JP2009149055A - Ink jet recording head and ink jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a temperature difference between an end part and a central part in a longitudinal direction of an ink jet recording head (an arrangement direction of electrothermal conversion elements).
In the ink jet recording head of the present invention, a liquid flow path H1213 for cooling the recording element substrate H1100 is provided along a recording element array of the recording element substrate inside a support plate H1200 that supports the recording element substrate. The shortest distance between the flow path on the end side of the support plate and the recording element is larger than the shortest distance between the flow path and the recording element in the center of the support plate.
[Selection] Figure 7

Description

  The present invention relates to an inkjet recording apparatus that performs a recording operation by discharging ink, and an inkjet recording head used in the recording apparatus.

  2. Description of the Related Art Conventionally, ink jet recording apparatuses are widely used and commercialized for computer-related output devices and the like because the running cost of color images is low and the apparatus can be miniaturized.

  In recent years, in order to realize high-definition image recording at higher speed, it is also desired to realize a recording head having a longer recording width (discharge port array length). Specifically, a recording head having a length of 4 inches to 13 inches has been required.

  As the recording head becomes longer and faster in this way, the input energy to the ink jet recording head increases and the temperature rise of the recording head during recording increases. As a result, it is necessary to cope with recording reliability, such as a variation in ejection amount for each page, unstable ejection at high temperatures, and a decrease in continuous recording performance.

Conventional ink jet recording heads are cooled by air cooling from the outside of the recording head or mounting a cooling pipe on the recording head (Patent Documents 1 and 2).
Japanese Patent Application Laid-Open No. 08-150711 Japanese Patent Laid-Open No. 08-276574

  However, the conventional inkjet recording head has a problem as shown in FIG. FIG. 18 shows a temperature distribution immediately after the execution of recording in the case where a cooling liquid flow path for circulating the cooling liquid is provided along the discharge port array of the recording head, and the horizontal axis indicates the recording element (electrothermal conversion body of the recording head). This represents the position in the column direction, and the vertical axis represents the temperature in the vicinity of the printing element. As described above, it has been experimentally found that the temperature near the end portion of the ink jet recording head is lower than that at the center portion as the end portion is approached.

  On the other hand, it has been found that as the temperature in the vicinity of the recording element of the ink jet recording head increases, the amount of ejected ink drops increases. For example, when the temperature of 1 ° C. rises, the amount of ink drops increases by 0.5 to 1.0%.

  Accordingly, when the temperature at the end of the recording head is lower than that at the center, the amount of ink droplets ejected from the ejection port at the end of the recording head is less than the amount of ink droplets ejected from the ejection port at the center of the recording head. Become. As a result, when an image having the same density is to be formed on the recording medium, the density of the edge image becomes lighter than the density of the central image.

  Patent Document 2 states that “a flow path portion is provided so that a liquid flows in a direction in which a distribution in the temperature of the print head can be generated, and the flow path portion The flow velocity distribution is generated by changing the cross-sectional area with respect to the flow direction ". In the recording head described in Patent Document 2, the above temperature distribution is eliminated by adopting such a configuration. For example, the cross-sectional area on the most upstream side of the flow path part is large, the cross-sectional area becomes smaller toward the downstream side, and the cross-sectional area after the central part is the smallest and constant cross-sectional area. With such a configuration, the temperature distribution can be eliminated.

  However, in order to actually eliminate the temperature distribution by this method, the cross-sectional area of the most upstream part needs to be considerably increased, resulting in an increase in the size of the recording head.

  In view of the above-described problems of the prior art, the present invention reduces the difference between the temperature near the recording element at the end of the recording head and the temperature near the recording element at the center of the recording head in the longitudinal direction. It is an object of the present invention to provide an ink jet recording head capable of achieving the above.

  To achieve the above object, the present invention provides a recording element substrate comprising a recording element array composed of a plurality of recording elements that generate thermal energy for ejecting ink, a support plate for supporting the recording element substrate, The support plate includes a liquid flow path for cooling the recording element substrate along the arrangement direction of the recording elements, and the support plate in the arrangement direction The shortest distance between the recording element disposed on the end side and the flow path is larger than the shortest distance between the recording element disposed on the center part of the support plate in the arrangement direction and the flow path. It is characterized by that.

  According to the present invention, since the difference between the temperature near the recording element at the end of the recording head and the temperature near the recording element at the center of the recording head in the longitudinal direction is reduced, the temperature difference between the end of the recording head and the center is discharged. It is possible to provide a recording head capable of reducing the influence on the recording head.

  Next, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 to FIG. 9 are explanatory diagrams for explaining a suitable ink jet recording head and ink jet recording apparatus to which the present invention is implemented or applied. Hereinafter, the entire configuration will be described with reference to these drawings while explaining the configuration of each part.

  An ink jet recording head H1000 shown in FIG. 1 is a recording head that performs recording using an electrothermal transducer (electrothermal transducer H1102) that generates thermal energy in accordance with an electrical signal as a recording element. As shown in the exploded perspective view of FIG. 2, the ink jet recording head H1000 includes a recording element unit H1001 and an ink supply member H1500 of the ink supply unit H1002. Further, as shown in the exploded perspective view of FIG. 3, the recording element unit H1001 includes a recording element substrate H1100, a support plate H1200, an electric wiring member H1300, a plate H1400, and a filter member H1600.

  FIG. 4A is a diagram illustrating the configuration of the recording element substrate H1100, and FIG. 4B is a cross-sectional view taken along line IVB-IVB in FIG. The recording element substrate H1100 is formed of, for example, a Si substrate H1108 having a thickness of 0.5 to 1 mm. In addition, an ink supply port H1101 composed of rectangular through-holes is formed as an ink flow path, and electrothermal conversion elements H1102 as recording elements are arranged in a staggered manner in each row on both sides of the ink supply port H1101. That is, rows of electrothermal conversion elements H1102 as recording elements are formed on both sides along the longitudinal direction of the ink supply port H1101 having a rectangular opening shape. Further, as shown in FIG. 3, a plurality of recording element substrates are arranged on the support plate so that the rows of electrothermal conversion elements as recording element rows are continuous along the longitudinal direction of the recording head. The electrothermal transducer H1102 and electric wiring such as Al are formed by a film forming technique. In addition, an electrode H1103 for supplying electric power to the electrical wiring is provided.

  The ink supply port H1101 forms an opening having an angle of about 54.7 degrees by performing anisotropic etching using the crystal orientation of the Si substrate H1108. Using this method, etching is performed to a desired depth.

  Further, a flow path forming member H1110 is provided on the Si substrate H1108, and an ink flow path H1104, a discharge port H1105, and a foaming chamber H1107 corresponding to the electrothermal conversion element H1102 are formed by photolithography. The ejection port H1105 is provided so as to face the electrothermal conversion element H1102, and the ink supplied from the ink supply port H1101 generates air bubbles by the electrothermal conversion element H1102 to eject the ink.

The support plate H1200 is made of, for example, an alumina (Al ₂ O ₃ ) material having a thickness of 0.5 to 10 mm. The material of the support 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 is equivalent to or equivalent to the thermal conductivity of the material of the recording element substrate H1100. It may be made of a material having the above thermal conductivity. The material of the support plate H1200 is, for example, any of silicon (Si), aluminum nitride (AlN), zirconia, silicon nitride (Si ₃ N ₄ ), silicon carbide (SiC), molybdenum (Mo), and tungsten (W). There may be.

  An ink supply port H1101 for supplying ink to the recording element substrate H1100 is formed in the support plate H1200, and the ink supply port H1101 of the recording element substrate H1100 corresponds to the ink supply port H1201 of the support plate H1200. . The recording element substrate H1100 is bonded and fixed to the support plate H1200 with high positional accuracy. Further, the support plate H1200 has an X-direction reference H1204, a Y-direction reference H1205, and a Z-direction reference H1206 that are positioning references.

  As shown in FIG. 1, the recording element substrates H1100 are arranged in a staggered manner on the support plate H1200, and wide recording with the same color is enabled by discharging the same color ink. For example, four recording element substrates H1100a, H1100b, H1100c, and H1100d having a discharge port array length of at least 1 inch or more are arranged in a staggered manner to enable recording with a width of 4 inches.

  In addition, as shown in FIG. 1, the recording element substrates arranged in a staggered manner have the ejection openings at the end of the ejection opening array along the arrangement direction of the ejection openings so that the ejection opening array is not interrupted as a whole recording head. Are duplicates. For example, the ejection port array H1106a and the ejection port array H1106b have an overlapping region L.

  The electrical wiring member H1300 applies an electrical signal for ejecting ink to the recording element substrate H1100, has an opening for incorporating the recording element substrate H1100, and has a plate H1400 on the back surface. Bonded and fixed. Further, the electric wiring member H1300 has an electrode terminal H1302 corresponding to the electrode H1103 of the recording element substrate H1100 and an external signal input terminal H1301 which is located at the end of the wiring and receives an electric signal from the recording apparatus main body. ing. The electrical wiring member H1300 and the recording element substrate H1100 are electrically connected. As the connection method, for example, the electrode H1103 of the recording element substrate H1100 and the electrode terminal H1302 of the electric wiring member H1300 are electrically connected by a wire bonding technique using a gold wire (not shown). As a material of the electrical wiring member H1300, for example, a flexible wiring board having a two-layer structure is used, and a surface layer is covered with a polyimide film.

  The plate H1400 is formed of, for example, a SUS plate having a thickness of 0.5 to 1 mm. The material of the plate is not limited to SUS, and may be made of a material having ink resistance and good flatness. The plate H1400 has an opening for taking in the recording element substrate H1100 bonded and fixed to the support plate H1200, and is fixed to the support plate H1200.

  A groove formed by the opening H1402 of the plate and the side surface of the recording element substrate H1100 is filled with the first sealing agent H1304, and the electric mounting portion of the electric wiring member H1300 is sealed. In addition, the electrode H1103 of the recording element substrate is sealed with a second sealant H1305, and the electrical connection portion is protected from ink corrosion and external impact.

  A filter member H1600 for removing foreign matter mixed in the ink is bonded and fixed to the back surface side ink supply port H1201 of the support plate H1200.

  The ink supply member H1500 is formed by resin molding, for example, and includes a common liquid chamber H1501 and a Z-direction reference surface H1502. The Z reference plane H1502 positions and fixes the recording element unit and serves as the Z reference for the recording head H1000.

  As shown in FIG. 2, the ink jet recording head H1000 is completed by coupling the recording element unit H1001 to the ink supply member H1500.

  The coupling is performed as follows.

  The opening of the ink supply member H1500 and the recording element unit H1001 are sealed with a third sealant H1503, and the common liquid chamber H1501 is sealed. Then, the Z reference H1502 of the recording element unit H1001 is positioned and fixed to the Z reference H1502 of the ink supply member by, for example, a screw H1900. Further, the external signal input terminal H1301 portion of the recording element unit H1001 is positioned and fixed on the back surface of the ink supply member H1500, for example.

  As shown in FIG. 5, an inkjet recording apparatus M4000 equipped with an inkjet recording head according to each embodiment of the present invention includes, for example, six color recording heads corresponding to photographic image quality recording. . The recording head H1000Bk is a recording head for black ink, the recording head H1000C is for cyan ink, the recording head H1000M for magenta ink, and the recording head H1000Y is for yellow ink. The recording head H1000LC is for light cyan ink, and the recording head H1000LM is for light magenta ink. These inkjet recording heads H1000 are fixedly supported by positioning means and electrical contacts M4002 of the head mounting portion M4001 mounted on the recording apparatus main body M4000.

  These recording heads are controlled by a drive circuit (not shown) to perform recording on a recording medium. In the recording apparatus of FIG. 5, the ink jet recording head is a full line type having a discharge port array length corresponding to the width of the recording medium, the ink jet recording head is fixed, and the recording medium scans in the direction of the arrow. It is a method to perform.

  On the other hand, in the recording apparatus of FIG. 6, the inkjet recording head is mounted on a carriage that is the head mounting portion M4001, and is a serial drive type recording apparatus that performs recording while reciprocating in the main scanning direction (carriage movement direction). is there.

  FIG. 17 is a schematic diagram showing an ink and cooling liquid supply system of the ink jet recording apparatus.

  As shown in FIG. 17, the supply system of the ink jet recording apparatus includes an ink tank 8 that stores ink 15, and two tubes 216 and 217 are disposed in the ink tank 8. One of the tubes 217 is connected to one end of the recording head 14 and communicates with the common liquid chamber of the recording head 14. The other tube 216 is connected to the other end of the recording head 14 via the pump 9 and communicates with the common liquid chamber of the recording head 14.

  The ink jet recording head 14 has a plurality of ink discharge port arrays. Even if bubbles exist in the ink flow path, the bubbles can be discharged from the ink tank 8 by driving the pump 11 to circulate the ink. When ink is ejected from the inkjet recording head 14 such as during recording, ink is supplied from the ink tank 8 to the recording head 14 via the tube 217 or tube 216 by capillary force.

  Reference numeral 10 denotes a coolant tank, and two tubes 218 and 219 are disposed in the coolant tank 10. One of the tubes 218 is connected to one end of the inkjet recording head 14 and communicates with a coolant flow path in the support plate H1200 of the inkjet recording head 14. The other tube 219 is connected to the other end of the inkjet recording head 14 via the pump 11 and communicates with the coolant flow path in the support plate H1200 of the inkjet recording head 14. When the temperature of the ink jet recording head 14 rises, the pump 11 is driven, and the coolant in the coolant tank 10 circulates in the order of the tube 218, the support plate H1200, and the tube 219, and the ink jet recording head 14 is cooled. .

  Further, the cooling liquid supply system includes a control device (not shown), and controls the temperature increase of the ink jet recording head by flowing the cooling liquid into the cooling flow path of the ink jet recording head. This control device is based on detection data such as cooling water flow rate, inlet temperature, outlet temperature, head temperature (recording element substrate built-in sensor, etc.), environmental temperature, etc. Set the cooling conditions and control the head temperature. In addition, the control device can independently control at least one of the flow direction of the cooling liquid, the fluid temperature, and the flow velocity, and performs fine control according to the difference in recording duty between the plurality of recording element substrates. Is possible.

  FIG. 7 is a diagram schematically showing a partial cross section of the ink jet recording head according to the embodiment of the present invention. FIG.7 (b) is the VIIB-VIIB sectional drawing in Fig.7 (a). The support plate H1200 is composed of two members H1211, H1212. A groove through which the cooling liquid passes is provided in the support plate H1212, and two flow paths (cooling liquid flow paths) H1213 and H1214 are formed by bonding the two sheets together. That is, a liquid flow path for cooling the recording element substrate H1100 is provided in the support plate H1200 along the row of recording elements H1102 of the recording element substrate H1100. The inlet / outlet of the coolant is taken out on the opposite side of the ink supply member H1500 from the recording element substrate H1100 (not shown). The flow paths H1213 and H1214 are formed so that two coolants can flow independently. The cross sections of the coolant flow paths H1213 and H1214 are constant at a width of 2 mm and a depth of 1.5 mm in this embodiment. The flow rate of the cooling liquid was about 20 ml / min to 300 ml / min. The flow rate that meets the conditions is set according to the recording conditions and head specifications (power, discharge amount, etc.). A common ink chamber H1501 is provided on the side of the support plate H1200 opposite to the recording element substrate H1100, and ink is supplied to the recording element substrate H1100 through each ink supply port provided in the support plate H1200.

  In this way, when the cooling flow path is divided into a plurality, the temperature of the ink jet recording head can be finely controlled according to the flow direction of the cooling liquid and the number of lines used.

  FIG. 8 shows a temperature distribution immediately after execution of recording by the ink jet recording head. The horizontal axis represents the position of the recording head in the direction of the recording elements (such as a heater as an electrothermal transducer), and the vertical axis represents the temperature near the discharge port. The solid line portion in the graph is the temperature distribution when the coolant flow path in FIG. 7B is shortened as shown by the hatched portion. Further, the broken line portion in FIG. 8 extends the coolant flow path to the broken line portion in the drawing that is substantially equal to the maximum recording area width (that is, the printing element row length or the ejection port row length) in the print head of FIG. 7B. Shows the temperature distribution. Here, since the portions other than both ends coincide with the solid line, description thereof is omitted.

  In the present embodiment, the shortest distance L1XY between the electrothermal conversion element and the coolant channel in the XY plane on the end side of the support plate along the Y direction is XY at the center of the support substrate along the Y direction. The configuration is larger than the shortest distance L2XY in the plane. In the present embodiment, the distance between the electrothermal converter and the coolant flow path is varied along a plane (XY plane) parallel to the main surface of the support plate. Then, the shortest distances (L1Z, L2Z, not shown) between the electrothermal conversion elements and the coolant flow paths on the end side and center of the support substrate in the Z direction are substantially the same value and constant. Therefore, in the relationship between L1XY and L2XY, if L1XY> L2XY, the shortest distance L1 on the end side of the support plate in the XYZ space between the electrothermal conversion element and the coolant flow path and the center portion of the support substrate For the shortest distance L2, the relationship L1> L2 is satisfied.

  With the configuration as described above, excessive cooling at both ends of the recording head is reduced, and the difference between the temperature at both ends of the recording head and the temperature at the center of the recording head is reduced. The temperature can be almost uniform over the entire length.

  Note that the position of the electrothermal transducer on the recording element substrate is regarded as the central portion of the recording element substrate in the X direction in FIG. 7B. This is because it can be considered that heat generated by the electrothermal conversion element is generated in the central portion in the X direction of the recording element substrate. Therefore, L1XY indicates the distance between the central portion in the X direction of the end portion of the recording element substrate close to the end portion side of the support plate in the Y direction and the coolant flow path close to the end portion side of the support plate. L2XY indicates the distance between the central portion in the X direction of the recording element substrate close to the cooling fluid flow path and the cooling liquid flow path in the central portion of the support plate in the Y direction.

  The shortest distance L1XY between the electrothermal conversion element on the end side of the support plate and the coolant flow path is the maximum heat generation amount of the recording element substrate H1100, the distance between the coolant flow path and the electrothermal conversion element array, and the support plate H1200. Different distances can be achieved by changing parameters such as thermal conductivity and coolant flow rate. Up to this point, an example of an inkjet recording head in which a plurality of recording element substrates H1100 are arranged in a staggered manner has been described. However, as shown in FIG. 9, the present invention can also be applied to an inkjet recording head using a long integrated recording element substrate H1210. . FIG. 9 is a diagram schematically showing a partial cross section corresponding to FIG. 7B of an ink jet recording head using a long integrated recording element substrate H1210.

  In the present embodiment, the two cooling fluid channels H1213 and H1214 have been described as examples. However, the number of the cooling fluid channels is not limited thereto. Further, although the explanation has been given by taking the example of the cooling fluid flow path continuous over the entire length of the recording head, it may be divided into a plurality of parts in the length direction, for example.

  Further, as shown in FIGS. 7 and 9, in the configuration in which the ink supply port is disposed between at least two cooling liquid channels in the direction perpendicular to the arrangement direction of the recording element substrates, the cooling liquid channel The direction in which the coolants H1213 and H1214 flow is preferably reversed. Since the temperature of the coolant in the coolant channel is higher on the downstream side than on the upstream side, a temperature gradient is generated in the coolant in the coolant channel along the Y direction. Therefore, determining the flow direction as described above is desirable in that the cooling effect can be made uniform as a whole by having opposite temperature gradients on both sides of the support plate in the Y direction.

(Second Embodiment)
FIG. 10 is a diagram schematically showing a partial cross section of an ink jet recording head for explaining another embodiment of the present invention. FIG.10 (b) is XB-XB sectional drawing in Fig.10 (a). FIG. 10C is a cross-sectional view taken along the line XC-XC in FIG. 10B (a cross-sectional view in which the recording head is cut along the coolant flow path).

  The support plate H2200 is composed of two members H2211, H2212, and a coolant passage H2213, H2214 is formed by providing a groove through which the coolant flows in the support plate H2212, and bonding the two together. The inlet / outlet of the cooling liquid is taken out on the opposite side of the ink supply member H2500 from the recording element substrate H2100 (not shown). The two coolant flow paths are formed so that the coolant can flow independently. In this embodiment, the cross section of the flow path is constant at a width of 2 mm and a depth of 1.5 mm. The flow rate of the cooling liquid was about 20 ml / min to 300 ml / min. A flow rate suitable for the conditions can be set according to recording conditions and head specifications (power, discharge amount, etc.). A common ink chamber H2501 is provided on the opposite side of the support plate H2200 from the recording element substrate H2100, and ink is supplied to the recording element substrate H2100 through each ink supply port provided in the support plate H2200.

  The distance in the Z direction between the coolant flow paths H2213 and H2214 and the recording element substrate H2100 (distance in the Z direction between the coolant flow path and the potential heat conversion element, L1Z, L2Z) was constant at 1 mm. The smaller this distance, the greater the cooling effect. Here, the Z direction represents the thickness direction of the recording element substrate or the support plate.

  The lengths of the coolant flow paths H2213 and H2214 in the Y direction are longer than the recording head of the first embodiment and are substantially equal to the maximum recording area width. The coolant flow paths H2213 and H2214 include parallel portions H2216 and H2218 that are parallel to the Y axis, and inclined portions H2215 and H2217 that are inclined at a constant angle with respect to the Y axis. The distance in the X direction between the inclined portions H2215 and H2217 and the ink supply port H2201 of the support plate H2200 is the largest at the end and gradually decreases toward the center. That is, as shown in FIG. 10B, the shortest distance L1XY between the electrothermal conversion element and the coolant flow path in the XY plane on the end side of the support plate along the Y direction is the center portion of the support substrate. It is configured to be larger than the shortest distance L2XY. Similar to the first embodiment, L1Z and L2Z are substantially the same value and constant. Therefore, in the relationship between L1XY and L2XY, if L1XY> L2XY, the shortest distance L1 on the end side of the support plate in the XYZ space between the electrothermal conversion element and the coolant flow path and the center portion of the support substrate For the shortest distance L2, the relationship L1> L2 is satisfied.

  The cooling liquid in the cooling liquid flow path H2213 is mainly effective in cooling the recording element substrates H2100a and H2100c. On the other hand, the cooling liquid in the cooling liquid flow path H2214 is mainly effective for cooling the recording element substrates H2100b and H2100d.

  With this configuration, the distance between the electrothermal conversion element of the recording element substrate H2100 and the coolant flow paths H2213 and H2214 is the largest on the end side along the Y direction of the support plate and gradually toward the center. And keeps constant in the center.

  In the present embodiment, the ends of the coolant flow paths H2213 and H2214 opposite to the inclined portions H2215 and H2217 do not contribute much to the cooling of the recording element substrate H2100 because the distance from the recording element substrate H2100 is large. Parallel to the Y axis.

  FIG. 11 shows a temperature distribution immediately after execution of recording by the ink jet recording head in the present embodiment. The horizontal axis represents the position in the head recording element array (electrothermal conversion element array) direction, and the vertical axis represents the temperature in the vicinity of the ejection port. By separating the end of the coolant flow path from the electrothermal transducer array of the recording element substrate, the cooling effect at both ends of the recording head is reduced and the temperature is higher than that at the center of the recording head. The temperature can be almost uniform over the entire length. Compared to the first embodiment, the cooling effect at the end can be gradually reduced, so that a finer temperature distribution can be controlled.

  The angle and length of the inclined portion differed by changing parameters such as the maximum heat generation amount of the recording element substrate, the distance between the coolant flow path and the electrothermal transducer array, the thermal conductivity of the support plate, and the coolant flow rate. Angle and length.

  Up to this point, an example of an inkjet recording head in which a plurality of recording element substrates H2100 are arranged in a staggered manner has been described. However, as shown in FIG. 12, the present invention can also be applied to an inkjet recording head using a long integrated recording element substrate H2110. . In this case, two coolant flow paths H3213 and H3214 are arranged along the electrothermal conversion element array in the Y direction. Therefore, cooling can be performed from both sides of the recording element substrate by the coolant flow path, and the cooling effect can be enhanced as compared with the configuration in which cooling is performed from one side of the recording element substrate. Further, by providing inclined portions as shown in FIG. 12 at both ends in the Y direction in both of the two coolant flow paths, a substantially uniform temperature distribution can be obtained.

  In the present embodiment, the two cooling fluid channels H3213 and H3214 have been described as an example, but the number of the cooling fluid channels is not limited thereto. Further, although the explanation has been given by taking the example of the cooling fluid flow path continuous over the entire length of the recording head, it may be divided into a plurality of parts in the length direction, for example.

(Third embodiment)
In the second embodiment, the end of the coolant flow path is arranged so as to be separated from the electrothermal transducer array of the recording element substrate in the X direction.

  In the present embodiment, as shown in FIG. 13, the second embodiment is configured except that the end portions of the two coolant flow paths H4213 and H4214 are arranged away from each other in the Z direction (direction away from the recording element substrate). It is the same. FIG.13 (b) is XIIIB-XIIIB sectional drawing in Fig.13 (a).

  As shown in FIG. 13B, in the present embodiment, the shortest distance L1Z between the electrothermal conversion element and the coolant flow path in the Z direction on the end side of the support plate along the Y direction is Y It is set as the structure larger than the shortest distance L2Z in the Z direction in the center part of the support substrate along a direction.

  Even when the coolant flow path is arranged so as to be separated in the Z direction as in the configuration of the present embodiment, the same effect as in the second embodiment can be obtained. Of course, it goes without saying that both the X direction component and the Z direction component may be separated in the increasing direction.

(Fourth embodiment)
In the second and third embodiments, the end of the cooling fluid channel is separated from the electrothermal conversion element array on the recording element substrate while keeping the cross-sectional area of the cooling fluid channel constant.

  In the present embodiment, as shown in FIG. 14, the two coolant flow paths H5213 and H5214 are linearly arranged, and the sectional area is gradually reduced at the end. With such a configuration, the distance between the coolant flow path and the electrothermal conversion element array on the recording element substrate can be configured such that L1XY is larger than L2XY. In this case, the cooling effect is reduced due to a decrease in the surface area per unit length of the cooling liquid flow path, in addition to the reduction in the cooling effect due to the distance between the cooling liquid flow path and the electrothermal conversion element array being separated. Therefore, the recording head can obtain a substantially uniform temperature distribution over the entire arrangement direction of the electrothermal conversion elements.

(Fifth embodiment)
FIGS. 15A and 15B are views schematically showing a partial cross section of the recording head in order to explain the fifth embodiment of the present invention. FIG. 15B is a cross-sectional view taken along XVB-XVB in FIG.

  In this embodiment, a cooling channel H5230 is also added to the central portion of the support plate in the X direction with respect to the second embodiment to further increase the cooling capacity. The coolant flow path H5230 includes a parallel portion H5231 parallel to the Y axis and inclined portions H5232 and H5233 inclined at a constant angle with respect to the Y axis, and cools the central side of the four recording element substrates H5100a to H5100d.

  In the support plate H5200, a cooling liquid path may not be provided in a region where the recording element substrate to be cooled is not disposed. That is, a cooling liquid path may be provided corresponding to only a portion where the four recording element substrates H5100a to H5100d are provided. Therefore, the parallel portions H5216 and H5218 parallel to the Y axis of the coolant flow paths H5213 and H5214 may be shortened to the end portions of the recording element substrates H5100b and H5100c as shown in FIG. Further, the shortened end portions of the parallel portions H5216 and H5218 may be inclined as shown by a broken line in FIG.

  In such a configuration, it is preferable that the direction in which the cooling liquid in the central cooling liquid flow path H5230 flows and the direction in which the cooling liquid in the outer cooling liquid flow paths H5213 and H5214 flow are opposite to each other. That is, it is preferable to reverse the direction in which the coolant flows in the coolant flow path disposed adjacent to the X direction. As in the case described in the first embodiment, the temperature of the coolant in the coolant channel is higher on the downstream side than on the upstream side, so that the temperature gradient in the coolant in the coolant channel is along the Y direction. Will occur. Therefore, when the flow direction is determined as described above, the temperature gradient is reversed in the Y direction, and thus there is an effect that the temperature gradient is hardly generated in the entire recording head.

(Sixth embodiment)
FIGS. 16A and 16B are views schematically showing a partial cross section of a recording head for explaining a sixth embodiment of the present invention. FIG. 16B is a cross-sectional view taken along the line X VI B-X VI B in FIG. In the present embodiment, the coolant flow path H6230 is arranged at the center of the support plate in the X direction. The coolant flow path H6230 includes a parallel portion H6231 parallel to the Y axis, and inclined portions H6232 and H6233 that are inclined at a constant angle with respect to the Y axis.

  The distance in the X direction perpendicular to the Y direction between the electrothermal transducer element arrays of the recording element substrates H6100a and H6100d and the coolant flow paths H6232 and H6233 in the XY plane parallel to the main surface of the support plate is the distance of the support plate in the Y direction. The closer to the edge, the bigger it becomes. Therefore, the cooling effect at both ends of the support plate along the Y direction is reduced, and the temperature can be made substantially uniform over the entire length of the recording head.

  In the present embodiment, the cooling effect of the recording head as a whole is slightly reduced as compared with the configuration examples described in the first to fifth embodiments, but the size of the support plate is reduced in the X direction. be able to. Therefore, the width of the recording head can be reduced in the X direction, and the recording head can be downsized.

1 is an external perspective view of an ink jet recording head according to an embodiment of the present invention. 1 is an exploded perspective view of an ink jet recording head according to an embodiment of the present invention. FIG. 4 is an exploded perspective view of a recording element unit. FIG. 3 is a diagram illustrating a recording element substrate according to the first embodiment. It is a figure explaining an inkjet recording device (full line system). It is a figure explaining an inkjet recording device (serial drive system). FIG. 2 is a diagram schematically showing a partial cross section of the ink jet recording head of the first embodiment. It is a figure explaining the temperature distribution immediately after recording execution of an inkjet recording head. It is the figure which showed typically the partial cross section corresponding to FIG.7 (b) of the inkjet recording head using a long integrated recording element board | substrate. It is the figure which showed typically the partial cross section of the inkjet recording head of 2nd Embodiment. It is a figure explaining the temperature distribution immediately after recording execution of the inkjet recording head of 2nd Embodiment. It is the figure which showed typically the partial cross section corresponding to FIG.10 (b) of the inkjet recording head using a long integrated recording element board | substrate. It is the figure which showed typically the partial cross section of the inkjet recording head of 3rd Embodiment. It is the figure which showed typically the partial cross section of the inkjet recording head of 4th Embodiment. It is the figure which showed typically the partial cross section of the inkjet recording head of 5th Embodiment. It is the figure which showed typically the partial cross section of the inkjet recording head of 6th Embodiment. FIG. 3 is a schematic diagram illustrating an ink and cooling liquid supply system of an ink jet recording apparatus. It is a figure explaining the temperature distribution immediately after recording execution of the conventional inkjet recording head.

Explanation of symbols

H1000 recording head H1001 recording element unit H1002 ink supply unit H1100 recording element substrate H1102 electrothermal conversion element H1200 support plate H1213, H1214 cooling channel H2216, H2218 cooling channel H3213, H3214 cooling channel H4213, H4214 cooling channel H5213, H5214 Cooling channel

Claims (9)

An inkjet recording head comprising: a recording element substrate comprising a recording element array comprising a plurality of recording elements that generate thermal energy for ejecting ink; and a support plate for supporting the recording element substrate,
The support plate includes a liquid flow path for cooling the recording element substrate along the arrangement direction of the recording elements.
The shortest distance between the recording element arranged on the end side of the support plate in the arrangement direction and the flow path is the recording element arranged in the center part of the support plate in the arrangement direction and the flow. An ink jet recording head characterized by being larger than the shortest distance from a road. The inkjet recording head has a plurality of the recording element substrates,
The inkjet recording head according to claim 1, wherein the plurality of recording element substrates are arranged so that the recording element rows are continuous along the arrangement direction.   The inkjet recording head according to claim 2, wherein the plurality of recording element substrates are arranged in a staggered manner.   4. The ink jet recording head according to claim 1, wherein a shortest distance between the recording element and the flow path decreases from an end portion of the support plate in the arrangement direction toward a central portion. 5. .   5. The ink jet recording head according to claim 1, wherein the flow path is disposed so that a distance from the recording element is different along a plane parallel to a main surface of the support plate.   5. The ink jet recording head according to claim 1, wherein the flow path is disposed along the thickness direction of the support plate so as to have a different distance from the recording element. The support plate includes a supply port for supplying ink to the recording element substrate, and at least two of the flow paths.
The inkjet recording head according to claim 1, wherein the supply port is disposed between the at least two flow paths in a direction parallel to the main surface of the support plate and perpendicular to the arrangement direction. The support plate includes at least two supply ports for supplying ink to the recording element substrate,
The ink jet recording head according to claim 1, wherein the flow path is arranged between the at least two supply ports in a direction parallel to the main surface of the support plate and perpendicular to the arrangement direction.   9. An ink jet recording apparatus comprising: the ink jet recording head according to claim 1; and means for flowing the liquid through the flow path.

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