JP2003534164A - Microwave energy ink drying system and method - Google Patents

Abstract

(57) Abstract: A microwave ink drying device for an ink jet printer, including a microwave applicator. The applicator may be mounted on a movable print carriage. The applicator may further have a slot antenna. The slot antenna can be formed as a dual slot, one part of the slot being connected to the wave generating cavity and the other part being connected to the impedance matching cavity. Microwave-based ink drying methods include heating a deposited ink by moving a microwave applicator thereon. In another embodiment, a band of ink droplets is deposited by multiple successive passes of an ink jet printhead, and the deposited droplets are dried between passes.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Technical Field The present invention relates to printing. Specifically, the present invention relates to drying ink using microwave energy during inkjet printing.

2. Description of Related Art In color inkjet printing, a relatively large amount of ink is deposited on a print medium in a relatively short time. Often there is a significant time interval between the completion of a portion of the image and the ink that is drying in that portion. In some cases, the printed image may be spoiled by being wound onto the take-up reel of the printer after the image has been printed but before the ink has dried. This is a particularly clear issue in moist environments where the drying time of the ink is fairly long.

Further, in multi-pass inkjet printing, the print head moves several times over the same portion of the media, depositing the required drop portions in each pass. For these types of printing operations, the quality will be improved if the ink deposited in the previous pass was sufficiently dry before the printhead subsequently moved over the same portion of media.

To alleviate the problems associated with slow ink drying, various methods have been developed to dry the ink at or after printing. Some of these methods involve heating various printer components with infrared light or by sending heated air over the media. These methods are inefficient at coupling heat to the printed media. In addition, water-based inks can be heated by microwaves and a microwave drying system was designed to heat and dry the deposited ink. These systems are licensed industrial bands, about 2.
Operates at 45 GHz. One such system is Carrie.
ra) et al., U.S. Pat. No. 5,220,346. In this system, after inking, the media is sent through a static microwave dryer. The dryer essentially comprises a waveguide with a magnetron, and a tuner coupled at one end. As the media moves, at least some microwaves in the waveguide are absorbed by the ink, thereby heating and drying the ink.

Various problems exist in this type of system. First, applied 6
At 00 watts, the resulting electric field is only about 3 × 10 ⁴ volts / meter. Second, different parts of the cavity have different average electric field strengths, resulting in non-uniform drying across the image. Furthermore, even if a constant field strength occurs across the image, different ink densities on different image portions will still result in uneven drying.

Image degradation is also associated with a relatively large amount of liquid adhering to the media. For example, heavy liquid deposits can cause image bleeding, coalescence, and image degradation such as paper breaks known as cockle. Since the print media does not dry until it is removed from the printer, US Pat.
, 631, 685, it is impossible to control the coalescence.

Additional examples of microwave dryers include Arthur Goo
U.S. Pat. No. 5,631,685 to Ray). The printer described in this patent is an inkjet type to dry the ink using a dryer similar to the low field device described in US Pat. No. 5,220,346 to Carriera et al. The printed paper is passed through multiple applicator sections. This static microwave dryer is bulky and requires sheets to be ejected from the printer in order to dry. in this way,
While the goal is to control the cockle, the delay between printing and drying with a static microwave applicator makes it impossible to fully control the cockle.

As another example, Wolfberg and Harper (Ha)
U.S. Pat. No. 4,234,775 to Rper) describes a system in which the electric field strength for drying a web or paper is enhanced by creating a standing wave resonance zone of the waveguide. Therefore, a number of waveguides with a quarter-lambda offset are used to achieve drying uniformity. However, non-uniform drying is still present and the equipment is large and bulky.

Thus, the state of the art of microwave drying for ink jet printers, and for webs, sheets, or films, generally utilizes large low field applicators, phase shifts or average unity. Whether to use a high electrolytic resonator using offset geometry in an attempt to obtain the characteristics.

SUMMARY OF THE INVENTION In one embodiment, an inkjet printer includes at least one platen forming a printed surface, a microwave frequency energy source, and at least one coupled to receive microwave frequency energy from the source. It consists of two microwave energy applicators. The microwave applicator is positioned against the print surface so that the ink dries when the swath of ink is deposited on the print media before the print media exits the print surface. A method of making an inkjet printer includes the act of attaching a microwave energy applicator to a movable print carriage.

In one embodiment of the present invention, a microwave energy applicator includes a first cavity having a first opening therein, a second cavity having a second opening therein, and first and second The second cavity comprises a barrier that is substantially conductive and defines a boundary between the first and second openings.

In another embodiment of the present invention, an inkjet printing method is provided. In one embodiment, a method of drying ink during or after an inkjet printing process includes passing a microwave energy applicator over the deposited ink droplets to heat the deposited ink droplets. Including that. In another embodiment, an inkjet printing method uses a plurality of successive passes of at least one inkjet print head to deposit a swath of ink and perform microwave radiation before performing the next pass. Is used to dry the deposited ink drops during at least one successive pass.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Embodiments of the present invention will now be described with reference to the accompanying drawings, in which like numerals refer generally to like elements. The terminology used in the description herein is merely that which is used in connection with the detailed description of certain specific embodiments of the invention, and can be used in any limited or restrictive manner. It is not intended to be interpreted in. Moreover, although embodiments of the invention may include some novel features, none of them are responsible for the desired attributes, or for the practice of the invention described herein. It is not essential.

Referring to FIG. 1, a large format inkjet printer 10
One particular embodiment includes left and right lateral housings 11, 12 and is supported by a pair of legs 14. The right housing 11, shown in FIG. 1, is equipped with a display and a keypad for operator input and control and includes various electrical and mechanical components related to the operation of the printer device. However, it is not directly related to the present invention. The left housing 12 includes an ink reservoir 36 that supplies ink to the inkjet cartridge 26 via a plastic conduit 38 that runs between each inkjet cartridge 26 and each ink reservoir 36. In some printer embodiments, a separate ink reservoir 36 or tube 38 is not provided and printing is performed with the ink reservoir integrated in the cartridge.

In order to make it possible to continuously supply paper to the printer 10, a continuous printing medium of a roll (
(Not shown) is attached to a roller at the rear of the printer 10 or individual paper (
(Not shown) is supplied to the printer 10. The platen 18 forms the lateral surface that supports the print media and printing is performed by the selective deposition of ink drops on the paper. During operation, continuous feeding of paper is provided by a plurality of upper rollers (not shown) spaced along the platen 18 from a paper roll mounted at the rear of the printer 10.
Guided across the platen 18. In an alternative embodiment, a sheet of paper or other print media is guided across platen 18 by rollers (not shown). The support structure 20 is suspended above the platen 18 and between the platen 18 and the support structure such that a piece of paper or other print media to be printed can pass between the platen 18 and the support structure 20. , Span its length with sufficient clearance.

A support structure 20 supports a print carriage 22 above the platen 18. The print carriage 22 includes a plurality of inkjet cartridge holders 24, each with an interchangeable inkjet cartridge 26 therein. In the preferred embodiment, four print cartridges 26
Although attached to a holder 24 on the carriage 22, any number of ink jet cartridges 26 could be attached. The support structure 20 is
It includes a guide rod 30 that is generally positioned parallel to the platen 18. Print·
The carriage 22 includes guide rods for determining a linear print path along which the print carriage 22 travels so that the print carriage is movable along the guide rods 30, as indicated by the double-headed arrow 32. A split sleeve is preferably included that slidably engages 30. A motor and drive belt mechanism (not shown) is installed along the guide rod 30 to the print carriage 2.
Used to drive the 2.

During printing, the carriage 24 passes over the media back and forth. During each pass, the inkjet cartridge 26 deposits a swath having a width approximately equal to the width of the inkjet nozzle array of the jet plate on the bottom of the cartridge. After each pass, the media is ejected and the carriage returns over the media to print the next swath. Depending on the print mode, the ink jet cartridge could print in only one direction or in both directions. Further, in the multi-pass print mode, the inkjet cartridge can pass through the same location on the media more than once. These aspects of inkjet printers are well known and conventional and will not be described in more detail herein.

FIG. 2 illustrates an inkjet printer incorporating a moveable print carriage 44 constructed in accordance with one embodiment of the present invention. As described above with reference to FIG. 1, print carriage 44 is mounted on guide rod 30 and reciprocates on platen 18 in the direction of arrow 32. The media 46 is printed between the platen 18 and the carriage 44. The carriage carries one or more ink applicators 48, but it could also consist of, for example, four ink jet cartridges as shown in FIG. However, any type of ink applicator or method can be used in connection with the present invention.

Also, two microwave energy applicators 50, 52 are mounted on the carriage 44. In the embodiment of FIG. 2, microwave energy applicators 50, 52 are mounted on the opposite side of ink applicator 48. The microwave energy applicators 50, 52 are coupled to a microwave energy source 56 and can be mounted within the housing (FIG. 1) at one or both ends.
The microwave energy source 56 may be, for example, a conventionally designed magnetron having an output at a center frequency of approximately 2.45 GHz. The microwave energy source 56 may also advantageously include means for converting the phase of the microwave to optimize the coupling of the microwave applicator to the print media, such as a 3-stub tuner. The design and manufacture of magnetrons with suitable output power and center frequency is well known and is currently in wide variety in mass production for the microwave oven market. Alternatively, microwave energy source 56
May be mounted on the carriage 44 rather than the end housing. In this embodiment, D
A C power supply may be provided to one or both of the end housings to power a carriage mounted on a microwave energy source.

The microwave energy source 56 is connected to a microwave applicator having commercially available coaxial cables 60a, 60b having a structure suitable for microwave transmission. Of course, the microwave energy source 56 may include a single magnetron or multiple magnetrons. In one embodiment, each microwave applicator 50, 52 is separately coupled to its own magnetron. In another embodiment, a single magnetron is connected to both microwave applicators 50, 52 via a splitter mounted in the printer housing or on print carriage 44. As described further below, each microwave energy applicator 50, 52 within the media 46 is
And regions 64, 66 of microwave frequency oscillating electric field passing through the medium 46. These electric fields heat the media 46 and the ink deposited thereon, thereby dramatically increasing the ink drying rate.

In this embodiment, when the carriage 44 moves to the left in FIG. 2 and deposits a swath of ink droplets, the microwave applicator 52 to the right of the ink applicator is the liquid just deposited by the ink applicator. Pass over the drops. As the microwave applicator 52 passes over the droplet, the ink absorbs microwave energy and the deposited droplet is heated and dried. Similarly, when the carriage 44 moves to the right in FIG. 2, the left microwave applicator 50 passes over the just deposited ink drop to dry. For bidirectional printing, the microwave applicator, which guides the ink applicator over the media, may be cut off, used to heat the media before printing, or applied in a previous pass. The drying of the ink may be completed, which may further enhance the ink drying process. The two microwave applicator embodiment shown in FIG. 2 is advantageous for bidirectional printing printers, as is the majority of high quality color ink jet printers. Of course, the carriage moves across the media 2
If the printer deposits ink in only one of the directions, then only one microwave applicator is required. In this embodiment, the microwave applicator is positioned in association with the ink applicator 48 so that the microwave applicator can track the ink applicator across the media as it deposits ink drops. It However, even in the case of unidirectional printing, it is advantageous to provide a second leading applicator, as described above for the bidirectional printer embodiment, to preheat the media and complete the drying process. Will be something. Alternatively, both applicators can be co-heated to regulate the drying process. For example,
The staging is minimized by the present invention.

FIG. 3 is suitable for mounting on the movable print carriage 44 shown in FIG.
FIG. 3 is a perspective view of a microwave applicator according to one embodiment of the present invention. This embodiment of microwave applicator 68 comprises a first chamber 70 and a second chamber 72. The first chamber 70 and the second chamber 72 are separated by a central plate 74. The first chamber 70 is a wave generating cavity and is equipped with a coupler 76 for the coaxial cable that supplies microwave energy to the applicator 68. The second chamber 72 is an impedance matching cavity that reflects microwave energy to the wave-generating cavity 70. If the impedance of the second chamber 72 matches the source, the microwave absorption by the ink will be maximum and the total energy reflected to the microwave energy source will be minimum. A bottom plate 80, which forms a slot antenna on the bottom surface of the applicator 68, is also provided, which provides a path for transmitting microwave energy back and forth between the two cavities 70, 72. The bottom plate 80 also mounts a mounting bracket 82 for attaching the microwave energy applicator 68 to the movable print carriage of the printer.
Can be formed.

4A and 4B show the bottom surface of the applicator 68, showing two examples of slot antenna configurations for the microwave energy applicator 68. In FIG. 4A, the bottom plate rectangular opening 86 is substantially bisected by the center plate 74. In FIG. 4B, the “butterfly” shaped opening 90 is shown in the center plate 7.
It is almost bisected by 4. In each of these embodiments, the dual slot configuration is
Half of the openings 86, 90 are in the wave generating cavity 70, and also the openings 86, 90.
The other half is connected to the impedance matching cavity 72 and is separated from each other by a central plate 74.

While the slot antenna design described above has proven to be particularly advantageous, other microwave antenna geometries can be used. Examples of other shapes include circular antennas, cross antennas and horn antennas. Many others are known to those of skill in the art and can be used in this application.

FIG. 5 shows a cross section of one embodiment of the microwave applicator 68 along line 5-5 of FIG. 3, separating the wave generating cavity 70 from the impedance matching cavity 72. The plate 74 is shown. Central plate 74
Is tapered at its lower end for convenience. As mentioned above, the wave-generating cavity is
Coaxial cable 60a driven by a microwave energy source (not shown)
A coupler 76 for receiving. In the direction of the applicator 68 shown in this figure, the print carriage reciprocates in and out of the plane of FIG. 5 to deposit a swath of ink parallel to the length of the dual slot 86 on the bottom of the applicator 68. . However, it will be appreciated that the applicator can be configured to move in any desired direction on the media surface. In particular, the parallel slots can be oriented at a constant angle with respect to the direction of travel of the printer to cover the print surface width, which can be as wide as the slot length.

Preferably, the dimensions of the cavity are as follows: Firing cavity 70
Is a WR284 waveguide whose internal cross section conveniently has a wide dimension of about 3 / 5λ and a small dimension 92 of about 1/4. Where λ is the wavelength emitted at the center frequency of the microwave energy source, which is approximately 4.75 inches for a 2.45 GHz microwave. Thus, in one embodiment, the wave generating cavity has an internal rectangular (horizontal) cross section of approximately 2.84 inches by 1.34 inches. The size of the wave generating cavity and the positioning of the coupler 76 are determined by the well known microwave principle of wave generation.

The cross-sectional view of the impedance matching cavity 72 may be substantially the same as the wave generating cavity 70. The height of the impedance matching cavity is preferably an odd multiple of 1 / 4λ. In particular, the height 92 is approximately 3 / 4λ
Good.

The combined width 96 of the double slot is conveniently slightly larger than the width of the printed swath, so that all ink deposited on the swath is centered under the slot. In one embodiment, the slot length is about 3 inches and the dual slot width 96 is about 1/2 inch.

The edge 102 of the rectangular opening 86 of the bottom plate 80 is preferably about 1 / 4λ from the outer edge 104 of the bottom plate 80. With these dimensions,
The gap between the bottom plate 80 and the electrically conductive platen 18 acts as a stop to limit the microwaves to that area. Additional protection from microwave leaks is
GAE in Modesto California
FGM- from Ecosorb available from Engineering
It can be obtained by covering the outer surface of the applicator with a microwave absorbing material, such as 125. Using the Holladay microwave detector, the system leakage was 1 mw / c at 2.45 GHz, 2 feet away from the applicator mounted on the movable print carriage.
It was below m ² . Radio frequency leakage management is achievable with this design and design modifications suitable for a wide range of inkjet printer applications, including desktop size inkjet printers.

The above dimensions maximize absorption of microwave energy by the ink. This is because an electric field of substantially constant amplitude microwave frequency is produced with high intensity in the region near the double slot and low intensity outside the body and bottom plate of the microwave applicator. .

The general configuration of these electric fields is shown in FIG. This figure is an enlarged view of the dual slot 86 of the cross section of FIG. The electric field strength at various locations in the double slot region is indicated by arrow 98, where the longer arrow 98 indicates greater field strength and the direction of arrow 98 indicates the direction of the electric field. The electric field strength is strongest in the vicinity of the central plate and the region directly below it, and is oriented substantially vertically in this region. Moving away from the center, the strength gradually decreases and the field strength will have a larger horizontal component. The electric field becomes more vertical closer to the platen surface of the substantially conductive platen 18. It is preferred to include a bottom plate 80 that is separated from the electrically conductive platen 18 by a distance of about 0.2 inches.

When the applicator is in operation, microwave radiation exits the first slot shown in the wave-generating cavity 70, permeates the print media, and is then bounded by the interface between the bottom plate 80 and the platen 18 for electrical processing. It is guided and absorbed a second time by the print media before passing through the slot in the bottom of the impedance matching cavity 72. The waves are then of the impedance matching cavity 72,
It is reflected by the top electrically conductive plate and then emitted from the second slot for the third pass through the print media. Once again, the wave is guided by the boundary between the bottom plate 80 and the electrically treating platen 18, passes a fourth time to the print media and is absorbed by the slot of the wave generating cavity. In the wave-generating cavity, some of the re-absorbed power is then re-reflected for another set of passes through the media.

With proper tuning, close to 100% of the force can be absorbed by a thin layer of ink in a typical inkjet print media, regardless of range. With a large range, only two or three passes of microwave energy through the media can absorb all the power. In the narrow range, two or more passes of microwave energy through the media occur, and substantially all of the power is still absorbed.

It has been found that the effect of energy transfer to the ink is improved when the media is exposed to an electric field that has a large horizontal component parallel to the media plane. As described above, it is inconvenient to bring the medium into contact with the surface layer of the platen 18 which is oriented substantially vertically even though the electric field is strong. Rather,
During printing, it has been found useful to position the media approximately midway between the platen 18 and the bottom of the applicator. This position is indicated by the dotted line 100 in FIG. At this location, the media is exposed to an electric field parallel to the media plane and having a significant component, enhancing absorption of microwave energy and drying of the ink. The electric field strength at the media surface ranges from 3 × 10 ⁴ Volts / meter to 3 × 10 ⁶ Volts / meter with an applied power of between 50 and 600 Watts.

If the microwave energy source is attached to one of the end housings,
The microwave applicator as described above weighs less than 1 pound. When the microwave energy source is mounted in the immediate vicinity of the applicator, the total weight of the applicator and microwave energy source is less than 3 pounds if a magnetron energy source is used. If a solid state microwave energy source is used, the total weight of the applicator and microwave energy source can be less than 1.5 pounds. The low weight is beneficial to the process of moving the microwave applicator with the print carriage.

It is also possible to use center microwave frequencies other than 2.45 Ghz. 2.45 GHz is a licensed industrial use frequency band, and since the magnetron designed for this frequency is widely and inexpensively available, it is convenient and yet another licensed frequency band. Those between 921 and 929 MHz could also be used. At this wavelength, the above dimensions are slightly more than doubled.
Higher frequencies such as 5.8 GHz, 24.125 GHz, 61.25 GHz, 122.5 GHz and 245 GHz can also be used, reducing the size of the applicator and increasing the efficiency of energy absorption by the ink. It is an advantage. For example, at 24.125 GHz, the moving microwave applicator size is more than 10 times smaller than the microwave applicator described above. This would create an entire applicator as wide as one inkjet print strip. It also reduces weight to about 2 ounces. Microwave absorption of inks and other materials is proportional to microwave frequency.
Thus, for a unit volume of material, a 24.125 GHz source is 2.45
It is more than 10 times more efficient than a GHz source. Smaller applicators may be desirable for desk top size ink jet printers.

7A to 7C to generate an electric field having the general features shown in FIG.
Various dual slot configurations can be used, as shown in. For example, as shown in FIG. 7A, the central plate 74 can include flat bottom blades rather than taper. Alternatively, and as also shown in FIG. 7B, the central plate 74 is
Extendable through the double slot below the bottom plate of the applicator 68. In another embodiment, as shown in Figure 7C, the plate 74 is configured as a wedge. In this embodiment, the bottom plates of the cavities 70, 72 may be tapered following the wedge shape of the central plate 74, or may be flat plates as shown in Figures 7A and 7B.

FIG. 8 shows a cross section of the microwave applicator proximate platen 18 and a piece of media 106 under applicator 68. In this illustrative example, media 106 is supported above the surface of platen 18 by a layer of material covering platen 18. This layer of material keeps the media in the region of the electric field containing the relatively strong horizontal component described above with reference to FIG. The layers are preferably composed of three different types of materials. In the region 108 just below the double slot and just past the double slot, the material consists of a dielectric polymeric material that is substantially transparent to microwave energy. Many common plastics are suitable, such as PTFE, glass reinforced nylon, or others. In the outer area 110 of the dual slot area, the material is Modesto Calif.
a) Ecosorb F available from GAE Engineering
It consists of a microwave absorbing material, such as GM-125. The presence of microwave absorbing material on the perimeter of the dual slot further reduces microwave leakage beyond the perimeter of the applicator 68 and also before printing the next swath and after printing the last swath. , Can heat the media and further improve the ink drying characteristics of the system. In one embodiment, the distance 112 between the platen 18 and the bottom of the applicator 68 is approximately 0.2 inches and the layer thickness 114 is approximately 0.1 inches.

Another alternative embodiment of the present invention is shown in FIG. In this embodiment, the microwave applicator is stationary rather than mounted on the movable print carriage. FIG. 9 has a series of dual slots 120 formed therein,
A top view of the platen 18 is shown. Each dual slot 120, as described above, connects to the wave generating and impedance matching cavity, but is mounted below the platen 18. Thus, a series of microwave applicators extends along the platen, below the swath of ink.

In this embodiment, the carriage 44 comprises two substantially conductive plates 122a, 122b extending from each side. These metal plates 122a,
122 b is arranged right above the surface layer of the platen 18. For example, when the carriage moves to the left in FIG. 9, the ink applicator 48 deposits the swath.
As the draw plate 122b passes through each double slot, the corresponding microwave applicator is activated, thereby drying the ink between the double slot and the plate 122b. Inking and drying to the right continues in a similar fashion, but the pulling plate at this point is plate 122a.

The microwave ink drying apparatus and method described above provide a number of advantages over previously known systems. Energy wasted by reflections back to the source is minimized. Moreover, all inks are exposed to an electric field of substantially the same strength, forming a more uniform drying process.

Up to the present invention, the realization of heating or drying uniformity with a microwave applicator having a strong electric field region is achieved in a uniform manner with respect to the printed media or web, by arranging such a high electric field region applicator. Was difficult, so it was impractical. By moving the microwave applicator with the inkjet printhead, geometric non-uniformity problems are eliminated. The print surface is
Substantially always the same electric field is exposed during drying. In addition, drying occurs at the time of inking, rather than after the image is complete, which improves the effectiveness of the multiple pass printing technique.

In some embodiments, the reflected power is measurable and the microwave power is dynamically adjustable to compensate for changes in deposited ink density, matching ink drying across the entire image. Will further improve the sex. In these examples,
Microwave power is adjustable on a microsecond time scale. In this way, the sensor located on the tuner can sense the signal reflected from the applicator and can adjust the power level according to the ink range. For example, the power can be kept low if there is no ink deposit. Alternatively, the signals used to control the inkjet printing process could be used to control the amount of microwave power being applied. That is, 1 ink jet
When instructed to print in the 00% range, the signal was also able to keep the microwaves at the appropriate power. In other words, the microwave power is controllable and synchronizable with the ink-media system that coordinates the preservation process. This helps for color management and also to minimize segmentation.

Example 1: Single-slot Applicator Using a single-slot applicator with a slot size of 3 ″ × 0.18 ″, the rate of temperature rise of water-immersed paper placed in the immediate vicinity of the slot was measured. , Cole-Parmer infrared thermometer. 60
With watts of net microwave power, the temperature rise is 19 times over a period of 1-2 seconds.
It was 8 ° C. This is a heating rate of 1.6 ° C / Watt sec. At 2 seconds, the paper was seen to burn.

By comparison, US Patent Office 5 to Carreira, L.
, 220,346, the temperature rise of a rectangular microwave applicator (with ink in the test tube) was 29 ° C. in 5 seconds at 330 watts. this is,
The heating rate is only 0.017 ° C./watt second.

Example 2: Double Slot Applicator A double slot applicator 68 as described above is an ENCAD 600 dpi GO-Cyan printed on 100% coverage plain paper with an inkjet printer. Was used to dry. The bottom plate 80 has two parallel slots spaced about 1/8 '' apart, each about 3 inches long and 1/8 inch wide. A layer of styrofoam about 1/8 '' thick was placed on the electrically conductive platen 18 and the bottom plate 80 was located 0.04 inches above the printing paper. The overall separation between the bottom plate 80 and the electrically conductive platen was about 0.2 inches.

The ink dried almost instantly when about 150 watts of net power was applied by the microwave applicator 68. When the microwave application was continued, the paper actually reached a charred state within about 2 seconds. The ink under both slots was completely dried.

Example 3: Dye Sublimation An ink that sublimes when heated is printable on textiles. In general, after being printed, the dye sublimes where it passes through an infrared oven or hot air dryer, which raises the temperature to 400 ° F, and fixes it to the fabric.

Subliget from Sawgrass
) A blue dye sublimation ink was printed on white polyester using an inkjet printer and exposed to 200 watts of microwave energy from a double slot in the applicator for 2 seconds. The fabric was then washed. The result was that each of the two slots immobilized dye along the length of the slot.

Example 4: Drying of ink on non-porous, uncoated vinyl Drying of inkjet printing ink on a non-porous, uncoated vinyl sheet results in the ink forming beads. It is desirable but difficult because it can move on the surface. Immediate drying with microwaves can stop the migration of the ink and allow the ink to dry on the untreated vinyl surface.

ENCAD experimental GO-magage
nta) ink was printed on an untreated vinyl sheet and exposed to microwave energy from a dual slot microwave energy applicator. Upon exposure at 200 watts for 4 seconds, the ink adhered.

The present invention thus shows that two of the significant problems associated with drying ink on print media are solved. First, the uniformity of the electric field geometry is provided by moving the applicator over the surface. Second, multiple microwave paths through the media can achieve near 100 percent absorption efficiency for all levels of the ink range, both narrow and wide. Finally, the power level can be adjusted to match the ink loading.

Some inkjet printers, such as desk top inkjet printers, do not have an electrically conductive platen. For example, in some cases, when the printer carriage traverses the paper, the paper is supported by a thin plastic support. In other words, there is a space of air only below the media. Alternatively, the space could be filled with a ceramic or dielectric material.
The mobile microwave energy applicator concept of the present invention is adaptable to this situation. The electric field pattern near the slot antenna is still strong.
Removing the electrically conductive platen 18 of FIG. 6 does not affect the direction and magnitude of the electric field near the print media surface when the print media surface is in close proximity to the print media. Multiple paths of microwave energy through the media with proper impedance matching are still created. An electrically conductive surface could be included to help prevent microwave leakage and could be incorporated into the box containing the printer.

The present invention has a wide variety of advantages and applications. As described in detail above, drying inkjet ink deposited on paper media is one useful application. The sharpness of individual ink dots can be maintained by preventing the dots from spreading in the media. The coalescence of adjacent points can be prevented by drying them before they coalesce. Microwave drying between passes can be used to dry, or partially dry, the first ensemble of dots before the second ensemble is applied. , Minimize coalescence with the second set. The shape of the individual dots can be maintained by contacting them with other dots or by wetting the fibers of the media, allowing them to dry before their shape changes. Most importantly, the speed of drying and the quality of multi-pass printing can be greatly improved.

Aqueous ink jet printing aqueous vehicles create quality challenges if not substantially removed from the media. For example, if the sheet is over 50% print covered and the liquid is not removed rapidly, image defects such as strike throughs and paper distortions such as cockle can result.
The present invention essentially minimizes this type of problem by removing the liquid immediately after printing. The use of this invention allows the use of inexpensive photographic paper as no special coating is required to achieve absorption of the liquid in the ink. Substrates such as uncoated vinyl can be printed by inkjet printers regardless of surface tension.

The present invention can also be used in fields other than inkjet printing. For example, the electric field strength of the slots could be increased directly above the vinyl surface, causing the plasma activity of surface molecules and producing a controlled electrical decay plasma in the air. This type of surface modification could improve the adhesion of the ink on the vinyl surface. Another application of this type of continuous damping source is for sterilizing the surface of materials. The microwave applicator can be mounted on a moveable assembly and moveable within a computer controlled system and can be completed using microwave heating, for example throughout the wood surface and wood burning of the surface or fibers. did it. The properties of laminated laminar inkjet products can also be improved by the present invention. For example, removal of substantially all liquid from the ink and media prior to layering can increase UV resistance and color stability over time. Other inkjet products were also envisioned. For example, the field of stereolithography has benefited from the present invention. Inkjet solid-state imaging via a microwave applicator that moves with an inkjet printer, by moving a printer similar to an inkjet printer around a platform and projecting plastic microdots to produce a solid object. There was a benefit to immediate setting. In these examples, the inkjet printer could make a toy or other useful item by downloading patterns from the Internet.

The above description details certain embodiments of the present invention. However,
It will be appreciated that the present invention can be implemented in various ways, no matter how detailed the above description is in the text. Also, as stated above, the use of a particular term in describing a particular feature or aspect of the invention includes any particular feature or aspect of the invention to which the term pertains. It should be noted that the term is not to be construed herein as being redefined as such. The scope of the invention is therefore defined by the appended claims,
And therefore any equivalent thereof shall be construed accordingly.

[Brief description of drawings]

FIG. 1 is a front view of a floor-standing ink jet printer.

FIG. 2 is a front view of a moveable print carriage of an inkjet printer according to one embodiment of the present invention.

FIG. 3 is a perspective view of a microwave applicator suitable for mounting on the print carriage of FIG.

FIG. 4A is a plan view of an example of a dual slot configuration for a microwave applicator.

FIG. 4B is a plan view of another example of a dual slot configuration for a microwave applicator.

5 is a cross-sectional view of a microwave applicator suitable for mounting on the print carriage of FIG.

FIG. 6 is a cross-sectional view of a microwave applicator placed in close proximity to a substantially conductive printer platen.

FIG. 7A is a cross-sectional view of an example of a dual slot configuration for a microwave applicator.

FIG. 7B is a cross-sectional view of another example of a dual slot configuration for a microwave applicator.

FIG. 7C is a cross-sectional view of yet another example of a dual slot configuration for a microwave applicator.

FIG. 8 is a cross-sectional view of a microwave applicator placed in the immediate vicinity of a substantially conductive printer platen.

FIG. 9 is a top view of another printer embodiment having a platen that incorporates a series of stationary microwave slot antennas.

[Explanation of symbols]

10 printers, 11 horizontal housings, 12 horizontal housings, 14 legs, 18 platens, 20 support structures, 22 print carriages, 26 cartridges, 30 guide rods, 36 ink storage tanks, 38 tubes.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H05B 6/70 H05B 6/72 C 6/72 D B41J 3/04 101Z (31) Priority claim number 09 / 580, 512 (32) Priority date May 25, 2000 (May 25, 2000) (33) Priority claiming country United States (US) (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE, TR), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, MZ, SD, SL, SZ, TZ, UG, ZW), EA (AM, AZ, BY, KG) , KZ, D, RU, TJ, TM), AE, AG, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, BZ, CA, CH, CN, CR, CU, CZ, DE, DK, DM, DZ, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, KE, KG, KP, KR, KZ, LC, LK , LR, LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, MZ, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, TZ, UA, UG, UZ, VN, YU, ZA, ZW (72) Inventor Andrew Hugh Bushnell, USA 92131 Semiron Boulevard, San Diego, CA 11874 ( 72) Inventor Paul Robert Everhart USA 92024 Orange Blossom Way 1718 (72) inventor Encinitas, CA Peter James Ferringham United States 92129 Togan Avenue 9054 (72) San Diego, CA Inventor Min Chi Duong USA 92126 Caminito Jovial 10165, San Diego, CA (72) Inventor Deya Mortada Alfecri United States 92128 Halfolk Terrace, 11976 F Term, San Diego, CA (Reference) 2C056 EA05 EC14 EC29 EC31 HA46 HA49 2H086 BA02 BA05 3K090 AA02 AB20 BA01 BB19 CA13 CA16 CA17 DA02 DA07 DA20 3L113 AA03 AB07 AC12 AC69 BA01 DA24

Claims (53)

[Claims] 1. A method of drying ink during or after an ink jet printing process comprising passing a microwave energy applicator over a deposited ink droplet, thereby heating the deposited ink droplet. 2. The method of claim 1, wherein the passing is performed at the same speed as the print carriage movement. 3. The method of claim 1, wherein the passing is performed within approximately 5 seconds after depositing the deposited ink drop. 4. The passage is approximately zero after depositing the deposited ink droplets.
The method of claim 1, wherein the method is performed within 1 second. 5. Depositing swaths of ink droplets using a plurality of successive passes of at least one inkjet printhead: between said at least one successive pass having microwave radiation. A method of inkjet printing, comprising drying the deposited ink droplets before performing the next pass of. 6. The method of claim 5, wherein the drying is performed by moving a microwave energy applicator over the deposited ink droplet during each pass of the continuous pass. 7. The method of claim 5, wherein the drying is performed by passing a metal plate attached to the print carriage through a dual slot radiator embedded in the platen. 8. The method of claim 7, wherein the dual slot radiators are sequentially turned on to dry the ink as the metal plates pass through them. 9. A platen forming a printed surface; a source of microwave frequency energy; and a combination of inks coupled to receive the microwave frequency energy from the source before the print media exits the printed surface. At least one microwave energy applicator positioned with respect to the printed surface such that the ink dries when the swath is deposited on the print media. Inkjet printer consisting of. 10. The ink jet printer according to claim 9, further comprising a print carriage configured to move on the platen during a printing process. 11. The at least one microwave energy applicator mounted to the print carriage such that at least one microwave cavity opening passes over the print surface during a printing operation. ,
The inkjet printer according to claim 10. 12. The ink jet printer of claim 10, wherein the microwave energy source is mounted on the print carriage. 13. The ink jet printer of claim 11, wherein the microwave energy source is mounted on the print carriage. 14. The inkjet printer of claim 10, wherein the microwave cavity opening comprises a microwave antenna. 15. The inkjet printer of claim 14, wherein at least one microwave slot antenna is integrated into the bottom plate of the microwave applicator. 16. The ink jet printer according to claim 14, wherein at least one circular antenna is integrated into the bottom plate. 17. The inkjet printer of claim 14, wherein at least one cruciform antenna is integrated into the bottom plate. 18. The ink jet printer according to claim 14, wherein at least one horn antenna is integrated into the bottom plate. 19. Microwave energy on a movable print carriage.
A method of making an inkjet printer, comprising mounting an applicator. 20. The method of claim 19, wherein mounting the microwave energy applicator comprises placing a microwave cavity opening in the immediate vicinity of the print surface of the inkjet printer. 21. The method of claim 20, comprising forming the microwave cavity opening in a bottom plate of the microwave energy applicator. 22. The method of claim 21, further comprising forming the printed surface from an electrically conductive material. 23. The method of claim 22, wherein the microwave electric field in the gap between the bottom plate and the platen is greater than 2 × 10 ⁴ volts / meter. 24. The method of claim 22, further comprising disposing a layer of dielectric material on the printed surface. 25. A media disposed on the surface is exposed to an electric field from the microwave energy applicator, the thickness of the dielectric material layer comprising a significant component parallel to the printed surface. 25. The method of claim 24, wherein 26. A platen forming a printed surface; a source of microwave frequency energy; a movable print carriage configured to pass through the printed surface during a printing operation; to receive the microwave frequency energy from the source. An ink jet printer comprising at least one microwave applicator mounted on the moveable print carriage, coupled and positioned proximate to the printing surface. 27. The inkjet printer of claim 26, wherein the microwave applicator includes a slot antenna. 28. The microwave applicator includes a circular antenna.
The inkjet printer according to claim 26. 29. The inkjet printer of claim 26, wherein the microwave applicator comprises a cross antenna. 30. The inkjet printer of claim 26, wherein the microwave applicator includes a horn antenna. 31. The inkjet printer of claim 26, wherein the microwave applicator includes a pair of cavities. 32. The ink jet printer according to claim 26, wherein the microwave applicator includes a pair of cavities substantially separated by electrically conductive walls. 33. The ink jet printer according to claim 32, wherein the cavity is substantially impedance matched. 34. The inkjet printer of claim 26, wherein the bottommost portion of the microwave applicator is separated from the platen by a distance of less than about 0.5 inches. 35. The inkjet printer of claim 26, wherein the platen comprises a substantially conductive material. 36. The ink jet printer according to claim 26, wherein the platen comprises a substantially conductive material having at least a portion covered with an electrostatic material. 37. The ink jet printer of claim 26, wherein the electrostatic material has a strip that is substantially disposed under the microwave applicator. 38. The inkjet printer of claim 37, further comprising a strip of microwave absorbing material on each side of the strip of electrostatic material. 39. A first cavity having a first opening therein; a second cavity having a second opening therein; the first and second cavities and the first and second cavities. A microwave energy applicator consisting of a substantially conductive barrier that bounds two openings. 40. The first cavity includes a connector for coupling to a microwave energy source and the second cavity is substantially impedance matched to the first cavity. 40. The microwave energy applicator of claim 39. 41. A source of microwave energy as an electromagnetic energy output at a substantially selected wavelength; including a microwave applicator coupled to the source of microwave energy, the microwave applicator having a first interior therein. A first cavity having an opening; a second cavity having a second opening therein; forming a boundary between the first and second cavities and the first and second openings , A substantially conductive barrier, wherein said first and second openings are arranged to be positionable adjacent a sheet to be heated and / or dried,
A bottom plate supporting the first cavity and the second cavity, disposed on one side of the microwave applicator substantially adjacent to each other. Microwave energy application system for heating and / or drying and / or immobilizing dyes on sheet material. 42. The first cavity has about 4 of the selected center wavelengths.
42. The microwave energy application system of claim 41, which is a wave generating cavity having a first dimension of / 5. 43. The microwave energy application system of claim 41, wherein the first cavity extends in a second dimension that is approximately one quarter of the selected center wavelength. 44. The microwave energy application system of claim 41, wherein the first cavity extends in a third dimension approximately 3/5 of the selected center wavelength. 45. The microwave energy application system of claim 41, wherein the second cavity extends with a first dimension that is an odd multiple of approximately one quarter of the selected center wavelength. 46. The microwave energy application system of claim 45, wherein the second cavity extends in a second dimension that is approximately one quarter of the selected center wavelength. 47. The microwave energy application system of claim 46, wherein the second cavity extends in a third dimension of approximately 3/5 of the selected center wavelength. 48. The microwave energy application system of claim 41, wherein the selected center wavelength corresponds to a frequency of approximately 2.45 GHz and is approximately 4.75 inches in free space. 49. The microwave energy application system of claim 41, wherein the selected wavelength matches a frequency between 300 MHz and 245 GHz. 50. The microwave energy application system of claim 41, wherein the bottom plate is less than 0.5 inches away from the platen. 51. The microwave energy application system of claim 41, wherein the conductive platen is absent and the print media is supported by a plastic support. 52. The microwave energy application system of claim 41, wherein the microwave energy source is mounted within the end housing of the printer and the microwave energy applicator is less than about 1 pound. 53. The microwave energy application system of claim 41, wherein the microwave energy application system is less than about 3 pounds.