JP2007276385A - Ink jet recording head and ink jet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure high quality high speed printing by promoting heat dissipation of a recording head equipped with a plurality of adjoining ejection port arrays corresponding to increase in number of ejection ports of a recoding head. <P>SOLUTION: Two rows of ejection ports 3a are opened in an ejection port plate 3 located on the surface of a recording element substrate 1, and two sets of ejection port arrays each consisting of two arrays are constituted. Two supply ports 5 for supplying recording liquid to the ejection port arrays of each set are formed in the recording element substrate 1. One supply channel 2a for supplying recording liquid to each recording liquid supply port 5 is formed in a member 2 for supporting the recording element substrate 1. A beam 6 is formed in the supply channel 2a of the supporting member 2 to traverse the supply channel 2a in the direction intersecting the ejection port array perpendicularly and in contact with the intermediate portion 5a of the supply port. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ink jet recording head that performs recording on a recording medium by ejecting ink droplets, and a recording apparatus equipped with the ink jet recording head. More specifically, the present invention relates to a configuration that improves the heat dissipation function of a member that supports a recording head.

  2. Description of the Related Art Conventionally, recording apparatuses that perform recording on recording media such as paper and OHP sheets have been proposed in the form of mounting recording heads using various recording methods. The recording head includes a wire dot method, a heat sensitive method, a thermal transfer method, an ink jet method, and the like. In particular, since the ink jet method directly injects ink onto recording paper, it is attracting attention as a quiet recording method with low running cost. Of the ink jet methods, the thermal energy recording method utilizing film boiling has been put into practical use as being superior in terms of high speed, high density and the like as compared with those utilizing piezoelectric elements. However, the market demands a further increase in recording speed along with improvement in image quality.

  In general, there are mainly a serial type recording method and a full line type recording method for an ink jet recording apparatus adopting a thermal energy recording method using film boiling. The serial recording method performs recording while reciprocating the recording head, and has a feature that it is less expensive than the full line recording method described later. On the other hand, the full-line recording method prints and records with a recording head width that covers the entire width of the recording medium, so that higher-speed recording is possible than the serial recording method.

  In any of the recording methods, the recording speed can be improved if the frequency of ejecting ink droplets of the recording head can be increased, but the frequency of ejecting ink droplets is limited. Therefore, as a method for improving the recording speed, it is effective to increase the number of ejection ports that eject ink droplets. As a specific method for increasing the number of ejection ports, in the serial type recording method, there is an increase in the length of the ejection port array in which a plurality of ejection ports are arranged corresponding to the print head print width in the paper feed direction. However, expansion of the print width of the recording head (expansion of the discharge port array length) has a certain limit to ensure the flatness of the recording area of the recording apparatus. In the full line type recording method, since the printing width is fixed, the increase in the ejection port array in the paper feed direction is the most effective means for improving the recording speed.

  Therefore, in order to greatly improve the printing speed, it is the most effective means to increase the number of discharge port arrays at the same time as increasing the print width (discharge port array length) to the limit. Therefore, a configuration has been proposed in which a plurality of ejection port arrays are provided to eject the same type of ink. Considering a configuration for supplying ink to the ejection port arrays, it is preferable from the viewpoint of cost that the ejection port arrays are adjacent to each other.

  By the way, the ink jet recording system applies electric energy to the electric resistance element to rapidly increase the temperature of the electric resistance element, foam the ink on the electric resistance element, and discharge the ink from the orifice. However, the applied electrical energy is larger than the energy released to the outside, such as the kinetic energy of the ejected ink. Accordingly, the excess energy of the difference is accumulated as heat in the recording head, and the temperature of the recording head itself is increased.

  When the printing operation is continuously performed by the ink jet recording apparatus, the recording head is heated one after another before releasing the accumulated heat to the outside, so that the temperature rises. If the temperature exceeds a certain temperature range, the ink ejection state becomes unstable, and the recorded image may be defective. Therefore, control is performed to reduce the printing speed before exceeding a certain temperature range.

  Therefore, how to dissipate the heat accumulated in the recording element substrate provided with the electric resistance element is an important requirement for improving the recording speed while ensuring the reliability of the recorded image. As a means for dissipating heat, heat is dissipated to a member or ink that is in close contact with the recording element substrate, but most of the ink component is composed of water. The specific heat of water is high, but the thermal conductivity is low, and in order to improve the heat dissipation, it is preferable that the water is adhered with a material having a relatively high thermal conductivity.

  Patent Document 1 discloses a configuration in which a support member is bonded and bonded to the bottom of a recording element substrate in the vicinity of a portion where an ejection energy generating element is provided, and heat is radiated to the support member.

  FIG. 19 is a diagram illustrating a state in which the recording element substrate of Patent Document 1 is mounted on a support member.

  As shown in FIG. 19, the discharge port 104a is opened in two rows on the discharge port plate 104 positioned on the surface of the first recording element substrate 103, and a plurality of discharge port rows are formed. Yes.

  A plurality of recording liquid supply ports 106 for supplying recording liquid to each set of ejection port arrays are formed in the first recording element substrate 103. The support member 101 that supports the first recording element substrate 103 is formed with a supply channel 101 a that supplies a recording liquid to each recording liquid supply port 106. The recording liquid supply channel 101 a has a channel width substantially equal to the opening width of the inlet portion of the recording liquid supply port 106. The thickness of the partition wall 101b separating the recording liquid supply channels 101a adjacent to each other is determined by the interval between the inlet portions of the recording liquid supply ports 106 adjacent to each other.

  In the recording element substrate 103 having such a plurality of discharge port arrays, the number of recording element substrates cut out from one silicon wafer may be increased to reduce the cost. Alternatively, there is a case where the number of ejection port arrays 103a is increased without increasing the size of the recording element substrate. In such a case, it is necessary to reduce the pitch of the recording liquid supply ports 106 and arrange them at high density. In order to achieve high-speed printing, it is very effective to increase the length of the discharge port array.

  When the pitch between the recording liquid supply ports 106 is reduced, the thickness of the partition wall 101b of the support member 101 needs to be reduced accordingly. However, a thin partition wall having a certain thickness or less is formed on the support member 101 made of ceramic. This is difficult to manufacture. Similarly, when the discharge port array length is increased, it becomes difficult to manufacture the partition wall.

FIG. 20 shows a recording head using a support member having no partition wall. The recording liquid is supplied to the two recording liquid supply ports 106 from one recording liquid supply channel 101a.
JP 2002-154209 A

  However, if the partition wall of the support member is not provided between the two recording liquid supply ports of the recording element substrate, the heat dissipation effect is reduced, and the quality of the recorded image is deteriorated. In such a case, the ejection frequency must be lowered, and the printing speed is lowered.

  The present invention was made in order to solve the above-described problem, and by promoting heat dissipation of a recording head having a plurality of adjacent ejection port arrays corresponding to an increase in the number of ejection ports of the recording head, high quality, An object of the present invention is to provide a high-speed ink jet recording apparatus.

  In order to achieve the above object, an ink jet recording head of the present invention comprises a recording element substrate and a support member. The recording element substrate includes a plurality of adjacent discharge port arrays that discharge the same type of liquid, a plurality of liquid supply ports that are formed corresponding to the respective discharge port arrays, and that supply the same type of liquid, and the discharge port arrays And an electric resistance element for generating thermal energy for discharging the liquid. The support member is provided with a supply flow path for supporting the recording element substrate and supplying a liquid to the plurality of liquid supply ports of the recording element substrate. A feature is that a beam is formed in the supply flow path of the support member so as to connect the inner walls of the supply flow path in a direction orthogonal to the discharge port array. In addition, the beam is in contact with a portion between adjacent liquid supply ports of the recording element substrate.

  According to the present invention, it is possible to quickly dissipate the heat accumulated in the recording element substrate by the beam provided in the supply flow path of the recording head support member. Therefore, the ink jet recording apparatus is less likely to increase the temperature between the liquid supply ports adjacent to the recording element substrate even in continuous printing, and the printing speed can be improved without degrading the print quality compared to the prior art. Become.

  Moreover, the heat radiation effect is further improved by providing a plurality of beams in one supply channel. Furthermore, even when the discharge port array becomes longer, the same effect as described above can be obtained by providing a plurality of portions where the beams are provided.

  Further, by having a concave portion in the portion corresponding to each liquid supply port on the recording element substrate side of the beam, when the liquid flows from the supply channel to the liquid supply port, the flow resistance is less. Become. This configuration can improve the printing speed without reducing the liquid supply amount when the width of the beam is increased in order to obtain a further heat radiation effect.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 2 to FIG. 15 are explanatory diagrams for explaining each of the preferred ink jet recording apparatus to which the present invention is applied or applied, and the recording head and ink tank which are constituent elements thereof, and their respective relationships. Hereinafter, each component will be described with reference to these drawings.

  FIG. 2 is a perspective view showing a schematic configuration of the ink jet recording apparatus according to the present embodiment, and the operation thereof will be described below.

  The ink jet recording apparatus shown in FIG. 2 repeats the reciprocating movement (main scanning) of the recording head H1001 and the conveyance (sub scanning) of the recording medium S such as general recording paper, special paper, and OHP film at a predetermined pitch. . This is a serial type recording apparatus that forms characters, symbols, images, and the like by ejecting ink droplets selectively from the recording head H1001 in synchronization with these movements and attaching them to the recording medium S.

  The ink jet recording apparatus includes an ink tank H1900 and a recording head H1001 that ejects ink supplied from the ink tank H1900 from nozzles according to recording information. The recording head H1001 is slidably supported on the guide rail 204, and is detachably mounted on a carriage 202 that is reciprocated along the guide rail 204 by a driving unit such as a motor (not shown). The recording medium S faces the ink ejection surface of the recording head H1001 by the conveyance roller 203. And it is conveyed in the direction (for example, the direction of arrow A which is an orthogonal direction) which cross | intersects the moving direction of the carriage 202 so that the distance with an ink discharge surface may be maintained constant. The recording head H1001 employs a so-called cartridge system and is detachably mounted on the carriage 202 described above.

  The recording head H1001 has four types of nozzle rows of black, cyan, magenta, and yellow in order to eject inks of different colors. Corresponding to the colors of ink ejected from the recording head H1001, four types of ink tanks H1900 of black, cyan, magenta, and yellow are detachably attached to the recording head H1001.

  The recovery unit 207 is disposed so as to face the ink ejection surface of the recording head H1001 in the non-recording area that is within the reciprocating range of the recording head H1001 and outside the passing range of the recording medium S. . Further, the recording head performs suction recovery from the cap unit 208 corresponding to each of the four types of discharge units of black, cyan, magenta, and yellow.

  FIG. 3 is a diagram illustrating a state in which the recording head H1001 and an ink tank H1900 that is detachably provided on the recording head H1001 are coupled to each other. FIG. 4 is a diagram showing a state before the recording head H1001 and the ink tank H1900 that is detachably provided on the recording head H1001 are coupled. In FIG. 3, four types of ink tanks (H1901, H1902, H1903, H1904) of black, cyan, magenta, and yellow are independent of the recording head H1001 corresponding to the color of ink ejected from the recording head H1001. And is detachably mounted. Next, the recording head H1001 will be described in more detail in order for each component constituting the recording head.

<1> Recording Head The recording head H1001 is a bubble jet (registered trademark) side that performs recording using an electrothermal transducer that generates thermal energy for causing film boiling to occur in ink in response to an electrical signal. This is a recording head that is of a shooter type.

  As shown in the exploded perspective view of FIG. 5, the recording head H1001 includes a recording element unit H1002, an ink supply unit H1003, and a tank holder H2000.

  Furthermore, the exploded perspective view of FIG. 6 explains the components of the recording element unit H1002. The constituent elements are a first recording element substrate H1100, a second recording element substrate H1101, a first plate H1200, an electrical wiring tape H1300, an electrical contact substrate H2200, and a second plate H1400. The ink supply unit H1003 includes an ink supply member H1500, a flow path forming member H1600, a joint rubber H2300, a filter H1700, and a seal rubber H1800.

<1-1> Recording Element Unit FIG. 7 is a schematic view of the ejection port arrays provided on the first recording element substrate H1100 and the second recording element substrate H1101 of the recording head H1001 in FIG. 6 as viewed from the recording medium side. It is. In FIG. 7, a discharge port array H1108a provided on the first recording element substrate H1100 discharges yellow, magenta, and cyan ink droplets from a discharge port that discharges black ink droplets in order to output a monochrome image at high speed. It has more than the discharge outlet. Actually, the discharge port row length is about 1.5 times, the discharge port row number is twice, and when both are included, the number is about three times. Therefore, in the case of black monochrome printing, it is possible to record at three times the speed even when the frequency at which ink is ejected from the ejection port is the same as in yellow, magenta and cyan colors.

  FIG. 8 is a perspective view illustrating a partially exploded configuration of the first recording element substrate H1100 that discharges black ink in FIG.

  In the first recording element substrate H1100, for example, an ink supply port H1102 including a long groove-like through-hole as an ink channel on an Si substrate having a thickness of 0.5 to 1 mm is anisotropically etched using the crystal orientation of Si. It is formed in two rows in parallel by a method such as sandblasting.

  The electrothermal conversion elements H1103, which are recording elements, are arranged in a staggered pattern in one row on both sides of each ink supply port H1102. The electrothermal conversion element H1103 and the electric wiring such as Al for supplying electric power to the electrothermal conversion element H1103 are formed by a film forming technique. Furthermore, electrode portions H1104 for supplying electric power to the electric wiring are arranged on both outer sides of the electrothermal transducer H1103, and bumps H1105 such as Au are formed on the electrode portion H1104. On the first recording element substrate H1100, an ink flow path wall H1106 and a discharge port H1107 for forming an ink flow path corresponding to the electrothermal conversion element H1103 are formed of a resin material by a photolithographic technique. An outlet row H1108 is formed. Accordingly, since the ejection port H1107 is provided opposite to the electrothermal conversion element H1103, the ink supplied from the ink flow path H1102 is ejected by bubbles generated by the electrothermal conversion element H1103.

  Next, FIG. 9 is a perspective view showing the second recording element substrate H1101 in a partially exploded state.

  The second recording element substrate H1101 is a recording element substrate for discharging ink of three colors of yellow, magenta, and cyan, and three ink supply ports H1102 are formed in parallel. The second recording element substrate H1101 has electrothermal conversion elements H1103 and ink ejection openings H1107 on both sides of each ink supply port. Of course, like the first recording element substrate H1100, an ink supply port, an electrothermal conversion element, an electric wiring, an electrode portion, and the like are formed on the Si substrate, and an ink flow path and an ink are formed on the resin material by a photolithography technique. A discharge port is formed.

  Similarly to the first recording element substrate, a bump H1105 such as Au is formed on the electrode portion H1104 for supplying electric power to the electric wiring.

Next, in FIG. 6, the first plate H1200 is made of an alumina (Al ₂ O ₃ ) material having a thickness of 0.5 to 10 mm, for example. The material of the first plate is not limited to alumina, and has a linear expansion coefficient equivalent to that of the material of the recording element substrate H1100, and the thermal conductivity of the material of the recording element substrate H1100. It may be made of a material having a thermal conductivity equivalent or equal to or higher. Examples of the material of the first plate H1200 include silicon (Si), aluminum nitride (AlN), zirconia, silicon nitride (Si ₃ N ₄ ), silicon carbide (SiC), molybdenum (Mo), and tungsten (W). Either may be sufficient. The first plate H1200 is provided with an ink supply port H1201 for supplying black ink to the first recording element substrate H1100, and for supplying cyan, magenta, and yellow ink to the second recording element substrate H1101. An ink supply port H1201 is formed. Further, the first recording element substrate H1100 and the second recording element substrate H1101 are bonded and fixed to the first plate H1200, respectively.

  Next, the electrical wiring tape H1300 applies an electrical signal for ejecting ink to the first recording element substrate H1100 and the second recording element substrate H1101. The electric wiring tape H1300 has a plurality of opening portions for incorporating the respective recording element substrates, and electrode terminals H1302 corresponding to the electrode portions H1104 of the respective recording element substrates.

  The electrical wiring tape H1300 has an electrode terminal portion H1303 for electrical connection with the electrical contact substrate H2200, and the electrode terminal H1302 and the electrode terminal 1303 are connected by a continuous copper foil wiring pattern. The electrical wiring tape H1300, the first recording element substrate 1100, and the second recording element substrate H1101 are electrically connected to each other.

The second plate H1400 is, for example, a single plate-like member having a thickness of 0.5 to 1 mm, and is formed of a ceramic material such as alumina (Al ₂ O ₃ ) or a metal material such as Al or SUS. Yes. Further, the second plate H1400 is bonded to the first plate H1200 so that the first recording element substrate H1100 and the second recording element substrate H1101 and the electric wiring tape H1300 can be electrically connected in a plane. Further, the back surface of the electric wiring tape H1300 is bonded and fixed to the second plate H1400.

  The first recording element substrate H1100 and the second recording element substrate H1101 are electrically connected to the electrical wiring tape H1300, and are electrically connected to an electrical contact substrate H2200 having an external signal input terminal H1301 at the end of the electrical wiring tape. The The electric wiring tape H1300 is bent at one side surface of the first plate H1200, and is bonded to the side surface of the first plate H1200 with the third adhesive H1306.

  Next, the detailed shapes of the first recording element substrate H1100 and the first plate H1200 will be described with reference to FIGS. In FIGS. 1, 10, and 11, the recording element substrate 1 corresponds to the first recording element substrate H1100, and the support member 2 corresponds to the first plate H1200.

  First, FIG. 10A shows a shape of a conventional support member viewed from the side opposite to the recording element substrate mounting surface. FIG. 10B is a view showing the relationship between the conventional support member and the recording element substrate in the cross section in the arrow direction in FIG. In this case, since the pitch P1 between the supply ports 5 is secured to some extent, the thickness of the partition wall 2b corresponding to the pitch P1 can be sufficiently secured, so that the thickness of the partition wall 2b of the support member 2 becomes a dimension capable of manufacturing parts. ing. Heat accumulated between the supply ports 3a of the recording element substrate is radiated through the partition walls 2b.

  Next, FIG. 11A shows a state in which the shape of the support member in which the pitch between the supply ports 5 is narrowed for cost reduction is viewed from the side opposite to the recording element substrate mounting surface. FIG. 11B is a view showing the relationship between the support member and the recording element substrate in the cross section in the arrow direction in FIG. In this case, since the dimension P2 is small, the thickness of the partition wall 2b corresponding to the dimension is difficult to manufacture the part. Accordingly, the partition wall 2b as shown by the alternate long and short dash line in FIG. 11 cannot be formed, and it is difficult to diffuse the heat accumulated in the supply port intermediate portion 5a during the continuous recording operation.

  FIG. 1A shows a state in which the shape of the support member of this embodiment is viewed from the side opposite to the recording element substrate mounting surface. FIG. 1B is a view showing the relationship between the support member 2 and the recording element substrate 1 in the cross section taken along the line BB in FIG. In this case, since the dimension P2 is small, the thickness of the partition wall corresponding to the dimension is difficult to manufacture the part. Therefore, a partition cannot be formed. Next, FIG. 1C is a diagram showing the relationship between the support member and the recording element substrate in the section taken along line CC in FIG. In this cross section, the beam 6 is formed so as to cross the supply flow path 2a in a direction orthogonal to the discharge port array, and is in contact with the supply port intermediate portion 5a. With this beam 6, it is possible to diffuse the heat accumulated in the supply port intermediate portion 5a during the continuous recording operation through the support member 2 as indicated by the dotted line in the drawing.

<1-2> Ink Supply Unit FIG. 12 is a view showing a cross-sectional shape in a state where the ink tank H1900 is coupled to the recording head H1001. As shown in FIG. 12, the ink supply member H1500 is a component of the ink supply unit H1003 (FIG. 6) for guiding ink from the ink tank H1900 to the recording element unit H1002 (FIG. 6). Further, the ink flow path H1501 is formed by ultrasonically welding the flow path forming member H1600. A filter H1700 is joined by welding to a joint H1517 that engages with the ink tank H1900, and a seal rubber H1800 is further attached.

  The ink supply member H1500 also has a part of the function of holding the removable ink tank H1900, and has a first hole H1503 for engaging the second claw H1910 of the ink tank H1900.

<1-3> Coupling of Recording Head Unit and Ink Supply Unit As shown in FIG. 5, the recording head H1001 is completed by connecting the recording element unit H1002 to the ink supply unit H1003 and further to the tank holder H2000. The coupling is performed as follows.

  In order to allow the ink supply port of the recording element unit H1002 and the ink supply port of the ink supply unit H1003 to communicate with each other so as not to leak ink, the recording element unit H1002 is fixed with a screw H2400 via a joint rubber H2300.

  The electrical contact substrate H2200 of the recording element unit H1002 is positioned on one side of the ink supply member H1500 by terminal positioning pins H1515 (2 places) and terminal positioning holes H1309 (2 places), and fixed as shown in FIG. .

  Further, the recording head H1001 is completed as shown in FIG. 14 by fitting and coupling the coupling hole and coupling portion of the ink supply member H1500 with the tank holder to the tank holder H2000.

<2> Recording Head FIGS. 3 and 4 are diagrams for explaining the mounting of the recording head H1001 and the ink tanks H1901, H1902, H1903, and H1904. Contains color ink. Further, as shown in FIG. 12, each ink tank is formed with an ink supply port H1907 for supplying ink in the ink tank to the recording head H1001. For example, when the ink tank 1901H is attached to the recording head H1001, the ink supply port H1907 of the ink tank H1901 is brought into pressure contact with the filter H1700 provided in the joint portion H1520 of the recording head H1001. Then, the black ink in the ink tank H1901 is supplied from the ink supply port H1907 to the first recording element substrate through the first plate H1200 via the ink flow path H1501 of the recording head H1001.

  Then, ink is supplied to the foaming chamber having the electrothermal conversion element H1103 and the discharge port H1107, and is ejected toward a recording sheet as a recording medium by the thermal energy given to the electrothermal conversion element H1103.

  Next, temperature characteristics of the recording head when printing is performed by the ink jet recording apparatus of the present embodiment will be described with reference to FIG. The support member 2 shown in FIG. 15 corresponds to the first plate H1200, and this point is the same in other embodiments.

  FIG. 15A shows the temperature measurement point of the recording head composed of the first recording element substrate H1100 of the recording head of the present invention shown in FIG. 1 and the support member 2 that supports the first recording element substrate H1100. FIG. FIG. 15B shows the temperature measurement of the recording head composed of the first recording element substrate H1100 of the conventional recording head shown in FIG. 11 and the support member 2 that supports the first recording element substrate H1100. It is a figure which shows a point. Further, FIG. 15 (c) is a graph showing the temperature measured at the measurement points shown in FIGS. 15 (a) and 15 (b).

  In FIG. 15A, the measurement point H1 is a location where the temperature sensor inside the first recording element substrate is provided. In addition, the measurement point H3 is a location that is located exactly in the middle of the two ejection port rows H1108a and that is also the center position of the beam 6. Furthermore, the measurement point H2 is a portion located on the opposite side to the H3 point with the ejection port array H1108a interposed therebetween. Next, in FIG. 15B, a measurement point K1 is a location where the temperature sensor inside the first recording element substrate is provided, and is the same position as the point H1. The measurement point K3 is the same position as the H3 point described above. Furthermore, the measurement point K2 is at the same position as the H3 point described above.

  In FIG. 15C, continuous discharge is performed using the recording head described in FIGS. 15A and 15B, and the temperatures at the six measurement points H1, H2, H3, K1, K2, and K3 described above are measured. It is measured. The printing condition is that droplets are continuously ejected from all the ejection ports at a frequency of 3 kHz, and actually the ink is ejected directly to the cap unit 208 shown in FIG. 2 without printing on the recording medium. is there. Since the point H1 and the point K1 have almost the same temperature, the value of the point K1 is omitted. Similarly, since the point H2 and the point K2 have almost the same temperature, the value of the point K2 is also omitted.

  The value of the point K3 is about 10 to 15 ° C. higher than the value of the point H1 because there is no support member that dissipates heat. On the other hand, the value at point H3 is lower by about 10 ° C. than the point K3 due to the heat radiation of the beam 6, and it can be confirmed that the heat of the recording element substrate is radiated to the support member. Further, the point H2 is slightly lower than the point H3 because it is in contact with only one side of the discharge port array and is in contact with a support member having a sufficient area.

  Here, with reference to FIGS. 16A and 16B, the influence of the temperature of the recording head on the ejection state will be described.

  FIG. 16A is a schematic diagram showing foaming at room temperature when electric energy is applied to the electric resistance element. Moreover, FIG.16 (b) is a schematic diagram which shows the foaming at the time of high temperature similarly.

  In FIG. 16A, the maximum foam 381A reaches the middle of the ink flow path 332, and then disappears. On the other hand, in FIG. 16B, the size of the maximum foam 381B at the high temperature is extremely larger than the size of the maximum foam 381A at the normal temperature, and the bubbles greatly protrude to the common liquid chamber 333. Then, the time for the bubbles to contract becomes longer, and the time until the ink is filled in the foaming chamber 331 becomes longer. If electric energy is applied again to the electric resistance element 304 before the ink is filled in the foaming chamber 331, the foaming failure occurs, the ink is not normally ejected, and the size of the ink droplet ejected from the ejection port is small. It becomes uneven. Furthermore, the ink may be ejected as a plurality of divided ink droplets instead of one ink droplet, or the ejection itself may not be performed.

  As a result, in the recorded image, the density varies depending on the recorded region, or a blurred image, a streak due to twisting, or the like may appear, resulting in an image that cannot be used. Therefore, when the recording head exceeds the limit temperature, the ejection frequency is lowered, a pause time is provided between printing operations, or the printing operation is interrupted in some cases to lower the temperature of the recording head. . In the present embodiment, the limit temperature at which ejection becomes abnormal is 70 ° C.

  Therefore, in this embodiment, by providing the beam 6 in contact with the supply port intermediate portion 5a of the recording element substrate in the supply flow path 2a of the support member 2, even when the same ink droplets are ejected per unit time, compared to the conventional case. It becomes possible to suppress the temperature rise. The frequency with which the ejection frequency of the recording head is lowered or the pause time is provided between printing operations is reduced, and the printing speed can be improved.

(Second Embodiment)
In the first embodiment, the configuration of the recording head having the structure in which one beam 6 is provided on the support member 2 has been described. In the second embodiment, the recording head having a configuration in which a plurality of beams 6 are provided is described. The description will be given with reference to FIG.

  FIG. 17A shows the temperature of the recording head composed of the first recording element substrate H1100 of the recording head according to the second embodiment of the present invention and the support member 2 that supports the first recording element substrate H1100. It is a figure which shows a measurement point. FIG. 17B shows a first recording element substrate H1100 of the recording head according to the first embodiment of the present invention and a recording head composed of a support member 2 that supports the first recording element substrate H1100. It is a figure which shows a temperature measurement point. Further, FIG. 17 (c) is a graph showing the temperature measured at the measurement points shown in FIGS. 17 (a) and 17 (b).

  In FIG. 17B, the measurement point H1 is a location where the temperature sensor inside the first recording element substrate is provided. In addition, the measurement point H3 is a location that is located exactly in the middle of the two ejection port rows H1108a and that is also the center position of the beam 6. Furthermore, the measurement point H4 is between the point H1 and the point H3, and is the point farthest from the support member 2 and the beam 6 in the discharge port array direction of the supply port intermediate portion 5a in FIG. Further, the measurement point M4 is at the same position as the H4 point described above, and the beam 6 is directly below.

  FIG. 17C shows the results of measuring the temperatures at the four measurement points H1, H3, H4, and M4 by performing continuous ejection using the recording head described in FIGS. 17A and 17B. is there. The printing condition was that droplets were continuously ejected from all the ejection ports at a frequency of 3 kHz, and actually the ink was ejected directly to the cap unit shown in FIG. 2 without printing on the recording medium. .

  As described in the first embodiment, the value of the point H3 is lower than that when there is no beam due to heat radiation of the beam 6, and the heat of the recording element substrate H1100 is radiated to the support member. It can be confirmed. On the other hand, the temperature of the point H4 is lower than the point K3 in the first embodiment because there is no beam underneath, although the beam 6 is relatively close, but it is 3-4 compared to the point H3. It is higher by about ℃.

  In contrast, at point M4, the heat of the beam 6 is about 3 to 4 ° C. lower than the point H4, and it is confirmed that the heat of the recording element substrate is radiated to the support member earlier by the beam. it can.

  Therefore, in the second embodiment, by providing a plurality of beams 6 on the support member 2, it is possible to further suppress the temperature rise, and even when the same ink droplets are ejected per unit time, the rise of the recording element substrate compared to the conventional case. Temperature can be suppressed. Accordingly, the frequency of lowering the ejection frequency of the recording head or providing a pause time between printing operations is reduced, and the printing speed can be further improved.

(Third embodiment)
In 1st Embodiment, the effect which suppresses temperature rising was confirmed by the beam provided in the supporting member. In the third embodiment, a configuration in which the width of the beam is widened to obtain a further effect will be described.

  FIG. 18A shows the support member of the recording head according to the third embodiment of the present invention in which the width of the beam of the support member is increased in order to enhance the heat dissipation effect, on the side opposite to the recording element substrate mounting surface. The figure of the state seen from is represented. FIG. 18B is a diagram illustrating the relationship between the support member and the recording element substrate on the BB cross section in FIG. FIG. 18C is a view showing the relationship between the support member and the recording element substrate in the CC cross section in FIG.

  L shown by Fig.18 (a) has shown the width | variety of the beam 6a of a supporting member. By increasing the width L of the beam 6 of the support member 2, the heat dissipation effect is enhanced, and the temperature at the point H3 shown in FIG. 15C becomes closer to the temperature at the point H2, thereby obtaining a greater effect. I can do it. However, when the viscosity of the ejected ink is high, or when an extremely fast printing speed is realized, there may be a problem in the supply of ink to the ejection port corresponding to the beam 6a. In the present embodiment, in order to eliminate the adverse effects, a concave groove 7 is provided in a portion corresponding to the supply port 5 on the surface of the beam 6a on the recording element substrate 1 side, and the supply flow path 2a divided by the beam 6 is provided. Provided to communicate. As a result, an increase in the flow resistance when the width L of the beam 6 is increased can be prevented, and the ink supply capability can be improved.

  As shown in FIG. 18B, the groove 7 is provided immediately below the supply port 5, and the beam 6 a exists at the portion where the recording element substrate 1 and the support member 2 are in contact with each other, so that the groove shape is provided. Does not interfere with heat dissipation. As indicated by the arrow in FIG. 18C, ink is supplied from the supply flow path 2a through the groove 7 and the supply port 5 to the electrothermal conversion element 4 on the beam 6a. The presence of the grooves 7 can increase the ink supply amount per short time.

  Accordingly, it is possible to increase the printing speed of the ink jet recording apparatus while preventing the ink supply while maintaining a higher heat dissipation effect.

  In the present embodiment, the groove shape has an arc-shaped cross section, but the present invention is not limited thereto. For example, the cross section may be a square or the cross section may change in the discharge port array direction. Any shape is applicable as long as the ink supply is improved.

  In each of the above embodiments, a bubble jet type using an electrothermal transducer that generates thermal energy as a recording method, particularly a side shooter type (a type that discharges perpendicularly to the formation surface of the electrothermal transducer) will be described. I came. However, the present invention is not limited thereto. For example, the present invention can also be applied to an ink jet recording head of a type such as an edge shooter type head (a type that ejects substantially parallel to the formation surface of the electrothermal transducer).

FIG. 3 is a diagram illustrating a state of a recording element substrate and a support member of the recording head according to the first embodiment of the present invention. 1 is a schematic perspective view illustrating an example of a configuration of an inkjet recording apparatus of the present invention. FIG. 3 is a perspective view illustrating a state in which the recording head and the ink tank are combined according to the embodiment of the present invention. FIG. 3 is a perspective view illustrating a state before the recording head and the ink tank are combined according to the embodiment of the present invention. FIG. 5 is an exploded perspective view of the recording head illustrated in FIG. 4. FIG. 6 is an exploded perspective view of the ink supply unit and the recording element unit shown in FIG. 5. FIG. 7 is a schematic view of the arrangement of the recording element substrate and the ejection port array of the recording head shown in FIG. 6 as viewed from the recording medium side. FIG. 8 is a perspective view showing the first recording element substrate shown in FIG. 7 with a part thereof broken. FIG. 8 is a perspective view showing the second recording element substrate shown in FIG. 7 with a part thereof broken. FIG. 6 is a diagram illustrating a state of a recording element substrate and a support member of a conventional recording head. FIG. 6 is a diagram illustrating a state of a recording element substrate and a support member of a conventional recording head. FIG. 4 is a cross-sectional view of a combined state of the recording head and the ink tank illustrated in FIG. 3. FIG. 4 is a perspective view illustrating a combined body of a recording element unit and an ink supply unit in the recording head illustrated in FIG. 3 and the like. FIG. 4 is a perspective view illustrating a bottom surface in a state where the recording head and the ink tank illustrated in FIG. FIG. 4 is a diagram illustrating temperature characteristics of the recording head according to the first embodiment of the invention. It is a conceptual diagram of the maximum foaming at the time of normal temperature and high temperature. FIG. 6 is a diagram illustrating temperature characteristics of a recording head according to a second embodiment of the present invention. FIG. 10 is a diagram illustrating a structure of a support member for a recording head according to a third embodiment of the invention. It is a figure shown in the state which mounted the recording element board | substrate of the prior art example used as the background art of this application on a support member. It is a figure which shows the recording head using the supporting member without a partition of a prior art example used as the background art of this application.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Recording element board | substrate 2 Support member 2a Supply flow path 2b Partition 3 Discharge port plate 3a, 303 Discharge port 4,304 Electrothermal conversion element 5 Supply port 6, 6a Beam 7 Groove

Claims (4)

A plurality of adjacent ejection port arrays that eject the same type of liquid, a plurality of liquid supply ports that are formed corresponding to each ejection port array and that supply the same type of liquid, and eject the liquid from the ejection port array A recording element substrate having an electrical resistance element that generates thermal energy for
An ink jet recording head using a liquid discharge head comprising: a member that supports the recording element substrate, and a support member provided with a supply flow path for supplying liquid to the plurality of liquid supply ports of the recording element substrate In
Between the liquid supply ports adjacent to each other in the recording element substrate, which is formed in the supply flow channel of the support member so as to connect the inner walls of the supply flow channel in a direction orthogonal to the discharge port array. An ink jet recording head comprising a beam in contact with the portion.   The inkjet recording head according to claim 1, wherein a plurality of the beams are provided in the supply flow path.   3. The ink jet recording head according to claim 1, wherein a concave portion is provided in a portion corresponding to each of the liquid supply ports on the recording element substrate side of the beam.   4. An ink jet recording apparatus comprising the ink jet recording head according to claim 1 and performing recording by ejecting recording droplets from the ink jet recording head onto a recording medium.

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