JP2007296522A - Method and apparatus for maintaining inkjet print head using parking structure with spray mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a print head parking structure which supplies a solvent and/or surface treatment agent to an inkjet print head. <P>SOLUTION: The apparatus using the print head parking structure returns the print head to the print head parking structure after one or more printing passings and/or with a sufficient frequency to prevent the drying and clogging, after printing the substrate. If the print head is once sealed within the print head parking structure, the solvent is sprayed to the print head (or its part) to dissolve or flush away the deposited ink on the print head. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

Priority claim

  No. 11/493310, filed Jul. 26, 2006 “Inkjet printhead maintenance method and apparatus using standby structure with spray mechanism” (Attorney Docket No. 11334, currently 10648). ), US Provisional Patent Application No. 60/795709, filed Apr. 29, 2006, “Maintenance Method and Apparatus for Inkjet Printhead Using Standby Structure” (Attorney Docket No. 10648 / L), and April 2006 Claimed priority based on US Provisional Application No. 60 / 79,297, “Method and apparatus for operating inkjet printing system” (Attorney Docket No. 10647 / L), filed 29 days, all incorporated herein by reference.

Cross-reference to related applications

  This application is filed on US patent application Ser. No. 11/061148, “Inkjet printing method and apparatus for color filter for display” (Attorney Docket No. 9521-5), filed on Nov. 4, 2004. U.S. Provisional Patent Application No. 60/625550 "Apparatus and Method for Manufacturing Color Filter for Flat Panel Display by Inkjet Method" (Attorney Docket No. 9521 / L), U.S. Patent Application No. No. “Inkjet printhead cleaning method and apparatus” (Attorney Docket No. 9838) and US Provisional Patent Application No. 60/721340, filed September 27, 2005 “Inkjet Delivery Module” (Attorney Docket No. 10145 / L Each of which is incorporated herein by reference.

Field of Invention

  The present invention relates generally to ink jet printing systems used during flat panel display manufacturing, and more particularly to an apparatus and method for maintaining an ink jet print head.

Background of the Invention

  The flat panel display industry has attempted to use inkjet printing to manufacture display devices, particularly color filters. However, ink jet print heads used in ink jet printing may become unsuitable for use in ink jet printing methods due to clogging with ink, clogging, film formation, or for other reasons. Conventional cleaning methods for inkjet printheads require manual wiping. This method often involves taking the ink jet print head off line and away from a clean manufacturing environment, which is time consuming and can damage the print head or cause the print head to deviate from the required print position. Accordingly, there is a need for an improved method and apparatus for maintaining an inkjet printhead.

Summary of the Invention

  In a particular aspect of the invention, the print head standby structure includes a housing that includes a spray device, and a standby location that is configured to be adjacent to the housing and exposed to the spray device within the housing upon receipt of the print head. including.

  In another aspect of the present invention, a method is provided that includes sealing a print head within a standby structure and spraying a solvent onto a nozzle plate of the print head without splashing to other portions of the print head.

  In yet another aspect of the invention, an ink jet printer adapted for manufacturing a color filter for a flat panel display, each including a plurality of print heads with nozzle plates, a spraying device, and receiving the print head There is provided a system including a printhead standby structure including a housing having a standby location configured to expose a printhead received therein to the sprayer.

  Other features and aspects of the present invention will become more fully apparent from the following detailed description, the appended claims and the accompanying drawings.

Detailed description

  Ink jet print head nozzles used in the manufacture of color filters for flat panel displays may be clogged or otherwise impeded by ink drying on or inside the print head. Various nozzle maintenance and purge methods can be used to remove the dried ink, but methods to remove or reduce the amount of ink that dries on the printhead include a solvent on the nozzle and / or a printhead. A printhead standby structure that includes a sprayer to apply the surface treatment agent can be used.

  In another maintenance technique, the print head is subjected to a solvent bath for a period of time. While this technique has proven to be progressive in the art, in some cases the solvent bath can be contaminated by the large amount of ink removed and absorbed. In this situation, the solvent bath reintroduces the problem that was intended to be solved because contaminated solvent dries or deposits on the printhead nozzles. The inventors of the present invention have come to the conclusion that this problem can be avoided by spraying only, or by spraying after a solvent bath.

  In operation, after printing the substrate, after one or more printing passes, and / or frequently enough to prevent drying and clogging on the printhead, the printhead is returned to the printhead standby structure. Once returned to the printhead standby structure, solvent is sprayed onto the surface of the printhead (or part thereof) to maintain the surface condition. The sprayed solvent is dripped from the print head together with the dissolved ink, and accumulates in the bath container. Alternatively, the print head is lowered into the solvent bath, the solvent bath is drained (or the print head is pulled up above the contaminating solvent), and then new solvent is sprayed onto the print head.

  In some embodiments, one or more atomizers deliver solvent that covers a wide range of printhead nozzle plate surfaces. One or more nebulizers may be movable to widen their spray range and apply solvent from various angles to loosen contaminants. The print head itself may be configured to eject all of the ink in the nozzles by jetting solvent into the bath container. Alternatively or in addition, the printhead standby structure may remove excess solvent from the printhead, for example, by applying clean dry air (CDA) before the printhead is reused for printing. Another nozzle may be included.

  In some embodiments, the printhead standby structure is used to apply a surface treatment to the printhead and / or nozzles of the printhead. The surface of the print head and / or nozzles may be sprayed or coated with a chemical or processing agent selected to make the ink oleophobic so that the ink does not wet the surface (eg, beads). In some embodiments, the surface treatment agent and the solvent are mixed in one solution. In some embodiments, the solution is applied to the nozzle plate of the print head, the solution is dropped into the bath, and the solution is collected and reused. In such embodiments, the solution may be filtered before reuse.

  FIG. 1 is a front perspective view of one embodiment of the inkjet printing system of the present invention, indicated generally by the reference numeral 100. The inkjet printing system 100 of the present invention includes a printing bridge 102 in one exemplary embodiment. The printing bridge 102 is positioned and / or connected above the stage 104. The stage 104 supports the substrate 106. Print heads 108, 110 and 112 are supported on the print bridge 102. The print heads 108, 110, 112, and the print bridge 102 are coupled (eg, logically and / or electrically) to the system controller 114. The inkjet printing system 100 of the present invention also includes one or more printhead standby stations 116, 118, 120 and one or more printhead cleaning stations 122.

  In the exemplary embodiment of FIG. 1, printing bridge 102 is supported on stage 104 in a manner that facilitates ink jet printing. The printing bridge 102 and / or stage 104 may move in both positive and negative X and Y directions, indicated by arrows X and Y in FIG. In the same or another embodiment, the printing bridge 102 and the stage 104 may be rotatable. The print bridge 102 can support and move any number of print heads 108, 110, 112 and / or other devices (eg, sensors, imaging systems, range finders, etc.). The substrate 106 is placed on the movable stage 104 or coupled in some embodiments.

  In FIG. 1A, only three print heads 108, 110, 112 are shown on the print bridge 102, but it should be noted that any number of print heads may be mounted and / or used together on the print bridge 102. It is important to do (for example, 1, 2, 4, 5, 6, 7 print heads, etc.). Each of the print heads 108, 110, and 112 can eject one color ink, and in some embodiments, can eject a plurality of color inks. In order to accurately deposit ink jet drops, the ink jet print heads 108, 110, 112 may be movable and / or aligned in the vertical, horizontal, and / or rotational directions. The print bridge 102 may also be movable and / or rotatable in order to position the print heads 108-112 for accurate inkjet printing. In operation, the inkjet print heads 108, 110, 112 eject ink in droplets (eg, from nozzles).

  An example of a commercially available print head suitable for use with the present invention is the Model S-128 series, 128 channel jet assembly manufactured by Spectra, Inc., Lebanon, New Hampshire. These particular jet assemblies include two electrically independent piezoelectric element slices, each having 64 addressable channels, for a total of 128 jets. The print head includes a nozzle plate having a number of nozzles, the nozzles being arranged in rows with a spacing of about 0.020 inches. Different print heads with different sized nozzles may be used. The nozzle may include an orifice in the nozzle plate 150 or a protrusion with an opening extending from the nozzle plate. In some embodiments, printheads / nozzles with gold plating or gold coating are used to further reduce printhead / nozzle wetting, particularly with sparse ink surface treatment. By reducing the wetting, the reliability of ink ejection and the reproducibility of the droplet size are improved, and the ink ejection performance is improved.

  In some embodiments, an imaging system 124 within the inkjet printing system 100 that can capture images of the substrate 106, ink droplets from the print heads 108, 110, 112 and / or nozzles of the print heads 108, 110, 112. Include. Such an imaging system 124 may be configured to capture an image of sufficient quality to identify ink droplets having a diameter of about 2 um to about 100 um. Accordingly, the imaging system 124 may include a telephoto zoom lens and may have a high resolution (eg, at least about 1024-768 pixels). Other camera types and / or resolutions may be used. The imaging system 124 may also include motorized / automatic aiming, zoom and / or focus functions. In operation, the imaging system 124 may be used to inspect the nozzles of the print heads 108, 110, 112 to determine whether the nozzles require cleaning and / or sparse ink surface treatment (eg, ink on the nozzles). Has accumulated or dried so that the new solvent that has passed through the nozzle is not transparent and has an ink color and / or the ink no longer beads on the nozzle / printhead surface).

  Print bridge 102, stage 104, and / or inkjet print heads 108, 110, 112 may be coupled to system controller 114. System controller 114 may be adapted to control the movement of print bridge 102, stage 104, and / or inkjet print heads 108, 110, 112 during an inkjet printing operation. The system controller 114 may also control firing pulse signals for the inkjet print heads 108, 110, 112. The system controller 114 may comprise a single controller or multiple controllers.

  The print head standby stations 116, 118, 120 may be positioned lower than the stage 104, and each may be individually raised to receive the print heads 108, 110, 112 independently. In some embodiments, the system 100 includes one print head standby station 116, 118, 120 per print head 108, 110, 112. In a supplemental or alternative embodiment, one standby station 116 is used for multiple print heads 108, 110, 112, or multiple standby stations 116, 118, 120 are used for one print head 108. For example, the first waiting station 116 sprays solvent onto the print head 108, the second waiting station 118 dries the print head 108 with compressed air, and the third waiting station coats the print head with a sparse ink surface treatment. . Similarly, a single stand-by station 116 can be configured to perform all three of the above functional examples in addition to other maintenance, cleaning, and / or protection functions performed on one or more print heads 108, 110, 112. Also good. Thus, in various embodiments, the print heads 108, 110, 112 are repaired or maintained by performing the functions of the standby stations 116, 118, 120, and the number of print heads, functions, standby stations can be any.

  One or more printhead wiping stations 122 may also be arranged in the same or similar manner and location as the printhead standby stations 116, 118, 120. US patent application Ser. No. 11 / 386,311, incorporated herein above, describes in detail the various features and aspects of an example print head cleaning station suitable for use in the inkjet printing system 100 of the present invention.

  FIG. 2 is an enlarged perspective view of the print head 108 positioned above the central structure of the three example embodiments of the print head standby structure 116, 118, 120. In contrast to FIG. 1, the print head 108 is shown waiting in a standby structure 118, which is one of the standby structures. Note that in some embodiments, printhead standby structures 116, 118, 120 are located adjacent to one side of stage 104. Alternatively or in addition, the standby structure may be located on both sides, in front, and / or behind the stage 104. These embodiments are configured to facilitate use of the standby structure while minimizing the time and / or distance required for the print head to reach the standby structure.

  The print head standby structures 116, 118, 120 may be configured to rise and engage the print heads 108, 110, 112 at the same height as the stage 104 or higher. Further, the clearance is formed so that the print heads 108, 110, 120 can move in the lateral direction on the standby structures 116, 118, 120 that have entered by being lowered to the same height as the stage 104 or lower. It may be configured. In some embodiments, the standby structures 116, 118, 120 have a fixed vertical position, and the print heads 108, 110, 120 are engaged with the standby structures 116, 118, 120 by raising and lowering. It is configured to leave.

  FIG. 3 is a front plan view of the print head 108 that is placed on standby by the standby structure example 116. The standby structure 116 includes a seal 302 configured to receive a lower portion of the print head 108 including the nozzle plate 150. Since the sealing portion 302 is in contact with a flat portion on the surface of the print head 108, the solvent sprayed in the standby structure 116 is confined in the structure 116 while the print head 108 is waiting (for example, during the purge process). Leakage is prevented. The seal 302 is compressed into the surface shape of the print head 108 when either the standby structure 116 is raised to engage the print head 108 or the print head 108 is lowered into the standby structure 116. You may comprise as a conforming bending bellows. The seal 302 can be formed from any material, such as rubber, plastic, sheet metal, flexible or semi-rigid polyvinyl chloride (PVC), can be compressed to form a seal, ink, solvent , Print head surface treatments, and / or practical materials that do not react with other chemicals or processes that may be used with the standby structure 116. The standby structure 116 may include a drainage channel 406 for removing solvent and / or ink that may accumulate in the structure after spraying or purging. The drainage channel 406 may lead to a waste treatment facility, and in some embodiments the drainage channel 406 returns the used solvent / surface treatment solution to a solution recycling system (not shown). The solution recycling system filters ink and other contaminants from the spent solution and returns the cleaned solution to a fluid supply tank (not shown). In some embodiments, the recovered solution need not be filtered before reuse.

  FIG. 4A illustrates an exemplary front cross-sectional view of the print head 108 waiting in the standby structure example 116. An example standby structure 116 illustrated in FIG. 4A includes a sprayer 402 configured to spray solvent and / or surface treatment chemicals onto the nozzle plate 150 of the print head 108 without splashing the solvent to the sides of the print head 108. 404 is included. Although only two sprayers 402, 404 are shown in the example of FIG. 4A, the standby structure may include any number of sprayers (eg, 1, 2, 3, 4, 5, 6, 7). Etc.), the sprayers 402, 404 can be positioned in various arrangements relative to the nozzles of the print head 108. In the arrangement shown in FIG. 4, the sprayers 402, 404 are located slightly below the opposed side ends 151, 153 of the nozzle plate 150 and are configured to direct the solvent flow with a small angular spread. Yes.

  As described above, the standby structure 116 may be configured to move in the vertical direction and engage / disengage from the print head 108. In some embodiments, the standby structure 116 is raised and lowered using an actuator 410 (eg, with only a pneumatic or hydraulic cylinder, or with a cam or lift axis).

  4B is a bottom plan view of an example embodiment of a print head in the standby structure shown in FIG. 4A. As can be seen, at each of its positions, each sprayer 402, 404 has (at least) half of the area to be sprayed 406, 408 of the nozzle plate surface 150 to which it is adjacent, so that the entire surface of the nozzle plate is Contact with sprayed solvent. In an example embodiment, the nebulizers 402, 404 are controlled to supply solvent and / or surface treatment solution, for example, to a region about 6 cm long x 0.5 cm wide at a total flow rate of about 5-20 ml / min. In some embodiments, the atomizers 402, 404 each perform intermittent or pulse atomization at a rate of about 3-6 pulses / minute. The spray may be applied continuously in pulses while the head is waiting. Other volumes of solvent / surface treating agent, solvent / surface treating agent pressure, spray area area and pulse rate may be used.

  The atomizers 402, 404 are connected to a fluid supply tank (also not shown) via one or more valves (not shown). The sprayers 402 and 404 are also connected to the spray control device 170. The spray control device 170 may be configured to control the movement of the sprayers 402, 404 and the supply of fluid to the sprayer. Further, the spray control device 170 may control the trigger signal for starting the sprayers 402 and 404 to spray the solvent onto the nozzles of the print head 108. The spray control device 170 may emit a trigger signal that operates the sprayers 402, 404 continuously for a specific time, or intermittently with discontinuous pulses at regular or irregular intervals. The spray control device 170 includes a single control device or a plurality of control devices.

  FIGS. 5A and 5B are perspective and bottom views, respectively, of another and / or supplemental arrangement embodiment for applying solvent to the printhead, with the sprayers 412, 414 in proximity to the longitudinal sides 157, 159. Arranged to spray the solvent at the spray angle Φ. Again, it should be noted that different numbers of sprayers and different arrangements can be used to spray the nozzle plate 150 without splashing solvent on the sides of the print head 108. Each of the sprayers 412 and 414 may include a slit valve and / or a fan-type spray nozzle for increasing the spray angle Φ for spraying the solvent. In the illustrated embodiment, the spray angle Φ is 45 to 75 °, the central axes of the sprayers 412 and 414 are arranged at an acute angle with respect to the vertical axis of the nozzle plate 150, and the entire nozzle plate surface is used as the spray solvent. It is easy to be exposed. In this connection, if the spray angle Φ is high, for example 90 ° or more, the central axis of the sprayers 412, 414 is correspondingly oriented at a larger angle with respect to the longitudinal axis of the nozzle plate 150. . Of course, the number of sprayers and their arrangement may be different.

  FIG. 6A is a bottom view of another and / or supplemental arrangement for applying solvent to the printhead nozzle plate 150 with nozzles 425 adapted to spray the solvent in a generally linear trajectory. The sprayer 422 can be pivoted by being controlled around the fixed end 427. In operation, the central axis of the nozzle can be selectively directed in the range from one side edge 151 of the nozzle plate to the other side edge 153. The fixed end 427 may comprise any joint, joint, or fixture that allows (at least) rotational movement in the plane of the nozzle plate 150. For example, the fixed end 427 includes a ball / socket joint that allows for further adjustment to correct for misalignment in addition to rotational motion. In operation, the spray control device 170 transmits an electrical signal to start the sprayer 422 and pivot to continuously spray the solvent as a continuous spray arc and / or pivot in a discontinuous step. Stop and spray. Again, although only one atomizer is shown, it should be noted that multiple atomizers with the same or different pivoting mechanisms may be used.

  FIG. 6B is a bottom view of yet another and / or supplemental arrangement for applying solvent to the printhead nozzle plate 150, with the sprayer 432 being routed to spray the solvent across the nozzle plate 150. It is comprised so that it may move along. The sprayer 432 is connected to the rail 435 and is driven by a motor (not shown) according to an instruction from the spray control device 170 to move along the rail parallel to the vertical dimension of the nozzle plate 150. In this embodiment, similar to the embodiment illustrated in FIG. 6A, the nebulizer includes nozzles 437 configured to inject a linear flow of solvent in a direction substantially perpendicular to the longitudinal dimension of the nozzle plate, along rail 435. Optimal nozzle exposure is achieved by moving the sprayer 432 continuously or non-continuously in stages, which allows the spray to be directed toward the nozzle plate 150 over its entire length.

  In the supplemental and / or alternative embodiments illustrated in FIGS. 7A and 7B, different solvent application methods are used. In these embodiments, the ink nozzles, eg, 152, 154, of the nozzle plate 150 are cleaned with a solvent using a purge method that circulates the solvent through the print head instead of the ink. The print head purge method is described, for example, in US Provisional Application No. 60 / 721,340 “Inkjet Delivery Module” incorporated herein above. In FIG. 7A, which is a cross-sectional view of the print head 108 within the standby structure, the solvent is jetted through nozzles 152, 154 toward a rebound surface 445 disposed in parallel and close proximity to the nozzle plate 150. The bounce surface 445 can be formed of any suitable elastic or inelastic material and raises (or lowers the print head) to a selected clearance distance from the nozzle plate 150. In operation, as the solvent is sprayed through the nozzles 152, 154 of the nozzle plate 150 during the purge process, the solvent is struck against the rebound surface 445, and some of the solvent is at various angles from the surface 445 to the nozzle plate 150, particularly Rebounds on the nozzle plate 150 between the nozzles 152 and 154.

  In the cross-sectional view of FIG. 7B, the print head 108 is aligned (or substantially aligned) and faces a row of nozzles 160 (eg, a second print head) that is disposed with its nozzle plate 165 facing upward. Waiting. The nozzle row 160 may be connected to a fluid reservoir (not shown) and operated in a purge mode, and solvent may be jetted from its nozzles, eg 162, 164, to the opposing nozzle plate 150 of the standby print head 108. When the relative arrangement of the nozzle plates 150 and 165 is adjusted so that the nozzle plates 150 and 165 are slightly shifted, the nozzles of the nozzle array 160, for example, 162 and 164, are the edges of the nozzles 152 and 154 or the nozzles 152. Facing part of the nozzle plate 150 between 154. In some embodiments, the nozzle row 160 is configured as an upward print head. In some embodiments, the nozzle row 160 is moved relative to the print head 108 (eg, reciprocating) to spray the multiple areas of the nozzle plate 150 in multiple ways.

  In some embodiments, specific areas of the nozzle plate 150 are targeted using specific nozzles 162, 164 of the nozzle array 160, for example based on information from the imaging system 124 (FIG. 1). For example, the imaging system 124 determines that the nozzle X on the print head Y may be clogged because ink is not deposited by the print head along a particular pixel well row corresponding to the nozzle X. To do. Once the print head Y waits in the standby structure 116, the solvent spray nozzles on the nozzle row 160 aligned to spray near the nozzles X on the print head Y are actuated to spray the solvent near the nozzles X. To eliminate clogging.

  FIG. 8 illustrates an example method 500 for processing the print head 108 in the standby structure 116. Method 500 begins at step 502. In step 504, the print head 108 is sealed within the standby structure 116. In operation, the system controller 114 instructs the system 100 to return the print head 108 to a standby position on the standby structure 116 after the printing operation is completed, before the start, and / or during that time. The standby position is a known position that the inkjet printing system 100 stores in the memory of the system controller 114. In some embodiments, the standby position is measured or verified through the use of sensors or other devices located on the standby structure 116 and / or the print head 108. Once the print head 108 is placed in the standby position, the actuator 410 (FIG. 4A) raises the standby structure 116 as instructed by the system controller 114 and the seal 302 engages the surface of the print head 108.

  In some embodiments, the actuator is configured to hold the standby structure 116 in a different position. The first position is sprayed onto the print head nozzle plate 150 (e.g., solvent or surface treatment agent, or CDA, e.g., to dry the print head 108), or printed with the print head positioned in the standby structure 116. Useful for checking / testing the head 108 (eg, checking the output of the print head 108 during ejection of the solvent). The second position is useful for other operations such as surface treatment. In either position, contact between the seal 302 and the print head 108 is maintained so that ink, solvent, surface treatment solution, and the like are confined within the standby structure 116. Accordingly, a camera (not shown) connected to and / or part of the imaging system 124 may be placed in the standby structure 116. In addition or alternatively, the standby structure 116 may include a window (not shown) through which the print head 108 can be inspected when the print head 108 is in the standby structure 116.

Once the print head is sealed within the standby structure 116, the print head 108 is subsequently subjected to spraying at step 506. In some embodiments, the print head 108 is immersed in a solvent bath prior to spraying. In step 508, all the ink remaining in the print head 108 is purged by ejecting each nozzle of the print head 108 in a state where the ink supply is shut off. In some embodiments, the solvent is then purged by spraying a solvent-only solution through each nozzle of the print head 108. In general, in order to purge ink from the print head 108, the ink remaining inside the inkjet print head 108 is pushed out by an appropriate method. As described above, this includes, for example, ejecting ink and / or air through the print head 108. In one or more embodiments, the ink and / or air is ejected through the print head 108 with pulses of about 0.5 second intervals, although other practical pulse widths may be used. In the exemplary embodiment, print head 108 purges about 3-6 cm ³ of ink per cycle. The print head 108 is purged onto the cleaning media of the cleaning station 122 and / or into the standby structure 116 as described above.

  After properly spraying the nozzle plate 150 of the print head 108 (including print head nozzles, eg, 152, 154) over a period of time, the spent solvent and dissolved ink from the standby structure is drained from the standby structure in step 510. Discharged through. In some embodiments, the print head 108 is sprayed with a solvent for a very short time. In another embodiment, the print head 108 is sprayed for an extended period of time (eg, minutes, hours, etc.). In some embodiments, lowering the standby structure 116 by the actuator 410 allows the operator and / or the system 100 to inspect (eg, using the imaging system 124) and / or test and print the print head 108. It can be determined whether ink remains in the head 108. In some embodiments, the print head 108 is moved from the standby structure to be tested / inspected. If ink remains, the print head 108 may be returned to the spray position within the standby structure 116 for further spraying and possibly additional cycles of purging, spraying, inspection, etc.

  After draining the solvent at step 510 and while the print head 108 is in the standby structure 116 (or back), the print head 108 is sprayed with CDA to dry the print head 108. Once the print head 108 has dried, the standby station 116 is lowered to disengage the sealing portion 302, and the print head 108 returns to a print work start preparation state or work.

  In some embodiments, before or after the print head 108 is dried, the print head is treated with an sparse ink surface treatment solution in step 512. In another embodiment, the print head 108 is not dried prior to step 512. In some embodiments, heat is also applied to the solution as part of the processing procedure of the print head 108. Similar to the solvent, in some embodiments, the print head 108 is only sprayed with a sparse ink surface treatment solution for a very short time. In another embodiment, the print head 108 is sprayed with a sparse ink surface treatment solution for an extended period of time (eg, minutes, hours, etc.). After the appropriate surface treatment, the print head 108 is dried at step 514 (eg, using CDA) and the standby structure is lowered to release the seal 302 and the print head 108 is removed at step 516. The printing operation can be started or continued. Method 500 ends at step 518.

  Aspects of the present invention include coating or treating the nozzle surface of the print head 108 with a hydrophobic or inkphobic material. Coating improves jetting reliability and droplet size reproducibility. Many different types of coatings can be used, depending on the ink and other factors used. For example, a mixture of alkyl thiol and ionic alkyl thiol is dissolved in a solvent to produce a solution for surface treatment. In some embodiments, for example, the ratio of alkyl thiol to ionic alkyl thiol in the solvent is about 0.5-5 mM: 0.3-5 mM. In some embodiments, the surface treatment solution has either a sulfur atom or a nitrogen atom at the end where the molecule is “active” (eg, the molecular end that binds to the nozzle surface) and the other ink-phobic molecular end. Are made of a material containing a fluorocarbon group (for example, CFx, where x is any number). Examples include CF3 (CF2) xCF2C2H4SH, eg 1H, 1H, 2H, 2H-perfluoro-1-decanethiol 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 10-heptadecafluoro-1-decanethiol and 1H, 1H, 2H, 2H-perfluoro-1-hexanethiol 3, 3, 4, 4, 5, 5, 6, 6, 6-nonafluoro- 1-hexyl mercaptan is included.

  During operation, the surface treatment solution may be sprayed onto the print head 108 at regular intervals (eg, after one or more printing passes, after printing head cleaning, after a period of non-use, etc.). In some embodiments, the surface treatment solution is used to facilitate other deposition processes in addition to printing color filters for flat panel displays.

  FIG. 9 shows the printing operation of method 600. Method 600 begins at step 602. In some embodiments, the print heads 108, 110, 112 remain sealed within each standby structure 116, 118, 120 during loading or removal of the substrate 106 from the stage. Accordingly, in step 604, the print heads 108, 110, 112 are stored within each standby structure 116, 118, 120.

  In step 606, the print heads 108, 110, 112 are processed within each standby structure 116, 118, 120 according to the method described above with respect to FIG. For example, the print heads 108, 110, 112 are sprayed with solvent in the standby structures 116, 118, 120. Further, the print heads 108, 110, 112 may be purged and / or inspected within the standby structures 116, 118, 120. In some embodiments, the print heads 108, 110, 112 are subjected to nozzle surface treatment in each standby structure 116, 118, 120 and / or dried with CDA.

  In some embodiments, subsequently, at step 608, one or more print heads 108, 110, 112 are moved to a cleaning station 112, where the print heads 108, 110, 112 are further processed. For example, the print heads 108, 110, 112 are wiped off or otherwise adjusted as described in US patent application Ser. No. 11 / 236,631, incorporated herein above. Also, at step 612, the print heads 108, 110, 112 are also pre-fired at the cleaning station 122 to stabilize the ink pressure within the system 100.

  In step 614, the print heads 108, 110, and 112 are returned to the printing position to start or continue printing. In another embodiment, wiping is performed at the cleaning station 122 prior to surface treatment of the nozzles with the standby structures 116, 118, 120. The print heads 108, 110, 112 may be returned to each standby structure 116, 118, 120 before processing the next substrate. In other embodiments, the order of use of the standby structures 116, 118, 120 and the cleaning station 122 can vary. For example, to perform a solvent or surface treatment spray, the print heads 108, 110, 112 are returned to each standby structure 116, 118, 120 for each print pass. At step 616, method 600 ends.

  The foregoing description discloses only exemplary embodiments of the invention, and modifications within the scope of the invention of the methods and apparatus disclosed above will be apparent to those skilled in the art. For example, although the example method described above has generally been described with one standby structure per printhead, as described with reference to FIG. 1, any suitable number of standby structures (e.g., 2 Those skilled in the art can understand that the present invention can be applied using three, four, etc.).

  In some embodiments, the position of the standby structure 116 may be practical, and instead of being mounted on a movable platform and moving the print head 108 to the standby structure 116, the standby structure 116 is moved to the print head 108. Including moving to.

  In some embodiments, the ink jet print head standby station of the present invention is disclosed in US Provisional Patent Application No. 60 / 625,550 entitled “Apparatus and Method for Manufacturing Color Filter for Flat Panel Display by Ink Jet Method” filed on Nov. 4, 2004. Mounted on and / or used with an ink jet printing system. Furthermore, the present invention can be applied to processes for spacer formation, polarizer coating, and nanoparticle circuit formation.

  Thus, while the invention has been disclosed in connection with specific embodiments thereof, it is to be understood that other embodiments are within the spirit and scope of the invention as defined by the claims. is there.

1 is a front schematic perspective view of an inkjet printing system according to some aspects of the present invention. FIG. FIG. 6 is an enlarged perspective view of a print head positioned on one embodiment of a print head standby structure according to some aspects of the present invention. FIG. 5 is a schematic front plan view of a print head waiting in an example standby structure according to some aspects of the present invention. FIG. 3 is a schematic front cross-sectional view of a print head waiting in an example standby structure according to some aspects of the present invention. FIG. 4B is a schematic bottom view of the print head waiting on the standby structure of FIG. 4A. FIG. 3 is a schematic perspective view of a sprayer arrangement and print head in a standby structure according to one aspect of the present invention. FIG. 5B is a schematic bottom view of the sprayer arrangement and print head of FIG. 5A. FIG. 6 is a schematic bottom view of another sprayer arrangement and print head in a standby structure according to an aspect of the present invention. FIG. 6 is a schematic bottom view of another sprayer arrangement and print head in a standby structure according to an aspect of the present invention. FIG. 6 is a schematic front cross-sectional view of a print head waiting in an example standby structure according to another aspect of the present invention. FIG. 6 is a schematic front cross-sectional view of a print head waiting in an example standby structure according to another aspect of the present invention. 6 is a flowchart illustrating an example method using a standby structure according to some aspects of the present invention. 6 is a flowchart illustrating an example method using an inkjet printing system according to some aspects of the present invention.

Claims (24)

A housing including a spraying device;
A print head standby structure including a standby location adjacent to the housing and configured to expose the print head to the spray device within the housing upon receipt of the print head. The spraying device is configured to spray at least one of a solvent, a surface treatment solution, and a combination of a solvent and a surface treatment solution;
The print head standby structure according to claim 1, wherein the casing is configured to drain the used solvent.   3. The print head standby structure according to claim 2, wherein the print head includes a nozzle plate, and the spray device is arranged to direct the spray toward the nozzle plate when the print head is in the standby position.   The printhead standby structure of claim 2, wherein the spraying device includes at least two sprayers.   The print head standby structure according to claim 4, wherein the sprayer is configured to spray over a wide angle.   The printhead standby structure of claim 5, wherein the sprayer is configured to spray over an angle of about 45 to about 75 degrees.   4. The print head standby structure according to claim 3, wherein the spraying device is pivotable, so that the spraying device can be oriented between each side end of the nozzle plate.   4. The print head standby structure according to claim 3, wherein the spraying device is movable along the dimension of the nozzle plate.   The print head standby structure according to claim 1, further comprising a sealing portion configured to hermetically connect the print head standby structure to a print head received at the standby position. Sealing the print head in the standby structure,
Spraying the solvent onto the nozzle plate of the print head without splashing to other parts of the print head.   The method of claim 10, further comprising draining the spent solvent from the standby structure without contacting the printhead.   The method of claim 10, wherein sealing the print head into the standby structure comprises contacting the surface of the print head with a flexible bellows structure.   The method of claim 10, wherein spraying the solvent onto the nozzle plate of the print head includes directing a plurality of solvent streams from a position below the nozzle plate toward the nozzle plate.   The method of claim 13, wherein directing the plurality of solvent streams comprises spraying the plurality of solvent streams intermittently.   The method of claim 13, wherein directing the plurality of solvent streams comprises spraying the plurality of solvent streams via a plurality of reciprocating spray devices. An inkjet printer adapted for manufacturing color filters for flat panel displays and including a plurality of print heads each provided with a nozzle plate;
A system comprising: a printhead standby structure including a spray device and a housing having a standby location configured to receive a printhead nozzle plate received therein to be exposed to the sprayer when the printhead is received. The spraying device is configured to spray at least one of a solvent, a surface treatment solution, a combination of a solvent and a surface treatment solution,
The system of claim 16, wherein the enclosure is configured to drain spent solvent.   The system of claim 17, wherein the spray device is arranged to direct the solvent toward the nozzle plate when the print head is in the standby position.   The system of claim 17, wherein the spray device comprises at least two sprayers.   The system of claim 19, wherein the nebulizer is configured to spray over a wide angle.   The system of claim 19, wherein the nebulizer is configured to spray over an angle of about 45 to about 75 degrees.   The system of claim 18, wherein the spray device is pivotable so that the spray device can be oriented between each side edge of the nozzle plate.   The system of claim 18, wherein the spray device is movable along the dimensions of the nozzle plate.   The system of claim 16, further comprising a seal configured to hermetically connect the print head standby structure to the print head received in the standby position.

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