JP3917977B2 - Inkjet printing device - Google Patents

Description

The present invention relates to a Lee ink jet printing apparatus, and more particularly, to Lee ink jet printing apparatus configured to suitably ensure the ejection straightness, etc. of droplets ejected from the print head body.

  In recent years, when printing with ink on a print medium made of paper or the like, when forming an alignment film or applying UV ink on a print medium made of a substrate (transparent substrate) such as a liquid crystal display, or organic EL In the case where a color filter is applied on a print medium composed of a substrate of a display device, an ink jet printing apparatus has been widely adopted.

  As this type of ink jet printing apparatus (including an alignment film forming apparatus, a coating apparatus, etc., the same applies hereinafter), a type in which the print head body is held so as to be movable relative to the print medium, or a print medium on a table There is a type in which the print head body is held so as to be movable relative to the table. In these printing apparatuses, during the relative movement of the print head main body, a gap between the nozzle surface of the print head main body (the surface on which one or a plurality of discharge nozzles are formed) and the print medium, that is, droplets of printing liquid are generated. A wind (air flow) accompanying relative movement is generated in the gap passing through the jet, and this wind causes a uniform thin film not to be formed on the print medium, or the droplets are not dropped at an accurate position. Invite such problems.

  Specifically, for example, as shown in FIG. 4, a type in which only a plurality of print head bodies 2 whose nozzle surfaces 2a are directed downward moves in the direction of arrow A (forward direction), or a print medium is placed on the upper surface. In the printing apparatus 1 of the type in which only the table 3 moves in the direction of arrow B (rearward) opposite to the above, or the type in which both the print head body 2 and the table 3 move in the directions of arrows A and B, respectively. Due to the front wall 2x and the rear wall 2y of the print head body 2, the wind indicated by the arrow E and the turbulent air flow indicated by the arrow F are generated. Then, these wind E and turbulent flow F flow into the gap between the print head body 2 and the table 3 and cause flight bending or the like in droplets discharged from the nozzle surface 2a of the print head body 2. . In particular, as shown in the figure, when a plurality of print head bodies 2 are arranged in the relative movement direction, the generation of the turbulent flow F in the vertical direction is promoted, and the turbulent flow F is caught in the gap, thereby causing the liquid Inconveniences such as flying flight of droplets become more prominent.

  In this case, as shown in a plan view in FIG. 5, in the type of printing apparatus 1 in which a plurality of print head bodies 2 are arranged in a staggered manner, a turbulent flow G in the horizontal direction, that is, a turbulent flow that rotates horizontally, is generated. The turbulent flow G may be caught in the gap between the print head main body 2 and the table 3, and in this case as well, an inappropriate flight curve of the droplets occurs.

  Furthermore, in these printing apparatuses, as shown in FIG. 6, the table 3 presses the wind indicated by the arrow H against the print head body 2 due to the gap between the print head body 2 and the table 3. The pressed wind H flows into the gap between the print head main body 2 and the table 3, and this also promotes the flying bend of the droplets.

  As described above, due to the influence of the winds E and H and the turbulent flows F and G generated by the movement of the print head body 2 and the table 3 in opposite directions, the flying curve of the droplets occurs. In addition, the thickness of the thin film formed on the print medium is not uniform, or the droplet landing position accuracy on the print medium is deteriorated. Such a problem can occur not only when both the print head body 2 and the table 3 move, but also when only one of them moves.

  As an apparatus created to avoid the above-described basic problems, for example, according to Patent Document 1 below, a carriage shell that covers a print head body (print cartridge in the same document), and a print head from the carriage shell. An ink jet printing apparatus having a carriage skirt extending in the scanning axis direction in parallel with the nozzle surface of the main body is disclosed. According to such a configuration, the presence of the carriage skirt can be expected to somewhat prevent the turbulence of wind and air from flowing into the gap between the print head body and the print medium.

  As another example, according to the following Patent Document 2, a substrate (corresponding to a part of a print head main body) having an ink discharge generating means is disposed below a recording paper as a print medium with a nozzle surface facing upward. There is disclosed a printing apparatus which is arranged in such a manner that inclined surfaces are formed on the lower surfaces of both ends in the relative movement direction of the substrate so that the center side is closer to the lower side. According to such a configuration, the air flow generated by the relative movement of the carriage (corresponding to the print head main body) is caused by the droplet discharge gap between the substrate and the recording paper and the inclined surface of the substrate. It is expected that the amount of air flow flowing into the droplet discharge gap can be halved since it is branched in the direction along the line.

JP 2002-361858 A JP-A-9-76524

  In the ink jet printing apparatus disclosed in the above-mentioned Patent Document 1, the carriage skirt can somewhat prevent wind and air turbulence from flowing into the gap between the print head body and the print medium. When the print head main body moves relatively, the body portion of the carriage shell can directly collide with air and generate wind or air turbulence.

  When wind or the like is generated in this way, even if the carriage skirt is provided, there is a possibility that an air flow may be caught in the gap between the print head main body and the print medium, and the flying curve of the droplet etc. This problem cannot be completely avoided. In addition, when wind or the like is generated as described above, foreign matters such as dust adhering to the periphery of the carriage shell body and the connection portion between the carriage shell and the carriage skirt rise up in the air flow and immediately after printing. There is a problem in that it adheres and remains on the surface of a print medium that is not dried, resulting in a decrease in print quality.

  On the other hand, the ink jet printing apparatus disclosed in Patent Document 2 can only halve the amount of airflow flowing into the gap between the print head body and the print medium, and the airflow still remains in the gap. Since it flows in, it is impossible to completely avoid problems such as flying bending of droplets. Further, even in this printing apparatus, when the carriage moves relatively, the body of the carriage directly collides with the air, so that wind or air turbulence can be generated. Therefore, in this case as well, foreign matter such as dust adhering to the body of the carriage remains attached to the surface of the print medium that has not been dried immediately after printing, which leads to a reduction in print quality. There's a problem.

  In the ink jet printing apparatus of the type in which the print head body is held so as to be relatively movable with respect to the table in a state where the print medium is placed on the table, in order to cope with the above-described problems, The technical idea of improving the table has not existed in the past, and the appropriate situation is desired.

  The present invention has been made in view of the above circumstances, and a situation in which wind or air turbulence or the like flows into a gap between a print head main body and a print medium to cause a flying curve of a droplet or the like. It is technically possible to avoid as much as possible the situation in which foreign matter adhering to the print head body is scattered due to wind or air turbulence and remains on the medium immediately after printing. Let it be an issue.

The present invention has been made to solve the above technical problem, in a state where a print medium is placed on a table, a print head main body is held above the table so as to be movable relative to the table, and at the time of the relative movement in configured Lee ink jet printing apparatus as print for liquid from the nozzle surface is discharged of the print head body, the nozzle surface of the printhead body, leaving tension from the print head body extends in the direction of relative movement with mounting the to plate, at one or both ends of the relative movement direction of the plate, the inclined surface which is inclined toward the side opposite to the nozzle surface of the printhead body brought to migrate to the relative movement direction central portion Yes to the nozzle surface of the printhead body by wind inclined surface generated by impinging air on the inclined surface when the relative movement Forming a first wind direction conversion portion for directing the direction of the opposite, and, at one or both ends of the relative moving direction of the table, opposite to the upper surface of the table take the shifts in the relative movement direction central portion A second wind direction that has an inclined surface that is inclined toward the surface and that directs wind generated by air colliding with the inclined surface during the relative movement in a direction opposite to the upper surface side of the table. The conversion unit is formed.

Here, it goes without saying that it is necessary to mount the plate so that the nozzle surface of the print head body is exposed. In this case, the nozzle surface protrudes from the back surface of the plate (the surface facing the print medium). It is preferable that the level difference between the two is 0.5 mm or less, more preferably , the back surface of the plate and the nozzle surface are flush or substantially flush. . If the print head main body or the board is relatively moved in both directions, it is preferable to form the first wind direction changing portions at both ends of the relative movement direction of the board. Alternatively, if the case where the plate relatively moves only in one direction is targeted, it is preferable to form the first wind direction changing portion only at one end of the plate that directly collides with air. The plate is preferably attached to the outer periphery of the print head main body without a gap, but may be present as long as the gap is within 1 mm.

According to such a configuration, when the print head main body moves relative to the print medium while discharging printing liquid (for example, ink) from the nozzle surface, air is applied to the inclined surface of the first wind direction changing portion of the plate . Collide. In this case, the inclined surface of the first wind direction changing portion is inclined so as to be directed to the side opposite to the nozzle surface side of the print head body as the plate moves toward the central portion in the relative movement direction. The air colliding with the surface does not flow toward the nozzle surface side (base end side) of the print head body, but flows toward the opposite side (tip side) of the print head body. By performing such an operation, there is a problem that the wind generated by the air colliding with the inclined surface of the first wind direction changing unit is caught in the gap between the print head body and the print medium and flows in. In addition to being avoided, the occurrence of a situation where air collides with the body of the print head body does not occur or is mitigated, so the probability of air turbulence is greatly reduced. As a result, ejection defects such as flying bends of droplets ejected from the nozzle surface of the print head body are less likely to occur, which can contribute to uniform film thickness and the like, and the body of the print head body, particularly the print head body. Even if foreign matter such as dust adheres to the nozzle surface side of the body of the printer, it is possible that this foreign matter will be scattered by wind or air turbulence and remain on the dry print medium immediately after printing. Therefore, the print quality can be improved. In this case, it is preferable that the inclination angle of the inclined surface is an angle such that the wind generated by the air colliding with the inclined surface does not directly hit the print head body.

Furthermore , if the print head main body moves relative to the table in both directions, it is preferable to form the second wind direction changer at both ends of the relative movement direction of the table. On the other hand, if the relative movement is made only in one direction, it is preferable to form the second wind direction changing portion only at one end of the table that directly collides with air.

As described above, in an ink jet printing apparatus having a print head body and a table on which a print medium is placed, when the print head body moves relative to the table while discharging the printing liquid from the nozzle surface, The air collides with the inclined surface in the second wind direction conversion portion of the table. In this case, the inclined surface of the second wind direction changing portion is inclined toward the opposite side (downward) from the upper surface side of the table as it moves toward the central portion in the relative movement direction of the table. The air colliding with the surface flows in a direction away from the gap between the print head body and the print medium. Therefore, the wind generated by the collision of air with the inclined surface is caught in the gap between the print head main body and the print medium and flows in, thereby avoiding problems such as causing flying bending of droplets.

That is, the wind adverse effects generated by impinging air on the table on which avoids as described above, for the printhead body side, as already mentioned, avoiding the adverse effect of turbulence wind and air it can.

According to engagement Louis ink jet printing apparatus in the present invention as described above, when the print head body moves relative to the table while discharging the printing liquid for the nozzle surface, the first wind direction conversion portion of the plate The wind generated when the air collides with the inclined surface of the print head avoids problems such as being caught in the gap between the print head main body and the print medium, and the air collides with the body of the print head main body. Since the situation does not occur or is reduced, the probability of air turbulence is greatly reduced. In addition, the air that has collided with the inclined surface in the second wind direction changing portion of the table flows in a direction away from the gap between the print head body and the print medium. This not only effectively avoids ejection failures such as flying bends of droplets, but also foreign matter such as dust adheres to the nozzle surface side of the body of the print head body, particularly the body of the print head body. However, it is possible to avoid the situation that the foreign matter is scattered by the turbulent flow of air or air and adheres to the dry print medium immediately after printing as much as possible, thereby improving the print quality.

Hereinafter, engagement Louis ink jet printing apparatus according to an embodiment of the present invention (hereinafter, simply referred to as printing apparatus) will be described with reference to the accompanying drawings. FIG. 1 is a schematic side view showing a printing apparatus according to the first embodiment of the present invention, FIG. 2 is a schematic plan view showing the printing apparatus according to the second embodiment of the present invention, and FIG. It is a schematic side view which shows the printing apparatus which concerns on 3rd Embodiment. In FIG. 1 to FIG. 3 and the following description based on them, the same reference numerals are used for the same constituent elements as those of the conventional example shown in FIG. 4 to FIG. In each of the printing apparatuses shown in FIGS. 1 to 3, the table 3 is fixed and held, and only the print head main body 2 moves, or the print head main body 2 is fixed and held. Although only the table 3 is shown as a type of printing apparatus 1, the following description will be given as an aspect in which both the print head body 2 and the table 3 move for convenience.

  As shown in FIG. 1, the printing apparatus 1 (for example, an alignment film forming apparatus) according to the first embodiment of the present invention has a plurality of print head bodies 2 that move in the direction of arrow A (forward direction). In the example shown in FIG. A single table 3 for placing a print medium (not shown) made of a glass substrate such as a liquid crystal display on the upper surface with a predetermined gap interposed between the print head body 2 and the above. Are arranged so as to move in the direction of the arrow B in the reverse direction (backward direction).

A plate 4 extending in the front-rear direction (relative movement direction) of the print head body 2 and projecting from the plurality of print head bodies 2 in the front-rear direction is mounted on the nozzle surface 2a side of the print head body 2. the rear surface of the plate 4 (the surface of the print medium opposite to the side) is a nozzle surface 2a is flush or substantially flush. Note that one or a plurality of ejection nozzles are disposed on the nozzle surface 2a of the print head body 2.

Further, before and after each of the opposite ends, the first wind direction conversion portion having an inclined surface 5a which is inclined toward the upper side of the print head body 2 As the shifts in the longitudinal direction central portion side of the plate 4 of the plate 4 5 is formed. Both of the first wind direction changing portions 5 are formed at portions excluding the peripheral region 4S of the print head main body 2. The first wind direction conversion portion 5 in this embodiment is formed by bending both ends in the front-rear direction of the plate 4.

  Moreover, the 2nd wind direction conversion part 6 which has the inclined surface 6a which inclines so that it may move below as it moves to the front-back direction center part side of the table 3 is formed in the front-back direction both ends of the table 3. As shown in FIG. The upper surface of the second wind direction changing portion 6 is flush with or substantially flush with the upper surface of the table 3, and the end 6 b on the center side in the front-rear direction protrudes below the lower surface of the table 3. .

  According to the printing apparatus 1 according to the first embodiment having such a configuration, the print head body 2 moves in the arrow A direction, or the table 3 on which the print medium is placed moves in the arrow B direction. At this time, a printing liquid (for example, a film material for forming an alignment film) is discharged from the nozzle surface 2a of the print head main body 2, and the droplets land on the upper surface of the print medium.

When such an operation is performed, on the print head main body 2 side, air collides with the inclined surface 5a of the first wind direction changing portion 5 formed at the front end of the plate 4. The generated wind is wound up obliquely upward as indicated by an arrow C by the action of the inclined surface 5a. Therefore, problems such as the wind C generated by the collision being caught in the gap S between the print head main body 2 and the print medium on the table 3 are avoided and discharged from the nozzle surface 2a of the print head main body 2. Flying bends are less likely to occur in the droplet, and the landing position accuracy of the droplet on the print medium is extremely good.

  In addition, the situation where the air collides with the body of the print head body 2 does not occur, or even if the air collides, it stays in a small area in the upper part of the print head body 2, so The probability of occurrence is greatly reduced. As a result, even if foreign matter such as dust adheres to the body of the print head body 2, particularly the nozzle surface 2 a side of the body of the print head body 2, this foreign matter is scattered by wind and air turbulence and printed. The situation of adhering and remaining on an undried print medium immediately after is avoided as much as possible, and the print quality is improved.

In addition, since the first wind direction changing portion 5 is formed in a portion of the plate 4 excluding the peripheral region 4S of the print head main body 2, air flows toward the peripheral region 4S of the print head main body 2. Even if foreign matter such as dust adheres to the peripheral area 4S of the print head body 2 in the plate 4 which is preferably blocked, the foreign matter is scattered by wind and air turbulence and is not dried immediately after printing. The situation of adhering and remaining on the surface is avoided as much as possible, and this also improves the print quality.

  On the other hand, on the table 3 side, air collides with the inclined surface 6a of the second wind direction changing portion 6 formed at the rear end of the table 3. The wind generated by the collision of the air is caused by the action of the inclined surface 6a. As shown by the arrow D, it is pushed down obliquely downward. Therefore, problems such as the wind D generated by the collision being caught in the gap S between the print head main body 2 and the print medium on the table 3 are avoided, and this also prevents the nozzle surface 2a of the print head main body 2. Flying bends are less likely to occur in the droplets ejected from, and the landing position accuracy of the droplets on the print medium is further improved.

In the printing apparatus 1 according to the second embodiment of the present invention shown in FIG. 2, a plurality of print head bodies 2 are arranged in a staggered manner in a double row, and one plate is provided on the nozzle surface side of these print head bodies 2. 4 is installed. The mounting state of the plate 4 with respect to the print head main body 2 is the same as that in the first embodiment. Further, each of the front and rear opposite ends of the plate 4, together with the first wind direction conversion portion 5 having the same inclined surface 5a and the first embodiment described above are formed, respectively in front and rear opposite ends of the table 3, the above-mentioned A second wind direction converter 6 having an inclined surface 6a similar to that of the first embodiment is formed. In FIG. 2, the same reference numerals are given to the constituent elements common to the first embodiment described above.

According to the printing apparatus 1 according to the second embodiment, when either one of the print head main body 2 and the table 3 moves in the direction of the arrow A or the direction of the arrow B, the above-described first embodiment is applied. In addition to the effects similar to those of the printing apparatus 1, a plurality of print head main bodies 2 are arranged in a staggered manner, and thus the turbulent air flow shown in FIG. Cease to occur, or the probability of occurrence is drastically reduced. As a result, the foreign matter adhering to the body of the print head body 2 and the plate 4 is swollen by the turbulent air flow, and then drops onto the dry print medium immediately after printing and remains attached. Things are avoided as much as possible.

In the printing apparatus 1 according to the third embodiment of the present invention shown in FIG. 3, the first wind direction changing portions 5 formed at both ends in the front-rear direction of the plate 4 are not formed by bending the plate 4, but have a triangular cross section. The body is fixed to the plate 4. Since the other configuration is the same as that of the first embodiment described above, in FIG. 3, the same reference numerals are given to the same constituent elements as those of the first embodiment described above, and the description thereof is omitted. The printing apparatus 1 according to the third embodiment also has the same effects as the printing apparatus 1 according to the first embodiment described above.

  In the above embodiment, the present invention is applied to the type of printing apparatus 1 in which only one of the print head main body 2 and the table 3 is moved. Similarly, the present invention can be applied to a printing apparatus in which both of them move.

  Further, in the above embodiment, the present invention is applied to the printing apparatus 1 in which the table 3 on which the print medium is placed is arranged below the print head body 2. The same applies to a printing apparatus in which only the print medium is disposed below the head body 2 or a printing apparatus in which only the print medium is disposed above or to the side of the print head body 2. It is possible to apply the present invention (invention relating only to the print head main body side).

To a first embodiment of the present invention is a schematic side view showing an overall configuration of the engagement Louis ink jet printing apparatus. It is a schematic plan view showing the overall configuration of the engagement Louis ink jet printing apparatus according to a second embodiment of the present invention. To a third embodiment of the present invention is a schematic side view showing an overall configuration of the engagement Louis ink jet printing apparatus. It is a schematic side view which shows the inkjet type printing apparatus which concerns on a prior art example. It is a schematic plan view which shows the inkjet type printing apparatus which concerns on a prior art example. It is a schematic side view which shows the inkjet type printing apparatus which concerns on a prior art example.

Explanation of symbols

1 printing device (Lee ink jet printing apparatus)
2 Print head body
2a Nozzle surface 3 Table 4 plate
4S peripheral area 5 1st wind direction change part
5a Inclined surface 6 of the first wind direction conversion section Second wind direction conversion section
6a Inclined surface of the 2nd wind direction change part

Claims (1)

With the print medium placed on the table, the print head main body is held above the table so as to be movable relative to the table, and the printing liquid is discharged from the nozzle surface of the print head main body during the relative movement. in Lee ink jet printing apparatus configured to,
Moves to the nozzle surface of the printhead body, the mounting plate to be emitted tension from the print head body extends in the direction of relative movement, at one or both ends of the relative movement direction of the plate, in the relative movement direction central portion wherein the wind inclined surface generated by the air impinging on the inclined surface to have the inclined surface during the relative movement which is inclined toward the side opposite to the nozzle surface of the printhead body brought to As the first wind direction changing portion is formed to be directed in the direction opposite to the nozzle surface side of the print head body , and at one or both ends in the relative movement direction of the table, as it moves toward the central portion side in the relative movement direction The table has an inclined surface that inclines toward the side opposite to the upper surface side of the table, and wind generated by air colliding with the inclined surface during the relative movement is generated by the inclined surface by the table. The upper surface side opposite characteristics and to Louis ink jet printing apparatus that forms a second wind direction conversion section for directing the direction of.

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