Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/135—Nozzles
  • B41J2/14—Structure thereof only for on-demand ink jet heads
  • B41J2/14016—Structure of bubble jet print heads
  • B41J2/14032—Structure of the pressure chamber
  • B41J2/1404—Geometrical characteristics
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/015—Ink jet characterised by the jet generation process
  • B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
  • B41J2/045—Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
  • B41J2/04501—Control methods or devices therefor, e.g. driver circuits, control circuits
  • B41J2/04573—Timing; Delays
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/135—Nozzles
  • B41J2/14—Structure thereof only for on-demand ink jet heads
  • B41J2/14016—Structure of bubble jet print heads
  • B41J2/14024—Assembling head parts
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/135—Nozzles
  • B41J2/14—Structure thereof only for on-demand ink jet heads
  • B41J2/1433—Structure of nozzle plates
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/135—Nozzles
  • B41J2/145—Arrangement thereof
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/135—Nozzles
  • B41J2/16—Production of nozzles
  • B41J2/1601—Production of bubble jet print heads
  • B41J2/1603—Production of bubble jet print heads of the front shooter type
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/135—Nozzles
  • B41J2/14—Structure thereof only for on-demand ink jet heads
  • B41J2002/14387—Front shooter
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/135—Nozzles
  • B41J2/14—Structure thereof only for on-demand ink jet heads
  • B41J2002/14475—Structure thereof only for on-demand ink jet heads characterised by nozzle shapes or number of orifices per chamber

Definitions

• the present invention relates to a liquid discharge head, a liquid discharge apparatus, a head cartridge, and a liquid discharge method that perform recording by discharging droplets toward a medium.
• a liquid discharge method (ink jet recording method)
• a heating element (heater) is used as a discharge energy generating element used for discharging droplets.
• a heating element (heater)
• FIG. 10 is a schematic diagram showing a general discharge process of a bubble jet (B J) discharge method using a conventional ink jet head in which bubbles do not communicate with the atmosphere.
• the liquid in the portion protruding from the orifice plate in which the discharge port is formed is referred to as discharge liquid, and the liquid inside the discharge port is referred to as channel liquid.
• the main droplet and the sub-droplet (Satellite ⁇ ) are further separated by the tension (Fig. 10 (h)). Since this satellite flies behind the main droplet, the landing position of the main droplet shifts and the surface of the paper drops. As a result, the image quality is degraded.
• Fig. 12 is a schematic diagram showing the general discharge process of the bubble-through jet (BT J) discharge method using conventional ink jet ⁇ heads and bubbles communicating with the atmosphere.
• the channel height is lower than that of the system.
• Fig. 10 Explanation of the same part as the BJ discharge method of 10 is omitted. Defoaming process (Fig. 1 2
• Japanese Patent Laid-Open No. 10-2 3 5 8 7 4 assumes a shape larger than the discharge port used for high-quality heads such as photographic output, and is discharged.
• the droplet size is also large.
• the mechanism of droplet separation is basically The amount by which tailing (droplet length) is shortened is about 5 ⁇ m at most, depending on the discharge speed. That is, in the configuration of Japanese Patent Application Laid-Open No.
• the present inventors considered that it is necessary to sufficiently shorten the separation time of the discharged liquid in order to reduce the length of the tail and reduce the satellite.
• the head of the discharge liquid continues to advance, so the earlier the timing at which the discharge liquid separates from the liquid in the discharge port, the earlier The tail of the flying droplet
• the length of the drill is shortened. From this point of view, it is desirable that the separation timing of the ejected liquid is advanced until the defoaming process.
• the present invention provides a liquid discharge head that discharges liquid from a discharge port by applying energy from an energy generating element to the liquid, and the discharge port discharges liquid.
• a liquid discharge head that discharges liquid from a discharge port by applying energy from an energy generating element to the liquid, and the discharge port discharges liquid.
• the first region is formed in a direction in which the protrusion is convex, and the second region is formed on both sides of the protrusion.
• a liquid discharge head that discharges liquid from the discharge port by applying energy to the liquid from the energy generating element, the discharge port being arranged on a cross section of the discharge port with respect to a direction of discharging the liquid.
• the protrusion has three or less protrusions protruding on the heel side of the discharge port, the length of the protrusion in the direction in which the protrusion is convex is X, and the width of the base of the protrusion in the width direction of the protrusion is x 2 , And satisfying 1.6 ⁇ ( ⁇ 2 / ⁇ ,)> 0.
• the discharge port is a cross-section of the discharge port in a direction of discharging the liquid.
• the distance from the tip of the protrusion to the edge of the discharge port in the direction in which the protrusion is convex H, the maximum diameter of the discharge port, the half width of the protrusion a, and the virtual of the discharge port Assuming that the minimum diameter of the outer edge is M, M ⁇ (L-a) Z2> H, and the shape of the tip of the protrusion in the section of the discharge port is a shape having a curvature or a direction in which the protrusion is convex It is a shape which has a linear part perpendicular
• the liquid ejection method of the present invention is a liquid ejection method for ejecting liquid from an ejection port by applying energy to the liquid from an energy generating element, in the section of the ejection port with respect to the direction of ejecting the liquid,
• the discharge liquid force extending from the discharge port to the outside can be greatly accelerated the timing of separation from the liquid in the discharge port, and satellites and mists that cause deterioration in image quality. Can be further reduced.
• FIG. 1A, 1B, and 1C respectively show a cross-sectional view of a nozzle, a shape of a heater, a flow path, and a discharge port shape as viewed from the discharge port direction in a liquid discharge head applicable to the present invention. It is a spear.
• FIG. 2 is a discharge process diagram in the cross-sectional view of the head along the line AA in FIG. 1B.
• FIG. 3 is a discharge process diagram in the head sectional view taken along the line BB in FIG. 1B.
• FIG. 4 shows the relationship between the minimum diameter of the liquid column in FIGS. 2 and 10 and the discharge process. It is a graph.
• 5A, 5B, and 5C show the shape of the discharge port of the liquid discharge head that can be applied to the present invention, each of which has a schematic shape with one protrusion, a schematic shape with three protrusions, and a protrusion at the circular discharge port. It is two schematic diagrams.
• FIGS. 1A, 1B, and 1C are schematic diagrams in which liquid is discharged using the heads shown in FIGS. 1A, 1B, and 1C.
• FIG. 7 is a schematic perspective view showing a main part of a liquid ejection apparatus applicable to the present invention.
• FIG. 8 shows a cartridge that can be mounted on a liquid discharge recording apparatus applicable to the present invention.
• 9A and 9B are a schematic perspective view and an enlarged view of the discharge port of the main part of the liquid discharge head applicable to the present invention, respectively.
• FIG. 10 is a discharge process diagram of a BJ discharge method using a conventional round discharge port.
• 1A, 1 1 B, 1 1 C, 1 1 D, 1 1 E, and 1 1 F are schematic views of a manufacturing process of a liquid discharge head applicable to the present invention.
• FIG. 12 is a discharge process diagram of a BJJ discharge method using a conventional round discharge port.
• FIG. 13 is a discharge process diagram of the present embodiment in the BJJ discharge method as seen from the vertical direction of the protrusion.
• FIG. 14 is a discharge process diagram of the present embodiment in the BJJ discharge method as seen from the protrusion direction.
• FIG. 15 is a schematic diagram showing an example of a head in the present embodiment.
• FIGS. 16A and 16B are schematic views showing examples of heads in this example.
• FIG. 17 is a schematic diagram of a discharge port applicable to the present embodiment.
• FIGS. 18A and 18B are schematic views of a discharge port of a comparative example.
• FIGS. 19A and 19B are schematic views of a discharge port of a comparative example.
• FIG. 20 is a schematic diagram of the protrusions in this example and the movement of the liquid formed therebetween.
• FIGS. 21A and 2IB are schematic views of the protrusions in the comparative example and the movement of the liquid formed therebetween.
• “recording” means forming significant information such as characters and figures. Furthermore, it includes those that form images, patterns, patterns, etc. on a wide range of recording media, regardless of whether they are manifested so that they can be perceived visually, regardless of significance. It also includes the case where the medium is processed by applying a liquid to the medium. “Recording media” includes not only paper used in general recording equipment, but also wide-ranging materials such as cloth, plastic film, metal plate, glass, ceramics, wood, leather, etc. that can accept ink. To express. Furthermore, “ink” and “liquid” indicate an image, a pattern, a pattern, or the like that is formed on a recording medium.
• liquids used as processing agents such as processing of the recording medium, or solidification or insolubilization of the liquid applied to the recording medium.
• Fluid resistance indicates the ease of movement of a liquid. For example, the liquid resistance is high because the liquid is difficult to move in a narrow part, and the fluid resistance is low because the liquid is easy to move in a wide part.
• terms such as parallel, vertical, and straight lines used in this specification include a range of manufacturing error.
• FIG. 7 is a schematic perspective view showing a main part of an example of a liquid discharge head to which the present invention can be applied and a liquid discharge recording apparatus (inkjet printer) as a liquid discharge apparatus using the head.
• a liquid discharge recording apparatus inkjet printer
• the liquid discharge recording apparatus includes a conveying device 10 0 30 that intermittently conveys a paper 10 28 as a recording medium in a casing 100 8 in the direction of arrow P.
• the liquid discharge recording apparatus is reciprocally moved in parallel with a direction S orthogonal to the conveyance direction P of the paper 10 28, and has a liquid discharge head.
• a movement drive unit 1 006 as drive means for reciprocating 1 0 10.
• the transport device 10 30 includes a pair of roller units 0 1 0 2 2 a and 10 2 2 b, a pair of roller units 0 1 0 24 a and 1 0 2 4 b, and each of these roller units And a drive unit 1 0 20 for driving the.
• the drive unit 1 0 20 is activated, the paper 1 0 2 8 is held by the guillotine ⁇ 1 0 2 2 a and 1 0 2 2 b and the roller unit 1 0 24 a and 1 0 24 b , Conveyed in the P direction with intermittent feed.
• the movement drive unit 1 006 includes a belt 1 0 1 6 and a motor 1 0 1 8.
• the bell ⁇ 1 0 1 6 is arranged to face the rotating shaft with a predetermined distance and is applied with a pulling force to the pulleys 1 0 2 6 a and 1 0 26 b, and the mouth rot unit 1 0 2 2 a and And 1 0 2 2 b.
• the motor 10 18 drives the belt 10 16 connected to the carriage member 10 10 10 a of the recording unit 10 10 10 in the forward direction and the reverse direction.
• the carriage member 1 0 1 0 a moves in the direction of arrow S by a predetermined amount of movement.
• the belt 1 0 16 rotates in the direction opposite to the arrow R direction
• the carriage member 1 0 1 0 a moves in a direction opposite to the arrow S direction by a predetermined amount of movement.
• the recovery unit 1 0 26 force for performing the discharge recovery processing of the recording unit 1 0 10 0 at the position that becomes the home position of the carriage member 1 0 1 0 a a surface that discharges the ink of the recording unit 1 0 1 0 Are provided opposite to each other.
• the recording unit 10 0 1 0 has a force ridge 1 0 1 2 that is detachably attached to the carriage member 1 0 1 0 a.
• yellow, magenta, cyan, and black are provided with 1 0 1 2 Y, 1 0 1 2M, 1 0 1 2 C, and 1 0 1 2 B, respectively.
• FIG. 8 shows an example of a force ridge that can be mounted on the above-described liquid discharge recording apparatus.
• the force trough 1 0 1 2 in this embodiment is of a serial type, and the main part is composed of a liquid discharge head 1 0 0 and a liquid tank 1 0 0 1 that stores liquid such as ink. ing.
• the liquid discharge head 10 0 formed with a large number of discharge ports 32 for discharging liquid corresponds to each embodiment described later.
• a liquid such as ink is guided from a liquid tank 1001 to a common liquid chamber of a liquid discharge head 100 via a liquid supply passage (not shown).
• the force ridge 1 0 1 2 in this application is a liquid discharge head 1 0 0 and a liquid tank 1 0 0 1 which are integrally formed, but the liquid discharge head 1 0 0
• a structure in which the liquid tanks 1 0 0 1 are connected in an exchangeable manner may be adopted.
• the liquid discharge head that can be mounted on the above-mentioned liquid discharge recording device (structure of the liquid discharge head)
• FIG. 9A is a schematic perspective view schematically showing the main part of the liquid discharge head applicable to the present invention. Electrical wiring for driving the heating element is omitted.
• the arrow S in Fig. 9A indicates the direction in which the head and the recording medium move relatively (main scanning direction) during the recording operation in which the head discharges droplets. In this embodiment, as shown in FIG. 7, an example is shown in which the head moves relative to the recording medium during the recording operation.
• the substrate 34 includes a supply port 33 including a long groove-like through-hole that supplies liquid to the flow path.
• a supply port 33 including a long groove-like through-hole that supplies liquid to the flow path.
• heat generating elements (heaters) 3 1 that are thermal energy generating means are arranged in a staggered manner. 0 0 dpi has been achieved.
• a flow path forming member for forming a flow path a flow path wall 36 and a discharge port plate 35 including a discharge port 32 are provided.
• Figures 1A, 1B and 1C are used for the shape of the discharge port applicable to the present invention.
• Fig. 1A shows a cross-sectional view of the nozzle
• Fig. 1B shows the shape of the heater and the flow path from the direction of the discharge port
• Fig. 1 C. shows the shape of the discharge port 32.
• the discharge port shape of the present invention has a characteristic configuration having at least one protrusion on the inner side with respect to the outer edge of the discharge port.
• the protrusions are provided symmetrically, and the minimum diameter H of the discharge port is formed in the gap between the protrusions.
• the width of the protrusion and the gap between the protrusions become a high fluid resistance region 55, which is a first region having a significantly higher fluid resistance than other portions of the discharge port.
• a low fluid resistance region 56 is provided as a second region on both sides of the high fluid resistance region 55 as a second region. In the present invention, the point is that there is a sufficient difference in fluid resistance between the high fluid resistance region and the low fluid resistance region.
• the protrusion is provided locally, and it is desirable that the fluid resistance in the low fluid resistance region is not so high as compared with the case where the protrusion is not provided.
• the outer edge of the discharge port can take any configuration such as a circle, an ellipse, or a rectangle.
• FIG. 9B is an enlarged view of an example of the discharge port shown in FIG. 9A.
• the image quality degradation due to the displacement of the position where the droplets land on the paper surface occurs because lines are formed on the recording medium by the droplets ejected from the same ejection port.
• the position of the droplet in the head scanning direction S is more greatly affected by the displacement of the droplet in the direction perpendicular to S.
• the landing deviation of the droplet when the protrusion shape, particularly the protrusion length varies and becomes asymmetric is the direction in which the protrusion extends ( It occurs in the S direction in Figs. 9A and 9B.
• the protrusions of the discharge ports are arranged in parallel to the main scanning direction S of the head.
• the direction of the protrusion is the main scanning direction (the head drops droplets). Record to discharge It is desirable that the head and the recording medium move relative to each other during operation.
• a water-repellent treatment is performed on the discharge port surface (surface facing the recording medium) 35 a and the discharge port surface side of the projection which is a convex portion.
• FIG. 2 is a discharge process diagram in this embodiment.
• Fig. 2 shows the discharge state of the bubble jet (B J) discharge method in which bubbles do not communicate with the atmosphere.
• Figures 2 (a) to (g) are head cross-sectional views along line A-A in Figure 1B
• Figures 3 (a) to (g) are head cross-sectional views along line B-B in Figure 1B.
• Figure 2 (a) to g) and Figure 3 (a) to (g) correspond to each other.
• the gas portion in the maximum foaming state has a sufficiently low pressure compared to the atmospheric pressure. For this reason, after this, the volume of the bubble decreases, and the surrounding liquid tries to take in the place where the bubble was abruptly.
• This liquid flow also returns the liquid to the heater inside the discharge port, but the shape of the discharge port is as shown in Fig. 1C, so it is positive from the point where the protrusion that is the low fluid resistance part is not provided. Liquid is drawn into the. At this time, a low flow between the inner side surface, which is the side surface of the discharge roller, and the columnar liquid. The liquid level formed on the body resistance part falls into a large concave shape on the heating element side.
• FIG. 6A is a perspective view of the simulation showing the state of the liquid column as seen from the direction perpendicular to the protrusion.
• Fig. 6B is a perspective view of an enlarged simulation of the “necked portion” of the liquid column as seen from the protrusion direction. The “necked portion” formed at the top of the protrusion and at the base of the liquid column can be seen from both directions in FIGS. 6A and 6B.
• the separation time can be shortened by 1 to 2 ⁇ sec or more than before. That is, if the droplet discharge speed is 15 m "sec, the length of the tail is reduced by 15 to 30 m or more.
• the ejected liquid tries to fly as before.
• the direction of the velocity vector is not the opposite direction, and the velocity of the trailing edge of the droplet is sufficiently faster than before.
• the phenomenon that the liquid columnar part of the discharge liquid is stretched and elongated does not occur substantially. As a result, the separation of the discharge liquid is performed smoothly, and conventionally, when separating the discharge liquid (liquid column), many The errors that have occurred are greatly reduced.
• the trailing edge of the flying droplet becomes spherical due to its surface tension and eventually separates into a main droplet and a sub-droplet (Satellite ⁇ ). Note that if the trailing edge velocity of the droplet is sufficiently small compared to the velocity of the droplet tip, the separated satellite wings are united during flight or on the paper surface, and the satellite wing is substantially prevented.
• FIG. 4 shows the relationship between the minimum diameter of the liquid column and the discharge process in FIG. 2 (line P) showing the discharge process of the present invention and FIG. 10 (line Q) showing the conventional discharge chamber. It is a graph.
• the minimum diameter of the liquid column thickness is the diameter of the portion of the liquid column that protrudes out of the discharge port and that has the smallest cross section in the liquid injection direction excluding the spherical portion that is the main droplet. It shows that.
• (d) to (g) on the horizontal axis correspond to the respective steps in FIGS.
• the initial liquid column has a different thickness because the discharge port shape corresponding to the present invention is a shape in which a conventional circular discharge port is divided into two semicircles and a protrusion is inserted between the semicircles. This is due to the fact that the maximum diameter of the discharge port is longer than before.
• the minimum diameter of the thickness of the liquid column becomes smaller at a substantially constant rate as time passes.
• the rate of change of the minimum diameter of the liquid column with time in the defoaming step changes rapidly.
• this is thought to be caused by the constriction at the base of the liquid column due to the drastic reduction of the amount of liquid in contact with the liquid column held by the protrusion due to partial pulling of the meniscus accompanying defoaming. It is.
• the step (e) the thickness of the liquid column becomes extremely thin, and the separation time of the discharged liquid is the conventional one. It is thought that it has been accelerated against.
• Figure 13 shows a schematic diagram of the discharge state of this example of BT J (bubble through jet) in which bubbles communicate with the atmosphere.
• Figures 13 (a) to (g) are head cross-sectional views as seen from the direction perpendicular to the protrusion direction
• Figure 14 (a) to (g) are head cross-sectional views as seen from the protrusion direction.
• 3 (a) to (g) and Fig. 14 (a) to (g) correspond to each other.
• the description of the same part as the above-described BJ discharge method is omitted.
• the condition for becoming BT J is that the distance OH from the heater to the discharge port should be shortened (20 to 30 um) compared to the previous BJ example ( Figures 1A, IB and 1C). .
• the shape of the protrusion suitably used in the present invention will be described in more detail.
• the shape of the protrusions here means the shape of the protrusions as seen from the discharge direction of the liquid, That is, the cross-sectional shape of the discharge port in the direction of discharging the liquid is shown.
• the length W of the shortest portion in the low fluid resistance region is the shortest distance formed by the protrusions (gap between protrusions). ) Desirably longer than H.
• the virtual outer edge of the discharge port when there is no protrusion Minimum diameter of discharge port In this example, when there are two protrusions, the distance from the root of the protrusion to the base of the opposite protrusion. When there is one protrusion, the distance from the root of the protrusion to the corresponding edge.
• the protrusion area X is the protrusion length (X,: the length from the protrusion root to the protrusion tip) in the direction in which the protrusion extends to the inside of the discharge port (the direction in which the protrusion becomes convex), and the protrusion in the width direction of the protrusion base width: consisting of (x 2 linear distance from refraction point of the projection root to the inflection point on the opposite side beyond the projecting tip) One to two sides rectangular or square. If the refraction point is not clear in X2, the two contact points when the tangent line is drawn at the base of the protrusion on the outer periphery of the discharge port are regarded as the refraction point.
• protrusions in the range of O x zZx 'l. 6 increase the retention of the liquid film between the protrusions, and the meniscus between the protrusions is ejected to the surface of the discharge port until the droplet is separated. It is possible to maintain it in the vicinity and shorten the tailing length. Further, the balance of the area between the semicircular portion and the protrusion at the discharge port implements the discharge method of the present invention by being in the range of M ⁇ (L-X 2 ) 2> H. Therefore, it becomes more suitable.
• FIG. 20 is a schematic diagram for explaining the movement of the liquid in the discharge port in the bubble contraction step in the present embodiment.
• the discharge port of this embodiment has a shape in which a semicircle is widened and a protrusion is inserted therebetween. For this reason, in the bubble contraction process, the force that the meniscus falls to the heater side in a semicircular shape acts as shown in white in the low fluid resistance region shown in FIG. The film is easily retained. Furthermore, since both sides of the protrusion have straight portions, and the straight portions are parallel, the meniscus of the low fluid resistance portion is more likely to fall in a semicircular shape.
• the tip of the projection has a curvature
• the tip of the projection has a shape having a straight portion perpendicular to the direction in which the projection becomes convex, for example, the tip of the projection has a square shape.
• the tip of the projection has a square shape.
• the central axis of the discharge port in the direction in which the liquid is discharged is perpendicular to the discharge port surface and the energy generating element. From the viewpoint of stability, it is preferable. If the central axis of the discharge port is not perpendicular to the surface of the discharge port or the heating element, When the meniscus position in the discharge port moves toward the heating element, the asymmetry of the meniscus position is strong and the effect of the present invention cannot be obtained satisfactorily.
• Figures 18A, 18B, 19A and 19B show the shape of the protrusions in the comparative example.
• Fig. 18 The discharge port in 8A has a shape in which two circles are joined together. The long side of the discharge port was 20.0 wm and the short side was 4.5 m.
• the X l (direction toward the discharge port center) in the projection area X indicated by the dotted square is 2.9 x 2 (the width of the base of the projection) is 9.8 ⁇ m.
• the discharge simulation is shown in Fig. 18B, which corresponds to the steps (e) to (! :) in Fig. 3 and (e) to (f) in Fig. 14.
• Fig. 18B The discharge simulation is shown in Fig. 18B, which corresponds to the steps (e) to (! :) in Fig. 3 and (e) to (f) in Fig. 14.
• Fig. 18B The discharge simulation is shown in Fig.
• the trailing length of the ejected droplets is not as short as the shape of this embodiment, which causes the occurrence of satellite wrinkles.
• the protrusion in Fig. 18 B sharply narrows as it goes to the tip and takes a shape with a sharp tip, so that the bubbles contract and the force acting on the meniscus when the liquid in the discharge port is drawn into the heater side This is because this is different from the present embodiment.
• the discharge port in Fig. 19A has a very gentle protrusion.
• the long side of the outlet was 20.6 m, and the short side was 7 ⁇ 7 ⁇ .
• a simulation showing this is shown in Figure 19B, which is shown in Figure 3 (e) to (f), Figure 1 This corresponds to the steps (e) to (f) in step 4.
• Figure 19B as well, as in Fig.
• the tailing length of the ejected droplet is not as short as the shape of the present embodiment, which causes the occurrence of satellite wrinkles.
• FIGS. 15, 16A and 16B examples viewed from the direction perpendicular to the heater surface are shown in FIGS. 15, 16A and 16B.
• the head structure in Fig. 15 has a shape with protrusions at the two-stage discharge port.
• a first discharge port 5 is provided so as to communicate with the flow path 5 on the heater, and a second discharge port 6 force smaller than the first discharge port is provided on the first discharge port 5;
• a protrusion 10 is formed at the second discharge port 6. Since the first discharge port is large, clogging of the discharge liquid can be suppressed, and minute droplets can be formed at the second discharge port. Furthermore, in addition to shortening the tail of the discharged liquid by the protrusion of the second discharge port, the discharge efficiency is improved by having the first discharge port portion with low resistance.
• Figures 16A and 16B show diagrams where the protrusions are tapered.
• Figure 1 6 A The discharge port has a straight shape with respect to the discharge direction, and the protrusion has a tapered shape that narrows in the discharge direction.
• Fig. 16B shows a taper shape in which the discharge port and the protrusion narrow toward the discharge direction. By adopting such a shape, the resistance in the discharge direction is reduced, so that the same effect as the two-stage discharge port described above can be obtained, and the effect of improving the discharge efficiency and shortening the droplet separation time is produced.
• the taper angles of the discharge port and the protrusion may be the same, but the protrusion is preferably narrower in the discharge direction.
• the gap between protrusions is narrower on the upper side of the discharge port (surface side of the discharge port plate) than on the lower side (one side of the heater), the liquid between the protrusions It is difficult to go to the lower side where the protrusions spread, where the energy increases, and the liquid film tends to be held on the upper side.
• the discharged liquid can be easily separated at a location close to the surface of the discharge port plate, and the tail length of the discharged liquid droplets can be shortened.
• the central axis of the discharge port in the direction in which the liquid is discharged is perpendicular to the surface of the discharge port and the heating element. It is preferable from the symmetry of the meniscus position and the stability of discharge.
• the number of protrusions is not limited to two, but includes one protrusion as shown in FIG. 5A or three protrusions as shown in FIG. 5B.
• the inter-projection gap H when the number of projections is one is the shortest distance from the tip of the projection to the outer edge of the discharge port.
• the thickness of the protrusion may be thinner than the member where the discharge port is formed.
• Substrate 3 4 functions as a part of the flow path forming member, heating element, flow path, discharge port It is not particularly limited as long as it can function as a support such as a plate, and examples thereof include glass, ceramics, plastics, and metals.
• the substrate 34 is an Si substrate (wafer).
• the discharge port can be formed by an exposure apparatus such as MPA (Mirror Projection A 1 igner) using the discharge port plate 35 on which the discharge port is formed as a photosensitive resin in addition to the formation by laser light. .
• MPA Microrror Projection A 1 igner
• the ink flow path wall 36 and the discharge port plate 35 can be formed simultaneously as the same member.
• the discharge port may be formed by patterning in one photolithography process.
• FIGS. 1A, 1 1 B, 1 1 C, 1 1 D, 1 1 E, and 1 1 F are diagrams schematically showing the manufacturing process of the head of this example.
• Prepare a silicon board 34 with a drive circuit and heater 31 (Fig. 11 A).
• Fig. 11 A photosensitive resin is applied on the silicon substrate 34 of 1 A, and the portion 38 that becomes the flow path is patterned by exposure and development (Fig. 11 B).
• the photosensitive resin 36 which becomes the discharge port plate is applied so as to cover the portion 38 which becomes the flow path (FIG. 11C).
• the discharge port 32 having the convex protrusion 10 is exposed and developed on the photosensitive resin 36, and is patterned (FIG. 11D).
• An ink supply port 33 is formed from the side opposite to the flow path forming surface of the silicon substrate 34 by using an anisotropic etching technique that utilizes the difference in etching rate depending on the crystal orientation of silicon (FIG. 11 E). Finally, the photosensitive resin 38 in the portion that becomes the flow path is dissolved out by the solvent, and the melted portion becomes the ink flow path, and the hollow head is completed (FIG. 11 F).
• the head part manufactured in this way is electrically mounted and a supply path for supplying ink from the ink tank to the head part is formed to create a head carriage.
• the state in which the liquid was ejected was observed with a stroboscopic photograph, and the time for separating the ejected liquid and the droplet length from the leading edge to the trailing edge of the droplet immediately after separation of the ejected liquid were determined. It was measured.
• the separation time of the discharged liquid is the time from when the voltage is applied to the heater until the liquid column is separated from the liquid film.
• the power input time to the heater was adjusted so that the discharge speed was 13 m / s.
• the number of satellites shows the average of 10 times the number of satellites observed in one discharge. Also, the number of mist particles was measured.
• Table 1 The configuration and measurement results of the heads of Example 1 and Comparative Example 1 are shown in Table 1 below. table 1
• a pair of protrusions 10 are provided in the discharge port, and in the cross section of the discharge port in the discharge direction, the tip of the protrusion is provided toward the center of gravity of the discharge port, and a straight line connecting the tips of the protrusions However, it passes through the center of the discharge port.
• the protrusion length X in the direction in which the protrusion is convex is equal to the protrusion length b.
• the minimum diameter M of the outlet at the virtual outer edge of the outlet is the distance from the base of the protrusion to the base of the opposite protrusion, and is equal to the outlet diameter ⁇ in the table.
• the maximum diameter L of the discharge port is the value obtained by adding the protrusion width a to the value of ⁇ in the table.
• the minimum diameter H of the discharge port is the gap between the protrusions, and is the value obtained by subtracting the value of b X 2 from the value of ⁇ .
• the relationship between the protrusion width a and the protrusion area X is that the base of the protrusion is In order to spread, the length of the protrusion region x 2 is several microns longer than the protrusion width a. In this example, ⁇ ⁇ ,- ⁇ . 8 and ⁇ 1 ⁇ 2 .
• the height h of the channel 5 is 14 ⁇ m.
• the distance (OH) from the heater 31, which is a heating element, to the surface of the discharge port plate 35 is 25.
• the size of the heater 3 1 that is in communication with the flow path and placed in the foaming chamber where bubbles are generated is 17.6 X 17.6 ⁇ m.
• the major diameter L of the discharge port is 19.6 m.
• the length b of the protrusion 10 is 5.9 A / m and the half width a of the protrusion is 3 m.
• the distance H from the tip of the protrusion to the tip of the opposing protrusion is 4.2.
• the tip of the protrusion 10 is rounded with a curvature diameter R of 2.2 ⁇ m.
• the discharge rate is about 5.4 ng.
• the protrusion has the same thickness as the discharge port plate.
• the shape of the discharge port is a shape in which a circle with a diameter of 16.6 ⁇ m is divided into two semicircles, and a protrusion is inserted between the semicircles. This head was discharged by adjusting the power input to the heater so that the droplet discharge speed was 13 mZ s.
• the shape of the discharge port was a circle, and the diameter was ⁇ 16.6 ⁇ m. Other configurations are the same as those in the first embodiment. .
• the discharge rate was 5.8 ng.
• the discharge liquid separation time was 8.5 ⁇ sec in Example 1, whereas it was 11 ⁇ sec in the head of Comparative Example 1-11, and until the discharge liquid in Example 1 was separated. The time was significantly shorter. In Example 1, the length of the droplet is 1 17 m, whereas in the head of Comparative Example 1-11, it is 15 6 ⁇ .
• Example 1 the average of Example 1 was 1.1, whereas that of Comparative Example 1-11 was 3. Also, measure the number of particles that make a mistake As a result, it was 15 in Example 1, whereas it was 3800 in the head of Comparative Example 1-11. As is clear from the above results, the configuration of this example shows that the number of satellites is remarkably reduced as compared with Comparative Example 1.
• the discharge speed is different from that in Example 1 but in Comparative Example 1 1-2, but the droplet length is almost the same, and the discharge port shape is 13 ⁇ m in diameter.
• the discharge rate at this time was 3 ng. Comparative example
• the discharge liquid separation time was 10 sec
• the droplet length was 1 16 jm
• the number of satellites was 2.2.
• Table 2 shows the results of measurement under the same conditions as in Example 1 except that the configuration of the head (discharge port diameter, flow path, OH distance, protrusion shape) was changed.
• Example 1 is an example in which protrusions are inserted between semicircles having a diameter of 11 ⁇ m as shown in FIG. 17.
• the relationship between M, L, and H and the values in the table is the same as in Example 1.
• M, L, and H is the same as in Example 1.
• Comparative Example 2 is a circular discharge port with a diameter of 11 and the discharge amount is 1.5 ng.
• the head of this example having protrusions has a faster liquid separation time than the circle of the comparative example, It was confirmed that the length of the ejected droplets was shortened and the satellite was reduced. In addition, the number of missed particles has drastically decreased. Table 2
• Table 3 shows the results of measurement under the same conditions as in Example 2 except that the configuration of the head (flow path height, OH distance, protrusion shape) was changed.
• Examples 3-1 to 3-5 are examples in which protrusions of the size described in the table were inserted between semicircles having a diameter of 11 m as shown in FIG. 17, and M, L, and H, The relationship with the values in the table is the same as in Example 1.
• the discharge amount of this embodiment is 1.7 ng.
• Comparative Example 3_ 1 is a circular discharge port with a diameter of 1 ⁇ ⁇ , and the discharge amount is 1.6 ng.
• Comparative Example 3_2 has a shape in which a protrusion with a length of 0.7 is inserted in a semicircle with a diameter of 11 ⁇ m, and the discharge rate is 1.7 ng.
• Comparative Example 3 - 2 of X in the projection area X the 0. 7 mu m, x 2 is 3.
• O ni, x 2 / x , 4. 3 next, the ejection liquid separation time, the liquid Both the drop length and satellite cocoon increased compared to this example.
• Table 4 shows the results measured under the same conditions as in Example 3 except that the diameter of the discharge port was further increased.
• Example 4 is an example in which protrusions of the size shown in the table were inserted between the semicircles with a diameter of 13 um as shown in Fig. 17 and M, .L and H, and the values in the table The relationship is the same as in Example 1.
• x 2 / x 1 0.8, and x, ⁇ x 2 .
• the discharge volume is 2.3 ng.
• Comparative Example 4 is a circular discharge port with a diameter of 13 ⁇ m, and the discharge amount is 2.3 ng.
• the head of this example having the protrusions has a faster liquid separation time, a shorter discharge droplet length, and a reduced satellite compared to the comparative circle. .
• the number of missed particles has drastically decreased.
• Example 4 13 20 7.5 2 4.4 3.5 0 + 8 6 75 0.1
• Comparative Example 4 Circle 13 20 7.5 ⁇ ⁇ ⁇ ⁇ 8.5 118 2.6 (Example 5, Comparative Example 5)
• Table 5 uses a head in which the head configuration (discharge port diameter, OH distance, flow path height, protrusion shape) is changed from that in Example 4 described above.
• the input power of the heater is adjusted so that the droplet discharge speed is 18 m / s.
• Example 5 is an example in which protrusions of the size shown in the table are inserted between semicircles having a diameter of 14.3 ⁇ ⁇ ⁇ ⁇ as shown in Fig. 17, and M, L and ⁇ , The relationship with values is the same as in Example 1.
• x 2 / x 1 0.9.9 and ⁇ 2 ⁇ ⁇ 2 .
• Comparative Example 5 is a circular discharge port having a diameter of 13.6 m, and the discharge port diameter was selected so that the discharge amount was consistent with Example 5 and 4.
• the droplet ejection speed is faster than in the above example, the number of satellites is higher than in the above example.
• the head of this example having protrusions is larger than the circle in the comparative example. It was confirmed that the liquid separation time was accelerated, the length of the ejected droplets was shortened, and the satellite was reduced. In addition, the number of particles that became mist also increased dramatically.
• the use of the head of this embodiment makes it possible to reduce deterioration in image quality due to satellite droplets or mistakes.
• the heater is used as the energy generating element.
• the present invention is not limited to this, and can be applied even when a piezoelectric element is used.
• a piezoelectric element When a piezoelectric element is used, there is no contraction process due to bubbles.
• an electric signal that expands the liquid chamber is given to the piezoelectric element, the meniscus is placed inside the discharge port. : Can be pulled in.

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