JP4211779B2 - Ink ejection device - Google Patents

Description

  The present invention relates to an ink ejection device for ejecting ink droplets from a nozzle to perform image recording on a recording medium.

In a conventional inkjet printer head, a thermal method in which ink is ejected using thermal energy, a piezo method in which ink is ejected using a piezoelectric element, and the like are known.
More specifically, in the thermal method, one surface of the ink liquid chamber is covered with a nozzle sheet on which minute nozzles are formed, and a heating resistor is provided in the ink liquid chamber, and ink is generated by rapid heating of the heating resistor. In this method, ink bubbles are generated in the ink in the liquid chamber, and ink droplets are ejected from the nozzles by the force at this time.

  FIGS. 15 to 18 are diagrams illustrating an example of a thermal printer head chip a (serial type). 15 is an external perspective view showing the printer head chip a, and FIG. 16 is an exploded perspective view showing the nozzle sheet g in the external perspective view of FIG. FIG. 17 is a plan view showing in detail the relationship among the ink liquid chamber b (barrier layer f), the heating resistor c, and the nozzle h. In FIG. 17, the nozzle h is superimposed on the heating resistor c by a two-dot chain line. Further, FIG. 18 is a cross-sectional view showing the AA cross section in FIG. 17 and also shows the nozzle sheet g.

  In the printer head a, the substrate member d includes a semiconductor substrate e made of silicon or the like, and a heating resistor c deposited on one surface of the semiconductor substrate e. The heating resistor c is electrically connected to an external circuit via a conductor portion (not shown) formed on the semiconductor substrate e.

The barrier layer f is made of, for example, an exposure curable dry film resist, and is laminated on the entire surface of the semiconductor substrate e where the heating resistor c is formed, and then unnecessary portions are removed by a photolithography process. It is formed by.
Furthermore, the nozzle sheet g is formed with a plurality of nozzles h. For example, the nozzle sheet g is formed by an electroforming technique using nickel, so that the position of the nozzle h matches the position of the heating resistor c, that is, the nozzle h. Is laminated on the barrier layer f so as to be positioned immediately above the heating resistor c.

  The ink liquid chamber b is composed of a semiconductor substrate e, a barrier layer f, and a nozzle sheet g so as to surround the heating resistor c. That is, in the drawing, the semiconductor substrate e constitutes the bottom wall of the ink liquid chamber b, the barrier layer f constitutes the side wall of the ink liquid chamber b, and the nozzle sheet g constitutes the top wall of the ink liquid chamber b. To do. Accordingly, the ink liquid chamber b has an opening surface on the right front surface in FIGS. 15 and 16, and the opening surface and the ink flow path i are communicated with each other. Then, the ink is sent into the ink liquid chamber b from this opening surface (only), and the ink is ejected from the nozzle h that is opened only at the opening other than the opening surface of the ink liquid chamber b.

  The one printer head chip a normally includes a plurality of heating resistors c in units of 100 and an ink liquid chamber b including the heating resistors c, and these commands are given by a command from the control unit of the printer. Each of the heating resistors c is uniquely selected, and the ink in the ink liquid chamber b corresponding to the heating resistor c can be ejected from the nozzle h.

  That is, in the printer head chip a, ink is filled from the ink tank (not shown) coupled to the printer head chip a through the ink flow path i. Then, by applying a pulse current to the heating resistor c for a short time, for example, 1 to 3 microseconds, the heating resistor c is rapidly heated, and as a result, the portion in contact with the heating resistor c is in a gas phase. Ink bubbles are generated and a certain volume of ink is pushed away by the expansion of the ink bubbles. A part of the pushed ink is pushed back from the ink chamber b to the ink flow path i side, and the other part is ejected from the nozzle h as an ink droplet and landed on a recording medium such as paper. .

  When ink droplets are ejected, ink droplets corresponding to the ejected amount are replenished into the ink liquid chamber b before the next ejection. Here, considering only that ink droplets are ejected efficiently (as fast as possible) at the moment of ink ejection, the opening surface (L1 × L2 portion in FIG. 18) of the inlet of the ink liquid chamber b is as much as possible. It is desirable that the pressure in the ink liquid chamber b during ejection and the pressure in the nozzle h be as high as possible. However, when doing so, the flow path resistance when ink droplets flow into the ink liquid chamber b increases, it takes time to replenish, and the time required to repeat ink ejection becomes longer. .

  Therefore, the effective area (Sn) of the opening surface of the nozzle h and the area of the opening surface of the inlet of the ink liquid chamber b (Si = L1 × L2) are set to an appropriate ratio R (= Sn / Si). It is determined. Of course, the ratio R may be a specific value depending on the purpose (depending on the ink ejection speed, printing accuracy, printing speed, etc.).

In the above configuration, in order to keep the size and direction of the ejected ink droplets within a certain range,
(1) The sum of the inner volume of the ink liquid chamber b and the inner volume of the nozzle h is within an error within a predetermined range;
(2) Even when the pressure in the ink liquid chamber b becomes high when ink droplets are ejected, the semiconductor substrate e, the barrier layer f, and the nozzle sheet g are securely bonded to each other, and ink does not leak from there. thing,
(3) The inner volume of the ink liquid chamber b does not change when ink droplets are ejected,
Etc. are required.

  Here, a relatively low resolution of about 300 dpi can be realized without requiring high processing accuracy. However, as the resolution is increased to 600 dpi or 1200 dpi, the accumulation of processing errors and adhesion errors affects the ink ejection characteristics.

  In the above-described printer head chip a, the ink liquid chamber b has only one inlet. Therefore, if the inlet is blocked for some reason, for example, dust mixed in the ink, the ink in the ink liquid chamber b is blocked. The supply speed decreases or sufficient ink cannot be supplied. For example, since the opening area of the inlet of the ink liquid chamber b is usually larger than the opening area of the discharge port of the nozzle h, even if the dust passes through the inlet of the ink liquid chamber b, the dust will pass through the discharge port. You may not be able to pass.

  For this reason, dust may remain in the vicinity of the heating resistor c. When the dust stays on top of the heating resistor c, it becomes difficult to eject ink droplets normally. In particular, the above phenomenon becomes more prominent as the number of ink droplets is decreased for high resolution. As a result, a predetermined amount of ink droplets cannot be ejected, and there is a risk that the print will be faded.

  Dust is present in all paths along which ink moves. Therefore, in order to prevent the discharge port of the nozzle h from being clogged with dust, it is necessary to arrange various dust removing filters in each place as well as finely cleaning each component in contact with the ink.

However, as the printing speed is increased, the amount of ink supplied to the ink chamber b also increases. Therefore, if the dust removal filter is too fine, the ink supply may not be able to catch up or may be used at the beginning. In the meantime, dust accumulates in the dust removal filter, making it difficult for the ink to pass through the dust removal filter, the supply of ink cannot catch up, and the print quality is degraded (the print is faint).
The same applies to the case of the piezo method.

  Further, the amount of ink droplets to be ejected is closely related to the volume in the ink liquid chamber b and the volume in the nozzle h, and in order to ensure a constant amount of ink droplets to be ejected, It is required to maintain the processing accuracy of the part. In particular, when the amount of ink droplets ejected at a time is large, that is, when the resolution is relatively low, the processing accuracy does not matter so much. Very little and high machining accuracy is required. Therefore, although technically possible, in order to maintain high processing accuracy, the cost becomes high.

  Therefore, today, ink droplets are landed multiple times at the same position (by overwriting a plurality of times) to average the ink droplets that have landed, and the ink droplet ejection unevenness and dust Even when a discharge failure or the like due to the mixing of the ink occurs, a device is made to make them inconspicuous.

  However, such a process is an effective method for improving the image quality, but it is a printer head chip that has the same amount of ink droplets discharged from each nozzle h, the discharge angle, etc., and has no inherent disadvantages. Even in the case of a, since the ink droplets are repeatedly ejected at the same position by ejecting the ink droplets a plurality of times without ending with one printing, there is a problem that the printing time becomes long. is there. This results in conflict with the market demand for higher printing speed.

On the other hand, a printer head for a line printer is known in which a large number of printer head chips a are arranged side by side in the print line direction, and the printer head does not move in the print line direction at the time of printing. There is a problem that it is structurally difficult to perform overprinting.
As described above, in the conventional structure, the processing accuracy and the difficulty in dealing with dust have hindered the realization of high resolution and high-speed printing.

  Accordingly, the problem to be solved by the present invention is that the processing accuracy of the ink discharge portion can be easily increased, and the change in the discharge amount, discharge angle, etc. of the ink droplets is also caused by mixing of dust into the ink. It is an object of the present invention to provide an ink ejection apparatus that can achieve both high printing quality and printing speed at a high level by reducing the ink supply speed to the ink ejection portion and reducing the ink supply speed.

The present invention solves the above-described problems by the following means.
According to a first aspect of the present invention, there is provided a plurality of energy generating means arranged in parallel on a substrate member, an ink liquid chamber for pressurizing ink by energy generated by the energy generating means, And an ink discharge device including a nozzle having a discharge port for discharging the pressurized ink in the ink liquid chamber, and an ink distribution space having a height H between the substrate member and the member on which the nozzle is formed. And a support member for securing a substantially constant height of the ink circulation space is disposed in a part of the ink circulation space, and further, the discharge port is formed above each energy generating means. The nozzle is arranged such that the opening surface on the ink circulation space portion side of the nozzle is an ink inlet, and the other opening surface is the discharge port. The minimum opening length of the internal space of the nozzle including the discharge port and the ink inlet is such that the internal space of the nozzle also serves as the ink liquid chamber without forming the ink liquid chamber separately and independently. And Dmin, a plurality of support member rows are arranged so that a relationship of H <Dmin / √2 is satisfied , and a plurality of the support members are arranged along the direction in which the energy generating means are juxtaposed. In the ink discharge device, the arrangement interval of the support members in the support member row is different from the arrangement interval of the support members in the other support member row.

(Function)
In the above invention, a nozzle is provided above the energy generating means, the internal space of the nozzle also serves as the ink liquid chamber, and no separate and independent ink liquid chamber is formed. Further, the opening surface of the nozzle on the energy generating means side is an ink inflow port, and the other opening surface is an ink discharge port. The ink enters the nozzle from the opening surface of the nozzle on the energy generating means side, and the ink is pressurized by the energy generated by the energy generating means and discharged from the discharge port.

In addition, among the dust that has entered the inside of the ink ejection device, dust that is larger than the height H of the ink circulation space portion does not enter the ink circulation space portion.
Furthermore, dust that is larger than the gap between the support members in the support member row does not enter the ink circulation space.
Further , dust smaller than the height H of the ink circulation space portion may enter the ink circulation space portion and enter the nozzle. However, since Dmin / √2 when the minimum opening length of the nozzle is Dmin is larger than the height H of the ink circulation space, the dust that has entered the ink circulation space and further entered the nozzle When a droplet is discharged, it is discharged from the discharge port to the outside.

According to the present invention, the processing accuracy of the ink discharge portion can be easily increased. In addition, changes in the discharge amount and discharge angle of ink droplets can also be reduced by the mixing of dust into the ink. Furthermore, it is possible to prevent a decrease in the ink supply speed to the ink discharge portion. Furthermore, the dust that has entered the nozzle can be discharged to the outside from the discharge port when an ink droplet is discharged. In addition, dust that is about to enter the energy generating means side can be blocked by the support member row.

Hereinafter, an embodiment of the present invention will be described.
(First embodiment)
FIG. 1 is an external perspective view showing a printer head chip 10 to which the ink ejection apparatus of the present invention is applied, and shows a hollow portion forming member 16 in an exploded manner. FIG. 2 is a plan view showing in detail the relationship among the heating resistor 13, the support member 14, the ejection port 17a, and the ink inflow port 17b of FIG. In FIG. 2, the ejection port 17 a and the ink inflow port 17 b are superimposed on the heating resistor 13 by a two-dot chain line. Further, FIG. 3 is a cross-sectional view showing the BB cross section of FIG. 2, and also shows the hollow portion forming member 16. 1, 2, and 3 correspond to FIGS. 16, 17, and 18 of the conventional example, respectively.

  The substrate member 11 includes a semiconductor substrate 12 made of silicon or the like, and a heating resistor (corresponding to energy generating means in the present invention) 13 deposited on one surface of the semiconductor substrate 12. A plurality of heating resistors 13 are arranged in parallel on the board member 11 and are electrically connected to an external circuit via a conductor portion (not shown) formed on the board member 11. The above configuration is the same as that shown in the conventional example.

  Further, as an example in the first embodiment, support members 14 are provided in the vicinity of four corners of one heating resistor 13 so as to surround the heating resistor 13 on the substrate member 11 on which the heating resistor 13 is formed. Arranged. The support member 14 is made of, for example, an exposure-curing dry film resist, and is laminated on the entire surface of the substrate member 11 on which the heating resistor 13 is formed, and then unnecessary portions are removed by a photolithography process. It is formed by. In the present embodiment, the support member 14 has an octagonal cross section.

Further, the height of the support member 14 is formed to be, for example, about 1/4 of the height of the ink liquid chamber b shown in the conventional example. That is, when the height of the ink chamber b in the conventional example is L2 (see FIG. 18), the height L4 (see FIG. 3) of the support member 14 is L4≈L2 / 4.
Furthermore, the gap L3 (see FIG. 3) between the support members 14 is approximately equal to the width L1 (see FIG. 18) of the ink chamber b in the conventional example, and is about 25 μm.

  Further, a hollow portion forming member 16 is laminated on the substrate member 11 on which the heating resistor 13 is formed. The hollow portion forming member 16 is made of a film-like material such as polyimide (PI) or a photosensitive resin, and the thickness thereof is substantially equal to, for example, the conventional barrier layer f and the nozzle sheet g superimposed. Have. For example, when the thickness of the barrier layer f in the conventional example is about 15 μm, the thickness of the nozzle sheet g is about 30 μm, and the thickness of the adhesive layer at the time of bonding is several μm, the barrier layer f and the nozzle sheet g are overlapped. The thickness is about 45 μm. Therefore, the hollow part forming member 16 is formed to such a thickness.

  The hollow portion forming member 16 is formed with a plurality of cylindrical hollow portions (nozzles) 17. The hollow portion 17 is formed in a truncated cone shape (a solid body obtained by cutting the tip portion of the cone, the longitudinal section having a trapezoidal shape, and the transverse section having a circular shape with a smaller diameter toward the upper portion). The hollow portion 17 serves both as the ink liquid chamber b and the nozzle h in the conventional example.

That is, the opening surface on the lower surface side of the hollow portion 17 is an ink inflow port 17b for allowing ink to flow into the hollow portion 17, and the opening surface on the upper surface side of the hollow portion 17 is an ejection port for ejecting ink. 17a. Then, ink that enters the hollow portion 17 from the ink inlet 17b is pressurized in the hollow portion 17 at the time of discharge, and is discharged from the discharge port 17a. The diameter of the discharge port 17a is substantially equal to the diameter of the discharge port of the conventional nozzle h, and is about 20 μm. The internal volume of the hollow portion 17 is formed to be substantially equal to, for example, the sum of the internal volumes of the conventional ink liquid chamber b and the nozzle h.
The hollow portion 17 is formed by etching, laser processing, punching processing, or the like on the film-like material.

  In the conventional example, the ink liquid chamber b and the nozzle h are bonded to each other. However, in the present embodiment, the hollow portion 17 is integrally formed in the same layer with one material. Since there is no joint, sufficient strength can be secured.

  Further, since the amount of ink droplets to be ejected is related to the internal volumes of both the ink liquid chamber b and the nozzle h in the conventional example, for example, particularly when a large number of nozzles h and ink liquid chambers b are arranged in parallel. It is necessary that the ink liquid chambers b and the nozzles h arranged in parallel are as uniform as possible. Here, in the conventional example, since there are two members of the ink liquid chamber b and the nozzle h, there are two elements into which an error enters, but in this embodiment, the ink liquid chamber b and the nozzle h in the conventional example are combined. Since the single hollow portion 17 serving as one is integrally formed by one processing, the error can be reduced accordingly. Therefore, even when many hollow portions 17 are arranged in parallel, variation in shape can be reduced.

  When the hollow portion forming member 16 is provided on the substrate member 11 on which the heating resistor 13 is formed, the hollow portion 17 is disposed on each heating resistor 13. As shown in FIG. 2, it arrange | positions so that the center of the heating resistor 13 and the center of the hollow part 17 may correspond substantially.

  In addition, when the hollow portion forming member 16 is disposed on the substrate member 11, the gap between the surface of the substrate member 11 (the surface of the heating resistor 13) and the hollow portion forming member 16 is higher than the height of the support member 14. That is L4. A space formed by the gap becomes an ink circulation space 15 of the printer head chip 10. That is, the ink circulation space 15 is provided in a space including the lower space of the hollow portion 17. The support member 14 keeps the height of the ink circulation space 15 constant. The ink circulation space 15 communicates with an ink tank (not shown), and ink freely circulates through the ink circulation space 15. In the ink circulation space 15, only the support member 14 suppresses the ink circulation.

  As described above, the peripheral portion of the heating resistor 13 is not closed in the ink liquid chamber b as in the conventional example, but is open. The space on the shortest distance between adjacent heating resistors 13 also forms a part of the ink circulation space portion 15. For this reason, the ink circulation space portion 15 has a structure in which ink can freely flow over the adjacent heating resistor 13, and does not have a single fixed ink flow path.

  In the ink circulation space 15 described above, ink flows from one direction into one hollow portion 17. That is, as shown in FIG. 2, any one of the four routes R1, R2, and R3 of the ink circulation space 15 is supported by the support members 14 disposed in the vicinity of the four corners of the heating resistor 13 so as to surround the heating resistor 13. Alternatively, the ink enters the hollow portion 17 through R4 (Q1 in FIG. 3). Thus, four ink inflow routes are secured in one hollow portion 17.

  Here, in the conventional example, the opening area of the inlet of the ink liquid chamber b is L1 × L2, whereas in this embodiment, the opening area of the inlet of the hollow portion 17 is 4 (locations) × L3 × L4. (See FIG. 3). As described above, since L1 = L3 and L4≈L2 / 4, the opening area of the inlet of the ink chamber b in the conventional example and the opening area of the inlet of the hollow portion 17 in the present embodiment are It is almost the same.

However, in this embodiment, four routes are provided for ink to enter one hollow portion 17 as described above. For example, even if one route is blocked by dust, the hollow portion 17 is closed. The inflow of ink into the inside is not hindered.
Further, since the ink circulation space portion 15 is also formed on the shortest distance between the adjacent hollow portions 17, for example, even if dust stagnates in the routes R1 and R3 in FIG. Since ink flows from the routes R2 and R4 from the adjacent hollow portion 17 side, the ink supply does not become insufficient.

  Further, the dust that can enter the ink circulation space 15 is limited to those having an outer shape smaller than the height L4 of the support member 14. The height L4 of the support member 14 is about 1/4 of the height L2 of the conventional ink liquid chamber b. Thereby, in this embodiment, the entrance of dust into the ink circulation space 15 can be prevented more than the conventional example.

  Although not shown, the heating resistor 13 and an external control unit are electrically connected by a flexible substrate, and the connecting piece of the flexible substrate is electrically connected to each of the heating resistors 13. The heating resistor 13 is rapidly heated by passing a current pulse through the heating resistor 13 uniquely selected by a command from the control unit of the printer for a short time, for example, 1 to 3 microseconds. Before the heating resistor 13 is heated, the hollow portion 17 is filled with ink through the ink circulation space portion 15.

  As a result, a gas phase ink bubble is generated at a portion in contact with the heating resistor 13, and the expansion of the ink bubble causes a certain volume of ink to be pushed away in the hollow portion 17. The part is pushed back to the outside of the hollow part 17, and the other part is ejected as an ink droplet from the ejection port 17a (Q2 in FIG. 3) and landed on a recording medium such as paper. Then, the ink is immediately replenished into the hollow portion 17 where the ink has been ejected through the ink circulation space portion 15 (Q1 in FIG. 3).

(Relationship between shock wave during ink ejection and ink ejection control)
Next, the influence of a shock wave generated when ink is ejected will be described.
In the ejection of thermal ink droplets as in the present embodiment, the instantaneous power required for one ejection of one heating resistor 13 is relatively high power of about 0.5 W to 0.8 W. Cost. Therefore, when a large number of heating resistors 13 are arranged in parallel as in the present embodiment, if ink is simultaneously ejected from a large number of hollow portions 17 at the same time, power consumption becomes extremely large and excessive heat generation occurs. For this reason, ink is not simultaneously ejected from a large number of hollow portions 17 at a time.

  On the other hand, when ink is discharged from the discharge port 17a of the hollow portion 17 by heating of the heating resistor 13, a shock wave is generated in the ink flowing through the ink circulation space portion 15, but the ink is discharged from one hollow portion 17. Thereafter, control is performed so that ink is not discharged from the hollow portion 17 adjacent to the hollow portion 17 within a time until the influence of the shock wave is eliminated. Within this time, the ink is ejected from the hollow portion 17 that is separated from the hollow portion 17 from which the ink has been ejected to some extent.

For example, at least adjacent heating resistors 13 are not selected as the heating resistors 13 that are driven almost simultaneously, and at least one heating resistor 13 that is not driven is interposed between the heating resistors 13 that are driven almost simultaneously. To control.
Therefore, by appropriately selecting the heating resistor 13 that is driven simultaneously, the influence of the shock wave upon ejection of the ink from the hollow portion 17 on the other hollow portion 17 can be reduced to a practically satisfactory level.

(Relationship between minimum opening length of hollow portion 17 and height L4 of support member 14)
In the present embodiment, the minimum opening length of the hollow portion 17 is formed to be larger than the height L4 of the support member 14. This is due to the following reason.
Dust having a size that can pass between the support members 14 at a plane distance, that is, dust having a lateral width of less than L3 passes through the support members 14. However, if the height of the dust is not less than the height L4 of the support member 14, the dust passes between the support members 14 and reaches the lower side of the hollow portion 17 (on the heating resistor 13). In the end, the ink distribution space 15 is not entered.

  In addition, fine dust having a height less than the height L4 of the support member 14 may enter the ink circulation space portion 15 and enter the hollow portion 17. However, if the minimum opening length (Dmin) of the hollow portion 17 is set to be larger than the height L4 of the support member 14, the dust that has entered the hollow portion 17 will be discharged from the discharge port 17a when ink droplets are discharged. There is a high possibility of being discharged to the outside. Here, since the dust usually has a three-dimensional shape, it is possible to assume that the maximum shape of the dust entering the hollow portion 17 is a cubic shape inscribed in the hollow portion 17. That is, by setting Dmin / √2, which is preferably one side of the cubic shape (cube height), to be larger than the height L4 of the support member 14, the possibility that dust entering the hollow portion 17 can be discharged is increased. . More preferably, it is desirable that Dmin / √3, which is a cubic diagonal, is set to be larger than the height L4 of the support member 14. Thereby, for example, it is possible to prevent the dust from stagnating in the vicinity of the discharge port 17a and causing a discharge failure. Therefore, it is possible to almost eliminate the influence when dust is mixed into the ink circulation space 15.

  If the shape of the hollow portion 17 is the shape as in the present embodiment, the minimum opening length is the diameter of the discharge port 17a, so that this diameter or Dmin / √2, Dmin / √3 is set to the support member 14. The height L4 may be greater than or equal to L4. On the other hand, when the shape of the hollow portion 17 is a shape other than that of the present embodiment, the minimum opening length (Dmin) in the cross section in the hollow portion 17 or Dmin / √2, more preferably Dmin / √. 3 may be equal to or higher than the height L4 of the support member 14.

  As shown in FIG. 4, when the cross-sectional shape of the hollow portion 17 is circular as in this embodiment, the minimum opening length Dmin is equal to its diameter. As shown in FIG. 5, when the cross-sectional shape of the hollow portion 17 is elliptical, the minimum opening length Dmin is the length in the minor axis direction. Furthermore, as shown in FIG. 6, when the cross-sectional shape of the hollow portion 17 is substantially a star shape, the minimum opening length Dmin is the length from one inner top to the other inner top. In any of the cross-sectional shapes, the effect of the present invention can be obtained by setting the minimum opening length Dmin to L4 or more, preferably Dmin / √2 to L4 or more, and more preferably Dmin / √3 to L4 or more. it can.

  As shown in FIGS. 5 and 6, the shape of the hollow portion 17 and the discharge port 17a (and the shape of the ink inflow port 17b) are not limited to the shape of the present embodiment, and various shapes can be used. Can be mentioned. For example, the cross-sectional shape of the hollow portion 17 and the opening shapes of the ejection port 17a and the ink inflow port 17b may be any shape such as a polygon.

  Furthermore, the present invention has an effect of improving the yield in manufacturing the printer head. Normally, the printer head is manufactured in a clean environment, but there is still dust having a size of about 10 μm. When such dust accumulates on the printer head, conventionally, the barrier layer f has a size of about 15 μm, and therefore there is a possibility that these dusts are mixed into the ink flow path i. When such dust enters the ink flow path i and reaches the substrate member d, conventionally, since the nozzle sheet g is formed of a conductive material such as nickel, the resistance value of the dust is low. In this case, it becomes easy to short-circuit between the substrate members d. When a short circuit occurs between the substrate members d, the substrate members d are damaged, and the printer head becomes defective. Such a manufacturing problem is particularly noticeable in a long head having a large number of nozzles h for a line head printer or the like. In the present invention, even if such dust accumulates on the surface of the printer head, the possibility that the dust enters the ink flow path (ink distribution space 15) is significantly reduced. Since the possibility of dust reaching the surface of the substrate member 11 can be significantly reduced, the above problem can be prevented. That is, the filter effect of the ink distribution space 15 of the present invention also improves the manufacturing yield.

(Relationship between the distance P1 between the centers of the adjacent heating resistors 13 and the shortest distance P2 from the surface of the heating resistor 13 to the center of the discharge port 17a)
Next, the relationship between the center-to-center distance P1 of the adjacent heating resistors 13 and the shortest distance P2 from the surface of the heating resistor 13 on the ink circulation space 15 side to the center of the ejection port 17a will be described.
As shown in FIG. 3, the distance between the centers of the adjacent heating resistors 13 is P1, and the shortest distance from the surface of the heating resistor 13 to the center of the discharge port 17a is P2.

At this time, in the conventional method, as shown in FIG. 17, there is a barrier layer f as a partition wall between the respective heating resistors c, so that it is general that P1 / P2> 1 because of its structure. It was.
However, in the case of requiring high resolution, for example, about 1200 dpi, the center-to-center distance P1 of the heating resistor 13 is short and is about 20 μm. Therefore, in the conventional configuration, there is a limit in structure in order to cope with high resolution. On the other hand, in the present invention, the hollow portion 17 needs to have a certain level of strength, and the height of the hollow portion 17 needs to be a certain height due to the structure of ink droplet ejection, but the barrier layer f does not exist. High resolution is possible. Therefore, in this embodiment, unlike the conventional example, the relationship of P1 / P2 <1 is satisfied.

(Arrangement of support members)
Next, the arrangement form of the support member 14 will be described.
The arrangement of the support member 14 shown in FIG. 1 is arranged so as to surround the heating resistor 13 in the vicinity of the four corners of one heating resistor 13 as described above. However, it is not necessarily limited to such an arrangement, and various shapes, sizes, arrangement numbers, arrangement patterns, and the like of the support member 14 can be used.
7 to 10 are plan views showing the arrangement of the support member 14, showing the positional relationship between the heating resistor 13 and the support member 14, and the ejection port 17 a and the ink inflow port 17 b with a two-dot chain line. Are superimposed and illustrated.

  In FIG. 7, as a first arrangement form of the support member 14, a wall 18 having the same height as the support member 14 is provided above the heating resistor 13 in the drawing. The heating resistor 13 is disposed along the longitudinal direction of the wall 18. The support member 14 is arranged in two stages on the lower side of the heating resistor 13 in the figure. That is, two rows of support members 14 arranged in the longitudinal direction at the same pitch as in FIG. 1 are provided.

  First, by arranging a large number of support members 14, the height of the ink circulation space 15 can be ensured more uniformly, and the strength can also be ensured. Furthermore, if the support member 14 is arranged as shown in FIG. 7, the dust that has entered the ink circulation space 15 stagnates in the support member 14 row as far as possible from the heating resistor 13 (hollow portion 17). Thus, the ink circulation space 15 close to the heating resistor 13 (hollow part 17) is not blocked, and uniform ink can be supplied to each hollow part 17 at all times. As described above, by arranging a plurality of support member 14 rows, the dust is caught on any one of the support member 14 rows before the dust flows through the ink circulation space 15 toward the hollow portion 17.

  In FIG. 8, as a second arrangement form of the support members 14, the space positions between the support members 14 in the two-stage support member 14 row in the figure are arranged so as not to be the same position in the vertical direction. That is, in the drawing, the support members 14 in the upper row of support members 14 are arranged so that the positions of the support members 14 in the lower row of support members 14 are different. By forming in this way, it is possible to more effectively prevent dust from passing through the support member 14 row and reaching the hollow portion 17.

  In FIG. 9, the third arrangement form of the support members 14 includes two rows of support members 14 as in FIGS. 7 and 8. The member 14 is positioned directly below the heating resistor 13. If the support member 14 is arranged in this way, the dust that has passed between the support members 14 in the lower support member 14 row is stagnated by the upper support member 14, and on the heating resistor 13 (below the hollow portion 17). Can be prevented from reaching directly.

In FIG. 10, as the fourth arrangement form of the support members 14, the support member 14 rows are provided in three stages. Thus, the 14 rows of support members do not necessarily have to be two stages as shown in FIGS. 7 to 9, but may be three stages as shown in FIG. 10, or four or more stages.
Further, in FIG. 10, the support members 14 are formed so as to have different sizes for each of the support member 14 rows. In FIG. 10, the support member 14A in the upper row of support members 14A is the smallest, and then the support member 14B in the middle row of support members 14B is the smallest. And the support member 14C of 14 rows of lower support members is the largest.

  By forming in this way, dust larger than the gap between the support members 14C is dammed by the lower support member 14 row, and therefore does not enter the heating resistor 13 (hollow portion 17) side. Of the dust passing through the gaps between the support members 14C in the lower row of the support members 14C, the dust larger than the gap between the support members 14B is blocked by the middle row of the support members 14B. 13 (hollow part 17) does not enter.

  Further, among the dust that has passed through the gap between the support members 14B, the dust that is larger than the gap between the support members 14A is blocked by the upper row of the support members 14A, so that the heating resistor 13 (hollow portion 17) side. Does not enter. In this way, larger dust can be blocked by the support member 14 row farther from the heating resistor 13 (hollow portion 17).

  As described above, in the first embodiment, the shape of the support member 14 is described as a columnar shape, but of course, the shape of the support member 14 is not limited to this. For example, the periphery of the heating resistor 13 may be surrounded by a U-shaped (concave) member having a length equal to or less than the length of one side of the heating resistor 13. The amount of ink flowing into the heating resistor 13 can be ensured in the same level as in the past while the filter 15 has a filter effect. Further, the shape of the support member 14 does not have to be the same, and it is of course possible to make the vicinity of the heating resistor 13 into a U-shape and the other into a columnar shape.

(Second Embodiment)
FIG. 11 is an external perspective view showing a printer head chip 10A according to the second embodiment of the present invention, showing the hollow portion forming member 16A in an exploded manner, and corresponds to FIG. 1 of the first embodiment. Is.
In the second embodiment, the heating resistor 13 is formed on the substrate member 11 as in the first embodiment, but the support member 14 is not formed on the substrate member 11.

The support member 14 is integrally formed with the hollow portion forming member 16A on the lower surface side in the drawing of the hollow portion forming member 16A. Other portions of the hollow portion forming member 16A are the same as the hollow portion forming member 16 of the first embodiment.
When the hollow portion forming member 16A is laminated on the substrate member 11 on which the heating resistor 13 is formed, the support member 14 is disposed on the hollow portion forming member 16A so as to be disposed at the same position as in the first embodiment. Is formed.

  When the hollow portion forming member 16A is made of a film-like material such as polyimide or photosensitive resin, the support member 14 can be integrally formed with the hollow portion forming member 16A by half-edging the lower surface in FIG. it can. If formed in this way, only one layer (hollow part forming member 16A) can be formed on the substrate member 11, so that the cost can be reduced.

In the second embodiment, the hollow portion forming member 16A only needs to be laminated and bonded onto the substrate member 11 on which the heating resistor 13 is formed, so that the intervening adhesive layer is provided at one place. In contrast, in the first embodiment, there are two places between the support member 14 and the substrate member 11 and between the support member 14 and the hollow portion forming member 16.
Therefore, since the number of the adhesive layers is reduced, the dimensional accuracy of the thickness of the entire printer head chip 10A can be made higher. Further, since the number of adhesive layers is reduced, the reliability in strength can be increased.
Other configurations and the like are the same as those of the first embodiment, and thus description thereof is omitted.

  As a method of forming the support member 14 other than the first embodiment and the second embodiment described above, for example, on the surface of the substrate member 11 on which the heating resistor 13 is provided, or on the lower surface of the hollow portion forming member 16, It is also possible to form the support member 14 by printing by forming a print layer having a thickness L4 of the support member 14.

Next, an example in which a printer head for a line printer is formed will be described.
FIG. 12 is a plan view showing an example in which a plurality of printer head chips 10B are arranged in parallel to form a printer head for a line printer. In FIG. 12, the support member 14 and the wall 18 are shown by solid lines.
In this example, the support member 14 of each printer head chip 10B includes three rows of support member 14 rows. Further, as shown in the second embodiment, the printer head chip 10B has a support member 14 formed on the hollow portion forming member 16A side. Therefore, only the heating resistor 13 is provided on the substrate member 11.

When formed in this way, the adjacent substrate members 11 are arranged so that the arrangement intervals of the heating resistors 13 at the joints of the adjacent substrate members 11 coincide with the arrangement intervals of the heating resistors 13 of each substrate member 11. . Then, all the substrate members 11 are affixed to one hollow portion forming member 16A in which the hollow portions 17 are formed at positions corresponding to the respective heating resistors 13 of all the substrate members 11. Further, a common flow path 19 of each printer head chip 10B is provided further outside the row of support members 14.
If formed in this way, it is possible to form a printer head for a line printer in which a large number of printer head chips 10B are arranged in a straight line (discharge ports 17a are arranged in a straight line).

Here, in the conventional example, when a large number of printer head chips a are arranged side by side, it is necessary to ensure the same ink droplet ejection performance as the other portions at the joints (ends). Therefore, it is necessary to process the ink liquid chamber b with high precision even at the joint, but this is difficult. For this reason, it has been difficult to stabilize ink ejection at the joint of the printer head chip a.
On the other hand, in the present embodiment, there is no partition wall or the like on the substrate member 11 side, so it is sufficient to ensure the accuracy of the arrangement interval of the heating resistors 13 at the joint of the substrate member 11.

  Further, a printer head for a line printer as described above may be formed using the printer head chip 10 of the first embodiment. In this case as well, a plurality of substrate members 11 provided with the heating resistor 13 and the support member 14 are similarly attached to one hollow portion forming member 16. At this time, depending on the arrangement of the support members 14, the shape and the arrangement interval of the support members 14 at the end of the substrate member 11 may be different from the shapes and arrangement intervals of the other support members 14. However, unlike the ink liquid chamber b, the support member 14 does not directly affect the ink droplet ejection performance. Therefore, even if the shape and arrangement interval of the support member 14 at the joint are different, there is a practical problem. There is no.

(Third embodiment)
FIG. 13 is a cross-sectional view showing a printer head chip 10C according to the third embodiment of the present invention, and corresponds to FIG. 3 of the first embodiment.
In the third embodiment, instead of the heating resistor 13 of the first embodiment, the diaphragm 21, the upper electrode 22, and the lower electrode 24 are provided as energy generating means, and the electrostatic discharge method is used. . An air layer 23 is provided between the upper electrode 22 and the lower electrode 24. Other structures are the same as those of the first embodiment.

  In the third embodiment, when a voltage is applied between the upper electrode 22 and the lower electrode 24, the diaphragm 21 is attracted and bent downward in the figure by electrostatic force. Thereafter, the voltage is set to 0 V and the electrostatic force is released. As a result, the vibration plate 21 returns to its original state due to its elastic force, but the ink in the hollow portion 17 is discharged from the discharge port 17a using the elastic force at this time. Even if it carries out as mentioned above, the effect similar to 1st Embodiment is acquired.

(Fourth embodiment)
FIG. 14 is a cross-sectional view showing a printer head chip 10D according to the fourth embodiment of the present invention, and corresponds to FIG. 3 of the first embodiment.
In the fourth embodiment, instead of the heating resistor 13 of the first embodiment, a laminated body of a piezoelectric element 25 having electrodes on both surfaces and a diaphragm 21 is provided as an energy generating means. Is. Other structures are the same as those of the first embodiment.

  In the fourth embodiment, when a voltage is applied to the electrodes on both surfaces of the piezo element 25, a bending moment is generated in the vibration plate 21 due to the piezoelectric effect, and the vibration plate 21 bends and deforms. By utilizing this deformation, the ink in the hollow portion 17 is ejected from the ejection port 17a. Even if it carries out as mentioned above, the effect similar to 1st Embodiment is acquired.

1 is an external perspective view showing a printer head chip to which an ink ejection apparatus of the present invention is applied, and shows a hollow portion forming member in an exploded manner. FIG. 2 is a plan view showing in detail a relationship among a heating resistor, a support member, an ejection port, and an ink inflow port of FIG. 1. It is sectional drawing which shows the BB cross section of FIG. 2, Comprising: A hollow part formation member is shown collectively. It is a figure which shows the thing whose cross-sectional shape of a hollow part is circular. It is a figure which shows that the cross-sectional shape of a hollow part is an ellipse. It is a figure which shows that the cross-sectional shape of a hollow part is a substantially star shape. It is a top view which shows the 1st arrangement | positioning form of a supporting member. It is a top view which shows the 2nd arrangement | positioning form of a supporting member. It is a top view which shows the 3rd arrangement | positioning form of a supporting member. It is a top view which shows the 4th arrangement | positioning form of a supporting member. It is an external appearance perspective view which shows the printer head chip which is 2nd Embodiment of this invention. It is a top view which shows the example at the time of arranging the some printer head chip | tip in parallel and setting it as the printer head for line printers. It is sectional drawing which shows the printer head chip which is 3rd Embodiment of this invention. It is sectional drawing which shows the printer head chip which is 4th Embodiment of this invention. It is an external appearance perspective view which shows the conventional printer head chip. In the external appearance perspective view of FIG. 15, it is a perspective view which decomposes | disassembles and shows a nozzle sheet | seat. It is a top view which shows the relationship between an ink liquid chamber (barrier layer), a heating resistor, and a nozzle in detail. In FIG. 17, it is sectional drawing which shows an AA cross section, Comprising: A nozzle sheet | seat is shown collectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Printer head chip 11 Substrate member 12 Semiconductor substrate 13 Heating resistor (energy generating means)
14 Support member 15 Ink flow space 16 Hollow part forming member 17 Hollow part (nozzle)
17a discharge port 17b ink inlet 18 wall

Claims (6)

A plurality of energy generating means arranged side by side on the substrate member;
An ink liquid chamber for pressurizing ink with energy generated by the energy generating means;
An ink ejection apparatus comprising: a nozzle having an ejection port for ejecting pressurized ink in the ink liquid chamber;
An ink circulation space portion having a height H is formed between the substrate member and the member on which the nozzle is formed, and the height of the ink circulation space portion is substantially constant in a part of the ink circulation space portion. A supporting member to be secured is disposed, and further, the nozzle is disposed so that the discharge port is located above each energy generating means,
here,
By setting the opening surface on the ink circulation space portion side of the nozzle as an ink inlet and the other opening surface as the discharge port, the inner space of the nozzle can be formed without forming the ink liquid chamber independently. To serve as the ink chamber,
And when the minimum opening length of the internal space of the nozzle including the ejection port and the ink inlet is Dmin,
H <Dmin / √2
So as to satisfy the relationship,
further,
A plurality of support member rows in which a plurality of the support members are arranged along the juxtaposed direction of the energy generating means are arranged,
An arrangement interval of the support members in one support member row is different from an arrangement interval of the support members in the other one support member row.
Ink ejection device . A plurality of energy generating means arranged side by side on the substrate member;
A hollow formed in a cylindrical hollow portion disposed above each of the energy generating means, wherein the opening surface on the energy generating means side is an ink inflow port, and the other opening surface is an discharge port for discharging ink. A part forming member,
here,
An ink circulation space portion communicating with the ink inlet is formed between the substrate member and the hollow portion forming member, the height of the ink circulation space portion is H, and the minimum opening length of the hollow portion is Dmin. And when
H <Dmin / √2
To satisfy the relationship
In addition, a support member for ensuring a substantially constant height of the ink circulation space is disposed in a part of the ink circulation space .
further,
A plurality of support member rows in which a plurality of the support members are arranged along the juxtaposed direction of the energy generating means are arranged,
An arrangement interval of the support members in one support member row is different from an arrangement interval of the support members in the other one support member row.
Ink ejection device . A plurality of energy generating means arranged side by side on the substrate member;
An ink liquid chamber for pressurizing ink with energy generated by the energy generating means;
An ink ejection device including: an ejection port for ejecting pressurized ink in the ink liquid chamber;
The ink disposed above each of the energy generating means, wherein the ink that has entered from the opening surface on the energy generating means side is pressurized by the energy generated by the energy generating means and discharged from the other opening surface A hollow portion forming member that forms a cylindrical hollow portion that also serves as a liquid chamber and the discharge port,
here,
An ink circulation space portion communicating with the opening surface on the energy generating means side is formed between the substrate member and the hollow portion forming member, the height of the ink circulation space portion is H, and the minimum opening of the hollow portion When the length is Dmin,
H <Dmin / √2
To satisfy the relationship
In addition, a support member for ensuring a substantially constant height of the ink circulation space is disposed in a part of the ink circulation space .
further,
A plurality of support member rows in which a plurality of the support members are arranged along the juxtaposed direction of the energy generating means are arranged,
An arrangement interval of the support members in one support member row is different from an arrangement interval of the support members in the other one support member row.
Ink ejection device . The ink ejection apparatus according to any one of claims 1 to 3 , wherein:
A plurality of the ink ejection devices are arranged such that the ejection ports of the ink ejection devices are arranged in a straight line.
Ink ejection device . A plurality of energy generating means arranged side by side on the substrate member;
An ink discharge apparatus comprising: a nozzle having a discharge port for discharging ink pressurized by the energy generated by the energy generating means;
When an ink circulation space having a height H is formed between the substrate member and the member on which the nozzle is formed,
When the minimum opening length of the nozzle is Dmin,
H <Dmin / √2
To satisfy the relationship
In addition, a support member for ensuring a substantially constant height of the ink circulation space is disposed in a part of the ink circulation space .
further,
A plurality of support member rows in which a plurality of the support members are arranged along the juxtaposed direction of the energy generating means are arranged,
An arrangement interval of the support members in one support member row is different from an arrangement interval of the support members in the other one support member row.
Ink ejection device . The ink ejection apparatus according to any one of claims 1 to 5, wherein:
Among the plurality of support member rows, the gap between the support members of the support member row located on the energy generating means side is the support member row located on the side farther from the energy generating means than the support member row. It is narrower than the gap between the support members
Ink ejection device.

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