Patent Publication Number: US-8534798-B2

Title: Ink jet recording head

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an ink jet recording head mounted on an ink jet recording apparatus that performs recording operation by discharging ink. 
     2. Description of the Related Art 
     Generally, an ink jet recording head mounted on an ink jet recording apparatus, which performs recording operation by discharging ink, includes a recording element substrate having a discharge port array of a plurality of discharge ports. The recording can be performed at higher speed when the length of the discharge port array is longer. 
     In such circumstances, in recent years, there has been a growing demand for ink jet recording heads, for example, with a recording width of 4 to 12 inches, which meet the demand for high-speed printing of fine images. However, if a recording element substrate with a long discharge port array is used, the possibility of the problems described below is increased. 
     Generally, in addition to the discharge port array, a recording element substrate includes recording elements (e.g., electrothermal conversion elements) of a great number that corresponds to the number of the discharge ports. Thus, when the recording elements are arranged on a single recording element substrate, the recording element substrate will be very long. As a result, the possibility of a crack or warpage of the recording element substrate is increased. 
     Japanese Patent Application Laid-Open No. 2007-296638 discusses an inkjet recording head that can solve such a problem. The inkjet recording head includes a plurality of recording element substrates arranged in an array. According to this configuration, an ink jet recording head of a long recording width is realized without using a single long recording element substrate. 
       FIG. 18  is a front view of an ink jet recording head with a plurality of recording element substrates according to an exemplary embodiment of the present invention. An ink jet recording head H 2000  illustrated in  FIG. 18  includes a plurality of recording element substrates H 2010 , an electric wiring member H 2020 , and a supporting member H 2030 . 
     The recording element substrate H 2010  and the electric wiring member H 2020  of the ink jet recording head H 2000  are secured to the supporting member H 2030 . Further, as illustrated in  FIG. 19 , the recording element substrate H 2010  is connected to the electric wiring member H 2020  by a gold or aluminum wire H 1303 .  FIG. 19  is an enlarged cross-sectional view of an electrical connection portion of the recording element substrate H 2010  and the electric wiring member H 2020 . 
     The material of the recording element substrate H 2010  is silicon, and its coefficient of linear expansion is approximately 3 ppm. The material of the electric wiring member H 2020  is resin, and its coefficient of linear expansion is approximately 10 to 30 ppm. The material of the supporting member H 2030  is alumina, and its coefficient of linear expansion is approximately 7 ppm. 
     When a change in temperature occurs due to a recording operation or change in environment, the recording element substrate H 2010 , the electric wiring member H 2020 , and the supporting member H 2030  of the ink jet recording head H 2000  expand/contract in the lengthwise direction of the supporting member H 2030  (direction of the arrow A 100  in  FIG. 20 ). 
     At this time, since the coefficient of linear expansion of the electric wiring member H 2020  is greater than the coefficient of linear expansion of the recording element substrate H 2010 , a difference in the amount of expansion/contraction of the components is generated. As a result, the wire H 1303  is pulled and the possibility of a breakage of the wire H 1303  is increased. If the wire H 1303  is broken, the recording element substrate H 2010  will not be able to receive electric signals and power and, consequently, ink is not properly discharged. Thus, the breaking of the wire H 1303  results in poor image quality. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a method useful for improving reliability of an electric connection of an ink jet recording head having a plurality of recording element substrates arranged in an array. 
     According to an aspect of the present invention, an ink jet recording head includes a supporting member, a plurality of recording element substrates secured to the supporting member while being arranged along a lengthwise direction of the supporting member and including a discharge port configured to discharge a droplet and an electrode formed at an end in the lengthwise direction and receives an electric signal that controls the discharge of the droplet from the discharge port, an electric wiring member secured to the supporting member and including a plurality of device holes configured to individually expose the plurality of recording element substrates and an electrode terminal formed in the periphery of the plurality of device holes in the lengthwise direction to transmit the electric signal to the electrode, and a wire configured to connect the electrode and the electrode terminal. The electric wiring member is at least discontinued between the device holes adjacent to each other in the lengthwise direction. 
     According to the present invention, when a temperature change occurs, since the electric wiring member is discontinued between the device holes adjacent in the lengthwise direction of the supporting member, the amount of expansion/contraction of the electric wiring member between the device holes can be reduced compared to when a conventional electric wiring member is used. Thus, the difference between the amount of expansion/contraction of the electric wiring member and the amount of expansion/contraction of the recording element substrate between the device holes is reduced. Further, since the wire that connects the electrode of the recording element substrate and the electrode terminal of the electric wiring substrate is less prone to breaking, reliability of the electrical connection between the recording element substrate and the electric wiring substrate is increased. 
     Further features and aspects of the present invention will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the invention and, together with the description, serve to explain the principles of the invention. 
         FIG. 1  is a perspective view of an ink jet recording apparatus mounting an ink jet recording head according to an exemplary embodiment of the present invention. 
         FIG. 2  is a perspective view of the inkjet recording head according to an exemplary embodiment of the present invention. 
         FIGS. 3A and 3B  are perspective views illustrating a configuration of the ink jet recording head according to the present invention. 
         FIG. 4  is an exploded perspective view of an ink supply unit. 
         FIG. 5  is an exploded perspective view of a recording element unit. 
         FIGS. 6A and 6B  illustrate a configuration of a recording element substrate in the ink jet recording head according to an exemplary embodiment of the present invention. 
         FIG. 7  is a front view of the ink jet recording head according to an exemplary embodiment of the present invention. 
         FIG. 8  is a front view of the ink jet recording head according to another exemplary embodiment of the present invention. 
         FIG. 9  is a front view of the ink jet recording head according to another exemplary embodiment of the present invention. 
         FIG. 10  is a front view of the ink jet recording head according to another exemplary embodiment of the present invention. 
         FIG. 11  is a front view of the ink jet recording head according to another exemplary embodiment of the present invention. 
         FIG. 12  is a front view of the ink jet recording head according to another exemplary embodiment of the present invention. 
         FIG. 13  is a front view of the ink jet recording head according to another exemplary embodiment of the present invention. 
         FIG. 14  is a front view of the ink jet recording head according to another exemplary embodiment of the present invention. 
         FIG. 15  is a front view of the ink jet recording head according to another exemplary embodiment of the present invention. 
         FIG. 16  is a front view of the ink jet recording head according to another exemplary embodiment of the present invention. 
         FIG. 17  is a front view of the ink jet recording head according to another exemplary embodiment of the present invention. 
         FIG. 18  is a front view of the ink jet recording head with a plurality of recording element substrates according to an exemplary embodiment. 
         FIG. 19  is a cross section of the ink jet recording head illustrated in  FIG. 18 . 
         FIG. 20  is a cross section of the ink jet recording head illustrated in  FIG. 18  when a change in temperature occurs. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Various exemplary embodiments, features, and aspects of the invention will be described in detail below with reference to the drawings. 
     In this specification, “recording” is to form an image, a design, a pattern, or the like, in addition to a character or a figure, on a recording medium or to process a medium regardless of whether the formed image, the design, the pattern, or the like is visualized so as to allow a user to visually perceive it. 
     Further, in this specification, various types of “recording media” can be used for recording so long as they can be printed with ink. The recording media include, for example, a cloth, a plastic film, a metal sheet, glass, ceramics, wood, and leather. 
     The terms “ink” or “liquid” should be widely construed as is with the “recording” described above, and includes all types of liquid used for recording. The “ink” is a liquid that is applied to a printing medium to form an image, a design, a pattern, or the like, or to process the printing medium. Further, the “ink” is a liquid used for ink processing (e.g., solidification or insolubilization of a color material in ink applied to the recording medium). 
       FIG. 1  is a perspective view of an ink jet recording apparatus mounting an ink jet recording head according to an exemplary embodiment of the present invention. The ink jet recording head according to the present invention is mountable, in addition to a common ink jet recording apparatus, on a recording apparatus such as a copying machine, a fax machine including a communication system, or a word processor including a print unit. Further, the ink jet recording head according to the present invention can be used in an industrial recording apparatus combined with various processing apparatuses. 
     An ink jet recording apparatus M 4000  illustrated in  FIG. 1  includes ink jet recording heads for six colors. 
     An ink jet recording head H 1000 Bk discharges black ink contained in an ink tank H 1800 Bk. An ink jet recording head H 1000 C discharges cyan ink contained in an ink tank H 1800 C. An ink jet recording head H 1000 M discharges magenta ink contained in an ink tank H 1800 M. An ink jet recording head H 1000 Y discharges yellow ink contained in an ink tank H 1800 Y. An ink jet recording head H 1000 LC discharges light cyan ink contained in an ink tank  1800 LC. An ink jet recording head H 1000 LM discharges light magenta ink contained in an ink tank H 1800 LM. The ink jet recording heads H 1000 Bk to H 1000 LM (simply referred to as an ink jet recording head H 1000  below) are carried by a carriage M 4100  and discharge an ink droplet according to an input electric signal. 
     The ink jet recording head H 1000  includes discharge port arrays corresponding to a width of a recording medium K 1000 . Regarding the recording performed by the ink jet recording apparatus M 4000 , the recording medium K 1000  is moved in the longitudinal direction (the direction of the arrow in  FIG. 1 ) while the ink jet recording head H 1000  is fixed. However, the ink jet recording head according to the present invention may also be used for a serial drive type ink jet recording apparatus. The recording head of the serial drive ink jet recording apparatus reciprocately moves in the widthwise direction of the recording medium together with the carriage while it performs recording. 
       FIG. 2  is a perspective view of the ink jet recording head according to an exemplary embodiment of the present invention. The ink jet recording head H 1000  illustrated in  FIG. 2  is any one of the above-described ink jet recording heads H 1000 Bk, H 1000 C, H 1000 M, H 1000 Y, H 1000 LC, and H 1000 LM. Details of the ink jet recording head according to the present exemplary embodiment will now be described referring to the figures. 
       FIGS. 3A and 3B  are perspective views of a configuration of the ink jet recording head according to the present invention.  FIG. 3A  is an external appearance perspective view, and  FIG. 3B  is an exploded perspective view. 
     The ink jet recording head H 1000  illustrated in  FIG. 3  has a smaller number of recording element substrates H 1100  compared to the ink jet recording head H 1000  illustrated in  FIG. 2  to simplify the illustration. Thus, the ink jet recording head H 1000  illustrated in  FIG. 3  has a similar configuration to the ink jet recording head H 1000  illustrated in  FIG. 2  except that the number of the recording element substrates H 1100  is different. 
     The discharge direction of an ink droplet of the ink jet recording head H 1000  according to the present invention is perpendicular with respect to the recording element. This type of recording head is called a side-shooter type recording head. As illustrated in  FIG. 3B , the ink jet recording head H 1000  includes a recording element unit H 1001  and an ink supply member H 1500  of an ink supply unit H 1002 . 
     First, the configuration of the ink supply unit H 1002  will be described.  FIG. 4  is an exploded perspective view of the ink supply unit H 1002 . As illustrated in  FIG. 4 , the ink supply unit H 1002  includes the ink supply member H 1500 , a joint rubber H 1700 , an ink supply tube H 1802 , and an ink tank H 1800 . 
     The ink supply member H 1500  is formed, for example, by resin molding. The ink supply member H 1500  includes a common liquid chamber H 1501 , which serves as a flow path, and also a Z direction reference plane H 1502 . The Z direction reference plane H 1502  is used for positioning the recording element unit H 1001  when it is fixed to the ink supply unit H 1002 . Further, the Z direction reference plane H 1502  serves as a reference plane of the ink jet recording head H 1000  in the height direction. 
     Further, the ink supply unit H 1002  includes an ink supply port H 1504  through which the ink supplied from the ink tank H 1800  flows in. The joint rubber H 1700  is provided at the ink supply port H 1504 . The joint rubber H 1700  prevents evaporation of the ink from the ink supply port H 1504 . 
     The ink supply tube H 1802 , which extends from the ink tank H 1800 , is connected to the ink supply member H 1500  by a needle H 1801 , which is provided at the end of the ink supply tube H 1802 , piercing the joint rubber H 1700 . The ink contained in the ink tank H 1800  of the ink supply unit H 1002  flows into the common liquid chamber H 1501  via the ink supply tube H 1802 . The ink in the common liquid chamber H 1501  flows out to the recording element unit H 1001 . 
     Next, securing processing of the recording element unit H 1001  to the ink supply member H 1500  will be described referring to  FIG. 3B . The ink jet recording head H 1000  is completed by securing the recording element unit H 1001  to the ink supply member H 1500 . The securing processing is as described below. 
     First, an opening portion of the ink supply member H 1500  and the recording element unit H 1001  are sealed by a sealing compound H 1503 . Accordingly, the common liquid chamber H 1501  is hermetically sealed. At this time, a Z direction reference plane H 1206  of the recording element unit H 1001  abuts the Z direction reference plane H 1502  of the ink supply member H 1500 . 
     A portion where the Z direction reference plane H 1206  abuts the Z direction reference plane H 1502  is clamped by a screw H 1900 . In this manner, the recording element unit H 1001  is secured to the ink supply member H 1500 . The sealing compound H 1503  is desirably a sealing compound, which is ink resistant and flexible. 
     After the recording element unit H 1001  is secured to the ink supply member H 1500 , the recording element unit H 1001  is bent along the side of the ink supply member H 1500  so that an input terminal H 1301  is secured to the back side of the ink supply member H 1500  (see  FIG. 3A ). 
     Next, the configuration of the recording element unit H 1001  will be described.  FIG. 5  is an exploded perspective view of the recording element unit H 1001 . As illustrated in  FIG. 5 , the recording element unit H 1001  includes the recording element substrate H 1100 , a supporting member H 1200 , an electric wiring member H 1300 , and a filter member H 1600 . 
       FIGS. 6A and 6B  illustrate a configuration of the recording element substrate H 1100 .  FIG. 6A  is a perspective view of the recording element substrate H 1100 .  FIG. 6B  is a cross-sectional view of the recording element substrate H 1100  along the line A-A in  FIG. 6A . The recording element substrate H 1100  is, for example, a silicon substrate H 1108  having a thickness of 0.2 to 1 mm. 
     The silicon substrate H 1108  includes an ink supply port H 1101 , which is a long channel-like port serving as an ink flow path. An electrothermal conversion element H 1102 , which is a recording element, is provided on either side of the ink supply port H 1101 . Further, the silicon substrate H 1108  includes the electrothermal conversion element H 1102  and electric wiring of, for example, aluminum formed by a film forming technique. The electric wiring is formed at the end of the recording element substrate H 1100  and is connected to an electrode H 1103 . Via the electrode H 1103 , the electric wiring receives an electric signal and power from the electric wiring member H 1300 . 
     Further, a discharge port plate H 1110  is provided at the upper portion of the silicon substrate H 1108 . An ink flow path H 1104 , a discharge port H 1105 , and a bubble generation chamber H 1107  are formed on the discharge port plate H 1110  using photolithography technique. The discharge port H 1105  is formed at such a position that it faces the electrothermal conversion element H 1102 . 
     Regarding the recording element substrate H 1100 , the electrothermal conversion element H 1102  generates a bubble in the ink that is supplied from the ink supply port H 1101  to the bubble generation chamber H 1107  according to an electric signal received by the electrode H 1103 . Due to this bubble, the ink is discharged from the discharge port H 1105 . 
     The supporting member H 1200  illustrated in  FIG. 5  is made from, for example, alumina (Al2O3) having a thickness of 0.5 to 10 mm. However, the material of the supporting member H 1200  is not limited to alumina, and may be a material having a coefficient of linear expansion similar to that of the recording element substrate H 1100  and having a thermal conductivity similar to or higher than the recording element substrate H 1100 . 
     The material that can be used for the supporting member H 1200  is silicon (Si), aluminum nitride (AlN), zirconia, silicon nitride (Si3N4), silicon carbide (SiC), molybdenum (Mo), and tungsten (W). The supporting member H 1200  has an ink supply port H 1201  used for supplying ink to the recording element substrate H 1100 . 
     The recording element substrate H 1100  is accurately positioned and secured to the supporting member H 1200  by an adhesive H 1202  so that the ink supply port H 1201  faces the ink supply port H 1101  of the recording element substrate H 1100 . The adhesive H 1202  is desirably a low-viscosity ink-resistant adhesive that allows thin adhesive layer on the contact face and exhibiting relatively high hardness after cure. In other words, the adhesive H 1202  is a thermal curing adhesive having epoxy resin as the main material or a thermal curing adhesive, which can also be cured by ultraviolet. The thickness of the adhesive layer is desirably 50 μm or thinner. 
     Further, the supporting member H 1200  includes an X direction reference plane H 1204 , a Y direction reference plane H 1205 , and the Z direction reference plane H 1206 . These are positional reference planes respectively in the lengthwise direction, crosswise direction, and height direction when the supporting member H 1200  is mounted on the ink supply member H 1500 . Further, since both sides of the supporting member H 1200  are polished, the principal surface (see  FIG. 5 ), to which the adhesive  1202  is applied, is accurately parallel to the other side (back side) of the principal surface. 
     For example, according to the present exemplary embodiment, the parallelism of the two sides is 10 μm or less. At the back side of the supporting member H 1200 , there is provided the filter member H 1600  used for filtering undesired matter in the ink. The filter member H 1600  is secured in such a manner that it covers the ink supply port H 1201 . 
     As illustrated in  FIGS. 2 and 3A , a plurality of the recording element substrates H 1100  are fixed to the principal surface of the supporting member H 1200  in an array in a lengthwise direction D 1  of the supporting member H 1200 . According to this arrangement, a wide area can be recorded with a same color. For example, according to the ink jet recording head H 1000  illustrated in  FIG. 3A , a 4-inch width recording is possible by arranging four recording element substrates H 1100   a , H 1100   b , H 1100   c , and H 1100   d  whose length of the discharge port array is longer than one inch. 
     Further, as illustrated in  FIGS. 2 and 3A , the recording element substrates H 1100   a  and H 1000   c  are arranged along a first straight line H 1309   a  on the ink jet recording head H 1000 . The first straight line H 1309   a  extends in the lengthwise direction D 1 . Additionally, the recording element substrates H 1100   b  and H 1000   d  are arranged along a second straight line H 1309   b . The second straight line H 1309   b  also extends in the lengthwise direction D 1  but is away from the first straight line H 1309   a . The four recording element substrates are provided in an alternating arrangement along the lengthwise direction D 1 . 
     Further, the recording element substrates adjacent to each other in a widthwise direction D 2  of the supporting member H 1200  have a region L where the ends of the discharge port arrays of the substrates overlap each other (see  FIGS. 2 and 3A ). According to this region L, a printing gap, which may be generated between the recording element substrates of the ink jet recording head H 1000 , is prevented. For example, a discharge port array H 1106   a  and a discharge port array H 1106   b  have overlapping regions H 1109   a  and H 1109   b  respectively (see  FIGS. 2 and 3A ). 
     The electric wiring member H 1300  is a resin component that supplies an electric signal for controlling discharge of ink to the recording element substrate H 1100 . The electric wiring member H 1300  is secured to the principal surface of the supporting member H 1200  by an adhesive H 1203  (see  FIG. 5 ). In other words, the electric wiring member H 1300  is a flexible film component having a circuit (not shown) made of a thin resin film, such as a polyimide film, clad with copper foil and covered with a cover lay. 
     The electric wiring member H 1300  includes a plurality of device holes H 1306 . Each of the device holes H 1306  individually exposes each of the recording element substrates H 1100 . Further, an electrode terminal H 1302  used for transmitting an electric signal to the electrode H 1103  is provided in the periphery of a device hole H 1306  on the sides in the lengthwise direction D 1 . Further, the input terminal H 1301 , which is provided at one portion of the electric wiring member H 1300 , is connected to the electrode terminal H 1302  via the above-described circuit. 
     The electrode terminal H 1302  is electrically connected to the electrode H 1103  with a gold or an aluminum wire H 1303  as is the electrode terminal of the ink jet recording head H 2000  in  FIG. 20 . Since the electrical connection portion is encapsulated by an encapsulant H 1305 , it is protected from erosion due to ink or from an external impact (see  FIG. 20 ). A gap portion, which is formed by the device hole H 1306  and the sides of the recording element substrate H 1100 , is encapsulated by an encapsulant H 1304  (see  FIG. 2 ). 
       FIG. 7  is a front view of the ink jet recording head according to the present exemplary embodiment. In  FIG. 7 , the electrode terminal H 1302 , the recording element substrate H 1100 , and the device hole H 1306  are illustrated without the wire H 1303  and the encapsulant H 1305  described above so that the positional relations between the components can be seen clearly. 
     As illustrated in  FIG. 7 , the electric wiring member H 1300  includes a terminal region H 1400  where a plurality of electrode terminals H 1302  are formed along the periphery of the device hole H 1306  on the sides in the longitudinal direction D 1 . Further, the electric wiring member H 1300  has an opening H 1307  between the device holes H 1306  adjacent to each other. An opening width w 1 , which is the width of the opening H 1307  in the widthwise direction D 2 , is longer than a region width w 2 , which is the length between the electrode terminals that are provided at both ends of the terminal region H 1400 . 
     An amount of expansion/contraction ΔL of a member due to temperature change is calculated by multiplying an amount of temperature change ΔT, a coefficient of linear expansion a of the member, and a length L of the member as shown in the following equation (1).
 
Δ L=ΔT×α×L   (1)
 
     Among the factors that define the amount of expansion ΔL, the amount of temperature change is difficult to control, and the coefficient of linear expansion is uniquely determined by the selected member. Thus, according to the present invention, in preventing the breaking of the wire H 1303  that occurs due to the difference of the amount of expansion/contraction between the electric wiring member H 1300  and the recording element substrate H 1100  caused by temperature changes, the opening H 1307  is formed so that the length of the electric wiring member H 1300  is changed. 
     In other words, by forming the opening H 1307 , whose opening width w 1  is longer than or equal to the region width W 2 , between the device holes H 1306 , which are adjacent to each other in the lengthwise direction of the recording element substrate, the amount of expansion/contraction of the electric wiring member H 1300  can be reduced. As a result, since the difference in the amount of expansion/contraction between the recording element substrate H 1100  and the electric wiring member H 1300  due to temperature change is reduced, the stress of the wire H 1303  is reduced. Accordingly, the wire H 1303  will be less prone to breaking, and reliability of the electrical connection between the recording element substrate H 1100  and the electric wiring member H 1300  will be increased. 
     As the opening width W 1  becomes wider than the region width w 2 , the region that helps reduce the amount of expansion/contraction of the electric wiring member H 1300  becomes longer. Accordingly, the effect to prevent the wire H 1303  from breaking will be increased. If the opening width W 1  is set to be wider than the region width w 2 , the wiring region enough for the circuit will be provided on the electric wiring member H 1300  by not allowing one end of the opening H 1307  to extend to the edge of the electric wiring member H 1300 . 
     According to the present exemplary embodiment, the opening H 1307  is provided at a same distance from the device holes H 1306  adjacent to each other in the lengthwise direction D 1 . The position is determined so that a similar effect is obtained in reducing the difference of the amount of expansion/contraction between the recording element substrate H 1100  and the electric wiring member H 1300  between the device holes H 1306  adjacent to each other. 
     Further, according to the present exemplary embodiment, the position of the opening H 1307  is not limited to the region between the device holes H 1306  adjacent to each other. For example, as illustrated in  FIG. 8 , if the region between the end of the electric wiring member H 1300  in the lengthwise direction D 1  and the terminal region H 1400  (see the region surrounded by a circle in  FIG. 8 ) is long, the opening H 1307  can be provided in that region. According to this opening H 1307 , the stress of the wire H 1303  near the end of the electric wiring member is reduced and, accordingly, the wire H 1303  will be less prone to breaking. 
     Further, according to the present exemplary embodiment, the length of the straight line region of the electric wiring member H 1300  can be reduced without using the above-described opening H 1307 . For example, as illustrated in  FIG. 9 , in place of the opening H 1307 , a cut portion H 1308  may be provided. In this case also, since the electric wiring member H 1300  is discontinued in the lengthwise direction D 1  between the device holes H 1306  adjacent to each other, an effect similar to the case where the opening H 1307  is used can be obtained. 
     Further, as illustrated in  FIG. 10 , a recording element substrate, which is longer than the recording element substrate H 1100  illustrated in  FIG. 7  in the lengthwise direction D 1 , may be used. In this case, the opening H 1307  is formed at a position adjacent to the terminal region H 1400 . According to the equation (1) above, if the recording element substrate H 1100  is longer, the amount of expansion/contraction of the recording element substrate H 1100  is increased. Thus, the difference of the amount of expansion/contraction between the recording element substrate H 1100  and the electric wiring member H 1300  due to temperature change is reduced. 
     Further, by arranging the opening H 1307  at a position adjacent to the terminal region H 1400 , the amount of expansion/contraction in the terminal region H 1400  is furthermore reduced. Thus, the difference in the amount of expansion/contraction between the recording element substrate H 1100  and the electric wiring member H 1300  due to temperature change is furthermore reduced, and the effect to prevent the breaking of the wire H 1303  is improved. 
     Further, as illustrated in  FIG. 11 , a recording element substrate shorter than the recording element substrate H 1100  illustrated in  FIG. 7  in the lengthwise direction D 1  may be used. In this case, since the distance between the device holes H 1306  is shorter than the distance illustrated in FIG.  7 , the amount of expansion/contraction of the electric wiring member H 1300  is reduced. Accordingly, the difference of the amount of expansion/contraction of the recording element substrate H 1100  and the electric wiring member H 1300  due to temperature change is reduced, and the wire H 1303  will be less prone to breaking. 
       FIG. 12  is a front view of an ink jet recording head according to a second exemplary embodiment of the present invention. Components illustrated in  FIG. 12 , which are similar to those described above according to the first exemplary embodiment, are given the same reference numerals and detailed descriptions will be omitted. Further, in  FIG. 12 , as is in  FIG. 7 , the electrode terminal H 1302 , the recording element substrate H 1100 , and the device hole H 1306  are illustrated without the wire H 1303  and the encapsulant H 1305  described above so that the positional relations between the components can be seen clearly. 
     As illustrated in  FIG. 12 , an interval W 3 , which is an interval of the device holes H 1306  in the widthwise direction D 2  of the electric wiring member H 1300  of the present exemplary embodiment, is longer than that of the electric wiring member H 1300  of the first exemplary embodiment. In other words, according to the present exemplary embodiment, the area between the device holes provided on the first straight line H 1309   a  and the device holes provided on the second straight line H 1309   b  of the electric wiring member H 1300  is greater than that of the electric wiring member H 1300  of the first exemplary embodiment. 
     In this case, an electrode terminal H 1310 , which is formed at the end of the terminal region H 1400 , is positioned near the area between the first straight line H 1309   a  and the second straight line H 1309   b . Thus, the electrode terminal H 1310  is affected by the expansion/contraction generated in that region between the straight lines. Since the amount of expansion/contraction of the region is greater than that of the region where the opening H 1307  is formed (the region between device holes H 1306  adjacent to each other), the difference of the amount of expansion/contraction of the recording element substrate H 1100  and the electric wiring member H 1300  at the electrode terminal H 1310  will be greater than that at other electrode terminals. Thus, the wire H 1303  connected to the electrode terminal H 1310  is easily broken compared to the wires connected to other electrode terminals. 
     However, according to the present exemplary embodiment, since one end of the opening H 1307  extends to the area between the first straight line H 1309   a  and the second straight line H 1309   b , the length of the straight region becomes shorter. Accordingly, the difference of the amount of expansion/contraction of the recording element substrate H 1100  and the electric wiring member H 1300  at the electrode terminal H 1310  is reduced. Thus, the wire H 1303  connected to the electrode terminal H 1310  is less prone to breaking. 
     Further, according to the present exemplary embodiment, one end of the opening H 1307  may be connected to the device hole H 1306  to which the opening H 1307  extends as illustrated in  FIG. 13 . In this case, since the region between the device holes positioned on the first straight line H 1309   a  and the device holes positioned on the second straight line H 1309   b  is discontinued, the amount of expansion/contraction of the electric wiring member H 1300  due to temperature change is reduced. 
     Accordingly, the wire H 1303  connected to the electrode terminal H 1310  is less prone to breaking. Further, since the opening H 1307  is connected to the device hole H 1306 , the encapsulant for encapsulating the gap portion formed between the device hole H 1306  and one side of the recording element substrate H 1100  can be injected through the opening H 1307 . 
     Further, according to the present exemplary embodiment, the length of the straight line region of the electric wiring member H 1300  can be reduced without forming the above-described opening H 1307  as is with the first exemplary embodiment. For example, a cut portion H 1308  may be formed in place of the opening H 1307  as illustrated in  FIGS. 14 and 15 . 
     In this case also, since one end of the cut portion H 1308  extends to the straight line region between the device holes provided on the first straight line H 1309   a  and the device holes provided on the second straight line H 1309   b , the straight line region can be reduced. Thus, an effect similar to the case where the opening H 1307  is formed can be obtained. 
     Further, as is with the first exemplary embodiment, a recording element substrate, which is shorter or longer in the lengthwise direction D 1  than the recording element substrate H 1100  illustrated in  FIG. 12  (see  FIGS. 11 and 12 ) may also be used as is with the first exemplary embodiment. 
     Further, according to the present exemplary embodiment, the opening H 1307  or the cut portion H 1308  may be formed in the region between the end of the electric wiring member H 1300  in the lengthwise direction D 1  and the terminal region H 1400  (see  FIG. 8 ) as is with the first exemplary embodiment. 
     Further, according to the present exemplary embodiment, not only one end of the opening H 1307  can be extended to the region between the first straight line H 1309   a  and the second straight line H 1309   b  but the other end can also be extended. 
     In other words, as illustrated in  FIGS. 16 and 17 , one end of the opening H 1307  can extend and cross over a fold line H 1311 , which is formed when the electric wiring member H 1300  is bent along the sides of the supporting member H 1200  in the lengthwise direction D 1 . According to these opening, the straight line region that extends in the lengthwise direction D 1  in the region near the electrical connection portion of the recording element substrate H 1100  and the electric wiring member H 1300  is reduced, the amount of expansion/contraction of the electric wiring member H 1300  due to temperature change can be furthermore reduced. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all modifications, equivalent structures, and functions. 
     This application claims priority from Japanese Patent Application No. 2009-138184 filed Jun. 9, 2009, which is hereby incorporated by reference herein in its entirety.