodes are available for example at 350 nm, 400 nm and 420 nm.

9 shows four rows 221-224 of lamp panel array 220 of UV LED assembly 226. The panel array 220 may be about 4 inches long and has two bus strips 227 and 228.

As shown in FIG. 10, the first UV LED assembly 221A in the first row 221 emits light at 370 nm, the first UV LED assembly 222A in the second row 222 emits light at 390 nm, and The first UV LED assembly 223A of the third row 223 emits light at 420 nm, and the first UV LED assembly 224A of the fourth row 221 emits light at 400 nm.

The second UV LED assembly 221B of the first row 221 emits light at 390 nm, the second UV LED assembly 222B of the second row 222 emits light at 400 nm, and the third row of the third row 223 The three UV LED assemblies 223B emit light at 370 nm, and the second UV LED assemblies 224B in the fourth row 224 may emit light at 420 nm.

In each row 221-224 the third UV LED assemblies 221C, 222C, 223C and 224C may emit light at 420 nm, 390 nm, 400 nm and 370 nm, respectively. It will be appreciated that the UV LEDs emit UV light in the spectral range and the peak wavelength in the spectral range is the specified wavelength.

Further, in order to obtain the maximum change in wavelength, the panel array 220 may be arranged after another light source, such as a fluorescent lamp, in which the phosphor is selected to increase the increase in the light wavelength. For example, Osram Sylvania, Inc., of Osram, Danvers, Massachusetts, has a phosphor type 2011C fluorescent lamp that emits 351 nm, a phosphor type 2052 lamp that emits 371 nm, a phosphor type 2092 lamp that emits 433 nm, and a phosphor type 2162 that emits 420 nm. Provide a lamp.

These are some examples of wavelengths that can easily be added to cure the mix. Furthermore, sterile lamps or Pen Ray lamps can be used to add 254 nm.

11 shows two fluorescent lamps that can be placed adjacent to an elongated panel 234 formed by three panel arrays 220 arranged one end to the other and electrically connected to each other (lead with lead). 231 and 232 are shown. Webs similar to the web 74 and carrying UV curable products, articles or other articles may be arranged to move across the long panel 234 as indicated by arrows 236.

The number of panel arrays 220, such as three (3)-eight (8), can be arranged one after the other to form a UV light emitting area, and one or more fluorescent lamps can be used for the light emitting area. It will be understood that.

The panel 234 can vibrate, as with a cam (FIG. 4), with a significant sweep to ensure overlap of four different wavelengths.

UV curable products, articles, inks, coatings, adhesives or other articles may also cross two fluorescent lamps 231 and 232 and additionally applied light sources.

In some embodiments of the article, the ink, coating or adhesive may comprise two or more photoinitiated monomers activated at two or more wavelengths, such as, for example, 365 nm and 385 nm and may be added to the article, article or other article. The losing rays will contain light of these wavelengths.

In addition, an inert gas may be injected into the space between the panel 234 and the moving web containing or above the UV curable product, article or other article, as shown in the structures shown in FIGS. 5 and 6 and described above. .

Experimental tests show that LED chips with larger areas can emit higher intensity UV light. This property may be important when the space between the panel 234 and the web is a factor in curing. In this regard, LED chips with a large junction area emit more light than small junction LED chips. Wide junction chips can have more than 400 microns on one side and small junction chips can have 400 microns or less on one side. Wider chips are called large junction LEDs and provide higher brightness than small junction LED chips.

12 shows a linear UV LED array assembly 250 including an aluminum heat sink 252 with extending heat dissipation fins 254. Above the heat sink 252 are two porcelain coated steel substrates 260 mounted thereon with UV LED chip arrays 254 and 256 similar to the array shown in FIG. Under the coated steel substrate 260 of the arrays 256 and 258, a heat sink compound 270 is provided to secure the coated ceramic substrate 260 to the top surface of the heat sink 252. The heat sink compound 270 not only secures the UV LED chip arrays 256 and 258 to the top surface of the heat sink 252, but also conducts heat from the UV LED arrays 256 and 258 to the heat sink 252. .

FIG. 13 is a perspective view of the UV LED array assembly 250 shown in FIG. 12. It will be appreciated that a second UV LED chip array 274 is disposed behind the UV LED chip array 256 and they are connected to each other by wire conductors 280 and 282. In addition, the heatsink (not shown) extends generally parallel to the heat fins 254 and is positioned with a passage 284 positioned to receive a pair of power supply wire conductors 288 and 290 from the UV LED chip array 274. It will be appreciated that 252 is provided. Furthermore, it extends generally parallel to the heat dissipation fins 254 adjacent the UV LED chip array 258 to accommodate a pair of power supply wire conductors 294 and 296 extending from the UV LED chip array 258. Another passage 292 is provided to the heat sink 252.

14 is a block diagram of a UV curing apparatus 300 including multiple, for example four UV LED chip array assemblies 250. The assemblies 250 may be fixed to one another and may vibrate, as by a cam, similar to the vibration of panel 28 shown in FIG. 5.

Web 301 (FIG. 5) rides on rollers 302, 304 and 306 so close to the heat of UV LED chip array assembly 250. One of the rollers 302, 304, and 306 may be a drive roller of a conveyor.

In the embodiment of FIG. 5, heat dissipation is achieved by heat dissipation fins 254 of heat of UV LED chip array assembly 250. This is important because the intensity of light from the UV LED chips in the arrays 256, 258 and 274 can be reduced by heating the UV LED chip arrays 256, 258 and 274. Thus, in this embodiment the temperature of the UV LED chip arrays 256, 258 and 274 is maintained within a predetermined temperature range by heat dissipation through the heat dissipation fins 254.

The temperature control of the UV LED arrays 256, 258 and 274 temperature in FIG. 5 can be further improved by providing fans such as the fans 312, 314, 316 and 318 shown in FIG. 14. It will be appreciated that a temperature sensor may be provided on the heat sink 252 to indicate the temperature of the array to a control circuit (not shown) of the fans 312-318. The control circuit may turn on the fans 312-318 when the sensor senses the temperature above a predetermined value, and turns off when the temperature senses below the predetermined value. In this way, the brightness of the light rays from the UV LED chip can be maintained at a high level.

FIG. 15 shows a number of four arrays similar to the array shown in FIG. 9, mounted on a substrate and covered with a protective sheet 320 of glass or plastic that provides a cover or cover to protect the LED array 220 from splatters. 220).

FIG. 16 is a partial cross-sectional view of the covered UV LED chip array panel 220 shown in FIG. 15. The product 324 to be cured here is shown on the glass or plastic cover sheet 320 and nitrogen gas is supplied to the space between the product 324 and the cover sheet 320. Next there is a UV LED chip array panel 220 under the cover sheet 320 as well.

17 shows a printing and curing station 400. Wherein the product, article or other object 402 (shown on adjacent support 404) is printed at printing station 406 and then placed on support 404 (which may be a support conveyor as shown in FIG. 18). Whereby the assembly 408 of the UV LED array 408 moves or reciprocates over the newly printed product, article, coating, adhesive or other object (or the support conveyor moves below the assembly 408 of the UV-LED array). The product, article or other article 402 may be flat or have a curved shape such as a cell phone housing.

18 shows a curing zone 420 where a conveyor 422 carrying printed compact discs 424 is moved down the assembly 426 of the UV-LED array.

19 shows a turntable 430 for carrying a compact disc 432 under the print head 434 and the assembly 436 of the UV-LED array. The turntable is first indexed to move the compact disc 432 below the spaced print head 434 at which printing of the compact disc 432 occurs and is then newly printed to cure the print. A second index of the turntable is followed to move the compact disc 432 past the assembly of spaced UV-LED arrays.

Since the heat is generated when the UV-LED chip emits light and the brightness decreases with increasing temperature, it is generally desirable to maintain the UV-LED chip at a constant temperature in order to maintain a constant brightness / output. This can be done using some other system. As shown in FIG. 20, generally one system 500 for maintaining a constant brightness is depicted realistically. Here, the system 500 is the UV-LED array in the assembly 506 of the UV-LED array 504 facing the printed product, article or other object 507, for example a compact disk (CD). A light sensor 502 for measuring the light intensity from the UV-LED chip of 504. The sensed light intensity is a variable speed cooling fan 510 that blows cooling air onto a heat sink 512 mounted on a substrate 514 that is also mounting the assembly 506 of the UV-LED array 504. Is used by the control circuit 508 to control the current or voltage. As the UV-LED chip heats up, the speed of the fan 510 to increase the cooling of the heat sink 512 to cool the heat sink 512 mounted on the substrate 514 and the UV-LED chip. Is increased. This allows the UV-LED chip to be generally maintained at a constant temperature, which results in a generally constant light output from the UV-LED chip.

Another system 600 is shown realistically in FIG. 21. The system 600, here generally for maintaining a constant brightness, is a heat sink 604 over a substrate 606 that is also equipped with an assembly 608 of a UV-LED array 610 comprising a plurality of UV-LED chips. Thermal / temperature sensor 602 for measuring the temperature of the < RTI ID = 0.0 > The sensed temperature draws current and voltage into a variable speed fan 614 that blows cooling air onto a heat sink 604 mounted on a substrate 606 on which the assembly 608 of the UV-LED array 610 is mounted. Used by the control circuit 612 to control. As the UV-LED chip heats up, the speed of the fan 614 to increase the cooling of the heat sink 604 to cool the heat sink 604 mounted on the substrate 606 and the UV-LED chip. Is increased. This allows the UV-LED chip to be generally maintained at a constant temperature, which results in a generally constant light output from the UV-LED chip.

In both systems 500 and 600, the heat sinks 512 or 604 are spaced apart from the UV-LED array 504 or 601 on the bottom surface of the substrate 514 or 606. In a practical implementation, the heat sink 512 or 604 is preferably disposed on the substrate 514 or 606 directly above the UV-LED array 504 or 610.

In accordance with the teachings of the present invention, the UV-LED array can be used in ink printing and curing systems, such as the system 620 shown in FIG. Here, the printing head 622 is arranged to reciprocate transverse movement over a material or article, article or other article, such as a piece of paper, to be printed with UV curable ink thereon. The first set of two UV-LED arrays 626 and 628 are arranged to move with the printing head 622 on either side of the printing head 626.

Next, the piece of paper 622 is in a non-crossing direction under another set 630 of one or more UV-LED arrays, which may have LED chips that emit UV light at one or more other wavelengths (arrows in FIG. 23). Index).

As shown in FIG. 23, the piece of paper 622 may be further indexed or moved past the fluorescent lamp 632 which emits light at another wavelength.

As shown in FIG. 24, at least one heat lamp 640 may be included in the curing station 642. In one preferred embodiment, the heat lamp 640 is an IR, infrared lamp. In some cases, other types of heat lamps may be used.

Here, the printed product, article or other article 644, such as a compact disc (CD), a computer disc, a bottle cap or a cell phone housing part, is used for the UV curable ink to cure better or faster than when heated. It is first moved above the conveyor 645 under the lamp 640. The article, article or other article 644 is then moved under the set 646 of the UV-LED array.

It will be appreciated that the sets 630 and 646 can reciprocate or oscillate as previously described herein if desired to provide more uniform light.

In addition, the UV-LED arrays of the sets 630 and 646 can be combined with the system 500 or 600 to keep the temperature of the UV-LED chip generally constant.

It will be apparent from the foregoing description that the methods and apparatus or apparatus of the present invention have a number of advantages. Some of these have been described above and others are inherent in the present invention.

While the embodiments of the invention have been shown and described, those skilled in the art will recognize that various modifications as well as configurations, parts, equipment, devices, manufacturing (methods) steps and uses thereof within the scope of the invention. And alternatives, and other products, articles, inks, coatings, adhesives and / or articles. Accordingly, the scope of the present invention is limited only by the accompanying claims.

Claims (6)

Printing products, articles, coatings, adhesives or other objects at a printing station and enhancing the application of ultraviolet (UV) light to UV photoinitiators in UV curable inks applied to the products, articles, coatings, adhesives or other objects at curing stations In the method for, the method Printing a UV curable ink on a product, article, coating, adhesive or other article from the printing station to the printing head; Providing a UV-LED array of at least one set of ultraviolet light emitting diode (UV-LED) chips to or near the curing station; And Causing relative movement between at least one set of UV-LED arrays and the printed article, article, coating agent, adhesive or other article; Method comprising a. The method of claim 1 wherein the method The printing head is reciprocated across the article, article, coating agent, adhesive or other article with at least some of the set of UV-LED arrays; And / or The article, article, coating agent, adhesive or other article is indexed and / or moved corresponding to at least one set of UV-LED arrays; And / or At least one set of UV-LED arrays is reciprocated and / or vibrated as the article, article, coating, adhesive or other article is indexed and / or moved corresponding to at least one set of UV-LED arrays; At least one fluorescent lamp is disposed in the curing station; And / or Wherein said printed article, article, coating agent, adhesive or other article is indexed and / or moved adjacent and / or near and / or below at least one fluorescent lamp. The method of any one of the preceding claims, wherein the method is At least one UV-LED chip in the set of UV-LED arrays emits light at a different wavelength than some other UV-LED chips of the UV-LED array; And / or The intensity of the UV light emitted from at least some of the UV-LED arrays is generally constant and / or uniform. The method of claim 1, wherein the method comprises staggering at least some of the UV-LED chips in the at least one UV-LED array. The method of any one of the preceding claims, wherein the method is At least one heat lamp is disposed near and / or at the inlet of the curing station; And / or UV curable inks are printed and heated on the article, article, coating, adhesive or other article; And / or UV curable inks are heated at the curing station; And / or UV curable inks are heated, polymerized and / or cured with an infrared heat lamp on a product, article, coating, adhesive or other article. In the UV curing apparatus for using the method of any one of the preceding claims, the UV curing apparatus is A UV-LED array of at least one set of UV-LED chips disposed at or adjacent to the curing station in proximity to, near and / or adjacent to the printing station; And / or A mechanism for causing relative movement between at least one set of UV-LED arrays and the article, article, ink, coating, adhesive or other article; And / or A reciprocating mechanism for reciprocating the printing head and at least two sets of UV-LED arrays together and / or transversely and / or across the article, article, ink, coating, adhesive or other article; And / or An indexing mechanism for indexing and / or moving the article, article, ink, coating agent, adhesive or other article in proximity, near, and / or below at least one set of UV-LED arrays; And / or A vibrating mechanism for vibrating at least one set of UV-LED arrays in response to the article, article, ink, coating, adhesive or other article; UV curing apparatus comprising a.

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