Patent Publication Number: US-2023148067-A1

Title: Inkjet printing apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to Korean Patent Application No. 10-2021-0152235 filed in the Korean Intellectual Property Office on Nov. 8, 2021; the Korean Patent Application is incorporated by reference. 
     BACKGROUND 
     1. Field 
     The technical field relates to an inkjet printing apparatus. 
     2. Description of the Related Art 
     A display device may display images in response to input signals. Modern display devices include liquid crystal display (LCD) devices and an organic light emitting diode (OLED) display devices. Display devices are included in various electronic devices such as mobile phones, navigation devices, digital cameras, electronic books, portable game machines, and various terminals. 
     In the process of manufacturing a display device, an inkjet printing apparatus may drop an organic compound on a substrate to form an organic emission layer. The inkjet printing process may be simple, time-saving, material-saving, and a cost-saving. 
     In the inkjet printing process, when the printing is paused, the ink inside the nozzle does not flow and becomes stagnant. Accordingly, the viscosity of the ink may increase. As a result, and problems such as a discharge failure and/or a distortion of the discharge direction may occur when the printing is resumed. 
     The Background section facilitates understanding of the background of the described technology and may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. 
     SUMMARY 
     Embodiments are related to an inkjet printing apparatus capable of maintaining sufficient fluidity of the ink in the nozzle in the inkjet printing process. 
     An inkjet printing apparatus according to an embodiment includes: a stage capable of seating a substrate; an auxiliary member positioned on the stage; and an inkjet head capable of moving on the stage and the auxiliary member. 
     The auxiliary member may be positioned on both edges above the stage. 
     At least one of the stage and the inkjet head may be capable of moving in at least one of a first direction and a second direction perpendicular to the first direction. 
     The inkjet head may discharge an ink on the substrate and the auxiliary member. 
     The inkjet printing apparatus according to an embodiment further includes a fixing member positioned on the side of the stage and fixing the auxiliary member to the stage. 
     The fixing member may be positioned on both edges of the auxiliary member. 
     The fixing member positioned on one edge of the auxiliary member may be capable of unwinding the auxiliary member, and the fixing member positioned on the other edge of the auxiliary member may be capable of winding the auxiliary member. 
     The fixing member may include: a first roller and a second roller; a supporting member supporting the first roller and the second roller; and a transferring member moving the supporting member in a third direction perpendicular to the first direction and the second direction. 
     The inkjet printing apparatus according to an embodiment may further include a drying member attached to the fixing member. 
     The drying member may irradiate ultraviolet rays or infrared rays. 
     The inkjet printing apparatus according to an embodiment may further include a suction member positioned between the stage and the auxiliary member. 
     The suction member may include at least one of a vacuum chuck, a porous chuck, an electrostatic chuck, and an adhesive chuck. 
     The auxiliary member may be positioned on one edge above the stage. 
     The inkjet printing apparatus according to an embodiment may further include a plurality of floating holes positioned on the stage, and the auxiliary member may be positioned at the center of the stage. 
     The substrate may be positioned over a plurality of floating holes, and the substrate may be floated from the stage or fixed to the stage by a plurality of floating holes. 
     The inkjet printing apparatus according to an embodiment may further include a substrate moving member fixed to one edge of the substrate, and the substrate moving member may move the substrate in the first direction, and the inkjet head may move in the second direction perpendicular to the first direction. 
     When the substrate is positioned between the inkjet head and the auxiliary member, the inkjet head may discharge the ink on the substrate, and when the inkjet head is positioned directly on the auxiliary member, the inkjet head may discharge the ink on the auxiliary member. 
     The inkjet printing apparatus according to an embodiment may further include a fixing member positioned on the side of the stage and fixing the auxiliary member to the stage, the fixing member may be positioned on both edges of the auxiliary member, the fixing member positioned on one edge of the auxiliary member may be capable of unwinding the auxiliary member, and the fixing member positioned on the other edge of the auxiliary member may be capable of winding the auxiliary member. 
     The inkjet printing apparatus according to an embodiment may further include a drying member attached to the fixing member. 
     The inkjet printing apparatus according to an embodiment may further include a suction member positioned between the stage and the auxiliary member. 
     An embodiment may be related to an inkjet printing apparatus for forming a material layer on a substrate. The inkjet printing apparatus may include a stage, a first ink-receiving member, and an inkjet head. The stage may support the substrate. The first ink-receiving member may be narrower than the substrate. The inkjet head may overlap at least one of the stage and the first ink-receiving member, may provide a first set of ink to the substrate, and may provide a second set of ink to the first ink-receiving member when the substrate is supported by the stage. 
     The inkjet printing apparatus may include a second ink-receiving member. The stage may support the substrate between the first ink-receiving member and the second ink-receiving member. The inkjet head may provide a third set of ink to the second ink-receiving member when the substrate is positioned on the stage. 
     At least one of the stage and the inkjet head may move in at least one of a first direction and a second direction perpendicular to the first direction. 
     The inkjet head may discharge no ink on the substrate when providing the second set of ink to the first ink-receiving member. 
     The inkjet printing apparatus may include a first fixing member neighboring the stage and at least partially supporting the first ink-receiving member. 
     The inkjet printing apparatus may include: a second fixing member partially supporting the first ink-receiving member. The stage may be positioned between the first fixing member and the second fixing member. 
     The first fixing member may unwind the first ink-receiving member when the second fixing member winds the first ink-receiving member. 
     The first fixing member may include a first roller directly contacting the first ink-receiving member, a second roller directly contacting the first-ink receiving member, a supporting member supporting the first roller and the second roller, and a transferring member for moving the supporting member relative to the stage in a third direction perpendicular to the first direction and the second direction. 
     The inkjet printing apparatus may include a drying member attached to the first fixing member, positioned farther from the inkjet head than the first ink-receiving member is, and configured to facilitate drying of the second set of ink. 
     The drying member may irradiate ultraviolet rays or infrared rays. 
     The inkjet printing apparatus may include a securing member positioned between the stage and the first ink-receiving member for securing a section of the first ink-receiving member in place on the stage. The securing member may release the section of the first ink-receiving member from the stage. 
     The securing member may include at least one of a vacuum chuck, a porous chuck, an electrostatic chuck, and an adhesive chuck. 
     The first ink-receiving member may be positioned between an edge of the stage and the substrate when the substrate is supported by the stage. 
     The inkjet printing apparatus may include holes positioned on the stage for changing an amount of air between the stage and the substrate. The first ink-receiving member may be positioned two opposite edges of the stage. 
     The substrate may overlap a first subset of the holes, may expose a second subset of the holes, and may be levitated from the stage or attached to the first subset of holes according to an operation of the first subset of holes. 
     The inkjet printing apparatus may include a substrate moving member fixed to at least one edge of the substrate and moving the substrate in a first direction. The inkjet head may move in a second direction perpendicular to the first direction and/or may move in a lengthwise direction of the first ink-receiving member. 
     When the substrate is positioned between the inkjet head and the first ink-receiving member, the inkjet head may discharge the first set of ink on the substrate. 
     When the substrate exposes the first ink-receiving member to the inkjet head, the inkjet head may discharge the second set of ink on the first ink-receiving member. 
     The inkjet printing apparatus may include a first fixing member supporting a first section of the first ink-receiving member and may include a second fixing member supporting a second section of the first ink-receiving member. A third section of the first ink-receiving member may move over the stage when the first fixing member unwinds the first section of the first ink-receiving member and when the second fixing member winds the second section of the first ink-receiving member. 
     The inkjet printing apparatus may include a drying member attached to the first fixing member, positioned farther from the inkjet head than the first ink-receiving member, and configured to facilitate drying of the second set of ink. 
     The inkjet printing apparatus may include a securing member positioned between the stage and the first ink-receiving member, positioned between the first subset of holes and the second subset of holes, and configured to secure the first ink-receiving in place on the stage. 
     According to embodiments, it is possible to prevent the ink in the nozzle from undesirably drying in the inkjet printing process. Since the characteristics of the discharged ink may be maintained, the characteristics of the layer produced from the ink may be desirably uniform. The quality of the display device formed using the inkjet printing apparatus may be satisfactory. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view showing an inkjet printing apparatus according to an embodiment. 
         FIG.  2   ,  FIG.  3   ,  FIG.  4   ,  FIG.  5   , and  FIG.  6    are perspective views showing a process in which an inkjet head is moved and/or moves in an inkjet printing process according to an embodiment. 
         FIG.  7    is a perspective view showing a process in which an auxiliary member is moved and/or moves in an inkjet printing process according to an embodiment. 
         FIG.  8    is a perspective view showing an inkjet printing apparatus according to an embodiment. 
         FIG.  9    is a perspective view showing an inkjet printing apparatus according to an embodiment. 
         FIG.  10    is a perspective view showing an inkjet printing apparatus according to an embodiment. 
         FIG.  11    is a perspective view showing an inkjet printing apparatus according to an embodiment. 
         FIG.  12   ,  FIG.  13   ,  FIG.  14   , and  FIG.  15    are perspective views showing an inkjet printing process according to an embodiment. 
         FIG.  16    is a perspective view showing an inkjet printing apparatus according to an embodiment. 
         FIG.  17    is a perspective view showing an inkjet printing apparatus according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Example embodiments are described with reference to the accompanying drawings. The described embodiments may be modified in various ways. 
     The same elements or equivalents may be denoted by the same reference numerals. 
     In the drawings, dimensions may be exaggerated for clarity. 
     Although the terms “first,” “second,” etc. may be used to describe various elements, these elements should not be limited by these terms. These terms may be used to distinguish one element from another element. A first element may be termed a second element without departing from teachings of one or more embodiments. The description of an element as a “first” element may not require or imply the presence of a second element or other elements. The terms “first,” “second,” etc. may be used to differentiate different categories or sets of elements. For conciseness, the terms “first,” “second,” etc. may represent “first-category (or first-set),” “second-category (or second-set),” etc., respectively. 
     When a first element is referred to as being “on” a second element, the first element can be directly on the second element, or one or more intervening elements may be present between the first element and the second element. When a first element is referred to as being “directly on” a second element, there are no intended intervening elements (except for environmental elements such as air) present between the first element and the second element. 
     Unless explicitly described to the contrary, the word “comprise”, and variations such as “comprises” or “comprising”, may indicated the inclusion of stated elements but may not indicate the exclusion of any other elements. 
     The term “auxiliary member” may mean “ink-receiving member.” The term “member” may mean “member set” or “set of members.” The term “fix” may mean “support” and/or “secure.” The term “pattern” may mean “material layer” or “material layer with features.” The term “stage” may mean “support unit” or “platform.” 
       FIG.  1    is a perspective view showing an inkjet printing apparatus according to an embodiment. 
     The inkjet printing apparatus includes a stage  1100 , an auxiliary member  1250  positioned on the stage  1100 , and an inkjet head  1300  movable on the stage  1100  and the auxiliary member  1250 . 
     The stage  1100  may support the substrate  500 . The substrate  500  may be moved in the first direction x and/or the second direction y. The second direction y may be perpendicular to the first direction x. 
     The auxiliary member  1250  may be positioned adjacent to the substrate when the substrate  500  is mounted on the stage  1100 . The substrate  500  and the auxiliary member  1250  may not substantially overlap each other. The substrate  500  and the auxiliary member  1250  may be spaced by a predetermined distance in the first direction x. The substrate  500  and the auxiliary member  1250  may overlap each other in the third direction z. The substrate  500  and the auxiliary member  1250  may be spaced by a predetermined distance in the third direction z. The third direction z may be perpendicular to the first direction x and the second direction y. 
     The auxiliary member  1250  may include a polyimide film and/or an ultra-thin glass (UTG) film. The ultra-thin glass may be foldable and flexible. 
     The inkjet head  1300  may be moved in the first direction x and/or the second direction y. At least one of the stage  1100  and the inkjet head  1300  may be moved relative to the other. The stage  1100  may move in the first direction x and the second direction y. The stage  1100  may move in the first direction x, and the inkjet head  1300  may move in the second direction y. The stage  1100  may move in the second direction y, and the inkjet head  1300  may move in the first direction x. The inkjet head  1300  may move in the first direction x and the second direction y. 
     The inkjet head  1300  includes a nozzle, and ink may be discharged from the nozzle. The discharged ink may be provided (e.g., dropped) on the substrate  500  (positioned on the stage  1100 ) to form a predetermined pattern. The ink discharged from the inkjet head  1300  onto the substrate  500  may form an organic emission layer and/or a quantum dot color filter. Through the movement of the stage  1100  and/or the inkjet head  1300 , a pattern may be formed on the substrate  500 . The inkjet head  1300  may form a strip of the pattern on the substrate  500  by moving from one edge of the substrate  500  to the other edge in the first direction x, and the pattern may be formed on the substrate  500  after multiple strips arranged in the second direction y have been formed. In the process of moving the inkjet head  1300  in the second direction y to form the next strip, if the ink discharge is paused, drying of the ink may occur. According to an embodiment, the inkjet head  1300  is positioned on the auxiliary member  1250  when moving in the second direction y, and the ink discharge may be continuously performed, for preventing the ink inside the inkjet head  1300  from drying out. The inkjet head  1300  may provide/discharge ink on the auxiliary member  1250  when providing no ink on the substrate  500  (which is supported by the stage  1100 ). 
     The auxiliary member  1250  may be supported and/or fixed by a fixing member  1200  positioned at one or more sides of the stage  1100 . The fixing member  1200  may include a first roller  1232 , a second roller  1234 , a supporting member  1220 , and a transferring member  1210 . 
     Each of the first roller  1232  and the second roller  1234  may be rotatable between two supporting members  1220 . The first roller  1232  may be positioned higher than the second roller  1234 . The auxiliary member  1250  is wound on the second roller  1234 , and the auxiliary member  1250  may be further wound or unwound through the rotation of the second roller  1234 . The first roller  1232  supports the auxiliary member  1250 , and when the auxiliary member  1250  is moved, the first roller  1232  rotates to minimize the frictional force acting on the auxiliary member  1250 . 
     The two supporting members  1220  are connected to the transferring member  1210 . The two supporting members  1220  may move in the third direction z by the transferring member  1210 . The supporting member  1220  may be moved upwardly or downwardly by the transferring member  1210  relative to the stage  1100 . When the inkjet head  1300  discharges the ink to the auxiliary member  1250 , the supporting member  1220  may be moved downward so that the auxiliary member  1250  is fixed to (and is stabilized by) the stage  1100 . When the auxiliary member  1250  is wound or unwound on the second roller  1234 , the supporting member  1220  may be moved upwards so that the auxiliary member  1250  may be moved smoothly. 
     Two auxiliary members  1250  may be respectively positioned at two edges of the stage  1100  that are opposite each other in the first direction x. Each auxiliary member  1250  may extend lengthwise in the second direction y. Two ends of each auxiliary member  1250  may be supported and/or fixed by two fixing members  1200 . The inkjet printing apparatus may include four fixing members  1200  for fixing two auxiliary members  1250 . In a pair of fixing members  1200 , when one fixing member  1200  winds the auxiliary member  1250 , and the other fixing member  1200  may unwind the auxiliary member  1250 . 
       FIGS.  2  to  6    are perspective views showing a process in which an inkjet head is moved in an inkjet printing process according to an embodiment.  FIG.  7    is a perspective view showing a process in which an auxiliary member is moved in an inkjet printing process according to an embodiment. 
     Referring to  FIG.  2   , the inkjet head  1300  may be positioned on an auxiliary member  1250  before forming a pattern on the substrate  500 . The inkjet head  1300  may overlap a left auxiliary member  1250 . The inkjet head  1300  may overlap an edge of the auxiliary member  1250  and an edge of the stage  1100  that are close to each other. The inkjet head  1300  may be positioned at a left rear corner of the stage  1100 . 
     When the inkjet head  1300  overlaps the auxiliary member  1250 , the inkjet head  1300  may discharge ink onto the auxiliary member  1250 . Therefore, the ink in the inkjet head  1300  may keep flowing and is not dried. 
     Referring to  FIG.  3   , the inkjet head  1300  may discharge ink on the substrate  500  when moving in the first direction x. A strip of a predetermined pattern may be formed on the substrate  500  by the discharged ink. Because the pattern on the substrate  500  is formed with substantially fluid ink after the inkjet head  1300  discharges the ink on the auxiliary member  1250 , portions of the pattern formed at the beginning of the inkjet printing process may have the same characteristics as other portions of the pattern. Advantageously, the uniformity of the pattern formed on the substrate  500  may be satisfactory. 
     Referring to  FIG.  4   , when the inkjet head  1300  moves in the first direction x to another edge of the stage  1100 , the inkjet head  1300  may overlap a right auxiliary member  1250 . The inkjet head  1300  may be positioned at a right rear corner of the stage  1100 . 
     When the inkjet head  1300  overlaps the right auxiliary member  1250 , the inkjet head  1300  may continue discharging ink and may provide ink onto the right auxiliary member  1250 . The ink discharge may continue even when the inkjet head  1300  does not provide ink onto the substrate  500 . Therefore, the ink positioned inside the inkjet head  1300  may continue flowing and may maintain desirable fluidity. 
     Referring to  FIG.  5   , the inkjet head  1300  may move forward in the second direction y when overlapping the right auxiliary member  1250 . When the inkjet head  1300  is moving on the auxiliary member  1250 , the inkjet head  1300  may continue discharging ink onto the auxiliary member  1250 . 
     Referring to  FIG.  6   , the inkjet head  1300  may discharge the ink on the substrate  500  when moving in the first direction x. The inkjet head  1300  may move leftward, opposite to the movement direction of  FIG.  3   . A strip of the predetermined pattern may be formed on the substrate  500  by the discharged ink. By providing ink on the substrate  500  after the inkjet head  1300  discharges ink on the auxiliary member  1250 , the portion of the pattern formed after the movement direction change of the inkjet head  1300  may have the same characteristics as other portions of the pattern. Accordingly, the uniformity of the pattern formed on the substrate  500  may be satisfactory. 
     The inkjet printing process may be performed when the stage  1100  is moved. The inkjet printing process may be performed when both the stage  1100  and the inkjet head  1300  are moved. 
     Referring to  FIG.  7   , two auxiliary members  1250  positioned at two opposite sides of the stage  1100  are movable. Two ends of each auxiliary member  1250  are respectively supported by two fixing members  1200 . Ink may be accumulated on the auxiliary member  1250  during the inkjet printing process. When a predetermined amount of the ink is accumulated on a part of the auxiliary member  1250 , the auxiliary member  1250  may be moved such that the part of the auxiliary member  1250  may not further receive ink. 
     The supporting member  1220  may be moved in the third direction z by the transferring member  1210 . The supporting member  1220  may be moved upward to be spaced from the stage  1100 . 
     The first roller  1232  and the second roller  1234  may rotate to move the auxiliary member  1250  backward in the second direction y. The part of the auxiliary member  1250  wound around the front second roller  1234  may be. The rear second roller  1234  may engage more of the auxiliary member  1250 . The amount of the auxiliary member  1250  wound around the front second roller  1234  may decrease, and the amount of the auxiliary member  1250  wound around the rear second roller  1234  may increase. 
     Alternatively or additionally, the auxiliary member  1250  may move forward in the second direction y. 
     Two auxiliary members  1250  positioned at opposite sides of the stage  1100  may move simultaneously or separately. The two auxiliary members  1250  may move simultaneously at regular time intervals. The amount of the ink accumulated on two auxiliary members  1250  may be different; therefore, the two auxiliary members  1250  may move according to different time intervals. The inkjet printing apparatus may include a sensing member for sensing the amount of the ink accumulated on each auxiliary member  1250 , and an auxiliary member  1250  may be moved when a certain amount of ink is accumulated on the auxiliary member  1250 . 
       FIG.  8    is a perspective view showing an inkjet printing apparatus according to an embodiment. Some features related to the inkjet printing apparatus shown in  FIG.  8    may be identical to or analogous to some features described with reference to one or more of  FIGS.  1  to  7   . 
     Referring to  FIG.  8   , the inkjet printing apparatus includes a stage  1100 , an auxiliary member  1250  positioned on the stage  1100 , and an inkjet head  1300  movable on the stage  1100  and the auxiliary member  1250 . 
     The inkjet printing apparatus may further include a securing member  1260  positioned above the stage  1100 . 
     The securing member  1260  may be positioned between the stage  1100  and the auxiliary member  1250 . The securing member  1260  may suck the air positioned between the stage  1100  and the auxiliary member  1250  so that the auxiliary member  1250  is fixed to the stage  1100 . The auxiliary member  1250  may be substantially thin and may be affected by the surrounding airflow. The securing member  1260  may secure the auxiliary member  1250  in place and may prevent the auxiliary member  1250  from failing off the stage  1100 . The securing member  1260  may secure the auxiliary member  1250  in place when ink is provided on the auxiliary member  1250 . The securing member  1260  may release (and may not secure) the auxiliary member  1250  in place when (or immediately before) the auxiliary member  1250  is moved in the second direction y and/or the third direction z relative to the stage  1100 . 
     The securing member  1260  may include at least one of a vacuum chuck, a porous chuck, an electrostatic chuck, an adhesive chuck, and the like. 
       FIG.  9    is a perspective view showing an inkjet printing apparatus according to an embodiment. Some features related to the inkjet printing apparatus shown in  FIG.  9    may be identical to or analogous to some features described with reference to one or more of  FIGS.  1  to  7   . 
     Referring to  FIG.  9   , the inkjet printing apparatus includes a stage  1100 , an auxiliary member  1250  positioned on the stage  1100 , and an inkjet head  1300  movable on the stage  1100  and the auxiliary member  1250 . 
     The auxiliary member  1250  may be supported and/or fixed by the fixing member  1200  positioned at a side of the stage  1100 . The inkjet printing apparatus may further include a drying member  1270  attached to the fixing member  1200 . 
     The drying member  1270  may be fixed to two supporting members  1220  of the fixing member  1200 . The drying member  1270  may be positioned at a position/height between the first roller  1232  and the second roller  1234  or at an alternative position significantly spaced from the inkjet head  1300 . The drying member  1270  may be positioned farther from the inkjet head  1300  than the auxiliary member  1250 . 
     The drying member  1270  may irradiate ultraviolet rays and/or infrared rays for facilitating and/or accelerating drying of ink on the auxiliary member  1250 . 
     One or more drying members  1270  may be formed on one or more of the four fixing members  1200 . The movement direction of the auxiliary member  1250  may be the backward direction or the forward direction, and two drying members  1270  may be respectively formed on two fixing members  1200  that are opposite each other in the first direction x. 
       FIG.  10    is a perspective view showing an inkjet printing apparatus according to an embodiment. Some features related to the inkjet printing apparatus shown in  FIG.  10    may be identical to or analogous to some features described with reference to one or more of  FIGS.  1  to  7   . 
     Referring to  FIG.  10   , the inkjet printing apparatus includes a stage  1100 , an auxiliary member  1250  positioned on the stage  1100 , and an inkjet head  1300  movable on the stage  1100  and the auxiliary member  1250 . 
     The inkjet printing apparatus may include only one auxiliary member  1250 . The auxiliary member  1250  may be positioned at one edge of the stage  1100 . The auxiliary member  1250  may be positioned at the right edge or left edge of the stage  1100 . 
     The inkjet head  1300  may suspend/pause the discharge of ink when it is positioned at the left edge of the stage  1100 . When the inkjet head  1300  is positioned at the right edge of the stage  1100 , the inkjet head  1300  may discharge ink onto the auxiliary member  1250 . Accordingly, desirable fluidity of the ink inside the inkjet head  1300  may be maintained. 
       FIG.  11    is a perspective view showing an inkjet printing apparatus according to an embodiment. Some features related to the inkjet printing apparatus shown in  FIG.  11    may be identical to or analogous to some features described with reference to one or more of  FIGS.  1  to  7   . 
     Referring to  FIG.  11   , an inkjet printing apparatus includes a stage  2100 , an auxiliary member  2250  positioned on the stage  2100 , and an inkjet head  2300  that is movable on the stage  2100  and the auxiliary member  2250 . 
     The substrate  500  may move relative to the stage  2100  when floating over the stage  2100 . 
     The inkjet printing apparatus may further include holes  2400  (e.g., airflow-controlling holes  2400 ) positioned on the stage  2100  for controlling the movement of the substrate  500 . The holes  2400  may be disposed in a matrix form in a first direction x and a second direction y. The substrate  500  may be positioned over/on some of the holes  2400 . At least some holes  2400  underlying the substrate  500  may output air to provide pressure for floating the substrate  500  to be spaced from the stage  2100  by a predetermined distance. Some hole  2400  may suck in air to cause the substrate  500  may be fixed on the stage  2100  by the pressure of the atmosphere. 
     The inkjet printing apparatus may further include a substrate moving member  2500  for moving the substrate  500  when the substrate is floating. Although not shown, the substrate moving member  2500  may be connected to a rail and may move in the first direction x along the rail. One edge of the substrate  500  may be fixed on the substrate moving member  2500  after the substrate  500  is levitated, and the substrate moving member  2500  may move the substrate  500  in the first direction x. 
     The inkjet printing apparatus may include a driving unit (not shown) for generating a driving force for moving the substrate moving member  2500  may be provided. The driving unit may move the substrate moving member  2500  using at least one of a mechanical force, an electric force, and a magnetic force. 
     The upper face of the stage  2100  may have about twice the size/length of the substrate  500 . On the stage  2100 , the substrate  500  may move in the first direction x. 
     The auxiliary member  2250  may be positioned at the center of the stage  2100 . When the substrate  500  is moved to the left edge in the first direction x, the substrate  500  may not overlap the auxiliary member  2250 . When the substrate  500  is moved to the right edge in the first direction x, the substrate  500  may not overlap the auxiliary member  2250 . In the process of the substrate  500  moving from one edge to the other edge on the stage  2100 , the substrate  500  may overlap the auxiliary member  2250 . 
     The inkjet head  2300  may move in the second direction y, and may not move in the first direction x. The inkjet head  2300  may keep overlapping the auxiliary member  2250 . The auxiliary member  2250  may extend lengthwise in the second direction y, and the inkjet head  2300  may move in the second direction y over the auxiliary member  2250 . 
     As the substrate  500  moves over the auxiliary member  2250 , the substrate  500  may be positioned between the inkjet head  2300  and the auxiliary member  2250 , and the ink discharged from the inkjet head  2300  may fall on the substrate  500  to form the pattern. When the substrate  500  is not positioned between the inkjet head  2300  and the auxiliary member  2250 , the ink discharged from the inkjet head  2300  may fall on the auxiliary member  2250 . The inkjet head  2300  provides ink to the auxiliary member  2250  when not providing ink to the substrate  500 . Advantageously, the ink inside the inkjet head  2300  may continuously flow and maintain desirable fluidity. 
     The auxiliary member  2250  may be fixed by one or more fixing members  2200  positioned at one or more sides of the stage  2100 . A fixing member  2200  may include a first roller  2232 , a second roller  2234 , a supporting member  2220 , and a transferring member  2210 . 
     The inkjet printing apparatus may include two fixing members  2200  positioned at opposite sides of the stage  2100  for fixing one auxiliary member  2250 . When one fixing member  2200  winds the auxiliary member  2250 , the other fixing member  2200  may unwind the auxiliary member  2250 , such that a portion of the auxiliary member  2250  may move in the second direction y over the stage  2100 . 
       FIGS.  12  to  15    are perspective views showing an inkjet printing process according to an embodiment. 
     Referring to  FIG.  12   , an inkjet head  2300  may keep overlapping an auxiliary member  2250  when forming a pattern on a substrate  500  by an inkjet printing method. The auxiliary member  2250  may extend lengthwise in the second direction y. The substrate  500  may be positioned on the left half of the stage  2100  and may expose the auxiliary member  2250  to the inkjet head  2300 . 
     The inkjet head  2300  may discharge ink onto the auxiliary member  2250  when the inkjet head  2300  does not overlap the substrate  500 . Therefore, the inkjet printing process may be performed with desirable fluidity of the ink. 
     Referring to  FIG.  13   , when the substrate moving member  2500  moves in the first direction x, the substrate  500  may be moved in the first direction x. The substrate  500  may be positioned between the inkjet head  2300  and the auxiliary member  2250 . The ink is discharged from the inkjet head  2300  onto the substrate  500 , and a strip of a predetermined pattern may be formed on the substrate  500  by the discharged ink through the movement of the substrate  500 . The inkjet head  2300  may move in the second direction y for forming multiple strips of the pattern to complete the pattern on the substrate  500 . By forming the pattern on the substrate  500  with desirable fluidity of the ink, the portion of the pattern formed at the beginning of the inkjet printing process may have substantially the same characteristics as other portions of the pattern. Accordingly, the uniformity of the pattern formed on the substrate  500  may be satisfactory. 
     Referring to  FIG.  14   , when the substrate moving member  2500  has moved the substrate  500  in the first direction x past the auxiliary member  2500  to the right side of the stage  2100 , the substrate  500  may not block the auxiliary member  2250  from the inkjet head  2300 . 
     The inkjet head  2300  may provide ink to the auxiliary member  2250  without stopping discharging ink. The ink discharge may continue even when the inkjet head  2300  does not overlap the substrate  500 . Therefore, desirable fluidity of the ink inside the inkjet head  2300  may be maintained. 
     Referring to  FIG.  15   , when the substrate moving member  2500  moves leftward in the first direction x, the substrate  500  may be moved leftward in the first direction x. For forming additional features in the same strip of the pattern on the substrate  500 , the inkjet head  2300  may remain at the same position as in  FIG.  13   . For forming another strip of the pattern on the substrate  500 , the inkjet head  2300  may be at a position different from the position of the inkjet head  2300  in  FIG.  13   . The substrate  500  may be positioned between the inkjet head  2300  and the auxiliary member  2250 . The ink is discharged from the inkjet head  2300  onto the substrate  500 , and additional features or a new strip of the predetermined pattern may be formed on the substrate  500  by the discharged ink. 
     By forming the pattern on the substrate  500  after the inkjet head  2300  discharges the ink onto the auxiliary member  2250 , the portion of the pattern formed after the movement direction change of the substrate  500  may have substantially the same characteristics as other portions of the pattern. Accordingly, the uniformity of the pattern formed on the substrate  500  may be satisfactory. 
     Although not shown, the position of the inkjet head  2300  may be changed in the process of changing the movement direction of the substrate  500 . The inkjet head  230  may move forward in the second direction y along the auxiliary member  2250 . 
       FIG.  16    is a perspective view showing an inkjet printing apparatus according to an embodiment. Some features related to the inkjet printing apparatus shown in  FIG.  16    may be identical to or analogous to some features described with reference to one or more of  FIGS.  1  to  15   . 
     Referring to  FIG.  16   , the inkjet printing apparatus includes a stage  2100 , an auxiliary member  2250  positioned on the stage  2100 , and an inkjet head  2300  that is movable on the stage  2100  and the auxiliary member  2250 . 
     The inkjet printing apparatus may further include a securing member  2260  positioned on the stage  2100 . 
     The securing member  2260  may be positioned between stage  2100  and auxiliary member  2250 . The securing member  2260  may suck in the air between the stage  2100  and the auxiliary member  2250  so that the auxiliary member  2250  is attached to the stage  2100 . The auxiliary member  2250  may be substantially thin and may be affected by the surrounding airflow. The securing member  2260  may secure the auxiliary member  2250  in place and may prevent the auxiliary member  2250  from falling off the stage  2100 . The securing member  2260  may secure the auxiliary member  2250  in place when ink falls on the auxiliary member  2250 . The securing member  2260  may release the auxiliary member  2250  when or immediately before the auxiliary member  2250  is moved in the second direction y so that the auxiliary member  2250  may be separated from the stage  2100 . 
     The securing member  2260  may include at least one of a vacuum chuck, a porous chuck, an electrostatic chuck, an adhesive chuck, and the like. 
       FIG.  17    is a perspective view showing an inkjet printing apparatus according to an embodiment. Some features related to the inkjet printing apparatus shown in  FIG.  17    may be identical to or analogous to some features described with reference to one or more of  FIGS.  1  to  16   . 
     Referring to  FIG.  17   , the inkjet printing apparatus includes a stage  2100 , an auxiliary member  2250  positioned on the stage  2100 , and an inkjet head  2300  that is movable on the stage  2100  and the auxiliary member  2250 . 
     The auxiliary member  2250  may be supported and/or fixed by one or more fixing members  2200  positioned at one or more sides of the stage  2100 . The inkjet printing apparatus may further include a drying member  2270  attached to a fixing member  2200 . 
     The drying member  2270  may be fixed to two supporting members  2220  of the fixing member  2200 . The drying member  2270  may be positioned at a height/position between the first roller  2232  and the second roller  2234  or at an alternative position significantly spaced from the inkjet head  1300 . 
     The drying member  2270  may irradiate ultraviolet rays and/or infrared rays for facilitating and/or accelerating drying of ink on the auxiliary member  2250 . 
     One or two drying members  2270  may be formed on one or both of two fixing members  2200 . The movement direction of the auxiliary member  2250  may be the backward direction or the forward direction, a drying member  2270  may be formed on one of the two fixing members  2200 , and no drying member  2270  may be formed on the other one of the two fixing members  2200 . 
     While examples of embodiments have been described, practical embodiments are not limited to the described embodiments. Practical embodiments cover various modifications and equivalent arrangements within the scope of the appended claims.