JP2004508220A - Method and apparatus for printing on rigid panels and on textured or textured surfaces - Google Patents

Abstract

Ink jet printing is performed on a rigid panel (15) having a textured surface (16). The panel (15) is printed using UV-curable ink and the ink can be more completely cured and dried off by using heating. The distance from the printhead to the panel is adjustable to maintain a predetermined constant distance from the printing element to the panel surface. Each of the print heads (130a-130d) is independently movable to control the distance of the print head from the substrate. A sensor (138) measures the distance from the printhead to the surface of the substrate. An ultraviolet curing head can be disposed on the print head carriage (129). A low temperature UV light source can be used to prevent thermal deformation of flat or uneven substrates, thereby effecting spot curing on heat-sensitive substrates.

Description

[0001]
This application claims priority to US patent application Ser. No. 09 / 650,596 filed on Aug. 30, 2000 and No. 09 / 822,795 filed on Mar. 30, 2001. The two are hereby expressly incorporated by reference.
(Field of the Invention)
The present invention relates to printing on rigid substrates and to printing on textured, textured or other three-dimensional substrates. In particular, the present invention relates to printing on substrates or objects having a woven fabric surface, rigid panels such as office partitions and automobile interior panels, and other textured objects. And to such printing using ink jet printing techniques.
[0002]
(Background of the Invention)
In order to deposit ink on a substrate by ink jet printing, a proper spacing between the ink jet nozzles and the surface of the substrate to be printed is required. In order to maintain effective printing by the ink jet method, such a distance must usually be set within one or two millimeters. If the distance between the nozzles and the printing surface is too large, the error of the droplets coming from different nozzles from the ideal parallel path will increase. Furthermore, the longer the flight path of the droplet from the print head to the substrate, the more the printing accuracy depends on the relative speed between the print head and the substrate. These dependencies, including changes in direction, limit the rate of change of the print head relative to the speed of the substrate. Also, as the speed at which the droplets move from the print head nozzle to the substrate decreases with the distance traveled from the nozzle, and as the distance from the nozzle to the substrate increases, the path of such droplets increases. Are increasingly affected by airflow and other factors. Moreover, as the droplet moves away from the nozzle, the shape of the droplet changes, thereby changing the effect of the droplet on the substrate. Thus, varying the distance from the print head to the substrate produces an irregular effect on the printed image.
[0003]
In addition to the problem of ink ejection onto a textured surface, if the surface is textured, the UV ink requires strictly focused UV energy to deliver sufficient curing energy to the ink. Curing is difficult to achieve.
[0004]
Some substrates deform, even temporarily, when heated. Such deformation may occur temporarily. For example, when the material is cooled, the material returns to the state before the deformation. However, print quality can be adversely affected, even if it is a temporary deformation, when it occurs while the ink is being ejected onto the substrate. Spot curing of ultraviolet ink, achieved by exposing the ink to ultraviolet light as soon as the ink comes into contact with the substrate, causes the foam to be exposed to ultraviolet radiation with exothermic radiation when the ink jet passes one or more times over the print area. -A printed material such as a board may be deformed.
[0005]
For the reasons mentioned above, ink-jet printing has not been successful on textured materials and other three-dimensional substrates, especially printing with UV-curable ink has been successful with ink-jet printing. Did not.
[0006]
(Summary of the Invention)
One object of the present invention is to provide textured surfaces such as quilts and mattress covers on three-dimensional substrates, especially on highly woven fabrics, tufted or irregular fabrics and other materials. Above, furthermore, printing on molded or stamped and otherwise shaped rigid or semi-rigid materials, and on other three-dimensional surfaces. One particular object of the present invention is to print on such surfaces using ink jet or digital printing techniques. Another specific object of the present invention is to print on such a substrate using an ultraviolet curable ink.
[0007]
According to the principles of the present invention, an image is printed on a three-dimensional substrate by a printing element that is movable with respect to a printing plane of the substrate. In some embodiments, the present invention provides ink jet printing devices for a wide range of substrates having printheads that move toward or away from the plane of the substrate. Maintain a fixed distance between the nozzles of the print head and the surface from which the ink is ejected. The variable distance above the substrate plane provides a controlled and uniform ink ejection distance.
[0008]
In one embodiment of the invention, the printing element is an ink jet print head set having a plurality of heads, typically four heads, each of the plurality of heads being a set of multi-colored heads. One color is quantitatively ejected onto a printing material to form a multicolor image. In order to maintain a constant distance or otherwise control the distance, one or the other is used to measure the distance from the trajectory of the printhead or printhead carriage to the point on the substrate where ink should be ejected. It has a plurality of sensors. The sensor generates a reference signal that is supplied to a controller that controls a servo motor on the printhead carriage. The print head is movably mounted on a carriage, for example, on a ball screw mechanism, and is movable toward and away from the plane of the substrate by operation of a servo motor.
[0009]
In one preferred embodiment of the invention, a set of four different color printheads are each individually movable with respect to a common printhead carriage and their position with respect to the plane of the substrate is Each is coupled to a set of four servo motors that can be controlled relative to other print head positions. A set of these printheads are arranged transversely side by side on the carriage so that the carriage sequentially scans across the width of the substrate as it scans the substrate in the transverse direction. Is preferred. Each head has a plurality of ink jet nozzles for dispensing ink of a given color in a corresponding plurality of dots, for example, 128 dots, and these nozzles are reciprocated. It extends in a straight line transverse to the table, ie in a longitudinal direction perpendicular to the scanning direction of the carriage. Two laser or optical sensors are provided on the carriage, one on each side of the head, so that when the head is scanning in both directions, the distance from its surface to the substrate can be measured in front of the print head. The control unit records the irregularities of the print object in front of the print head and controls each print head so that each independently movable head follows the recess of the print object and maintains a fixed distance from the printing surface. As it passes over the location where the measurements were taken, the position of the respective print head is changed towards and away from the substrate plane.
[0010]
It is preferred to adjust the position of the print head or its nozzles with respect to the substrate fixed on the frame of the printing machine, but, alternatively, for a print head maintained at a fixed vertical position. The substrate surface can be positioned on the frame.
[0011]
Preferably, UV ink is printed on the material and curing of the ink is initiated by exposure to UV light. Ultraviolet curing light sources can be mounted on the printhead carriage, one on each side of the printhead set, to expose the print surface behind the head. By mounting the UV curing light source on the print head carriage in such a manner, the ejected ink can be spot cured immediately after contacting the substrate, thereby solidifying the dots into place and allowing them to solidify. Prevents diffusion on or infiltration of the substrate. In some substrates, a conventional or broad-spectrum, ultraviolet-curing light source includes radiation that can heat the substrate. In the case of foam boards and some other commonly used substrates, this light source heats and deforms the substrate. Normally, this deposition is temporary in that the substrate is blistered or expanded when heated, but returns to its original state when cooled. No harm occurs if the UV irradiation is performed downstream of the print head carriage. However, spot curing deforms the substrate at the time of printing, thereby adversely affecting the quality of the ink jet printing operation. This may be a "cold UV" source or filter or other energy source, such as a limited bandwidth UV light source, such that the energy from the light source pouring onto the substrate does not include enough energy to heat the substrate. This is prevented by using a light source that includes a limiting device. This can be done by supplying sufficient UV energy at the appropriate frequency to cure the ink without heating the substrate. INDUSTRIAL APPLICABILITY The present invention is useful for printing on a printing material that may be deformed when heated, even temporarily. This deformation causes the substrate to deform when the ink jet passes one or more times over the print area, even temporarily, such that the material returns to its pre-deformation state when the material cools. Spot curing has an adverse effect on print quality. This is especially a problem when printing on a foam board, which constitutes most applications of printing on rigid substrates. If the board were to be deformed in this way during printing, the head height would have to be adjusted separately above the deformation area. The higher the head height, the lower the quality of the print, due to flight satellites and time issues, to name a few. In low temperature UV systems, the print quality can be maximized by minimizing the distance from the head to the substrate.
[0012]
In conventional practice, except for those proposed by the applicant in the parent application, spot-curing has never been ink jet printed on a rigid substrate. However, low temperature ultraviolet light, which cures the ultraviolet ink downstream of the printing station, is known, if used to prevent permanent deformation or thermal damage to the substrate. Temporary deformation, which disappears when the substrate cools, has not been a problem in the prior art. If the surface is slightly bumpy or warped as the ink is being ejected onto the substrate, it can occur during spot curing, but such deformation may be a problem.
[0013]
Simultaneously with or after irradiation with UV light, the printed fibrous material or other texture or porous fabric receives heat, preferably by blowing hot air on these materials downstream of the printing station, which is Is to continue the curing process started in and remove the uncured components of the ink. For quilted substrate fiber materials, the UV curable ink is injected onto the fabric and the injected ink is exposed to an UV light source to cure the ink, preferably to about 90 to 97% polymerization, and then partially cured. The fabric containing the ejected ink is UV-initiated to produce a printed image of the UV ink containing a small amount of uncured monomer or other ink component, eg, less than 0.01%. The polymerization proceeds or the uncured monomer evaporates or they are heated in a hot air blow-curing oven.
[0014]
When injecting ultraviolet ink onto highly woven fabrics such as cotton fabric materials for mattress covers, the ink is ejected at a dot density from about 180 × 254 dpi per color to about 300 × 300 dpi per color. You. Some common UV inks utilize a UV ink jet printhead to color the four colors of the CMYK color palette at, for example, about 75 picoliters or about 80 nanograms per drop or dot, respectively. Attach. With a UV curable light head that moves with or independently of the printhead, the light is approximately 1 cm per linear inch at approximately 300 watts. ² Irradiating the deposited droplets of UV ink with about 1 Joule of energy per shot, thereby producing at least 90% UV cure. The fabric, thereby partially UV curing the ejected ink, is passed through an oven that heats it to about 149 ° C (300 ° F) for about 30 seconds to about 3 minutes. In the oven, heating is preferably performed using forced hot air, but other heating methods such as infrared or other radiant heating devices can also be used. The same parameters may be used for rigid panels covered with cloth, such as office partitions.
[0015]
When printing on textured materials, determine the distance from the print head to the substrate to which ink is to be applied by measuring the distance from the sensor to the substrate in front of the print head and mapping the position of the surface. Can be. For a bi-directional print head moving across a longitudinally advancing fabric, having two distance measurement sensors, one on each opposing side of the print head, allows the print head to move in either direction. When moving, measure the distance to the uneven fabric ground. For some inks or sufficiently rigid materials, for example, two rollers and a printing roller may be provided, with one roller in front of the print head and one head having a pair of rollers behind the print head. A mechanical rolling sensor can be used so that the average distance between reference points on the head can be used to control the distance of the print head from the plane of the substrate. To accomplish this, one or more printheads are mounted on a carriage having rollers on the ends such that the mechanical link between the rollers moves the printhead relative to the plane of the substrate. be able to. In most cases, instead of a respective roller, a non-contact sensor such as a laser or photo eye sensor is preferred. The outputs of the two sensors on opposing sides of the printhead are transmitted to a processor to measure the distance from the head to the fabric in front of the bidirectional head, the printhead moves parallel to the uneven surface and A servo motor coupled to the print head can be driven to raise and lower the head relative to the surface of the substrate so as to eject ink over a fixed distance onto the fabric.
[0016]
These and other objects of the invention will be readily apparent from the following detailed description of preferred embodiments of the invention.
[0017]
(Detailed description of preferred embodiments)
FIG. 1 illustrates a machine 10 for printing on a rigid panel. The machine 10 includes a stationary frame 11 having a longitudinal length indicated by arrow 12 and a transverse length indicated by arrow 13. The machine 10 has a front end 14 that feeds a rigid panel 15 forward such that an office partition can be made. The panel 15 can include a metal or wooden frame 17 over which the cladding forming the surface 16 to be printed is spread. The surface 16 may be a flat but highly woven fabric, a molding such as a foamed resin product or some other textured or varied surface. The panels 15 are conveyed longitudinally over the machine 10 by a conveyor or conveyor system 20, which extends along the length of the machine 10 and places the panels 15 thereon. It is formed from a pair of opposing pin tentering belt sets 21 supplied at the front end 14. In order to transport the panel 15 along the longitudinal length of the machine 10, the panel is positioned at a precisely recognized longitudinal position on the belt set 21, preferably with an accuracy of 1/4 inch. Hold 15 The movement of the conveyor 20 in the longitudinal direction of the belt 21 is controlled by a conveyor driving device 22. The conveyor 20 may be an opposed toothed belt side anchoring device, a longitudinally movable positive side clamp that engages the panel 15, or other anchoring that holds the panel 15 secured to the conveyor 20. Alternatives, such as structure, may be taken, but are not limited thereto.
[0018]
Three stations are provided along the conveyor 20, including an ink jet printing station 25, an ultraviolet curing station 24, and a heat drying station 26. Printing station 25 includes an ink jet carriage having one or more ink jet print heads 30. The carriage of the print head 30 can be traversed on the front of a cross bar 28 extending across the frame 11 by the power of a transverse servo drive motor 31 and an optional longitudinal drive 32. Although shown and not required, it is also movable longitudinally on the frame 11. Alternatively, the head 30 may be configured to extend across the web 15 and print the entire traversal of the selectable points simultaneously on the panel 15.
[0019]
The ink jet print head 30 is configured, for example, to emit ultraviolet ink at 75 picoliters or about 80 nanograms per drop, and may do so for each of the four colors according to the CMYK color palette. Preferably, these dots are provided at a resolution of about 180 dpi times about 254 dpi. The resolution can be higher or lower as desired, but a resolution of 180 × 254 is preferred. If a sharper image or higher saturation is desired, 300 × 300 dpi is preferred. Droplets of different colors can be side-by-side or dot-on-dot. Dot-on-dot (sometimes called drop-on-drop) produces high density.
[0020]
The print head 30 includes a controller that can selectively operate the head 30 to selectively print one or more color designs on the surface of the panel 15. The operations of the drive unit 22 for the conveyor 20, the drive units 31 and 32 for the print head 30, and the print head 30 are program-controlled by the control unit 35 to print the pattern 33 at a known location on the panel 15. However, the control system provides the programmed pattern, the machine control program and current data regarding the nature and longitudinal and transverse positions of the printed design 33 on the panel 15 and the relative position of the panel 15 on the machine 10. And a storage device 36 for storing various longitudinal positions.
[0021]
The UV curing station 24 includes an UV curing head 23 that is movable with the print head 30 or, as shown, independently of the print head 30. The ultraviolet curing head 23 is configured to precisely focus a narrow, vertically extending light beam of ultraviolet light onto the printing surface of the fabric. The UV curing head 23 is provided with a transverse drive 19 which controls the transverse scanning of the printed surface of the fabric to move the light beam across the fabric.
[0022]
The curing head 23 is preferably intelligently controlled by the controller 35 and operates selectively to move quickly across unprinted areas and to cure the ink with ultraviolet light. At slow speeds, the UV only scans the printed image, thereby avoiding the waste of time and UV energy scanning over unprinted areas. If the head 23 is included in the printing station 25 and is coupled so as to move with the print head 30, the ultraviolet curing light can be used immediately after the ink is dispensed in synchronization with the dispensing of the ink.
[0023]
UV curing station 24 is preferably located on the printhead carriage immediately downstream of printing station 25, or on both sides of the printhead in the illustrated embodiment, such that the fabric is exposed to UV curing immediately after printing. Has become. By mounting the curing head on the carriage in this way, the ink dots can be coagulated at the locations where they are attached, thereby preventing the diffusion of small droplets and the infiltration of ink. In particular, when an ultraviolet curing head is mounted on a carriage, the ultraviolet curing head is low-temperature ultraviolet light, and a filter or a narrow band of radiation is used to heat a heat-sensitive printing material such as a foam board to form an ink. Do not deform the droplets where they adhere. Such low temperature UV curing light systems use low temperature mirrors, IR blocking filters and water cooled UV curing to keep the temperature of the substrate low.
[0024]
Theoretically, one photon of UV light is needed to cure one free radical of the ink monomer to fix the ink. In practice, the printing surface area is 1 cm ² Irradiate 1 joule of UV energy per shot. This is accomplished by sweeping ultraviolet light across the printed area of the fabric at a power of 300 watts per linear inch of light width. This is sufficient to produce at least 90% UV cure. Ultraviolet power can be increased to 600 watts per linear inch to achieve 97% or greater cure. Alternatively, if the fabric is not too thick and opaque, curing light can be applied from both sides of the fabric to promote curing of the UV ink. If a larger power is used, the fabric may be burned or burned, so that there is a practical upper limit to the power of the ultraviolet light.
[0025]
The heat curing or drying station 26 may be mounted on the downstream frame 11 of the UV curing station or may be located off-line. With 97% UV curing, the color fastness is sufficient and allows the drying station to be offline. When on-line, the drying station must be extended sufficiently along the length of the fabric to properly cure the printed ink at the speed of printing the fabric. When located off-line, the heat cure station can be operated at a speed different from the printing speed. For heat curing in oven or drying station 26, the ink on the fabric is maintained at about 149 ° C (300 ° F) for up to three minutes. Heating from 30 seconds to 3 minutes is an advantageous value range to expect. Heating with forced hot air is preferred, but other heat sources such as infrared heaters may be used as long as they adequately penetrate the fabric to the depth of the ink.
[0026]
The quilting station can be located on-line or off-line with the printing station, and can be located before or after the printing station. The placement of the quilting station downstream of oven 26 is advantageous in the case of quilted hangers and mattress covers and where quilting and alignment should be performed while printing on fabric. Described in U.S. Pat. No. 5,832,849 entitled "Rewindable Chain Stitch Single-needle Mattress Cover Quilting Machine to Compensate for Needle Distortion" issued to Kaetterhenry et al. And specifically incorporated herein by reference. A single-needle quilting station can be used, as is the case. Other suitable single-needle quilting machines in which the present invention can be used are disclosed in U.S. Patent Nos. 5,640,916 and 5,685,250, respectively, both entitled "Quilting Methods and Apparatus". And they are hereby expressly incorporated by reference. Such a quilting station may also include a double-needle quilting structure as disclosed in US Pat. No. 5,154,130, also specifically incorporated herein by reference.
[0027]
If quilting, molding or other irregularities are to be applied to the substrate before printing on it, it is usually desirable to align the print with the previously applied irregularities. In order to align the print with the previously applied asperities, the position of the asperity pattern can be calculated relative to a reference point on the substrate that can be detected by a sensor at the printing station. As shown in FIGS. 2 and 2A as 40a and 40b, respectively, the pattern position can be directly detected by the sensor 40 mounted on the print head 30. The print head 30 includes an array 41 of nozzles or ink jet nozzles that face downward relative to the upper surface 16 of the substrate, such as the panel 15. For example, panel 15 may include a recess or groove 43 formed on its surface 16 by stitching or molding, as shown in FIG. Sensor 40 measures the distance from nozzle 41 to surface 16. The information from the sensor 40 is transmitted to the control device 35, and further correlated with the longitudinal and transverse position information of the print head 30 and converted so as to specify the position of the concavo-convex pattern. So that the print image can be printed on the surface 16.
[0028]
In the embodiment of FIG. 2, the sensor 40 is a mechanical sensor 40a including a wheeled carriage 45. Nozzle 41 is mounted at the midpoint of carriage 45, which is then pivotally connected to print head 30 about a longitudinal axis 46 passing through its center. The carriage 45 has left and right detection wheels 47 and 48 which ride on the surface 16 of the panel 15 and follow irregularities, respectively. The carriage 45 moves perpendicular to the print head 30 and follows the irregularities on the surface 16. The nozzle 41 is located in the middle between the wheels 47 and 48, but is arranged vertically at the vertical average position of the wheels 47 and 48. In this way, when the wheels 47, 48 ride on the surface 16, in response to the detection position of the surface 16 of the panel 15 measured by the carriage 45, the nozzle 41 is moved to a control distance with respect to the surface 16 of the panel 15. Position passively.
[0029]
Preferably, the distance between the UV head 23 and the fabric is also controllable such that the curing light is always accurately focused on the uneven printing surface of the fabric. Such distance control may be provided by transmitting ultraviolet light via optical fibers adjacent to the printhead, for example, with one fiber on each side of the printhead, or by a separate carriage. This is possible by mounting the UV-curing head 23 thereon, and by mounting a UV-curing head that moves with the print head, such as by providing a separate servo motor for adjusting the distance. Individual control of the UV curing head 23 can be performed by responding to a sensor used to measure the print head distance, or by responding to a separate sensor provided to measure the curing head distance. . If the printhead sensor is used to control the distance from the curing head to the fabric, a storage device may be used to store a map of the surface or a portion of the surface, and the control device may store the map from the storage device. , Accurate distance information corresponding to the position of the curing head located above is obtained. Alternatively, the focal length of the ultraviolet light from the light source can be automatically changed while the ultraviolet curing head is fixed.
[0030]
Whether there is an embossed pattern on the surface 16 of the panel 15 or simply includes textured material, the quality of the print is such that a precise spacing between the nozzle 41 and the surface 16 of the panel 15 is maintained. Therefore, it is maintained. FIG. 2A illustrates a rigid panel 15 having an upward facing surface 16 that is coarsely woven or covered with a woven fabric. As the print head 30 moves transversely over the cross bar 28, the vertical position relative to the print head 30 where the nozzles 41 are directed on the panel 15 surface 16 often changes by more than one millimeter. To measure such a change in distance, an optical or laser sensor 40b is provided on the printhead 30 or on the carriage at a fixed height above the fabric support surface. The sensor 40 b immediately measures the distance from the nozzle 41 to the surface 16 of the panel 15, and transmits the measured value to the control device 35. The nozzle 41 is mounted on an output actuator 51 of a servo motor 50 mounted in the print head 30. The controller 35 sends a control signal to the servomotor 50 in response to the distance measurement from the sensor 40b to maintain a constant distance from the nozzle 41 to the surface 16 of the panel 15, and The nozzle 41 on 30 is moved in the vertical direction.
[0031]
Even when printing on a rigid panel with no texture or irregularities on the surface, when supporting it on the frame of the printing device, the rigid frame of the panel and the thickness of the panel make the top surface of the panel unpredictable. There may be advantages by sensing and adjusting the distance from the print nozzle to the panel surface.
[0032]
FIG. 1A illustrates one alternative embodiment 100 of the machine 10. This machine embodiment 100 includes a stationary frame 111 having a longitudinal length indicated by arrow 112 and a transverse length indicated by arrow 113. The machine 100 loads the rigid office partition panel 15 onto a belt 121 of a conveyor system 120 having one or more flights that carry the rigid office partition panel 15 through the length of the machine 100. It has a front end 114 that can be used. The belt 121 of the conveyor 120 extends across the width of the frame 111 and rests on a smooth stainless steel vacuum table 105 which communicates with the back of the belt 121 therein. It has a number of upwardly directed vacuum holes 106. The belt 121 is sufficiently porous that the vacuum from the table 105 communicates with the back surface of the rigid panel 15 via the belt 121 and assists gravity in holding the panel 15 in place against the upper surface of the belt 121. It becomes. The belt 121 preferably has a high friction rubber-like surface 108 that assists in preventing horizontal sliding of panels resting on the belt, which surface 108 has a number of vacuum connections from the table 105 to the substrate. Are provided.
[0033]
The upper surface of the belt 121 of the conveyor 120 provides sufficient friction between its upper surface and the backside of the panel 15 to prevent the panel 15 from sliding horizontally on the conveyor 120. In addition, the conveyor 120 is sufficiently inelastic to allow precise advancement. To this end, an inelastic and coarse backing material 107 is provided on the belt 121 to provide dimensional stability to the belt, and a vacuum communicates between the holes 106 in the table 105 and the holes 109 in the surface of the belt 121. can do. The forward movement of the panel 15 on the frame 111 can be precisely controlled by indexing the belt 121 by controlling the servo drive motor 122 with a signal from the control device 35. The belt 121 thereby holds the panel 15 in a precise, recognized longitudinal position on the belt 121 to transport the panel 15 through the longitudinal length of the machine 100. Such indexing of the belt 121, when used to move the panel 15 relative to the printhead (an embodiment not shown) on the fixed bridge, is about 0.0005 inches (0.0012 cm). Must be controllable up to the accuracy of
[0034]
In the embodiment 100 of FIG. 1A, the longitudinal movement of the belt 121 of the conveyor 120 is controlled by a conveyor drive 122 to move the panel to a printing position and then send it downstream after printing. One or more additional individually controllable drives 132 may be provided to control the downstream flight (if provided) of the conveyor 120.
[0035]
Three stations, including an ink jet printing station 125 and one or more curing or drying stations, which may include an ultraviolet curing station 124 and / or a heating station 126, are along the length of the travel of the conveyor 120. Equipped. Printing station 125 includes bridge 128. If the belt 121 is operable to accurately index the panel 15 against this bridge 128, the bridge can be attached to the frame 111 and extend across it. The printhead carriage 129 is traversable across the bridge 128 and has one or more sets of ink jet printheads 130 thereon. Preferably, the carriage 129 is mounted on the armature of a linear servomotor 131 having a linear array of stator magnets extending transversely across the bridge 128, and the carriage 129 is positioned so that It becomes traversable from end to end, and the drive control signal is transmitted to the servo 131 by the controller 35 as described above.
[0036]
In the illustrated embodiment, a bridge 128 is attached to a movable armature 133a, 134a that rides on a longitudinal track 133b, 134b of a linear servo motor 133, 134 on each side of the conveyor 120. Once the panel 15 is positioned below the bridge 128 by moving the belt 121, the bridge 128 is moved longitudinally while the transverse image band is printed in a continuous scan of the print head 130, as described below. Find out. The index must be as accurate as necessary to ensure that scan lines are aligned and skippable as needed to produce the desired print quality and resolution. . Preferably, such precision is about 0.0005 inches. Low resolution, and thus low accuracy, is acceptable for printing on different fiber surfaces than on smooth surfaces such as vinyl.
[0037]
FIG. 3 illustrates a set 130 of four ink jet print heads 130a-130d configured to respectively cover the four colors of the CMYK color set. Each of these ink jet print heads 130a-130d has 128 ink jet nozzles extending in a row longitudinally with respect to the frame 111 and perpendicular to the direction of movement of the carriage 129 on the bridge 128. Linear arrays. The nozzles of each head 130 eject one UV ink of the CMYK color side-by-side simultaneously, but selectively, across the substrate 15 and in a continuous cycle as the nozzles scan the substrate 15. It is configured and controlled to do so. A set of heads 130a-130d are arranged in parallel such that carriage 129 continuously prints across the same substrate 15 area moving across the bridge, each having a respective dot location across substrate 15. One of the four colors is sequentially deposited on the top.
[0038]
Each of the heads 130a to 130d is movably mounted on a carriage so as to move vertically, that is, perpendicularly to the plane of the printing object 15 independently. The distance of each of the heads 130a to 130d from the plane of the printing object 15 is controlled by each of a set of servos 137a to 137d attached to the carriage 129 so that the heads 130a to 130d follow the same unevenness of the printing object 15 one after another. . Servos 137a to 137d are provided by a signal from a controller 35 for controlling the positions of the heads 130a to 130d in order to maintain the control distance from the surface 16 of the printing material 15 having the unevenness on the surface 16 of the printing material 15. Respond to
[0039]
It is usually desirable for these heads to keep them at a certain distance from the surface 16 to be printed. This is realized by providing the optical sensors 138a and 138b on the opposite lateral sides of the carriage 129. The print head set 130 is bidirectional and prints whether it moves to the left or right. As the print head carriage 129 moves over the bridge 128, the leading of the sensor 138a or 138b may be directly collinear with the sensor 138, i.e., typically the sensor 138 and the surface 16 of the substrate 15 directly beneath. Measure the distance between Such measurements are transmitted to the controller 35, which records the measured distance and the coordinates on the surface 16 of the substrate 15 from which the measurements were taken. These coordinates need only include the transverse position on the substrate 15 that will use this information in the same pass or scan line of the carriage from which the measurements were taken. However, the controller 35 can also record longitudinal coordinates by considering the position of the panel 15 on the frame 111 relative to the bridge 128.
[0040]
When each head reaches the transverse position on the substrate 15 from which each measurement was taken, the controller 35 responds to these measurements by moving each of the heads 130 from the uneven surface 16 of the substrate 15 to a predetermined position. The servo 137 is controlled so as to be positioned at a distance of the vertical direction. Therefore, of the heads 130, the head closest to the leading sensor 138 (separated from the sensor 138 by the distance B) follows the unevenness of the fabric with a delay of V / B seconds after taking an arbitrary measurement value (where V is Speed of carriage 129 on bridge 128). Similarly, these heads 130 are separated by a distance A, so that after V / A seconds of the preceding head, they will each follow the same irregularities as the first head one after the other.
[0041]
The length of the head 130 in the longitudinal direction determines the accuracy with which the head can follow the unevenness of the printing medium 15. By using a narrower head, for example a head with 64 or 32 jets per head in the longitudinal direction, it is possible to maintain higher accuracy and follow more variable irregularities Becomes possible. Therefore, a plurality of sets of the plurality of heads 130 are arranged in a square, or another array is arranged on the carriage 129, and a different set of the plurality of heads is moved in the longitudinal direction of the printing object 15 and the frame 111. 129 can be arranged side by side. For example, two sets of multiple heads with 64 jets per head or four sets of multiple heads with 32 jets per head produce the same 128 dot width scan lines. However, when the unevenness changes in the longitudinal direction on the printing material 15, the ability to maintain the interval from the head to the printing material is high.
[0042]
If an ultraviolet curable ink is used, an ultraviolet station 124 is provided as shown in FIG. 1A. It may include a print head 23 traversable independently of the print head 130 across the downstream side of the bridge 128, i.e., separately located downstream of the print station 125, and / or on the carriage 129. It may include mounted UV curing heads 123a and 123b. As the carriage 129 moves across the bridge 128, only the curing heads 123a, 123b, which follow the print head 130, operate to deposit ink on the substrate 15 and irradiate it with ultraviolet light. The curing heads 123a, 123b are also movable toward or away from the plane of the substrate 15 and, as illustrated in FIG. 139b. Proper curing of ultraviolet ink requires focusing ultraviolet light on the surface containing the ink. Therefore, the focus of the curing ultraviolet light is maintained by moving the ultraviolet heads 123a and 123b to keep a certain distance from the surface 16. UV curing heads are typically configured to tightly focus narrow, vertically extending light rays of ultraviolet light on the printing surface. Therefore, instead of physically moving the ultraviolet curing head, that is, the light sources 123a and 123b, the focal length of the light curing heads 123a and 123b can be changed to trace the unevenness of the printing object 15. The light curing head 123, when used, is also configured to move perpendicular to the surface 16 of the substrate 15.
[0043]
A heat cure or dry cure station 126 can be attached to the frame 111 downstream of the print station 125 and, if provided, the UV cure station can be located off-line. Such a drying station 126 can be used to dry the solvent ink by hot air, radiation, or other heating techniques. It can also be used to further cure or dry the UV ink.
[0044]
Even when printing on a rigid panel with no texture or irregularities on the surface, when supporting it on the frame of the printing device, the rigid frame of the panel and the thickness of the panel make the top surface of the panel unpredictable. There may be advantages by sensing and adjusting the distance from the print nozzle to the panel surface.
[0045]
The above description is exemplary of some preferred embodiments of the present invention. Those skilled in the art will appreciate that various changes and additions can be made to the embodiments described above without departing from the principles of the present invention.
[Brief description of the drawings]
FIG.
1 is a perspective view of one embodiment of an apparatus embodying the principles of the present invention for ink-jet printing a rigid office divider panel coated with a textured or textured fibrous material or fabric. .
FIG. 1A
FIG. 3 is a perspective view of another embodiment of an apparatus embodying the principles of the present invention for performing ink jet printing on a rigid panel, similar to FIG. 1.
FIG. 2
FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. 1 illustrating a structure for maintaining a distance between a printer head and a print object when the print object has a larger unevenness.
FIG. 2A
FIG. 3 is a cross-sectional view similar to FIG. 2, showing an alternative structure for maintaining the distance between the print head and the substrate.
FIG. 3
FIG. 3B is a cross-sectional view illustrating a structure for maintaining a distance between the print head and the print substrate on the uneven substrate, taken along line 3-3 in FIG. 1A.

Claims (40)

Moving a printhead carriage having a plurality of ink jet printheads, the plane being parallel to a plane supporting a substrate having a surface varying with respect to said plane;
Separately adjusting the distance from each head to a plane to position each of the heads at a predetermined distance from the surface of the substrate on which ink is ejected from the print head;
Ejecting ink from a head across a predetermined distance onto a surface of the substrate, wherein the method comprises printing on the substrate. 2. The method of claim 1, wherein the ink is an ultraviolet curable ink, and further comprising at least partially curing the ejected ink by exposing the ejected ink on a surface to ultraviolet light. 3. The method of claim 2, wherein exposing the ink comprises adjusting a distance of the ultraviolet light from a light source to focus the ultraviolet light on a surface containing the ejected ink. The step of exposing the ink includes adjusting a focal length of the ultraviolet light from the light source on the surface containing the ejected ink to maintain the focus of the ultraviolet light as the distance from the light source to the surface changes. 3. The method according to 2. The ink is an ultraviolet curable ink,
By exposing the ejected ink to ultraviolet light, the ejected ink is at least partially cured, and then the surface having the at least partially cured ink on the surface is heated to reduce the ink on the substrate. 2. The method of claim 1, further comprising reducing a component of the unpolymerized monomer. 6. The method of claim 5, wherein the heating includes flowing heated air over a substrate surface having the at least partially cured ultraviolet curable ink to remove uncured components of the ink from the substrate. the method of. Combining one or more second material layers with the substrate;
The method of claim 1, further comprising: quilting the quilt pattern on the combined layer of material and substrate in cooperation with the pattern printed on the substrate. Bonding one or more second material layers to the substrate and quilting the bonded layer of material and substrate, and then aligning the surface from which ink is to be ejected with the irregularities of the quilted substrate; 8. The method of claim 7, further comprising performing a printing step by printing on the substrate in alignment with the quilt pattern. Responsive to bonding one or more second material layers to a substrate and quilting the bonded layer of material and substrate and then detecting irregularities in the quilted substrate and detecting irregularities 8. The method of claim 7, further comprising: performing a printing step by printing on the substrate at the identified location. 10. The method of claim 9, wherein adjusting a distance from the printhead to a plane further comprises responding to detecting irregularities in the substrate. Detecting the position of the substrate surface relative to the carriage,
2. The method of claim 1, further comprising adjusting a distance from a printhead to a plane in response to the sensing. Detecting the position is performed during movement of the printhead carriage, and the adjusting maintains a predetermined distance of each printhead from the substrate surface in response to the detected position. The method of claim 11, comprising changing a position of the printhead relative to a plane as the printhead carriage moves. Moving a printhead carriage having a plurality of ink jet printheads directed at the panel surface parallel to the rigid panel;
Automatically and individually adjusting the distance of the printhead from the panel surface, respectively, to maintain a predetermined distance between the printhead and the panel surface as the ejected ink travels from the printhead across the panel surface. When,
Ejecting ink from a printhead across a predetermined distance and onto a surface of the rigid panel during movement of the printhead carriage, a method for printing on a rigid panel coated with a substrate. The distance of the surface of the panel from which the ink is ejected from the carriage varies across the panel, and said adjusting prints to maintain a predetermined distance between the printhead and the surface of the panel from which the ink is ejected. 14. The method of claim 13, comprising changing the position of the plurality of print heads relative to the panel as the head moves. Detecting the distance between the print head carriage and the panel surface from which ink is to be ejected;
15. The method of claim 14, further comprising: changing a position of the print head relative to the print head carriage in response to the sensed distance. Detecting irregularities on the panel surface;
15. The method of claim 14, further comprising: moving the carriage parallel to the panel to a location determined in response to the detected asperity, and ejecting ink at the location on the panel surface. The ink is an ultraviolet curable ink,
14. The method of claim 13, further comprising at least partially curing the ejected ink by exposing the ejected ink to ultraviolet light on a surface. 18. The method of claim 17, wherein the exposing comprises focusing ultraviolet light from the light source during movement of the light source to maintain the focus of the ultraviolet light on the surface containing the ejected ink. 18. The method of claim 17, wherein the exposing comprises focusing ultraviolet light from a light source to maintain the focus of the ultraviolet light on the surface containing the ejected ink. An apparatus for printing on a three-dimensional surface of a printing object,
A substrate support defining a substrate support plane;
A printhead trajectory extending parallel to the plane;
A plurality of ink jet print heads each movably supported on a track and directed at the surface of the substrate when supported by the substrate support;
A sensor operable to identify a position on the surface of the substrate,
A printhead is individually and automatically movable in response to a sensor, perpendicular to said plane, a predetermined distance from a specified location on the substrate surface, and further traversing the predetermined distance and the substrate. A printing apparatus, comprising: a control device that operates to move and control the print head by ejecting ink from the print head upward to print on a printing substrate. A carriage that is movable on a trajectory parallel to the plane of the substrate, and the print head is individually and selectively movable perpendicular to the plane;
At least one UV curing head mounted on the carriage and oriented to irradiate ink on the substrate surface on the substrate support;
21. The printing apparatus according to claim 20, wherein the controller is operable to move the carriage and operate the ultraviolet curing head. 22. The printing device according to claim 21, wherein at least one ultraviolet curing head is a low temperature ultraviolet light source. At least one UV curing head includes at least two UV curing heads, one on each side of the print head on the carriage, the carriage moving on the track in one of two opposing directions. The one leading the print head and the other following the print head, and the controller drives at least one of the UV curing heads to follow to eject the exposed ink. 22. The printing apparatus according to claim 21, wherein the print head is operable to irradiate ink ejecting onto the substrate surface in the same carriage pass above. 24. The printing device according to claim 23, wherein at least two UV curing heads are low temperature UV light sources. 21. The printing apparatus according to claim 20, further comprising an ultraviolet curing head arranged to expose the ink ejected by the print head onto the substrate surface to ultraviolet light. 26. The printing device according to claim 25, wherein the ultraviolet curing head is a low temperature ultraviolet light source. An ultraviolet curing head is moveable relative to the plane, and a controller is operable to move the curing head to maintain a focus of ultraviolet light from the print head on ink ejected onto the substrate surface. 26. The printing device according to claim 25. 26. The printing apparatus according to claim 25, further comprising a heating station arranged to heat the ink exposed to ultraviolet light on the substrate. 29. The printing apparatus of claim 28, wherein the heating station includes a blower oriented to direct heated air onto the substrate on the support. 21. The printing apparatus according to claim 20, further comprising a quilting station arranged to quilt the substrate to impart irregularities to the substrate surface. 21. The printing device according to claim 20, wherein the sensor is a non-contact distance measuring device including a light source and a light detector mounted on a track. The sensor is a non-contact distance measuring device that includes a light source and a photodetector mounted on the track, and the track is equipped with multiple servo motors, each of which prints in response to an output signal from the sensor 21. The printing apparatus according to claim 20, wherein the position of the print head is adjusted with respect to the substrate during printing. 21. The sensor of claim 20, wherein the sensor includes a movable mechanical element that maintains contact with the substrate surface, and the printhead is coupled thereto for moving in response to the mechanical element. Printing device. A plurality of ink jet print heads are spaced apart in the direction of movement of the carriage so as to sequentially pass over the same area of the substrate, and a plurality of ones of a plurality of colors are printed on the surface thereof. Including an independently movable printhead,
A print head that is individually and selectively movable perpendicular to a plane in response to a sensor so as to maintain a constant distance of travel of the ink from each print head to a substrate surface; 21. The printing apparatus according to claim 20, further comprising a controller operable to control the print head to sequentially follow the asperities on the substrate as it moves across the substrate. The plurality of ink jet print heads include a plurality of sets of independently movable print heads arranged in parallel on the carriage perpendicular to the direction of movement of the carriage, each of which has irregularities on the substrate. 35. The printing apparatus according to claim 34, wherein a controlled spacing from the substrate, which varies perpendicular to the direction of movement of the carriage, can be maintained. The plurality of ink jet print heads include a plurality of independently movable print heads arranged in parallel on the carriage in a direction perpendicular to the direction of movement of the carriage, and each of the print heads has irregularities on the carriage. 21. The printing apparatus according to claim 20, wherein a controlled distance from the printing material that changes perpendicular to the moving direction can be maintained. A substrate comprising automatically adjusting the position of the ink jet print head while depositing the ink on the substrate to maintain a uniform distance at which ink is ejected from the print head to the substrate surface. How to print on. The printhead comprises a plurality of ink jet printheads and deposits ink on the substrate such that the distance at which the ink is ejected from each printhead to the substrate surface remains constant during printing. 38. The method of claim 37, further comprising adjusting the position of each printhead individually during operation. Measuring the distance between the substrate surface and the print head;
38. The method of claim 37, further comprising: adjusting a position of the print head in response to the distance measurement to maintain the distance constant during printing. A printhead comprising a plurality of ink jet printheads;
38. The method of claim 37, further comprising individually adjusting the position of each printhead and applying different ink colors by different ones of the printheads.

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