Patent Publication Number: US-11642891-B2

Title: Liquid ejection head, liquid ejection apparatus, and method of supplying liquid

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a liquid ejection head, a liquid ejection apparatus, and a method of supplying liquid, and specifically relates to a liquid ejection head that performs an ejection operation while allowing liquid to flow through a passage between a liquid ejection opening and an element generating ejection energy. 
     Description of the Related Art 
     Japanese Patent Laid-Open No. 2002-355973 describes this type of liquid ejection head that performs ink ejection operation while circulating ink in a passage between an ejection opening and a heating resistor that generates ejection energy, of the liquid ejection head, by causing ink circulation in the liquid ejection head. According to this configuration, it is possible to eject ink which is thickened when moisture, etc. of ink evaporates due to heat generated as a result of the ejection operation, and to supply new ink. As a result, it is possible to prevent clogging of the ejection opening due to the thickened ink. 
     However, in a configuration in which liquid is allowed to flow through a passage between an ejection opening and an energy generation element as described in Japanese Patent Laid-Open No. 2002-355973, quality of liquid existing adjacent to the ejection opening may vary depending on shapes of the passage or the ejection opening, even though liquid flows. For example, in a liquid ejection head that ejects ink, ink may be thickened or a color material concentration may be changed, which may result in ink ejection defect or an uneven density of a printed image. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a liquid ejection head, a liquid ejection apparatus, and a method of supplying liquid capable of suppressing a change in quality of liquid adjacent to an ejection opening in a configuration in which liquid is allowed to flow through a passage between the ejection opening and an energy generation element. 
     In a first aspect of the present invention, there is provided a liquid ejection head comprising: an ejection opening for ejecting a liquid; a passage in which an energy generation element for generating energy used to eject the liquid is disposed; an ejection opening portion that allows communication between the ejection opening and the passage; a supply passage for allowing the liquid to flow into the passage from an outside; and an outflow passage for allowing the liquid to flow out to the outside from the passage, wherein an expression of H −0.34 ×P −0.66 ×W&gt;1.7 is satisfied when a height of the passage at an upstream side of a communication portion between the passage and the ejection opening portion in a flow direction of the liquid inside the passage is set to H, a length of the ejection opening portion in a direction in which the liquid is ejected from the ejection opening is set to P, and a length of the ejection opening portion in the flow direction of the liquid inside the passage is set to W. 
     In a second aspect of the present invention, there is provided a method of supplying a liquid in a liquid ejection head including an ejection opening for ejecting a liquid, a passage in which an energy generation element for generating energy used to eject the liquid is disposed, an ejection opening portion that allows communication between the ejection opening and the passage, a supply passage for allowing the liquid to flow into the passage from an outside, and an outflow passage for allowing the liquid to flow out to the outside from the passage, wherein when supplying the liquid is performed such that the liquid flows into the passage from the outside through the supply passage, and flows out to the outside through the outflow passage from the passage, a flow of the liquid is generated such that the liquid entering an inside of the ejection opening portion from the passage arrives at a position of a meniscus of the liquid formed in the ejection opening, and then returns to the passage. 
     In a third aspect of the present invention, there is provided a liquid ejection apparatus comprising: a liquid ejection head including an ejection opening for ejecting a liquid, a passage in which an energy generation element for generating energy used to eject the liquid is disposed, an ejection opening portion that allows communication between the ejection opening and the passage, a supply passage for allowing the liquid to flow into the passage from an outside, and an outflow passage for allowing the liquid to flow out to the outside from the passage; and supply means for allowing the liquid to flow into the passage from the outside through the supply passage, and flow out to the outside through the outflow passage from the passage, wherein an expression of H −0.34 ×P −0.66 ×W&gt;1.7 is satisfied when a height of the passage at an upstream side of a communication portion between the passage and the ejection opening portion in a flow direction of the liquid inside the passage is set to H, a length of the ejection opening portion in a direction in which the liquid is ejected from the ejection opening is set to P, and a length of the ejection opening portion in the flow direction of the liquid inside the passage is set to W. 
     In a fourth aspect of the present invention, there is provided a liquid ejection head comprising: an orifice plate including an ejection opening for ejecting a liquid; and a substrate, a passage for supplying the liquid from one end side to the other end side being formed between the orifice plate and the substrate, and the ejection opening being formed between the one end side and the other end side of the passage, wherein an expression of H −0.34 ×P −0.66 ×W&gt;1.7 is satisfied when a height of the passage in a communication portion between an ejection opening portion, which allows communication between the ejection opening and the passage, and the passage on the one end side is set to H, a length of the ejection opening portion in a direction in which the liquid is ejected from the ejection opening is set to P, and a length of the ejection opening portion in a direction from the one end side toward the other end side is set to W. 
     In a fifth aspect of the present invention, there is provided a liquid ejection head comprising: an ejection opening for ejecting a liquid; a passage in which an energy generation element for generating energy used to eject the liquid is disposed; an ejection opening portion that allows communication between the ejection opening and the passage; a supply passage for allowing the liquid to flow into the passage from an outside; and an outflow passage for allowing the liquid to flow out to the outside from the passage, wherein an expression of H −0.34 ×P −0.66 ×W&gt;1.7 and an expression of 0.350×H+0.227×P−0.100×Z&gt;4 are satisfied when a height of the passage at an upstream side of a communication portion between the passage and the ejection opening portion in a flow direction of the liquid inside the passage is set to H, a length of the ejection opening portion in a direction in which the liquid is ejected from the ejection opening is set to P, a length of the ejection opening portion in the flow direction of the liquid inside the passage is set to W, and an effective diameter of the inscribed circle of the ejection opening portion is set to Z. 
     In a sixth aspect of the present invention, there is provided a liquid ejection head comprising: an ejection opening for ejecting a liquid; a passage in which an energy generation element for generating energy used to eject the liquid is disposed; an ejection opening portion that allows communication between the ejection opening and the passage; a supply passage for allowing the liquid to flow into the passage from an outside; and an outflow passage for allowing the liquid to flow out to the outside from the passage, wherein an expression of H −0.34 ×P −0.66 ×W&gt;1.5 is satisfied when a height of the passage at an upstream side of a communication portion between the passage and the ejection opening portion in a flow direction of the liquid inside the passage is set to H, a length of the ejection opening portion in a direction in which the liquid is ejected from the ejection opening is set to P, and a length of the ejection opening portion in the flow direction of the liquid inside the passage is set to W. 
     In a seventh aspect of the present invention, there is provided a method of supplying a liquid in a liquid ejection head including an ejection opening for ejecting a liquid, a passage in which an energy generation element for generating energy used to eject the liquid is disposed, an ejection opening portion that allows communication between the ejection opening and the passage, a supply passage for allowing the liquid to flow into the passage from an outside, and an outflow passage for allowing the liquid to flow out to the outside from the passage, wherein a flow of the liquid is generated such that the liquid entering an inside of the ejection opening portion from the passage arrives at a position corresponding to at least a half the inside of the ejection opening portion in a direction in which the liquid inside the ejection opening portion is ejected, and then returns to the passage when the liquid is supplied such that the liquid flows into the passage from the outside through the supply passage, and flows out to the outside through the outflow passage from the passage. 
     According to the above configuration, it is possible to suppress a change in quality of liquid adjacent to an ejection opening by allowing liquid in a passage of the liquid ejection head to flow. Thereby, it is possible to for example, suppress thickening of ink due to evaporation of liquid from the ejection opening and reduce color unevenness of an image. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a view illustrating a schematic configuration of an ink jet printing apparatus according to an embodiment of a liquid ejection apparatus of the present invention that ejects a liquid; 
         FIG.  2    is a diagram illustrating a first circulation configuration in a circulation path applied to a printing apparatus of the embodiment; 
         FIG.  3    is a diagram illustrating a second circulation configuration in the circulation path applied to the printing apparatus of the embodiment; 
         FIG.  4    is a diagram illustrating a difference in ink inflow amount to a liquid ejection head between the first circulation configuration and the second circulation configuration; 
         FIGS.  5 A and  5 B  are perspective views illustrating the liquid ejection head of the embodiment; 
         FIG.  6    is an exploded perspective view illustrating components or units constituting the liquid ejection head; 
         FIG.  7    is diagram illustrating front and rear faces of each of first to third passage members; 
         FIG.  8    is a transparent view illustrating a passage in the passage members which is formed by connecting the first to third passage members; 
         FIG.  9    is a cross-sectional view taken along a line IX-IX of  FIG.  8   ; 
         FIGS.  10 A and  10 B  are perspective views illustrating one ejection module; 
         FIG.  11 A  is a plan view of a surface of a printing element board on which ejection openings are formed,  FIG.  11 B  is a partial enlargement view of the surface of a printing element board, and  FIG.  11 C  is a view of opposite side of the surface of a printing element board; 
         FIG.  12    is a perspective view illustrating cross-sections taken along a line XII-XII of  FIG.  11 A ; 
         FIG.  13    is a partially enlarged plan view of an adjacent portion of adjacent two ejection modules of the printing element board; 
         FIGS.  14 A and  14 B  are perspective views illustrating the liquid ejection head according to ether another example of the embodiment; 
         FIG.  15    is a perspective exploded view illustrating the liquid ejection head according to the other example of the embodiment; 
         FIG.  16    is a diagram illustrating passage members making up the liquid ejection head according to the other example of the embodiment; 
         FIG.  17    is a transparent view illustrating a liquid connection relation between the printing element board and the passage member in the liquid ejection head according to other example of the embodiment; 
         FIG.  18    is a cross-sectional view taken along a line XVIII-XVIII of  FIG.  17   ; 
         FIGS.  19 A and  19 B  are a perspective view and an exploded view respectively illustrating ejection modules of the liquid ejection head according to other example of the embodiment; 
         FIG.  20    is a schematic diagram illustrating a surface of the printing element board on which ejection openings are arranged, a surface of the printing element board in a condition that a cover plate is removed from an opposite side of the printing element board, and an opposite side surface to the surface on which ejection openings are arranged; 
         FIG.  21    is a perspective view illustrating a second application example of an inkjet printing apparatus according to the embodiment; 
         FIGS.  22 A,  22 B, and  22 C  are diagrams for description of a configuration of an ejection opening and an ink passage adjacent to the ejection opening in a liquid ejection head according to a first embodiment of the invention; 
         FIG.  23    is a diagram illustrating an aspect of a flow of an ink flow of ink flowing inside a liquid ejection head according to a second embodiment; 
         FIG.  24 A  and  FIG.  24 B  are diagrams illustrating states of color material densities of ink inside ejection opening portions according to the second embodiment and a comparative example; 
         FIG.  25    is a diagram for description of a comparison between color material densities of ink ejected from respective liquid ejection heads of the second embodiment and the comparative example; 
         FIG.  26    is a diagram illustrating a relation between the liquid ejection head that generates a flow mode of the second embodiment and the liquid ejection head that generates a flow mode of the comparative example; 
         FIGS.  27 A,  27 B,  27 C, and  27 D  are diagrams for description of aspects of ink flows around ejection opening portions in liquid ejection heads corresponding to respective regions above and below a threshold line illustrated in  FIG.  26   ; 
         FIG.  28    is a diagram for description of whether a flow corresponds to a flow mode A or a flow mode B with regard to various shapes of liquid ejection heads; 
         FIGS.  29 A and  29 B  are diagrams illustrating a relation between the number of ejections (the number of ejections) after pausing for a certain time after ejection from a liquid ejection head in each flow mode and an ejection velocity corresponding thereto; 
         FIG.  30    is a diagram illustrating an aspect of a flow of an ink flow of ink flowing inside a liquid ejection head according to a third embodiment of the invention; 
         FIG.  31    is a diagram illustrating an aspect of a flow of an ink flow of ink flowing inside a liquid ejection head according to a fourth embodiment of the invention; 
         FIG.  32    is a diagram illustrating an aspect of a flow of an ink flow of ink flowing inside a liquid ejection head according to a fifth embodiment of the invention; 
         FIG.  33    is a diagram illustrating an aspect of a flow of an ink flow of ink flowing inside a liquid ejection head according to a sixth embodiment of the invention; 
         FIG.  34    is a diagram illustrating an aspect of a flow of an ink flow of ink flowing inside a liquid ejection head according to a seventh embodiment of the invention; 
         FIGS.  35 A and  35 B  are diagrams illustrating a shape of a liquid ejection head, in particular, an ejection opening according to an eighth embodiment of the invention; 
         FIGS.  36 A and  36 B  are diagrams illustrating an aspect of a flow in each flow mode of ink flowing inside a liquid ejection head according to a ninth embodiment of the invention; 
         FIGS.  37 A and  37 B  are diagrams illustrating a state of color material concentration of ink inside an ejection opening portion according to the ninth embodiment; 
         FIG.  38    is a diagram illustrating a relation between an evaporation rate in each flow mode and a circulation flow velocity in the ninth embodiment; 
         FIGS.  39 A,  39 B, and  39 C  are diagrams illustrating flow modes of three passage shapes according to a tenth embodiment of the invention; 
         FIG.  40    is a contour line diagram illustrating a value of a flow mode determination value when a diameter of an ejection opening is changed according to the tenth embodiment; 
         FIGS.  41 A,  41 B, and  41 C  are diagrams illustrating results of observing ejected liquid droplets of ejection openings of respective passage shapes according to the tenth embodiment; 
         FIG.  42    is a contour line diagram illustrating a time at which bubbles communicate with the atmosphere when the diameter of the ejection opening is changed according to the tenth embodiment; 
         FIG.  43    is a diagram illustrating an aspect of a flow of an ink flow of ink flowing inside the liquid ejection head according to the first embodiment; 
         FIGS.  44 A and  44 B  are diagrams illustrating a liquid ejection head according to an eighth embodiment; 
         FIGS.  45 A and  45 B  are diagrams illustrating a liquid ejection head according to the eighth embodiment; 
         FIG.  46    is a view illustrating a printing apparatus of a first application example; 
         FIG.  47    is a diagram illustrating a third circulation configuration; 
         FIGS.  48 A and  48 B  are views illustrating a modified example of a liquid ejection head according to the first application example; 
         FIG.  49    is a view illustrating a modified example of a liquid ejection head according to the first application example; 
         FIG.  50    is a view illustrating a modified example of a liquid ejection head according to the first application example; 
         FIG.  51    is a view illustrating a printing apparatus according to a third application example; 
         FIG.  52    is a diagram illustrating a fourth circulation configuration; 
         FIGS.  53 A and  53 B  are views illustrating a liquid ejection head according to the third application example; and 
         FIGS.  54 A,  54 B and  54 C  are views illustrating a liquid ejection head according to the third application example. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, application examples and embodiments to which the present invention is applied will be described with reference to the drawings. Additionally, a liquid ejection head that ejects liquid such as ink and a liquid ejection apparatus that mounts the liquid ejection head according to the present invention can be applied to a printer, a copying machine, a facsimile machine having a communication system, a word processor having a printer, and an industrial printing apparatus combined with various processing devices. For example, the liquid ejection head and the liquid ejection apparatus can be used to manufacture a biochip or print an electronic circuit. Further, since the embodiments to be described below are detailed examples of the invention, various technical limitations thereof can be made. However, embodiments of the present invention are not limited to the embodiments or the other detailed methods of the specification and can be modified within the spirit of the present invention. 
     First Application Example 
     &lt;Inkjet Printing Apparatus&gt; 
       FIG.  1    is a diagram illustrating a schematic configuration of a liquid ejection apparatus that ejects a liquid in the invention and particularly an inkjet printing apparatus (hereinafter, also referred to as a printing apparatus)  1000  that prints an image by ejecting ink. The printing apparatus  1000  includes a conveying unit  1  which conveys a print medium  2  and a line type (page wide type) liquid ejection head  3  which is disposed to be substantially orthogonal to the conveying direction of the print medium  2 . Then, the printing apparatus  1000  is a line type printing apparatus which continuously prints an image at one pass by ejecting ink onto the relative moving print mediums  2  while continuously or intermittently conveying the print mediums  2 . The liquid ejection head  3  includes a negative pressure control unit  230  which controls a pressure (a negative pressure) inside a circulation path, a liquid supply unit  220  which communicates with the negative pressure control unit  230  so that a fluid can flow therebetween, a liquid connection portion  111  which serves as an ink supply opening and an ink ejection opening of the liquid supply unit  220 , and a casing  80 . The print medium  2  is not limited to a cut sheet and may be also a continuous roll medium. The liquid ejection head  3  can print a full color image by inks of cyan C, magenta M, yellow Y, and black K and is fluid-connected to a liquid supply member, a main tank, and a buffer tank (see  FIG.  2    to be described later) which serve as a supply path supplying a liquid to the liquid ejection head  3 . Further, the control unit which supplies power and transmits an ejection control signal to the liquid ejection head  3  is electrically connected to the liquid ejection head  3 . The liquid path and the electric signal path in the liquid ejection head  3  will be described later. 
     The printing apparatus  1000  is an inkjet printing apparatus that circulates a liquid such as ink between a tank and the liquid ejection head  3  to be described later. In the ink jet printing apparatus of a first application example, various circulation configurations including a first circulation configuration and a second circulation configuration, which are described below, can be applied. The first circulation configuration is a configuration in which the liquid is circulated by the activation of two circulation pumps (for high and low pressures) at the downstream side of the liquid ejection head  3 . A second circulation configuration is a configuration in which the liquid is circulated by the activation of two circulation pumps (for high and low pressures) at the upstream side of the liquid ejection head  3 . Hereinafter, the first circulation configuration and the second circulation configuration will be described. 
     (Description of First Circulation Configuration) 
       FIG.  2    is a schematic diagram illustrating the first circulation configuration in the circulation path applied to the printing apparatus  1000  of the application example. The liquid ejection head  3  is fluid-connected to a first circulation pump (the high pressure side)  1001 , a first circulation pump (the low pressure side)  1002 , and a buffer tank  1003 . Further, in  FIG.  2   , in order to simplify a description, a path through which ink of one color of cyan C, magenta M, yellow Y, and black K flows is illustrated. However, in fact, four colors of circulation paths are provided in the liquid ejection head  3  and the printing apparatus body. 
     In the first circulation configuration, ink inside a main tank  1006  is supplied into the buffer tank  1003  by a replenishing pump  1005  and then is supplied to the liquid supply unit  220  of the liquid ejection head  3  through the liquid connection portion  111  by a second circulation pump  1004 . Subsequently, the ink which is adjusted to two different negative pressures (high and low pressures) by the negative pressure control unit  230  connected to the liquid supply unit  220  is circulated while being divided into two passages having the high and low pressures. The ink inside the liquid ejection head  3  is circulated in the liquid ejection head by the action of the first circulation pump (the high pressure side)  1001  and the first circulation pump (the low pressure side)  1002  at the downstream side of the head  3 , is discharged from the head  3  through the liquid connection portion  111 , and is returned to the buffer tank  1003 . 
     The buffer tank  1003  which is a sub-tank includes an atmosphere communication opening (not illustrated) which is connected to the main tank  1006  to communicate the inside of the tank with the outside and thus can discharge bubbles inside the ink to the outside. The replenishing pump  1005  is provided between the buffer tank  1003  and the main tank  1006 . The replenishing pump  1005  delivers the ink from the main tank  1006  to the buffer tank  1003  after the ink is consumed by the ejection (the ink ejection) of the ink from the ejection opening of the liquid ejection head  3  in the printing operation and the suction collection operation. 
     Two first circulation pumps  1001  and  1002  draw the liquid from the liquid connection portion  111  of the liquid ejection head  3  so that the liquid flows to the buffer tank  1003 . As the first circulation pump, a displacement pump having quantitative liquid delivery ability is desirable. Specifically, a tube pump, a gear pump, a diaphragm pump, and a syringe pump can be exemplified. However, for example, a general constant flow valve or a general relief valve may be disposed at an outlet of a pump to ensure a predetermined flow rate. When the liquid ejection head  3  is driven, the first circulation pump (the high pressure side)  1001  and the first circulation pump (the low pressure side)  1002  are operated so that the ink flows at a predetermined flow rate through a common supply passage  211  and a common collection passage  212 . Since the ink flows in this way, the temperature of the liquid ejection head  3  during a printing operation is kept at an optimal temperature. The predetermined flow rate when the liquid ejection head  3  is driven is desirably set to be equal to or higher than a flow rate at which a difference in temperature among the printing element boards  10  inside the liquid ejection head  3  does not influence printing quality. Above all, when a too high flow rate is set, a difference in negative pressure among the printing element boards  10  increases due to the influence of pressure loss of the passage inside a liquid ejection unit  300  and thus unevenness in density is caused. For that reason, it is desirable to set the flow rate in consideration of a difference in temperature and a difference in negative pressure among the printing element boards  10 . 
     The negative pressure control unit  230  is provided in a path between the second circulation pump  1004  and the liquid ejection unit  300 . The negative pressure control unit  230  is operated to keep a pressure at the downstream side (that is, a pressure near the liquid ejection unit  300 ) of the negative pressure control unit  230  at a predetermined pressure even when the flow rate of the ink changes in the circulation system due to a difference in ejection amount per unit area. As two negative pressure control mechanisms constituting the negative pressure control unit  230 , any mechanism may be used as long as a pressure at the downstream side of the negative pressure control unit  230  can be controlled within a predetermined range or less from a desired set pressure. As an example, a mechanism such as a so-called “pressure reduction regulator” can be employed. In the circulation passage of the application example, the upstream side of the negative pressure control unit  230  is pressurized by the second circulation pump  1004  through the liquid supply unit  220 . With such a configuration, since an influence of a water head pressure of the buffer tank  1003  with respect to the liquid ejection head  3  can be suppressed, a degree of freedom in layout of the buffer tank  1003  of the printing apparatus  1000  can be widened. 
     As the second circulation pump  1004 , a turbo pump or a displacement pump can be used as long as a predetermined head pressure or more can be exhibited in the range of the ink circulation flow rate used when the liquid ejection head  3  is driven. Specifically, a diaphragm pump can be used. Further, for example, a water head tank disposed to have a certain water head difference with respect to the negative pressure control unit  230  can be also used instead of the second circulation pump  1004 . 
     As illustrated in  FIG.  2   , the negative pressure control unit  230  includes two negative pressure adjustment mechanisms H, L respectively having different control pressures. Among two negative pressure adjustment mechanisms, a relatively high pressure side (indicated by “H” in  FIG.  2   ) and a relatively low pressure side (indicated by “L” in  FIG.  2   ) are respectively connected to the common supply passage  211  and the common collection passage  212  inside the liquid ejection unit  300  through the liquid supply unit  220 . The liquid ejection unit  300  is provided with the common supply passage  211 , the common collection passage  212 , and an individual passage  215  (an individual supply passage  213  and an individual collection passage  214 ) communicating with the printing element board. The negative pressure control mechanism H is connected to the common supply passage  211 , the negative pressure control mechanism L is connected to the common collection passage  212 , and a differential pressure is formed between two common passages. Then, since the individual passage  215  communicates with the common supply passage  211  and the common collection passage  212 , a flow (a flow indicated by an arrow direction of  FIG.  2   ) is generated in which a part of the liquid flows from the common supply passage  211  to the common collection passage  212  through the passage formed inside the printing element board  10 . The two negative pressure adjustment mechanisms H, L are connected to passages from the liquid connection portion  111  through the filter  221 . 
     In this way, the liquid ejection unit  300  has a flow in which a part of the liquid passes through the printing element boards  10  while the liquid flows to pass through the common supply passage  211  and the common collection passage  212 . For this reason, heat generated by the printing element boards  10  can be discharged to the outside of the printing element board  10  by the ink flowing through the common supply passage  211  and the common collection passage  212 . With such a configuration, the flow of the ink can be generated even in the pressure chamber or the ejection opening not ejecting the liquid when an image is printed by the liquid ejection head  3 . Accordingly, the thickening of the ink can be suppressed in such a manner that the viscosity of the ink thickened inside the ejection opening is decreased. Further, the thickened ink or the foreign material in the ink can be discharged toward the common collection passage  212 . For this reason, the liquid ejection head  3  of the application example can print a high-quality image at a high speed. 
     (Description of Second Circulation Configuration) 
       FIG.  3    is a schematic diagram illustrating the second circulation configuration which is a circulation configuration different from the first circulation configuration in the circulation path applied to the printing apparatus of the application example. A main difference from the first circulation configuration is that two negative pressure control mechanisms constituting the negative pressure control unit  230  both control a pressure at the upstream side of the negative pressure control unit  230  within a predetermined range from a desired set pressure. Further, another difference from the first circulation configuration is that the second circulation pump  1004  serves as a negative pressure source which reduces a pressure at the downstream side of the negative pressure control unit  230 . Further, still another difference is that the first circulation pump (the high pressure side)  1001  and the first circulation pump (the low pressure side)  1002  are disposed at the upstream side of the liquid ejection head  3  and the negative pressure control unit  230  is disposed at the downstream side of the liquid ejection head  3 . 
     In the second circulation configuration, the ink inside the main tank  1006  is supplied to the buffer tank  1003  by the replenishing pump  1005 . Subsequently, the ink is divided into two passages and is circulated in two passages at the high pressure side and the low pressure side by the action of the negative pressure control unit  230  provided in the liquid ejection head  3 . The ink which is divided into two passages at the high pressure side and the low pressure side is supplied to the liquid ejection head  3  through the liquid connection portion  111  by the action of the first circulation pump (the high pressure side)  1001  and the first circulation pump (the low pressure side)  1002 . Subsequently, the ink circulated inside the liquid ejection head by the action of the first circulation pump (the high pressure side)  1001  and the first circulation pump (the low pressure side)  1002  is discharged from the liquid ejection head  3  through the liquid connection portion  111  by the negative pressure control unit  230 . The discharged ink is returned to the buffer tank  1003  by the second circulation pump  1004 . 
     In the second circulation configuration, the negative pressure control unit  230  stabilizes a change in pressure at the upstream side (that is, the liquid ejection unit  300 ) of the negative pressure control unit  230  within a predetermined range from a predetermined pressure even when a change in flow rate is caused by a change in ejection amount per unit area. In the circulation passage of the application example, the downstream side of the negative pressure control unit  230  is pressurized by the second circulation pump  1004  through the liquid supply unit  220 . With such a configuration, since an influence of a water head pressure of the buffer tank  1003  with respect to the liquid ejection head  3  can be suppressed, the layout of the buffer tank  1003  in the printing apparatus  1000  can have many options. Instead of the second circulation pump  1004 , for example, a water head tank disposed to have a predetermined water head difference with respect to the negative pressure control unit  230  can be also used. Similarly to the first circulation configuration, in the second circulation configuration, the negative pressure control unit  230  includes two negative pressure control mechanisms respectively having different control pressures. Among two negative pressure adjustment mechanisms, a high pressure side (indicated by “H” in  FIG.  3   ) and a low pressure side (indicated by “L” in  FIG.  3   ) are respectively connected to the common supply passage  211  or the common collection passage  212  inside the liquid ejection unit  300  through the liquid supply unit  220 . When the pressure of the common supply passage  211  is set to be higher than the pressure of the common collection passage  212  by two negative pressure adjustment mechanisms, a flow of the liquid is formed from the common supply passage  211  to the common collection passage  212  through the individual passage  215  and the passages formed inside the printing element boards  10 . 
     In such a second circulation configuration, the same liquid flow as that of the first circulation configuration can be obtained inside the liquid ejection unit  300 , but has two advantages different from those of the first circulation configuration. As a first advantage, in the second circulation configuration, since the negative pressure control unit  230  is disposed at the downstream side of the liquid ejection head  3 , there is low concern that a foreign material or a trash produced from the negative pressure control unit  230  flows into the liquid ejection head  3 . As a second advantage, in the second circulation configuration, a maximal value of the flow rate necessary for the liquid from the buffer tank  1003  to the liquid ejection head  3  is smaller than that of the first circulation configuration. The reason is as below. 
     In the case of the circulation in the print standby state, the sum of the flow rates of the common supply passage  211  and the common collection passage  212  is set to a flow rate A. The value of the flow rate A is defined as a minimal flow rate necessary to adjust the temperature of the liquid ejection head  3  in the print standby state so that a difference in temperature inside the liquid ejection unit  300  falls within a desired range. Further, the ejection flow rate obtained when the ink is ejected from all ejection openings of the liquid ejection unit  300  (the full ejection state) is defined as a flow rate F (the ejection amount per each ejection opening×the ejection frequency per unit time×the number of the ejection openings). 
       FIG.  4    is a schematic diagram illustrating a difference in ink inflow amount to the liquid ejection head between the first circulation configuration and the second circulation configuration.  FIG.  4   -( a ) illustrates the standby state in the first circulation configuration and  FIG.  4   -( b ) illustrates the full ejection state in the first circulation configuration.  FIG.  4   -( c ) to  FIG.  4   -( f ) illustrate the second circulation passage. Here,  FIG.  4   -( c ) and  FIG.  4   -( d ) illustrate a case where the flow rate F is lower than the flow rate A and  FIG.  4   -( e ) and  FIG.  4   -( f ) illustrate a case where the flow rate F is higher than the flow rate A. In this way, the flow rates in the standby state and the full ejection state are illustrated. 
     The case of the first circulation configuration ( FIG.  4   -( a ) and  FIG.  4   -( b )) in which the first circulation pump  1001  and the first circulation pump  1002  each having a quantitative liquid delivery ability are disposed at the downstream side of the liquid ejection head  3  will be described. In this case, the total flow rate of the first circulation pump  1001  and the first circulation pump  1002  becomes the flow rate A ( FIG.  4   -( a )). By the flow rate A, the temperature inside the liquid ejection unit  300  in the standby state can be managed. Then, in the case of the full ejection state of the liquid ejection head  3 , the total flow rate of the first circulation pump  1001  and the first circulation pump  1002  remains in the flow rate A. However, negative pressure generated by the ejection of the liquid ejection head  3  acts. Thereby, a maximal flow rate of the liquid supplied to the liquid ejection head  3  is obtained such that the flow rate F consumed by the full ejection is added to the flow rate A of the total flow rate. Thus, a maximal value of the supply amount to the liquid ejection head  3  satisfies a relation of the flow rate A+the flow rate F since the flow rate F is added to the flow rate A ( FIG.  4   -( b )). 
     Meanwhile, in the case of the second circulation configuration ( FIG.  4   -( c ) to  FIG.  4   -( f )) in which the first circulation pump  1001  and the first circulation pump  1002  are disposed at the upstream side of the liquid ejection head  3 , the supply amount to the liquid ejection head  3  necessary for the print standby state becomes the flow rate A similarly to the first circulation configuration. Thus, when the flow rate A is higher than the flow rate F ( FIG.  4   -( c ) and  FIG.  4   -( d )) in the second circulation configuration in which the first circulation pump  1001  and the first circulation pump  1002  are disposed at the upstream side of the liquid ejection head  3 , the supply amount to the liquid ejection head  3  sufficiently becomes the flow rate A even in the full ejection state. At that time, the discharge flow rate of the liquid ejection head  3  satisfies a relation of the flow rate A—the flow rate F ( FIG.  4   -( d )). However, when the flow rate F is higher than the flow rate A ( FIG.  4   -( e ) and  FIG.  4   -( f )), the flow rate becomes insufficient when the flow rate of the liquid supplied to the liquid ejection head  3  becomes the flow rate A in the full ejection state. For that reason, when the flow rate F is higher than the flow rate A, the supply amount to the liquid ejection head  3  needs to be set to the flow rate F. At that time, since the flow rate F is consumed by the liquid ejection head  3  in the full ejection state, the flow rate of the liquid discharged from the liquid ejection head  3  becomes almost zero ( FIG.  4   -( f )). In addition, if the liquid is not ejected in the full ejection state when the flow rate F is higher than the flow rate A, the liquid which is attracted by the amount consumed by the ejection of the flow rate F is discharged from the liquid ejection head  3 . 
     In this way, in the case of the second circulation configuration, the total value of the flow rates set for the first circulation pump  1001  and the first circulation pump  1002 , that is, the maximal value of the necessary supply flow rate becomes a large value among the flow rate A and the flow rate F. For this reason, as long as the liquid ejection unit  300  having the same configuration is used, the maximal value (the flow rate A or the flow rate F) of the supply amount necessary for the second circulation configuration becomes smaller than the maximal value (the flow rate A+the flow rate F) of the supply flow rate necessary for the first circulation configuration. 
     For that reason, in the case of the second circulation configuration, the degree of freedom of the applicable circulation pump increases. For example, a circulation pump having a simple configuration and low cost can be used or a load of a cooler (not illustrated) provided in a main body side path can be reduced. Accordingly, there is an advantage that the cost of the printing apparatus can be decreased. This advantage is high in the line head having a relatively large value of the flow rate A or the flow rate F. Accordingly, a line head having a longer longitudinal length among the line heads is beneficial. 
     Meanwhile, the first circulation configuration is more advantageous than the second circulation configuration. That is, in the second circulation configuration, since the flow rate of the liquid flowing through the liquid ejection unit  300  in the print standby state becomes maximal, a higher negative pressure is applied to the ejection openings as the ejection amount per unit area of the image (hereinafter, also referred to as a low-duty image) becomes smaller. For this reason, when the passage width is narrow and the negative pressure is high, a high negative pressure is applied to the ejection opening in the low-duty image in which unevenness easily appears. Accordingly, there is concern that printing quality may be deteriorated in accordance with an increase in the number of so-called satellite droplets ejected along with main droplets of the ink. Meanwhile, in the case of the first circulation configuration, since a high negative pressure is applied to the ejection opening when the image (hereinafter, also referred to as a high-duty image) having a large ejection amount per unit area is formed, there is an advantage that an influence of satellite droplets on the image is small even when many satellite droplets are generated. Two circulation configurations can be desirably selected in consideration of the specifications (the ejection flow rate F, the minimal circulation flow rate A, and the passage resistance inside the head) of the liquid ejection head and the printing apparatus body. 
     (Description of Third Circulation Configuration) 
       FIG.  47    is a schematic diagram illustrating a third circulation configuration which is one of the circulation paths used in the printing apparatus of the application example. A description of the same functions and configurations as those of the first and second circulation paths will be omitted and only a difference will be described. 
     In the circulation path, the liquid is supplied into the liquid ejection head  3  from three positions including two positions of the center portion of the liquid ejection head  3  and one end side of the liquid ejection head  3 . The liquid flowing from the common supply passage  211  to each pressure chamber  23  is collected by the common collection passage  212  and is collected to the outside from the collection opening at the other end of the liquid ejection head  3 . The individual supply passage  213  communicates with the common supply passage  211  and the common collection passage  212 , and the printing element board  10  and the pressure chamber  23  disposed inside the printing element board are provided in the path of the individual supply passage  213 . Accordingly, a part of the liquid flowing from the first circulation pump  1002  flows from the common supply passage  211  to the common collection passage  212  while passing through the pressure chamber  23  of the printing element board  10  and flows (see an arrow of  FIG.  47   ). This is because a differential pressure is generated between a pressure adjustment mechanism H connected to the common supply passage  211  and a pressure adjustment mechanism L connected to the common collection passage  212  and the first circulation pump  1002  is connected only to the common collection passage  212 . 
     In this way, in the liquid ejection unit  300 , a flow of the liquid passing through the common collection passage  212  and a flow of the liquid flowing from the common supply passage  211  to the common collection passage  212  while passing through the pressure chamber  23  inside each printing element board  10  are generated. For this reason, heat generated by each printing element board  10  can be discharged to the outside of the printing element board  10  by the flow from the common supply passage  211  to the common collection passage  212  while pressure loss is suppressed. Further, according to the circulation path, the number of the pumps which are liquid transporting units can be decreased compared with the first and second circulation paths. 
     (Description of Configuration of Liquid Ejection Head) 
     A configuration of the liquid ejection head  3  according to the first application example will be described.  FIGS.  5 A and  5 B  are perspective views illustrating the liquid ejection head  3  according to the application example. The liquid ejection head  3  is a line type (a page wide type) liquid ejection head in which fifteen printing element boards  10  each of which is capable of ejecting inks of four colors of cyan C, magenta M, yellow Y, and black K are arranged in series (an in-line arrangement). As illustrated in  FIG.  5 A , the liquid ejection head  3  includes the printing element boards  10  and a signal input terminal  91  and a power supply terminal  92  which are electrically connected to each other through a flexible circuit board  40  and an electric wiring board  90  capable of supplying electric energy to the printing element board  10 . The signal input terminal  91  and the power supply terminal  92  are electrically connected to the control unit of the printing apparatus  1000  so that an ejection drive signal and power necessary for the ejection are supplied to the printing element board  10 . When the wirings are integrated by the electric circuit inside the electric wiring board  90 , the number of the signal input terminals  91  and the power supply terminals  92  can be decreased compared with the number of the printing element boards  10 . Accordingly, the number of electrical connection components to be separated when the liquid ejection head  3  is assembled to the printing apparatus  1000  or the liquid ejection head is replaced decreases. As illustrated in  FIG.  5 B , the liquid connection portions  111  which are provided at both ends of the liquid ejection head  3  are connected to the liquid supply system of the printing apparatus  1000 . Accordingly, the inks of four colors including cyan C, magenta M, yellow Y, and black K4 are supplied from the supply system of the printing apparatus  1000  to the liquid ejection head  3  and the inks passing through the liquid ejection head  3  are collected by the supply system of the printing apparatus  1000 . In this way, the inks of different colors can be circulated through the path of the printing apparatus  1000  and the path of the liquid ejection head  3 . 
       FIG.  6    is an exploded perspective view illustrating components or units constituting the liquid ejection head  3 . The liquid ejection unit  300 , the liquid supply unit  220 , and the electric wiring board  90  are attached to the casing  80 . The liquid connection portions  111  (see  FIG.  3   ) are provided in the liquid supply unit  220 . Also, in order to remove a foreign material in the supplied ink, filters  221  (see  FIGS.  2  and  3   ) for different colors are provided inside the liquid supply unit  220  while communicating with the openings of the liquid connection portions  111 . Two liquid supply units  220  respectively corresponding to two colors are provided with the filters  221 . The liquid passing through the filter  221  is supplied to the negative pressure control unit  230  disposed on the liquid supply unit  220  disposed to correspond to each color. The negative pressure control unit  230  is a unit which includes different colors of negative pressure control valves. By the function of a spring member or a valve provided therein, a change in pressure loss inside the supply system (the supply system at the upstream side of the liquid ejection head  3 ) of the printing apparatus  1000  caused by a change in flow rate of the liquid is largely decreased. Accordingly, the negative pressure control unit  230  can stabilize a change negative pressure at the downstream side (the liquid ejection unit  300 ) of the negative pressure control unit within a predetermined range. As described in  FIG.  2   , two negative pressure control valves of different colors are built inside the negative pressure control unit  230 . Two negative pressure control valves are respectively set to different control pressures. Here, the high pressure side communicates with the common supply passage  211  (see  FIG.  2   ) inside the liquid ejection unit  300  and the low pressure side communicates with the common collection passage  212  (see  FIG.  2   ) through the liquid supply unit  220 . 
     The casing  80  includes a liquid ejection unit support portion  81  and an electric wiring board support portion  82  and ensures the rigidity of the liquid ejection head  3  while supporting the liquid ejection unit  300  and the electric wiring board  90 . The electric wiring board support portion  82  is used to support the electric wiring board  90  and is fixed to the liquid ejection unit support portion  81  by a screw. The liquid ejection unit support portion  81  is used to correct the warpage or deformation of the liquid ejection unit  300  to ensure the relative position accuracy among the printing element boards  10 . Accordingly, stripe and unevenness of a printed medium is suppressed. For that reason, it is desirable that the liquid ejection unit support portion  81  have sufficient rigidity. As a material, metal such as SUS or aluminum or ceramic such as alumina is desirable. The liquid ejection unit support portion  81  is provided with openings  83  and  84  into which a joint rubber  100  is inserted. The liquid supplied from the liquid supply unit  220  is led to a third passage member  70  constituting the liquid ejection unit  300  through the joint rubber. 
     The liquid ejection unit  300  includes a plurality of ejection modules  200  and a passage member  210  and a cover member  130  is attached to a face near the print medium in the liquid ejection unit  300 . Here, the cover member  130  is a member having a picture frame shaped surface and provided with an elongated opening  131  as illustrated in  FIG.  6    and the printing element board  10  and a sealing member  110  (see  FIG.  10 A  to be described later) included in the ejection module  200  are exposed from the opening  131 . A peripheral frame of the opening  131  serves as a contact face of a cap member that caps the liquid ejection head  3  in the print standby state. For this reason, it is desirable to form a closed space in a capping state by applying an adhesive, a sealing material, and a filling material along the periphery of the opening  131  to fill unevenness or a gap on the ejection opening face of the liquid ejection unit  300 . 
     Next, a configuration of the passage member  210  included in the liquid ejection unit  300  will be described. As illustrated in  FIG.  6   , the passage member  210  is obtained by laminating a first passage member  50 , a second passage member  60 , and a third passage member  70  and distributes the liquid supplied from the liquid supply unit  220  to the ejection modules  200 . Further, the passage member  210  is a passage member that returns the liquid re-circulated from the ejection module  200  to the liquid supply unit  220 . The passage member  210  is fixed to the liquid ejection unit support portion  81  by a screw and thus the warpage or deformation of the passage member  210  is suppressed. 
       FIGS.  7 ( a ) to  7 ( f )  are diagrams illustrating front and rear faces of the first to third passage members.  FIG.  7   -( a ) illustrates a face onto which the ejection module  200  is mounted in the first passage member  50  and  FIG.  7   -( f ) illustrates a face with which the liquid ejection unit support portion  81  comes into contact in the third passage member  70 . The first passage member  50  and the second passage member  60  are bonded to teach other so that the parts illustrated in  FIG.  7   -( b ) and  7 -( c ) and corresponding to the contact faces of the passage members face each other and the second passage member and the third passage member are bonded to each other so that the parts illustrated in  FIGS.  7 ( d ) and  7 ( e )  and corresponding to the contact faces of the passage members face each other. When the second passage member  60  and the third passage member  70  are bonded to each other, eight common passages ( 211   a ,  211   b ,  211   c ,  211   d ,  212   a ,  212   b ,  212   c ,  212   d ) extending in the longitudinal direction of the passage member are formed by common passage grooves  62  and  71  of the passage members. Accordingly, a set of the common supply passage  211  and the common collection passage  212  is formed inside the passage member  210  to correspond to each color. The ink is supplied from the common supply passage  211  to the liquid ejection head  3  and the ink supplied to the liquid ejection head  3  is collected by the common collection passage  212 . A communication opening  72  (see  FIG.  7   -( f )) of the third passage member  70  communicates with the holes of the joint rubber  100  and is fluid-connected to the liquid supply unit  220  (see  FIG.  6   ). A bottom face of the common passage groove  62  of the second passage member  60  is provided with a plurality of communication openings  61  (a communication opening  61 - 1  communicating with the common supply passage  211  and a communication opening  61 - 2  communicating with the common collection passage  212 ) and communicates with one end of an individual passage groove  52  of the first passage member  50 . The other end of the individual passage groove of the first passage member  50  is provided with a communication opening  51  and is fluid-connected to the ejection modules  200  through the communication opening  51 . By the individual passage groove  52 , the passages can be densely provided at the center side of the passage member. 
     It is desirable that the first to third passage members be formed of a material having corrosion resistance with respect to a liquid and having a low linear expansion coefficient. As a material, for example, a composite material (resin) obtained by adding inorganic filler such as fiber or fine silica particles to a base material such as alumina, LCP (liquid crystal polymer), PPS (polyphenyl sulfide), PSF (polysulfone), or modified PPE (polyphenylene ether) can be appropriately used. As a method of forming the passage member  210 , three passage members may be laminated and adhered to one another. When a resin composite material is selected as a material, a bonding method using welding may be used. 
       FIG.  8    is a partially enlarged perspective view illustrating a part α of  FIG.  7   -( a ) and illustrating the passages inside the passage member  210  formed by bonding the first to third passage members to one another when viewed from a face onto which the ejection module  200  is mounted in the first passage member  50 . The common supply passage  211  and the common collection passage  212  are formed such that the common supply passage  211  and the common collection passage  212  are alternately disposed from the passages of both ends. Here, a connection relation among the passages inside the passage member  210  will be described. 
     The passage member  210  is provided with the common supply passage  211  ( 211   a , 211   b , 211   c ,  211   d ) and the common collection passage  212  ( 212   a ,  212   b ,  212   c ,  212   d ) extending in the longitudinal direction of the liquid ejection head  3  and provided for each color. The individual supply passages  213  ( 213   a ,  213   b ,  213   c ,  213   d ) which are formed by the individual passage grooves  52  are connected to the common supply passages  211  of different colors through the communication openings  61 . Further, the individual collection passages  214  ( 214   a ,  214   b ,  214   c ,  214   d ) formed by the individual passage grooves  52  are connected to the common collection passages  212  of different colors through the communication openings  61 . With such a passage configuration, the ink can be intensively supplied to the printing element board  10  located at the center portion of the passage member from the common supply passages  211  through the individual supply passages  213 . Further, the ink can be collected from the printing element board  10  to the common collection passages  212  through the individual collection passages  214 . 
       FIG.  9    is a cross-sectional view taken along a line IX-IX of  FIG.  8   . The individual collection passage ( 214   a ,  214   c ) communicates with the ejection module  200  through the communication opening  51 . In  FIG.  9   , only the individual collection passage ( 214   a ,  214   c ) is illustrated, but in a different cross-section, the individual supply passage  213  and the ejection module  200  communicates with each other as illustrated in  FIG.  8   . A support member  30  and the printing element board  10  which are included in each ejection module  200  are provided with passages which supply the ink from the first passage member  50  to a printing element  15  provided in the printing element board  10 . Further, the support member  30  and the printing element board  10  are provided with passages which collect (re-circulate) a part or the entirety of the liquid supplied to the printing element  15  to the first passage member  50 . 
     Here, the common supply passage  211  of each color is connected to the negative pressure control unit  230  (the high pressure side) of corresponding color through the liquid supply unit  220  and the common collection passage  212  is connected to the negative pressure control unit  230  (the low pressure side) through the liquid supply unit  220 . By the negative pressure control unit  230 , a differential pressure (a difference in pressure) is generated between the common supply passage  211  and the common collection passage  212 . For this reason, as illustrated in  FIGS.  8  and  9   , a flow is generated in order of the common supply passage  211  of each color, the individual supply passage  213 , the printing element board  10 , the individual collection passage  214 , and the common collection passage  212  inside the liquid ejection head of the application example having the passages connected to one another. 
     (Description of Ejection Module) 
       FIG.  10 A  is a perspective view illustrating one ejection module  200  and  FIG.  10 B  is an exploded view thereof. As a method of manufacturing the ejection module  200 , first, the printing element board  10  and the flexible circuit board  40  are adhered onto the support member  30  provided with a liquid communication opening  31 . Subsequently, a terminal  16  on the printing element board  10  and a terminal  41  on the flexible circuit board  40  are electrically connected to each other by wire bonding and the wire bonded portion (the electrical connection portion) is sealed by the sealing member  110 . A terminal  42  which is opposite to the printing element board  10  of the flexible circuit board  40  is electrically connected to a connection terminal  93  (see  FIG.  6   ) of the electric wiring board  90 . Since the support member  30  serves as a support body that supports the printing element board  10  and a passage member that fluid-communicates the printing element board  10  and the passage member  210  to each other, it is desirable that the support member have high flatness and sufficiently high reliability while being bonded to the printing element board. As a material, for example, alumina or resin is desirable. 
     (Description of Structure of Printing Element Board) 
       FIG.  11 A  is a top view illustrating a face provided with an ejection opening  13  in the printing element board  10 ,  FIG.  11 B  is an enlarged view of a part A of  FIG.  11 A , and  FIG.  11 C  is a top view illustrating a rear face of  FIG.  11 A . Here, a configuration of the printing element board  10  of the application example will be described. As illustrated in  FIG.  11 A , an ejection opening forming member  12  of the printing element board  10  is provided with four ejection opening rows corresponding to different colors of inks. Further, the extension direction of the ejection opening rows of the ejection openings  13  will be referred to as an “ejection opening row direction”. As illustrated in  FIG.  11 B , the printing element  15  serving as an ejection energy generation element for ejecting the liquid by heat energy is disposed at a position corresponding to each ejection opening  13 . A pressure chamber  23  provided inside the printing element  15  is defined by a partition wall  22 . The printing element  15  is electrically connected to the terminal  16  by an electric wire (not illustrated) provided in the printing element board  10 . Then, the printing element  15  boils the liquid while being heated on the basis of a pulse signal input from a control circuit of the printing apparatus  1000  via the electric wiring board  90  (see  FIG.  6   ) and the flexible circuit board  40  (see  FIG.  10 B ). The liquid is ejected from the ejection opening  13  by a foaming force caused by the boiling. As illustrated in  FIG.  11 B , a liquid supply path  18  extends at one side along each ejection opening row and a liquid collection path  19  extends at the other side along the ejection opening row. The liquid supply path  18  and the liquid collection path  19  are passages that extend in the ejection opening row direction provided in the printing element board  10  and communicate with the ejection opening  13  through a supply opening  17   a  and a collection opening  17   b.    
     As illustrated in  FIG.  11 C , a sheet-shaped lid member  20  is laminated on a rear face of a face provided with the ejection opening  13  in the printing element board  10  and the lid member  20  is provided with a plurality of openings  21  communicating with the liquid supply path  18  and the liquid collection path  19 . In the application example, the lid member  20  is provided with three openings  21  for each liquid supply path  18  and two openings  21  for each liquid collection path  19 . As illustrated in  FIG.  11 B , openings  21  of the lid member  20  communicate with the communication openings  51  illustrated in  FIG.  7   -( a ). It is desirable that the lid member  20  have sufficient corrosion resistance for the liquid. From the viewpoint of preventing mixed color, the opening shape and the opening position of the opening  21  need to have high accuracy. For this reason, it is desirable to form the opening  21  by using a photosensitive resin material or a silicon plate as a material of the lid member  20  through photolithography. In this way, the lid member  20  changes the pitch of the passages by the opening  21 . Here, it is desirable to form the lid member by a film-shaped member with a thin thickness in consideration of pressure loss. 
       FIG.  12    is a perspective view illustrating cross-sections of the printing element board  10  and the lid member  20  when taken along a line XII-XII of  FIG.  11 A . Here, a flow of the liquid inside the printing element board  10  will be described. The lid member  20  serves as a lid that forms a part of walls of the liquid supply path  18  and the liquid collection path  19  formed in a substrate  11  of the printing element board  10 . The printing element board  10  is formed by laminating the substrate  11  formed of Si and the ejection opening forming member  12  formed of photosensitive resin and the lid member  20  is bonded to a rear face of the substrate  11 . One face of the substrate  11  is provided with the printing element  15  (see  FIG.  11 B ) and a rear face thereof is provided with grooves forming the liquid supply path  18  and the liquid collection path  19  extending along the ejection opening row. The liquid supply path  18  and the liquid collection path  19  which are formed by the substrate  11  and the lid member  20  are respectively connected to the common supply passage  211  and the common collection passage  212  inside each passage member  210  and a differential pressure is generated between the liquid supply path  18  and the liquid collection path  19 . When the liquid is ejected from the ejection opening  13  to print an image, the liquid inside the liquid supply path  18  provided inside the substrate  11  at the ejection opening not ejecting the liquid flows toward the liquid collection path  19  through the supply opening  17   a , the pressure chamber  23 , and the collection opening  17   b  by the differential pressure (see an arrow C of  FIG.  12   ). By the flow, foreign materials, bubbles, and thickened ink produced by the evaporation from the ejection opening  13  in the ejection opening  13  or the pressure chamber  23  not involved with a printing operation can be collected by the liquid collection path  19 . Further, the thickening of the ink of the ejection opening  13  or the pressure chamber  23  can be suppressed. The liquid which is collected to the liquid collection path  19  is collected in order of the communication opening  51  (see  FIG.  7   -( a )) inside the passage member  210 , the individual collection passage  214 , and the common collection passage  212  through the opening of the lid member  20  and the liquid communication opening  31  (see  FIG.  10 B ) of the support member  30 . Then, the liquid is collected from the liquid ejection head  3  to the collection path of the printing apparatus  1000 . That is, the liquid supplied from the printing apparatus body to the liquid ejection head  3  flows in the following order to be supplied and collected. 
     First, the liquid flows from the liquid connection portion  111  of the liquid supply unit  220  into the liquid ejection head  3 . Then, the liquid is sequentially supplied through the joint rubber  100 , the communication opening  72  and the common passage groove  71  provided in the third passage member, the common passage groove  62  and the communication opening  61  provided in the second passage member, and the individual passage groove  52  and the communication opening  51  provided in the first passage member. Subsequently, the liquid is supplied to the pressure chamber  23  while sequentially passing through the liquid communication opening  31  provided in the support member  30 , the opening  21  provided in the lid member  20 , and the liquid supply path  18  and the supply opening  17   a  provided in the substrate  11 . In the liquid supplied to the pressure chamber  23 , the liquid which is not ejected from the ejection opening  13  sequentially flows through the collection opening  17   b  and the liquid collection path  19  provided in the substrate  11 , the opening  21  provided in the lid member  20 , and the liquid communication opening  31  provided in the support member  30 . Subsequently, the liquid sequentially flows through the communication opening  51  and the individual passage groove  52  provided in the first passage member, the communication opening  61  and the common passage groove  62  provided in the second passage member, the common passage groove  71  and the communication opening  72  provided in the third passage member  70 , and the joint rubber  100 . Then, the liquid flows from the liquid connection portion  111  provided in the liquid supply unit  220  to the outside of the liquid ejection head  3 . 
     In the first circulation configuration illustrated in  FIG.  2   , the liquid which flows from the liquid connection portion  111  is supplied to the joint rubber  100  through the negative pressure control unit  230 . Further, in the second circulation configuration illustrated in  FIG.  3   , the liquid which is collected from the pressure chamber  23  passes through the joint rubber  100  and flows from the liquid connection portion  111  to the outside of the liquid ejection head through the negative pressure control unit  230 . The entire liquid which flows from one end of the common supply passage  211  of the liquid ejection unit  300  is not supplied to the pressure chamber  23  through the individual supply passage  213   a . That is, the liquid may flow from the other end of the common supply passage  211  to the liquid supply unit  220  while not flowing into the individual supply passage  213   a  by the liquid which flows from one end of the common supply passage  211 . In this way, since the path is provided so that the liquid flows therethrough without passing through the printing element board  10 , the reverse flow of the circulation flow of the liquid can be suppressed even in the printing element board  10  including the large passage with a small flow resistance as in the application example. In this way, since the thickening of the liquid in the vicinity of the ejection opening or the pressure chamber  23  can be suppressed in the liquid ejection head  3  of the application example, a slippage or a non-ejection can be suppressed. As a result, a high-quality image can be printed. 
     (Description of Positional Relation among Printing Element Boards) 
       FIG.  13    is a partially enlarged top view illustrating an adjacent portion of the printing element board in two adjacent ejection modules  200 . In the application example, a substantially parallelogram printing element board is used. Ejection opening rows ( 14   a  to  14   d ) having the ejection openings  13  arranged in each printing element board  10  are disposed to be inclined while having a predetermined angle with respect to the longitudinal direction of the liquid ejection head  3 . Then, the ejection opening row at the adjacent portion between the printing element boards  10  is formed such that at least one ejection opening overlaps in the print medium conveying direction. In  FIG.  13   , two ejection openings on a line D overlap each other. With such an arrangement, even when a position of the printing element board  10  is slightly deviated from a predetermined position, black streaks or missing of a print image cannot be seen by a driving control of the overlapping ejection openings. Even when the printing element boards  10  are disposed in a straight linear shape (an in-line shape) instead of a zigzag shape, black streaks or white streaks at the connection portion can be handled. Specifically, the black streaks or the white streaks at the connection portion between the printing element boards  10  can be handled while an increase in the length of the liquid ejection head  3  in the print medium conveying direction is suppressed by the configuration illustrated in  FIG.  13   . Further, in the application example, a principal plane of the printing element board has a parallelogram shape, but the invention is not limited thereto. For example, even when the printing element boards having a rectangular shape, a trapezoid shape, and the other shapes are used, the configuration of the invention can be desirably used. 
     (Description of Modified Example of Configuration of Liquid Ejection Head) 
     A modified example of a configuration of the liquid ejection head illustrated in  FIG.  46    and  FIGS.  48 A to  50    will be described. A description of the same configuration and function as those of the above-described example will be omitted and only a difference will be mainly described. 
     In the modified example, as illustrated in  FIGS.  46  and  48   , the liquid connection portions  111  between the liquid ejection head  3  and the outside are intensively disposed at one end side of the liquid ejection head in the longitudinal direction. The negative pressure control units  230  are intensively disposed at the other end side of the liquid ejection head  3  ( FIG.  49   ). The liquid supply unit  220  that belongs to the liquid ejection head  3  is configured as an elongated unit corresponding to the length of the liquid ejection head  3  and includes passages and filters  221  respectively corresponding to four liquids to be supplied. As illustrated in  FIG.  49   , the positions of the openings  83  to  86  provided at the liquid ejection unit support portion  81  are also located at positions different from those of the liquid ejection head  3 . 
       FIG.  50    illustrates a lamination state of the passage members  50 ,  60 , and  70 . The printing element boards  10  are arranged linearly on the upper face of the passage member  50  which is the uppermost layer among the passage members  50 ,  60 , and  70 . As the passage which communicates with the opening  21  formed at the rear face side of each printing element board  10 , two individual supply passages  213  and one individual collection passage  214  are provided for each color of the liquid. Accordingly, as the opening  21  which is formed at the lid member  20  provided at the rear face of the printing element board  10 , two supply openings  21  and one collection opening  21  are provided for each color of the liquid. As illustrated in  FIG.  32   , the common supply passage  211  and the common collection passage  212  extending along the longitudinal direction of the liquid ejection head  3  are alternately arranged. 
     Second Application Example 
     &lt;Ink Jet Printing Apparatus&gt; 
     Next, configurations of an inkjet printing apparatus  2000  and a liquid ejection head  2003  according to a second application example of the invention, which are different from the above described first application example, will be described with reference to the drawings. In the description below, only a difference from the first application example will be described and a description of the same components as those of the first application example will be omitted. 
       FIG.  21    is a diagram illustrating the inkjet printing apparatus  2000  according to the application example used to eject the liquid. The printing apparatus  2000  of the application example is different from the first application example in that a full color image is printed on the print medium by a configuration in which four monochromic liquid ejection heads  2003  respectively corresponding to the inks of cyan C, magenta M, yellow Y, and black K are disposed in parallel. In the first application example, the number of the ejection opening rows which can be used for one color is one. However, in the application example, the number of the ejection opening rows which can be used for one color is twenty. For this reason, when print data is appropriately distributed to a plurality of ejection opening rows to print an image, an image can be printed at a higher speed. Further, even when there are the ejection openings that do not eject the liquid, the liquid is ejected complementarily from the ejection openings of the other rows located at positions corresponding to the non-ejection openings in the print medium conveying direction. The reliability is improved and thus a commercial image can be appropriately printed. Similarly to the first application example, the supply system, the buffer tank  1003  (see  FIGS.  2  and  3   ), and the main tank  1006  (see  FIGS.  2  and  3   ) of the printing apparatus  2000  are fluid-connected to the liquid ejection heads  2003 . Further, an electrical control unit which transmits power and ejection control signals to the liquid ejection head  2003  is electrically connected to the liquid ejection heads  2003 . 
     (Description of Circulation Path) 
     Similarly to the first application example, the first, second and third circulation configurations illustrated in  FIG.  2   ,  FIG.  3   , and  FIG.  47    can be used as the liquid circulation configuration between the printing apparatus  2000  and the liquid ejection head  2003 . 
     (Description of Structure of Liquid Ejection Head) 
       FIGS.  14 A and  14 B  are perspective views illustrating the liquid ejection head  2003  according to the application example. Here, a structure of the liquid ejection head  2003  according to the application example will be described. The liquid ejection head  2003  is an inkjet line type (page wide type) print head which includes sixteen printing element boards  2010  arranged linearly in the longitudinal direction of the liquid ejection head  2003  and can print an image by one kind of liquid. Similarly to the first application example, the liquid ejection head  2003  includes the liquid connection portion  111 , the signal input terminal  91 , and the power supply terminal  92 . However, since the liquid ejection head  2003  of the application example includes many ejection opening rows compared with the first application example, the signal input terminal  91  and the power supply terminal  92  are disposed at both sides of the liquid ejection head  2003 . This is because a decrease in voltage or a delay in transmission of a signal caused by the wiring portion provided in the printing element board  2010  needs to be reduced. 
       FIG.  15    is an oblique exploded view illustrating the liquid ejection head  2003  and components or units constituting the liquid ejection head  2003  according to the functions thereof. The function of each of units and members or the liquid flow sequence inside the liquid ejection head is basically similar to that of the first application example, but the function of guaranteeing the rigidity of the liquid ejection head is different. In the first application example, the rigidity of the liquid ejection head is mainly guaranteed by the liquid ejection unit support portion  81 , but in the liquid ejection head  2003  of the second application example, the rigidity of the liquid ejection head is guaranteed by a second passage member  2060  included in a liquid ejection unit  2300 . The liquid ejection unit support portion  81  of the application example is connected to both ends of the second passage member  2060  and the liquid ejection unit  2300  is mechanically connected to a carriage of the printing apparatus  2000  to position the liquid ejection head  2003 . The electric wiring board  90  and a liquid supply unit  2220  including a negative pressure control unit  2230  are connected to the liquid ejection unit support portion  81 . Each of two liquid supply units  2220  includes a filter (not illustrated) built therein. 
     Two negative pressure control units  2230  are set to control a pressure at different and relatively high and low negative pressures. Further, as in  FIGS.  14 B and  15   , when the negative pressure control units  2230  at the high pressure side and the low pressure side are provided at both ends of the liquid ejection head  2003 , the flows of the liquid in the common supply passage and the common collection passage extending in the longitudinal direction of the liquid ejection head  2003  face each other. In such a configuration, a heat exchange between the common supply passage and the common collection passage is promoted and thus a difference in temperature inside two common passages is reduced. Accordingly, a difference in temperature of the printing element boards  2010  provided along the common passage is reduced. As a result, there is an advantage that unevenness in printing is not easily caused by a difference in temperature. 
     Next, a detailed configuration of a passage member  2210  of the liquid ejection unit  2300  will be described. As illustrated in  FIG.  15   , the passage member  2210  is obtained by laminating a first passage member  2050  and a second passage member  2060  and distributes the liquid supplied from the liquid supply unit  2220  to ejection modules  2200 . The passage member  2210  serves as a passage member that returns the liquid re-circulated from the ejection module  2200  to the liquid supply unit  2220 . The second passage member  2060  of the passage member  2210  is a passage member having a common supply passage and a common collection passage formed therein and improving the rigidity of the liquid ejection head  2003 . For this reason, it is desirable that a material of the second passage member  2060  have sufficient corrosion resistance for the liquid and high mechanical strength. Specifically, SUS, Ti, or alumina can be used. 
       FIG.  16   -( a ) shows a diagram illustrating a face onto which the ejection module  2200  is mounted in the first passage member  2050  and  FIG.  16   -( b ) shows a diagram illustrating a rear face thereof and a face contacting the second passage member  2060 . Differently from the first application example, the first passage member  2050  of the application example has a configuration in which a plurality of members are disposed adjacently to respectively correspond to the ejection modules  2200 . By employing such a split structure, a plurality of modules can be arranged to correspond to a length of the liquid ejection head  2003 . Accordingly, this structure can be appropriately used particularly in a relatively long liquid ejection head corresponding to, for example, a sheet having a size of B2 or more. As illustrated in  FIG.  16   -( a ), the communication opening  51  of the first passage member  2050  fluid-communicates with the ejection module  2200 . As illustrated in  FIG.  16   -( b ), the individual communication opening  53  of the first passage member  2050  fluid-communicates with the communication opening  61  of the second passage member  2060 .  FIG.  16   -( c ) illustrates a contact face of the second passage member  60  with respect to the first passage member  2050 ,  FIG.  16   -( d ) illustrates a cross-section of a center portion of the second passage member  60  in the thickness direction, and  FIG.  16   -( e ) shows a diagram illustrating a contact face of the second passage member  2060  with respect to the liquid supply unit  2220 . The function of the communication opening or the passage of the second passage member  2060  is similar to each color of the first application example. The common passage groove  71  of the second passage member  2060  is formed such that one side thereof is a common supply passage  2211  illustrated in  FIG.  17    and the other side thereof is a common collection passage  2212 . These passages are respectively provided along the longitudinal direction of the liquid ejection head  2003  so that the liquid is supplied from one end thereof to the other end thereof. The application example is different from the first application example in that the liquid flow directions in the common supply passage  2211  and the common collection passage  2212  are opposite to each other. 
       FIG.  17    is a perspective view illustrating a liquid connection relation between the printing element board  2010  and the passage member  2210 . A pair of the common supply passage  2211  and the common collection passage  2212  extending in the longitudinal direction of the liquid ejection head  2003  is provided inside the passage member  2210 . The communication opening  61  of the second passage member  2060  is connected to the individual communication opening  53  of the first passage member  2050  so that both positions match each other. The liquid supply passage communicating with the communication opening  51  of the first passage member  2050  through the communication opening  61  from the common supply passage  2211  of the second passage member  2060  is formed. Similarly, the liquid the supply path communicating with the communication opening  51  of the first passage member  2050  through the common collection passage  2212  from the communication opening  72  of the second passage member  2060  is also formed. 
       FIG.  18    is a cross-sectional view taken along a line XVIII-XVIII of  FIG.  17   . The common supply passage  2211  is connected to the ejection module  2200  through the communication opening  61 , the individual communication opening  53 , and the communication opening  51 . Although not illustrated in  FIG.  18   , it is obvious that the common collection passage  2212  is connected to the ejection module  2200  by the same path in a different cross-section in  FIG.  17   . Similarly to the first application example, each of the ejection module  2200  and the printing element board  2010  is provided with a passage communicating with each ejection opening and thus a part or the entirety of the supplied liquid can be re-circulated while passing through the ejection opening that does not perform the ejection operation. Further, similarly to the first application example, the common supply passage  2211  is connected to the negative pressure control unit  2230  (the high pressure side) and the common collection passage  2212  is connected to the negative pressure control unit  2230  (the low pressure side) through the liquid supply unit  2220 . Thus, a flow is formed so that the liquid flows from the common supply passage  2211  to the common collection passage  2212  through the pressure chamber of the printing element board  2010  by the differential pressure. 
     (Description of Ejection Module) 
       FIG.  19 A  is a perspective view illustrating one ejection module  2200  and  FIG.  19 B  is an exploded view thereof. A difference from the first application example is that the terminals  16  are respectively disposed at both sides (the long side portions of the printing element board  2010 ) in the ejection opening row directions of the printing element board  2010 . Accordingly, two flexible circuit boards  40  electrically connected to the printing element board  2010  are disposed for each printing element board  2010 . Since the number of the ejection opening rows provided in the printing element board  2010  is twenty, the ejection opening rows are more than eight ejection opening rows of the first application example. Here, since a maximal distance from the terminal  16  to the printing element is shortened, a decrease in voltage or a delay of a signal generated in the wiring portion inside the printing element board  2010  is reduced. Further, the liquid communication opening  31  of the support member  2030  is opened along the entire ejection opening row provided in the printing element board  2010 . The other configurations are similar to those of the first application example. 
     (Description of Structure of Printing Element Board) 
       FIG.  20   -( a ) shows a schematic diagram illustrating a face on which the ejection opening  13  is disposed in the printing element board  2010  and  FIG.  20   -( c ) shows a schematic diagram illustrating a rear face of the face of  FIG.  20   -( a ).  FIG.  20   -( b ) shows a schematic diagram illustrating a face of the printing element board  2010  when a cover plate  2020  provided in the rear face of the printing element board  2010  in  FIG.  20   -( c ) is removed. As illustrated in  FIG.  20   -( b ), the liquid supply path  18  and the liquid collection path  19  are alternately provided along the ejection opening row direction at the rear face of the printing element board  2010 . The number of the ejection opening rows is larger than that of the first application example. However, a basic difference from the first application example is that the terminal  16  is disposed at both sides of the printing element board in the ejection opening row direction as described above. A basic configuration is similar to the first application example in that a pair of the liquid supply path  18  and the liquid collection path  19  is provided in each ejection opening row and the cover plate  2020  is provided with the opening  21  communicating with the liquid communication opening  31  of the support member  2030 . 
     Third Application Example 
     &lt;Ink Jet Printing Apparatus&gt; 
     Configurations of the inkjet printing apparatus  1000  and the liquid ejection head  3  according to a third application example of the present invention will be described. The liquid ejection head of the third application example is of a page wide type in which an image is printed on a print medium of a B2 size through one scan. Since the third application example is similar to the second application example in many respects, only difference from the second application example will be mainly described in the description below and a description of the same configuration as that of the second application example will be omitted. 
       FIG.  51    is a schematic diagram illustrating an inkjet printing apparatus according to the application example. The printing apparatus  1000  has a configuration in which an image is not directly printed on a print medium by the liquid ejected from the liquid ejection head  3 . That is, the liquid is first ejected to an intermediate transfer member (an intermediate transfer drum)  1007  to form an image thereon and the image is transferred to the print medium  2 . In the printing apparatus  1000 , the liquid ejection heads  3  respectively corresponding to four colors (C,M,Y,K) of inks are disposed along the intermediate transfer drum  1007  in a circular-arc shape. Accordingly, a full-color printing process is performed on the intermediate transfer member, the printed image is appropriately dried on the intermediate transfer member, and the image is transferred to the print medium  2  conveyed by a sheet conveying roller  1009  to a transfer portion  1008 . The sheet conveying system of the second application example is mainly used to convey a cut sheet in the horizontal direction. However, the sheet conveying system of this application example can be also applied to a continuous sheet supplied from a main roll (not illustrated). In such a drum conveying system, since the sheet is easily conveyed while a predetermined tension is applied thereto, a conveying jam hardly occurs even at a high-speed printing operation. For this reason, the reliability of the apparatus is improved and thus the apparatus is suitable for a commercial printing purpose. Similarly to the first and second application examples, the supply system of the printing apparatus  1000 , the buffer tank  1003 , and the main tank  1006  are fluid-connected to each liquid ejection head  3 . Further, an electrical control unit which transmits an ejection control signal and power to the liquid ejection head  3  is electrically connected to each liquid ejection head  3 . 
     (Description of Fourth Circulation Configuration) 
     The first to third circulation paths illustrated in  FIG.  2 ,  3  or  47    can be also applied as the liquid circulation path, but the circulation path illustrated in  FIG.  52    is desirably applied. The circulation path illustrated in  FIG.  52    is similar to the second circulation path illustrated in  FIG.  3   . However, a main difference from the second circulation path of  FIG.  3    is that a bypass valve  1010  is additionally provided to communicate with each of the passages of the first circulation pumps  1001  and  1002  and the second circulation pump  1004 . The bypass valve  1010  has a function (a first function) of decreasing the upstream pressure of the bypass valve  1010  by opening the valve when a pressure exceeds a predetermined pressure. Further, the bypass valve  1010  has a function (a second function) of opening and closing the valve at an arbitrary timing by a signal from a control substrate of the printing apparatus body. 
     By the first function, it is possible to suppress a large or small pressure from being applied to the downstream side of the first circulation pumps  1001  and  1002  or the upstream side of the second circulation pump  1004 . For example, when the functions of the first circulation pumps  1001  and  1002  are not operated properly, there is a case in which a large flow rate or pressure may be applied to the liquid ejection head  3 . Accordingly, there is concern that the liquid may leak from the ejection opening of the liquid ejection head  3  or each bonding portion inside the liquid ejection head  3  may be broken. However, when the bypass valves  1010  are added to the first circulation pumps  1001  and  1002  as in the application example, the bypass valve  1010  is opened in the event of a large pressure. Accordingly, since the liquid path is opened to the upstream side of each circulation pump, the above-described trouble can be suppressed. 
     Further, by the second function, when the circulation driving operation is stopped, all bypass valves  1010  are promptly opened on the basis of the control signal of the printing apparatus body after the operation of the first circulation pumps  1001  and  1002  and the second circulation pump  1004  are stopped. Accordingly, a high negative pressure (for example, several to several tens of kPa) at the downstream portion (between the negative pressure control unit  230  and the second circulation pump  1004 ) of the liquid ejection head  3  can be released within a short time. When a displacement pump such as a diaphragm pump is used as the circulation pump, a check valve is normally built inside the pump. However, when the bypass valve  1010  is opened, the pressure at the downstream portion of the liquid ejection head  3  can be also released from the downstream portion of the buffer tank  1003 . Although the pressure at the downstream portion of the liquid ejection head  3  can be released only from the upstream side, pressure loss exists in the upstream passage of the liquid ejection head and the passage inside the liquid ejection head. For that reason, since some time is taken when the pressure is released, the pressure inside the common passage inside the liquid ejection head  3  transiently decreases too much. Accordingly, there is concern that the meniscus in the ejection opening may be broken. However, since the downstream pressure of the liquid ejection head is further released when the bypass valve  1010  at the downstream side of the liquid ejection head  3  is opened, the risk of the breakage of the meniscus in the ejection opening is reduced. 
     (Description of Structure of Liquid Ejection Head) 
     A structure of the liquid ejection head  3  according to the third application example of the present invention will be described.  FIG.  53 A  is a perspective view illustrating the liquid ejection head  3  according to the application example, and  FIG.  53 B  is an exploded perspective view thereof. The liquid ejection head  3  is an inkjet page wide type printing head which includes thirty six printing element boards  10  arranged in a line shape (an in-line shape) in the longitudinal direction of the liquid ejection head  3  and prints an image by one color. Similarly to the second application example, the liquid ejection head  3  includes a shield plate  132  which protects a rectangular side face of the head in addition to the signal input terminal  91  and the power supply terminal  92 . 
       FIG.  53 B  is an exploded perspective view illustrating the liquid ejection head  3 . In  FIG.  53 B , components or units constituting the liquid ejection head  3  are divided according to the functions thereof and illustrated (where the shield plate  132  is not illustrated). The functions of the units and the members, and the liquid circulation sequence inside the liquid ejection head  3  are similar to those of the second application example. A main difference from the second application example is that the divided electric wiring boards  90  and the negative pressure control unit  230  are disposed at different positions and the first passage member has a different shape. As in this application example, for example, in the case of the liquid ejection head  3  having a length corresponding to the print medium of a B2 size, the power consumed by the liquid ejection head  3  is large and thus eight electric wiring boards  90  are provided. Four electric wiring boards  90  are attached to each of both side faces of the elongated electric wiring board support portion  82  attached to the liquid ejection unit support portion  81 . 
       FIG.  54 A  is a side view illustrating the liquid ejection head  3  including the liquid ejection unit  300 , the liquid supply unit  220 , and the negative pressure control unit  230 ,  FIG.  54 B  is a schematic diagram illustrating a flow of the liquid, and  FIG.  54 C  is a perspective view illustrating a cross-section taken along a line LIVC-LIVC of  FIG.  54 A . In order to easily understand the drawings, a part of the configuration is simplified. 
     The liquid connection portion  111  and the filter  221  are provided inside the liquid supply unit  220  and the negative pressure control unit  230  is integrally formed at the lower side of the liquid supply unit  220 . Accordingly, a distance between the negative pressure control unit  230  and the printing element board  10  in the height direction becomes short compared with the second application example. With this configuration, the number of the passage connection portions inside the liquid supply unit  220  decreases. As a result, there is an advantage that the reliability of preventing the leakage of the printing liquid is improved and the number of components or assembly steps decreases. 
     Further, since a water head difference between the negative pressure control unit  230  and the ejection opening forming face of the liquid ejection head  3  decreases relatively, this configuration can be suitably applied to the printing apparatus in which the inclination angle of the liquid ejection head  3  illustrated in  FIG.  51    is different for each of the liquid ejection heads. Since the water head difference can be decreased, a difference in negative pressure applied to the ejection openings of the printing element boards can be reduced even when the liquid ejection heads  3  having different inclination angles are used. Further, since a distance from the negative pressure control unit  230  to the printing element board  10  decreases, a flow resistance therebetween decreases. Accordingly, a difference in pressure loss caused by a change in flow rate of the liquid decreases and thus the negative pressure can be more desirably controlled. 
       FIG.  54 B  is a schematic diagram illustrating a flow of the printing liquid inside the liquid ejection head  3 . Although the circulation path is similar to the circulation path illustrated in  FIG.  52    in terms of the circuit thereof,  FIG.  54 B  illustrates a flow of the liquid in the components of the actual liquid ejection head  3 . A pair of the common supply passage  211  and the common collection passage  212  extending in the longitudinal direction of the liquid ejection head  3  is provided inside the elongated second passage member  60 . The common supply passage  211  and the common collection passage  212  are formed so that the liquid flow therein in the opposite directions and the filter  221  is provided at the upstream side of each passage so as to trap foreign materials intruding from the connection portion  111  or the like. In this way, since the liquid flows through the common supply passage  211  and the common collection passage  212  in the opposite directions, a temperature gradient inside the liquid ejection head  3  in the longitudinal direction can be desirably reduced. In order to simplify the description of  FIG.  52   , the flows in the common supply passage  211  and the common collection passage  212  are indicated by the same direction. 
     The negative pressure control unit  230  is connected to the downstream side of each of the common supply passage  211  and the common collection passage  212 . Further, a branch portion is provided in the course of the common supply passage  211  to be connected to the individual supply passages  213   a  and a branch portion is provided in the course of the common collection passage  212  to be connected to the individual collection passages  213   b . The individual supply passage  213   a  and the individual collection passage  213   b  are formed inside the first passage members  50  and each individual supply passage communicates with the opening  10 A (see  FIG.  20   ) of the cover plate  20  provided at the rear face of the printing element board  10 . 
     The negative pressure control units  230  indicated by “H” and “L” of  FIG.  54 B  are units at the high pressure side (H) and the low pressure side (L). The negative pressure control units  230  are back pressure type pressure adjustment mechanisms which control the upstream pressures of the negative pressure control units  230  to a high negative pressure (H) and a low negative pressure (L). The common supply passage  211  is connected to the negative pressure control unit  230  (the high pressure side) and the common collection passage  212  is connected to the negative pressure control unit  230  (the low pressure side) so that a differential pressure is generated between the common supply passage  211  and the common collection passage  212 . By the differential pressure, the liquid flows from the common supply passage  211  to the common collection passage  212  while sequentially passing through the individual supply passage  213   a , the ejection opening  11  (the pressure chamber  23 ) in the printing element board  10 , and the individual collection passage  213   b.    
       FIG.  54 C  is a perspective view illustrating a cross-section taken along a line LIVC-LIVC of  FIG.  54 A . In the application example, each ejection module  200  includes the first passage member  50 , the printing element board  10 , and the flexible circuit board  40 . In the embodiment, the support member  30  ( FIG.  18   ) described in the second application example does not exist and the printing element board  10  including the lid member  20  is directly bonded to the first passage member  50 . The liquid is supplied from the communication opening  61  formed at the upper face of the common supply passage  211  provided at the second passage member to the individual supply passage  213   a  through the individual communication opening  53  formed at the lower face of the first passage member  50 . Subsequently, the liquid passes through the pressure chamber  23  and passes through the individual collection passage  213   b , the individual communication opening  53 , and the communication opening  61  to be collected to the common collection passage  212 . 
     Here, differently from the second application example illustrated in  FIG.  15   , the individual communication opening  53  formed at the lower face of the first passage member  50  (the face near the second passage member  60 ) is sufficiently large with respect to the communication opening  61  formed at the upper face of the second passage member  50 . With this configuration, the first passage member and the second passage member reliably fluid-communicate with each other even when a positional deviation occurs when the ejection module  200  is mounted onto the second passage member  60 . As a result, the yield in the head manufacturing process is improved and thus a decrease in cost can be realized. 
     Though description is made for the first to third application examples to which the present invention can be applied, the description of the above-described application example does not limit the scope of the invention. As an example, in the application example, a thermal type has been described in which bubbles are generated by a heating element to eject the liquid. However, the invention can be also applied to the liquid ejection head which employs a piezo type and the other various liquid ejection types. 
     In the application example, the inkjet printing apparatus (the printing apparatus) has been described in which the liquid such as ink is circulated between the tank and the liquid ejection head, but the other application examples may be also used. In the other application examples, for example, a configuration may be employed in which the ink is not circulated and two tanks are provided at the upstream side and the downstream side of the liquid ejection head so that the ink flows from one tank to the other tank. In this way, the ink inside the pressure chamber may flow. 
     In the application example, an example of using a so-called page wide type head having a length corresponding to the width of the print medium has been described, but the invention can be also applied to a so-called serial type liquid ejection head which prints an image on the print medium while scanning the print medium. As the serial type liquid ejection head, for example, the liquid ejection head may be equipped with a printing element board ejecting black ink and a printing element board ejecting color ink, but the invention is not limited thereto. That is, a liquid ejection head which is shorter than the width of the print medium and includes a plurality of printing element boards disposed so that the ejection openings overlap each other in the ejection opening row direction may be provided and the print medium may be scanned by the liquid ejection head. 
     Next, a description will be given of embodiments, mainly focusing on characteristics of the present invention. 
     First Embodiment 
       FIGS.  22 A,  22 B, and  22 C  are diagrams for description of a configuration of an ejection opening and an ink passage adjacent to the ejection opening in a liquid ejection head according to a first embodiment of the invention.  FIG.  22 A  is a plan view of the ink passage, etc. viewed from a side at which ink is ejected,  FIG.  22 B  is a cross-sectional view taken along XXIIB-XXIIB line of  FIG.  22 A , and  FIG.  22 C  is a perspective view of a cross section taken along XXIIB-XXIIB line of  FIG.  22 A . 
     As illustrated in these figures, the circulation of ink described with reference to  FIG.  12   , etc., generates a flow  17  of ink in a pressure chamber  23  provided with a printing element  15  and passages  24  in front and back of the pressure chamber  23  on a substrate  11  of the liquid ejection head. In more detail, a differential pressure that causes ink circulation causes the flow of ink supplied from a liquid supply path (supply passage)  18  through a supply opening  17   a  provided in the substrate  11  to pass through the passage  24 , the pressure chamber  23 , and the passage  24 , and arrive at a liquid collection path (outflow passage)  19  through a collection opening  17   b.    
     In addition to the above-described ink flow, a space from the printing element (energy generation element)  15  to an ejection opening  13  above the printing element  15  is full of ink in a non-ejection state, and a meniscus of ink (ink boundary  13   a ) is formed around an end portion of the ejection opening  13  at a side in an ejection direction. The ink boundary is indicated by a straight line (plane) in  FIG.  22 B . However, a shape thereof is determined according to a member that forms a wall of the ejection opening  13  and ink surface tension. Normally, the shape becomes a curved line (curved surface) having a concave or convex shape. The ink boundary is indicated by the straight line to simplify illustration. When an electro-thermal conversion element (heater) corresponding to the energy generation element  15  is driven in a condition that the meniscus is formed, bubbles may be generated in ink using generated heat to eject ink from the ejection opening  13 . In the present embodiment, an example in which the heater is used as the energy generation element is described. However, the invention is not restricted thereto. For example, various energy generation elements such as a piezoelectric element, etc. may be used. In the present embodiment, for example, a speed of the ink flow flowing through the passages  24  is in a range of about 0.1 to 100 mm/s, and an influence on impact accuracy, etc. may be made relatively small even when an ejection operation is performed while ink flows. 
     &lt;With Regard to Relation Among P, W, and H&gt; 
     Referring to the liquid ejection head of the present embodiment, a relation among a height H of the passage  24 , a thickness P of an orifice plate (a passing forming member  12 ), and a length (diameter) W of the ejection opening is determined as described below. 
     In  FIG.  22 B , the height of the passage  24  at an upstream side at a lower end (a communication portion between the ejection opening portion and the passage) of a portion corresponding to the thickness P of the orifice plate of the ejection opening  13  (hereinafter referred to as an ejection opening portion  13   b ) is indicated by H. In addition, a length of the ejection opening portion  13   b  is indicated by P. Further, a length of the ejection opening portion  13   b  in a flow direction of liquid inside the passage  24  is indicated by W. Referring to the liquid ejection head of the present embodiment, H is in a range of 3 to 30 μm, P is in a range of 3 to 30 μm, and W is in a range of 6 to 30 μm. In addition, referring to ink, non-volatile solute concentration is adjusted to 30%, color material concentration is adjusted to 3%, and viscosity is adjusted to a range of 0.002 to 0.01 Pa·s. 
     The present embodiment is configured as below to inhibit ink from thickening due to evaporation of ink from the ejection opening  13 .  FIG.  43    is a diagram illustrating an aspect of a flow of the ink flow  17  in the ejection opening  13 , the ejection opening portion  13   b , and the passages  24  when the ink flow  17  (see  FIGS.  22 A,  22 B, and  22 C ) of ink flowing inside the passages  24  and the pressure chamber  23  of the liquid ejection head is in a steady state. In this figure, a length of an arrow does not indicate a magnitude of a velocity of the ink flow.  FIG.  43    illustrates a flow when ink flows into the passages  24  from the liquid supply path  18  at a flow amount of 1.26×10 −4  ml/min in the liquid ejection head in which the height H of the passage  24  is 14 μm, the length P of the ejection opening portion  13   b  is 10 μm, and the length (diameter) W of the ejection opening is 17 μm. 
     The present embodiment has a relation in which the height H of the passage  24 , the length P of the ejection opening portion  13   b , and the length W of the ejection opening portion  13   b  in the flow direction of ink satisfy Expression (1) below.
 
 H   −0.34   ×P   −0.66   ×W &gt;1.5  Expression (1)
 
     When the liquid ejection head of the present embodiment satisfies this condition, as illustrated in  FIG.  43   , the ink flow  17  flowing into the passage  24  flows into the ejection opening portion  13   b , arrives at a position corresponding to at least half the thickness of the orifice plate of the ejection opening portion  13   b , and then returns to the passage  24  again. Ink returning to the passage  24  flows to the common collection passage  212  described above through the liquid collection path  19 . In other words, at least a portion of the ink flow  17  arrives at a position corresponding to half or more of the ejection opening portion  13   b  in a direction toward the ink boundary  13   a  from the pressure chamber  23 , and then returns to the passage  24 . It is possible to inhibit ink from thickening by this flow in a large region inside the ejection opening portion  13   b . When such an ink flow inside the liquid ejection head is generated, ink of the ejection opening portion  13   b  in addition to the passage  24  may flow out to the passage  24 . As a result, it is possible to inhibit ink from thickening and ink color material concentration from increasing in the ink ejection opening  13  and the ejection opening portion  13   b . A liquid droplet of ink ejected from the ejection opening includes ink in the ejection opening portion  13   b  and ink in the pressure chamber  23  (the passage  24 ) to be ejected in a mixed state. In the embodiment, it is desirable that a rate of the ink from the pressure chamber  23  (the passage  24 ) is greater than a rate of ink from the ejection opening portion in the ejected liquid droplet. This condition corresponds to for example a case in which a bubble generating for ejection communicates with an outer air. Especially, a liquid ejection head, which has sizes of H being equal to or less than 20 μm, P being equal to or less than 20 μm and W being equal to or less than 30 μm and is then capable of performing higher-definition printing, is desirable. As described above, the embodiment can suppress variation in a quality of liquid adjacent to the ejection opening and thus can achieve suppressing increase of ink viscosity due to liquid evaporation from the ejection opening and reducing color unevenness in an image. 
     Second Embodiment 
       FIG.  23    is a diagram illustrating an aspect of a flow of ink flowing into a liquid ejection head according to a second embodiment of the invention. The same reference symbol will be assigned to the same portion as that in the above-described first embodiment, and a description thereof will be omitted. 
     The present embodiment is configured as below to further reduce an influence of thickening of ink due to evaporation of liquid from an ejection opening.  FIG.  23    is a diagram illustrating an aspect of a flow of an ink flow  17  in an ejection opening  13 , an ejection opening portion  13   b , and a passage  24  when the ink flow  17  flowing inside the liquid ejection head is in a steady state similarly to  FIG.  43   . In this figure, a length of an arrow does not correspond to a magnitude of a velocity, and a certain length is indicated irrespective of a magnitude of a velocity.  FIG.  23    illustrates a flow when ink flows into the passage  24  at a flow amount of 1.26×10 −4  ml/min from a liquid supply path  18  in the liquid ejection head in which H is 14 μm, P is 5 μm, and W is 12.4 μm. 
     The present embodiment has a relation in which the height H of the passage  24 , the length P of the ejection opening portion  13   b , and the length W of the ejection opening portion  13   b  in a flow direction of ink satisfy Expression (2) described below. Thereby, staying of ink at a vicinity of the ink boundary  13   a  of the ejection opening portion  13   b , in which color material concentration of the ink changes and a viscosity of the ink increases due to ink evaporation through the ejection opening, can be inhibited in a more effective manner than the first embodiment. In more detail, in the liquid ejection head of the present embodiment, as illustrated in  FIG.  23   , the ink flow  17  flowing into the passage  24  flows into the ejection opening portion  13   b , arrives at a position adjacent to the ink boundary  13   a  (a meniscus position), and then returns to the passage  24  again through the inside of the ejection opening portion  13   b . Ink returning to the passage  24  flows to the common collection passage  212  described above through a liquid collection path  19 . Such ink flow allows not only the ink inside the ejection opening portion  13   b  at which the influence of evaporation is easily received but also the ink near the ink boundary  13   a  at which an influence of evaporation is particularly remarkable to flow out to the passage  24  without staying inside the ejection opening portion  13   b . As a result, ink around the ejection opening, particularly at a position at which an influence of evaporation of ink moisture, etc. is easily received, may be allowed to flow out without staying there, and it is possible to inhibit ink from thickening or ink color material concentration from increasing. The present embodiment may inhibit at least a portion of the ink boundary  13   a  from increasing in viscosity, and thus may further reduce an influence on ejection such as a change in ejection velocity, etc. when compared to a case in which the entire ink boundary  13   a  increases in viscosity. 
     The above-described ink flow  17  of the present embodiment has a velocity component in a flow direction of ink (a direction from a left side to a right side in  FIG.  23   ) inside the passage  24  (hereinafter referred to as a positive velocity component) at least at a central portion around the ink boundary  13   a  (a central portion of the ejection opening). In the present specification, a flow mode in which the ink flow  17  has a positive velocity component at least at the central portion around the ink boundary  13   a  is referred to as a “flow mode A”. In addition, a flow mode in which the ink flow  17  has a negative velocity component in an opposite direction to that of the positive velocity component at the central portion around the ink boundary  13   a  as in a comparative example described below is referred to as a “flow mode B”. 
       FIGS.  24 A and  24 B  are diagrams illustrating a state of color material concentration of ink inside the ejection opening portion  13   b .  FIG.  24 A  illustrates a state of the present embodiment, and  FIG.  24 B  illustrates a state of a comparative example. In more detail,  FIG.  24 A  illustrates the case of the flow mode A, and  FIG.  24 B  illustrates the case of the flow mode B related to the above-described comparative example in which a flow around the central portion of the ink boundary  13   a  inside the ejection opening portion  13   b  has a negative velocity component. Further, contour lines illustrated in  FIGS.  24 A and  24 B  indicate color material concentration distributions in ink inside the ejection opening portion  13   b.    
     Flow modes A and B are determined based on values of P, W, and H indicating a structure of a passage, etc.  FIG.  24 A  illustrates a state of the flow mode A when ink flows in at 1.26×10 −4  ml/min from the liquid supply path  18  to the passage  24  of the liquid ejection head which has a shape in which H is 14 μm, P is 5 μm, and W is 12.4 μm. Meanwhile,  FIG.  24 B  illustrates a state of the flow mode B when ink flows in at 1.26×10 −4  ml/min from the liquid supply path  18  to the passage  24  of the liquid ejection head which has a shape in which H is 14 μm, P is 11 μm, and W is 12.4 μm. Color material concentration of ink inside the ejection opening portion  13   b  is higher in the flow mode B illustrated in  FIG.  24 B  than in the flow mode A illustrated in  FIG.  24 A . In other words, in the flow mode A illustrated in  FIG.  24 A , ink inside the ejection opening portion  13   b  may be replaced (allowed to flow out) up to the passage  24  by the ink flow  17  arriving at a portion around the ink boundary  13   a  with a positive velocity component. In this way, ink inside the ejection opening portion  13   b  may be inhibited from staying. As a result, it is possible to suppress an increase in color material concentration and viscosity. 
       FIG.  25    is a diagram for description of a comparison between color material concentration of ink ejected from a liquid ejection head (head A) that generates the flow mode A and color material concentration of ink ejected from a liquid ejection head (head B) that generates the flow mode B. This figure illustrates data corresponding to a case in which ink is ejected while the ink flow  17  is generated in the passage  24  and a case in which ink is ejected while the ink flow  17  is not generated and no ink flow is present inside the passage in each of head A and head B. In addition, in this figure, a horizontal axis indicates elapsed time after ink is ejected from the ejection opening, and a vertical axis indicates a color material concentration ratio of a dot formed on a printing medium by ejected ink. This density ratio is a ratio of density of a dot formed by ink ejected after each elapsed time when density of a dot formed by ink ejected at an ejection frequency of 100 Hz is set to 1. 
     As illustrated in  FIG.  25   , when the ink flow  17  is not generated, a density ratio becomes 1.3 or more after an elapsed time of 1 second or more in both the heads A and B, and color material concentration of ink rises in a relatively short time. In addition, when the ink flow  17  is generated in the head B, a density ratio is in a range up to about 1.3, and an increase in color material concentration may be suppressed when compared to a case in which any ink flow is not generated. However, ink having increased color material concentration, which corresponds to a density ratio of up to 1.3, stays in the ejection opening portion. On the other hand, when an ink flow is generated in the head A, a range of a color material concentration ratio is 1.1 or less. It is understood from an examination that a human has difficulty in visually recognizing color unevenness when a change in color material concentration is about 1.2 or less. In other words, the head A suppresses a change in color material concentration which causes color unevenness to be visually recognized, even when an elapsed time is about 1.5 second and therefore is much desirable than the head B.  FIG.  25    illustrates a case in which color material concentration increases with evaporation. However, the liquid ejection head of the present embodiment may similarly suppress a change in color material concentration when color material concentration decreases with evaporation. 
     From an examination of the inventors, etc., it is understood that, in the liquid ejection head generating the flow mode A in the present embodiment, a relation among the height H of the passage  24 , the thickness P of the orifice plate (passing forming member  12 ), and the length (diameter) W of the ejection opening satisfies Expression (2) below.
 
 H   −0.34   ×P   −0.66   ×W&gt; 1. 7   Expression (2)
 
     Hereinafter, a value of a right side of the above Expression (2) will be referred to as a determination value J. From the examination of the inventors, etc., it is understood that a liquid ejection head satisfying Expression (2) is in the flow mode A illustrated in  FIG.  23   , and a liquid ejection head generating the flow mode B does not satisfy Expression (2). 
     Hereinafter, Expression (2) will be described. 
       FIG.  26    is a diagram illustrating a relation between the liquid ejection head that generates the flow mode A of the second embodiment and the liquid ejection head that generates the flow mode B of the comparative example. A horizontal axis of  FIG.  26    indicates a ratio of P to H (P/H), and a vertical axis thereof indicates a ratio of W to P (W/P). A threshold line  20  is a line that satisfies Expression (3) below.
 
( W/P )=1.7×( P/H ) −0.34   Expression (3)
 
     In  FIG.  26   , a relation among H, P, and W corresponds to the flow mode A in a liquid ejection head present in a region indicated by diagonal lines above the threshold line  20 , and corresponds to the flow mode B in a liquid ejection head present in a region below and on the threshold line  20 . In other words, the relation corresponds to the flow mode A in a liquid ejection head that satisfies Expression (4) below.
 
( W/P )&gt;1.7×( P/H ) −0.34   Expression (4)
 
     When Expression (4) is transformed, Expression (2) is obtained. Thus, a head in which the relation among H, P, and W satisfies Expression (2) (a head whose determination value J is 1.7 or more) corresponds to the flow mode A. 
     The relation will be further described with reference to  FIGS.  27 A to  27 D  and  FIG.  28   .  FIGS.  27 A to  27 D  are diagrams for description of an aspect of the ink flow  17  around the ejection opening portion  13   b  in the liquid ejection head corresponding to each of the regions above and below the threshold line  20  illustrated in  FIG.  26   .  FIG.  28    is a diagram for description of whether a flow corresponds to the flow mode A or the flow mode B with regard to various shapes of liquid ejection heads. In  FIG.  28   , a black round mark indicates a liquid ejection head corresponding to the flow mode A, and an x mark indicates a liquid ejection head corresponding to the flow mode B. 
       FIG.  27 A  illustrates an ink flow in a liquid ejection head having a shape in which H is 3 μm, P is 9 μm, and W is 12 μm, and having a determination value J of 1.93, which is larger than 1.7. In other words, an example illustrated in  FIG.  27 A  corresponds to the flow mode A. This head corresponds to a point A in  FIG.  28   . 
       FIG.  27 B  illustrates an ink flow in a liquid ejection head having a shape in which H is 8 μm, P is 9 μm, and W is 12 μm, and having a determination value of 1.39, which is smaller than 1.7. In other words, this flow corresponds to the flow mode B. This head corresponds to a point B in  FIG.  28   . 
       FIG.  27 C  illustrates an ink flow in a liquid ejection head having a shape in which H is 6 μm, P is 6 μm, and W is 12 μm, and having a determination value of 2.0, which is larger than 1.7. In other words, this flow corresponds to the flow mode A. In addition, this head corresponds to a point C in  FIG.  28   . 
     Finally,  FIG.  27 D  illustrates an ink flow in a liquid ejection head having a shape in which H is 6 μm, P is 6 μm, and W is 6 μm, and having a determination value of 1.0, which is smaller than 1.7. In other words, this flow corresponds to the flow mode B. In addition, this head corresponds to a point D in  FIG.  28   . 
     As described above, liquid ejection heads may be classified into liquid ejection heads corresponding to the flow mode A and liquid ejection heads corresponding to the flow mode B using the threshold line  20  of  FIG.  26    as a boundary. In other words, a liquid ejection head, in which the determination value J of Expression (2) is larger than 1.7, corresponds to the flow mode A, and the ink flow  17  has a positive velocity component at least at the central portion of the ink boundary  13   a.    
     Next, a description will be given of a comparison of ejection velocities of ink drops ejected from the liquid ejection head (head A) that generates the flow mode A and the liquid ejection head (head B) that generates the flow mode B, respectively. 
       FIGS.  29 A and  29 B  are diagrams illustrating a relation between the number of ejections (the number of ejections) after pausing for a certain time after ejection from a liquid ejection head in each flow mode and an ejection velocity corresponding thereto. 
       FIG.  29 A  illustrates a relation between the number of ejections and an ejection velocity when pigment ink containing 20 wt. % or more of solid content, ink viscosity of which is about 4 cP at an ejection temperature, is ejected using the head B. As shown in  FIG.  29 A , the ejection velocity decreases until about a 20 th  ejection depending on the pause time even when the ink flow  17  is present.  FIG.  29 B  illustrates a relation between the number of ejections and an ejection velocity when the same pigment ink as that of  FIG.  29 A  is ejected using the head A, and the ejection velocity does not decrease from a first ejection after a pause. In this experiment, ink containing 20 wt. % or more of solid content is used. However, concentration does not restrict the invention. Even though easiness of dispersion of solid content in ink is involved, an effect of the mode A is clearly exhibited when ink containing approximately 8 wt. % or more of solid content is ejected. 
     As described above, in the head that generates the flow mode A, a decrease in ejection velocity of an ink droplet may be suppressed even when ink, an ejection velocity of which easily decreases due to thickening of ink resulting from evaporation of ink from the ejection opening, is used. 
     As described in the foregoing, a relation among P, W, and H associated with a shape of a passage, etc. has a dominant influence on whether a flow of the ink flow  7  inside the ejection opening corresponds to the flow mode A or the flow mode B in a case of a normal environment. Besides these conditions, for example, conditions such as a velocity of the ink flow  17 , viscosity of ink, and a width of the ejection opening  13  in a direction perpendicular to a direction of the flow of the ink flow  7  (a length of the ejection opening in a direction intersecting W) have an extremely small influence when compared to P, W, and H. Therefore, a flow velocity of ink or viscosity of ink may be appropriately set based on a required specification of the liquid ejection head (inkjet printing apparatus) or a condition of a used environment. For example, the flow velocity of the ink flow  17  in the passage  24  may be set to 0.1 to 100 mm/s, and 30 cP or less of ink at an ejection temperature may be applied to viscosity of ink. In addition, when the amount of evaporation from the ejection opening increases due to a change in environment at the time of use, etc., the flow mode A may be obtained by appropriately increasing a flow amount of the ink flow  17 . In the liquid ejection head in the flow mode B, the flow mode A is not obtained even when the flow amount is increased. In other words, the relation among H, P, and W associated with the shape of the liquid ejection head described above rather than the condition of the flow velocity of ink or viscosity of ink has a dominant influence on whether the mode A or the mode B is obtained. In addition, among various liquid ejection heads corresponding to the flow mode A, in particular, a liquid ejection head in which H is 20 μm or less, P is 20 μm or less, and W is 30 μm or less can perform high-resolution printing, and thus is preferable. 
     As described in the foregoing, the liquid ejection head that generates the flow mode A allows ink inside the ejection opening portion  13   b , in particular, ink around the ink boundary to flow out to the passage  24  by the ink flow  17  that arrives at a portion around the ink boundary  13   a  with a positive velocity component. Therefore, ink is inhibited from staying inside the ejection opening portion  13   b . In this way, with regard to evaporation of ink from the ejection opening, an increase in color material concentration, etc. of ink inside the ejection opening portion may be reduced. In addition, in the present embodiment, an ink ejection operation is performed while ink inside the passage  24  flows as described above. Thus ink is ejected while a flow of ink, which enters the inside of the ejection opening portion  13   b  from the passage (pressure chamber  23 ), arrives at the ink boundary, and then returns to the ink passage, is present. As a result, even in a printing operation pause state, an increase in color material concentration inside the ejection opening portion  13   b  is reduced at all times. Thus, ejection of a first ejection may be favorably performed after a pause in a printing operation, and occurrence of color unevenness, etc. may be reduced. However, the invention is applicable to a liquid ejection head that performs an ink ejection operation while an ink flow in the ink passage  24  is suspended. Thickening of ink inside the ejection opening portion  13   b  may be reduced by generating a circulation flow inside the ink passage after the pause in the printing operation, and ink may be ejected after suspending the circulation flow. 
     Third Embodiment 
       FIG.  30    is a diagram illustrating an aspect of a flow of an ink flow of ink flowing inside a liquid ejection head according to a third embodiment of the invention. The same reference symbol will be assigned to the same portion as that in the above-described embodiments, and a description thereof will be omitted. As illustrated in  FIG.  30   , in the present embodiment, a height of a passage  24  adjacent to an ejection opening  13  (an ejection opening portion  13   b ) is lower than a height of the passage  24  in another portion. Specifically, a height H of the passage  24  at an upstream side of a communication portion between the passage  24  and the ejection opening portion  13   b  in a flow direction of liquid inside the passage is lower than a height of the passage  24  in the communication portion between the passage  24  and the liquid supply path  18  (see  FIGS.  22 A to  22 C ). Also in the present embodiment, setting of sizes of H, P and W so that satisfy the expression (1) allows at least a part of the ink flow  17  to arrive at a position corresponding to half or more of the ejection opening portion  13   b  in a direction from the pressure chamber  23  to the ink boundary  13   a  and then return to passage  24 . Further, also in the configuration of the present embodiment, setting the size of each H, P and W so as to satisfy the expression (2) generates the flow mode A. 
     In the present embodiment, when a height of a passage from the communication portion between the passage  24  and the liquid supply path  18  to a portion adjacent to the ejection opening portion, and a height of a passage from the portion adjacent to the ejection opening portion to a liquid collection path  19  are set to be relatively high, a passage resistance of the part may be set to be low. In addition, when a height H of a passage around the ejection opening portion  13   b  is set to be relatively small, the liquid ejection head of the flow mode A described in the first embodiment may be obtained. Normally, when the height of the passage  24  is set to be low as a whole in order to satisfy Expression (2), a passage resistance from the liquid supply path  18  or the liquid collection path  19  to the ejection opening  13  increases, and a speed (refilling speed) of refilling with ink, which is insufficient due to ejection, decreases in some cases. Therefore, as a configuration of the present embodiment, setting a height of the passage near the ejection opening to be smaller than that of other passage allows a necessary refilling speed to be ensured while satisfying Expressions (1) and (2). Thereby, both of suppressing increase of ink viscosity at the ejection opening and a high speed printing (improving of throughput) can be achieved. 
     Fourth Embodiment 
       FIG.  31    is a diagram illustrating an aspect of a flow of an ink flow of ink flowing inside a liquid ejection head according to a fourth embodiment of the invention. In  FIG.  31   , a concave portion  13   c  is formed around an ejection opening  13  on a surface of an orifice plate  12 . In other words, the ejection opening  13  is formed inside the concave portion  13   c  (a bottom surface of the concave portion  13   c ) which is formed on the orifice plate. In a normal state and a steady state in which a circulation flow exists, a meniscus of ink (an ink boundary  13   a ) is formed on a boundary surface between the ejection opening  13  and the bottom surface of the concave portion  13   c . Also in the present embodiment, setting of sizes of H, P and W so that satisfy the expression (1) allows at least a part of the ink flow  17  to arrive at a position corresponding to half or more of the ejection opening portion  13   b  in a direction from the pressure chamber  23  to the ink boundary  13   a  and then return to passage  24 . Further, also in the configuration of the present embodiment, setting of sizes of H, P and W so that satisfy the expression (2) generates the flow mode A. In the present embodiment, P of Expressions (1) and (2) corresponds to a length of an ejection opening portion, that is, a length from a portion in which the meniscus of ink is formed to a passage  24  as illustrated in  FIG.  31   . That is, a thickness of the orifice plate  12  around a place coming into contact with the ejection opening  13  is thinner than another place. Specifically, the thickness of the orifice plate  12  around the ejection opening  13  is thinner than the thickness of the orifice plate in the communication portion between the passage  24  and the liquid supply path  18  (see  FIGS.  22 A to  22 C ). 
     In the present embodiment, the thickness P of the orifice plate around the ejection opening portion  13   b  may be set to be small while the thickness of the orifice plate  12  is kept thick to a certain extent as the whole head. Normally, when the length P of the ejection opening portion is set to be short in order to satisfy Expressions (1) and (2), the thickness of the whole orifice plate becomes thin, and strength of the orifice plate decreases. However, according to a configuration of the present embodiment, it is possible to ensure strength of the orifice plate  12  as a whole in addition to effects of the first embodiment and the second embodiment. 
     Fifth Embodiment 
       FIG.  32    is a diagram illustrating an aspect of a flow of an ink flow of ink flowing inside a liquid ejection head according to a fifth embodiment of the invention. As illustrated in  FIG.  32   , a height of a passage  24  around a portion connected to an ejection opening  13  is lower than another place. In addition, a concave portion  13   c  is formed around the ejection opening  13  on a surface of an orifice plate  12 . As a specific configuration, a height H of the passage  24  at an upstream side of a communication portion between the passage  24  and an ejection opening portion  13   b  in a flow direction of liquid inside the passage is lower than a height of the passage  24  near the communication portion between the passage  24  and the liquid supply path  18  (see  FIGS.  22 A to  22 C ). Also in the configuration of the present embodiment, similarly to the fourth embodiment, in a normal state and a steady state in which a circulation flow exists, a meniscus of ink (an ink boundary  13   a ) is formed on a boundary surface between the ejection opening  13  and the bottom surface of the concave portion  13   c.    
     The present embodiment may set the height H of the passage around the ejection opening to be low while a passage resistance from a liquid supply path  18  or a liquid collection path  19  to the ejection opening  13  is kept low. Further, present embodiment may set a length P of the ejection opening portion  13   b  to be short. Normally, when the height of the passage  24  around the portion connected to the ejection opening  13  is set to be lower than another place, a thickness of the orifice plate  12  around the ejection opening  13  becomes thick accordingly, and a length P of the ejection opening  13  becomes long. On the other hand, according to a configuration of the present embodiment, it is possible to ensure a necessary refilling speed in addition to the effects of the first embodiment and the second embodiment. 
     Sixth Embodiment 
       FIG.  33    is a diagram illustrating an aspect of a flow of an ink flow of ink flowing inside a liquid ejection head according to a sixth embodiment of the invention. As illustrated in  FIG.  33   , the liquid ejection head of the present embodiment has a stepped portion in a communication portion between a passage  24  and an ejection opening portion  13   b . In the present embodiment, a portion from an ejection opening  13  to a part in which the stepped portion is formed corresponds to the ejection opening portion  13   b , and the ejection opening portion  13   b  is connected to the passage  24  through a part (a portion of the passage) having a lager diameter than that of the ejection opening portion  13   b . Therefore, P, W, and H in the present embodiment are defined as illustrated in the figure. Also in the liquid ejection head, setting of sizes of H, P and W so that satisfy the expression (1) allows at least a part of the ink flow  17  to arrive at a position corresponding to half or more of the ejection opening portion  13   b  in a direction from the pressure chamber  23  to the ink boundary  13   a  and then return to passage  24 . Further, setting of sizes of H, P and W so that satisfy the expression (2) generates the flow mode A. 
     In this way, when a part from the passage toward the ejection opening has a multi-step structure, a flow resistance in a direction from an energy generation element toward the ejection opening  13  may be set to be relatively small. In this way, a configuration of the present embodiment allows an ejection efficiency to be improved and therefore in addition to the effects of the first embodiment and the second embodiment, for example, the configuration of the present embodiment is preferable when a small liquid droplet of 5 pl or less is ejected. 
     Seventh Embodiment 
       FIG.  34    is a diagram illustrating an aspect of a flow of an ink flow of ink flowing inside a liquid ejection head according to a seventh embodiment of the invention. As illustrated in  FIG.  34   , an ejection opening portion  13   b  that allows communication between an ejection opening  13  and a passage  24  has a shape of a truncated cone. Specifically, an opening size of the ejection opening portion  13   b  on the passage side is larger than an opening size of the ejection opening portion  13   b  on the ejection opening  13  side, and a side wall has a tapered shape. According to this configuration, a flow resistance in a direction from an energy generation element  15  toward the ejection opening  13  can be set to be relatively small and thus the ejection efficiency can be improved. Also in the present embodiment, setting of sizes of H, P and W so that satisfy the expression (1) allows at least a part of the ink flow  17  to arrive at a position corresponding to half or more of the ejection opening portion  13   b  in a direction from the pressure chamber  23  to the ink boundary  13   a  and then return to passage  24 . Further, also in the present embodiment, setting of sizes of H, P and W so that satisfy the expression (2) generates the flow mode A. In the present embodiment, referring to W of Expressions (1) and (2), as illustrated in  FIG.  34   , a length of a communication portion between the ejection opening portion  13   b  and the passage  24  is defined as W. In addition to the effect of the first embodiment, for example, a configuration of the present embodiment is a preferable configuration when a small liquid droplet of 5 pl or less is ejected. 
     Eighth Embodiment 
       FIGS.  35 A and  35 B  are diagrams illustrating two examples of a shape of a liquid ejection head, in particular, an ejection opening according to an eighth embodiment of the invention, and show plan views (schematic views) of the liquid ejection head looked from a direction in which a liquid is ejected from the ejection opening  13 . The ejection opening  13  of the present embodiment has a shape in which protrusions  13   d , each of which elongates toward the center of the ejection opening, are formed at opposite positions to each other. The protrusions  13   d  continuously extend from an outer surface of the ejection opening  13  up to an inside of an ejection opening portion  13   b . Also in the shape having the protrusions, setting of sizes of H, P and W so that satisfy the expression (1) allows at least a part of the ink flow  17  to arrive at a position corresponding to half or more of the ejection opening portion  13   b  in a direction from the pressure chamber  23  to the ink boundary  13   a  and then return to passage  24 . Further, setting of sizes of H, P and W so that satisfy the expression (2) generates the flow mode A. 
     In the ejection opening of the example illustrated in  FIG.  35 A , the protrusions  13   d  protruding in a direction intersecting a flow of liquid inside a passage are formed. In the ejection opening of the example illustrated in  FIG.  35 B , the protrusions  13   d  protruding in a direction of an ink flow are formed. When the protrusions are formed in the ejection opening  13 , a meniscus formed between the protrusions  13   d  may be more easily maintained than a meniscus in another portion inside the ejection opening, and tailing of an ink droplet extending from the ejection opening may be cut at an earlier time. In this way, it is possible to suppress occurrence of mist corresponding to a minute liquid droplet concomitant with a main droplet. 
       FIGS.  44 A to  45 B  are diagrams illustrating more specific configurations of the liquid ejection head shown in  FIG.  35 B . Specific sizes of respective portions in the present embodiment are H=16 μm, P=6 μm, W=22 μm and a determination value J=2.6 in a configuration of  FIGS.  44 A,  44 B  and H=5 μm, P=5 μm, W=20 μm and a determination value J=4.3 in a configuration of  FIGS.  45 A,  45 B . 
     Ninth Embodiment 
       FIGS.  36 A to  38    are diagrams illustrating a liquid ejection head according to a ninth embodiment of the invention. The present embodiment improves the second to eighth embodiments, and does not restrict the above-described embodiments. A description will be given of a relation between the amount of evaporation of ink water, etc. from an ink boundary  13   a  formed in an ejection opening  13  and a flow amount of an ink flow  17  with reference to  FIGS.  36 A and  36 B  and  FIGS.  37 A and  37 B . When the amount of evaporation from the ink boundary  13   a  is relatively large, and the flow rate of the ink flow  17  is small with respect to the amount of evaporation according to an environmental condition, etc., a flow directed toward the ink boundary  13   a  is dominant in a flow of ink inside an ejection opening portion  13   b  as illustrated in  FIG.  36 A . Hereinafter, a state in which the flow directed toward the ink boundary  13   a  is dominant in the flow of ink in the ejection opening portion  13   b  as described above will be referred to as a state D. In the case of the state D, color material concentration inside the ejection opening portion becomes relatively high due to evaporation as illustrated in  FIG.  37 A . In contrast, when the ink flow  17  is sufficient with respect to the amount of evaporation even when the amount of evaporation is large, the ink flow is dominant over the flow directed toward the ink boundary  13   a  in a flow of ink inside an ejection opening portion  13   b  as illustrated in  FIG.  36 B . Hereinafter, a state in which the ink flow  17  is dominant over the flow directed toward the ink boundary  13   a  in the flow of ink in the ejection opening portion  13   b  as described above will be referred to as a state C. In this way, as illustrated in  FIG.  37 B , color material concentration inside the ejection opening portion becomes relatively low. In other words, in liquid ejection heads that satisfy Expressions (1) and (2) described in the first and second embodiments, the state C can exist. More specifically, the state C can be obtained by sufficiently increasing the flow amount of the ink flow even when the amount of evaporation from the ink boundary  13   a  increases due to an environmental condition, etc. at the time of using the liquid ejection head. Thereby, ink having changed color material concentration due to evaporation of ink from the ejection opening may be further inhibited from staying in the ejection opening portion  13   b.    
     A description will be given of the case of a liquid ejection head that does not satisfy Expression (2) as a comparative example. In this example, the flow mode A is not obtained even when the flow amount of the ink flow  17  is increased. In other words, Expression (2) needs to be satisfied to obtain the flow mode A. 
     Herein, even in the case of the liquid ejection head that satisfies Expression (2), pressure loss increases as the amount of the ink flow  17  is increased. For this reason, a pressure difference between the common supply path  211  and the common collection passage (see  FIG.  2    and  FIG.  3   ) needs to be increased. In addition, a pressure difference up to each ejection opening inside the liquid ejection head increases, and there is difficulty in making an ejection characteristic uniform. Therefore, from these points of view, it is desirable that the flow amount of the ink flow  17  be set to be as small as possible. 
     In this regard, an example of a condition of flow velocity of the ink flow  17  for obtaining the state C in the liquid ejection head that generates the flow mode A will be described below. 
     The present embodiment sets a condition below to inhibit ink having changing color material concentration due to evaporation from staying inside the ejection opening portion  13   b  in the liquid ejection head in which H is in a range of 3 to 6 μm, P is in a range of 3 to 6 μm, and W is in a range of 17 to 25 μm. In other words, a relation between an average flow velocity V 17  of the ink flow  17  and an average evaporation flow velocity V 12  from the ink boundary  13   a  is set to Expression (5) below.
 
 V 17≥27 ×V 12  Expression (5)
 
     From an examination of the inventors, etc., it is understood that a liquid ejection head satisfying Expression (5) corresponds to the flow mode A. Since a liquid ejection head in which H is in a range of 3 to 6 μm, P is in a range of 3 to 6 μm, and W is greater than or equal to 17 μm satisfies Expression (2), the state C can be obtained by circulating a sufficient amount of ink with respect to the amount of evaporation. The above Expression (5) is an expression that indicates a circulation flow velocity necessary to obtain the state C. Expression (5) will be described with reference to  FIG.  38   . 
       FIG.  38    is a diagram illustrating a relation between an evaporation rate at which the state C is obtained and a circulation flow velocity, and a relation between an evaporation rate at which the state D is obtained and a circulation flow velocity. A horizontal axis of  FIG.  38    indicates an evaporation rate V 12 , and a vertical axis of  FIG.  38    indicates a flow velocity V 17  of an ink flow resulting from circulation. Data for each flow mode is indicated with respect to respective liquid ejection heads  1  to  4  corresponding to four shapes. In the liquid ejection head  1 , H is 6 μm, P is 6 μm, W is 17 μm, and the determination value J is 2.83. In the liquid ejection head  2 , H is 6 μm, P is 6 μm, W is 21 μm, and the determination value J is 3.5. In the liquid ejection head  3 , H is 5 μm, P is 3 μm, W is 21 μm, and the determination value J is 5.88. In the liquid ejection head  4 , H is 5 μm, P is 3 μm, W is 25 μm, and the determination value J is 7.0. 
     It can be understood from  FIG.  38    that a circulation flow velocity V 17  necessary to obtain the state C rather than the state D is proportional to an evaporation flow velocity V 12  in one liquid ejection head. In addition, it can be understood that the circulation flow velocity necessary to obtain the state C increases as the determination value J decreases. Further, in the case in which the liquid ejection head having H is in the range of 3 to 6 μm, P in the range of 3 to 6 μm, and W in the range of 17 to 25 μm is used, and the determination value J is 2.83 corresponding to a smallest value (the liquid ejection head  1 ), the state C is obtained when the circulation flow velocity is set to be 27 times or more the evaporation flow velocity. Therefore, in the liquid ejection head in which H is in the range of 3 to 6 μm, P is in the range of 3 to 6 μm, and W is greater than or equal to 17 μm, the state C is obtained when Expression (5) is satisfied, and ink having changed color material concentration due to evaporation may be inhibited from staying in the ejection opening portion  13   b . In other words, it is possible to reduce occurrence of color unevenness of an image resulting from liquid evaporation from the ejection opening  13 . For example, in an experiment of the inventors, etc., the amount of evaporation from a circular ejection opening having W of 18 μm is about 140 pl/s, and an average evaporation flow velocity is about 1.35×10 −4  m/s. Thus, in this case, a circulation flow velocity, an average of which is 0.0036 m/s or more, is necessary. Herein, the amount of evaporation indicates the amount of evaporation when concentration of ink in the ejection opening portion  13   b  does not change. 
     Similarly, in the case in which the liquid ejection head having H of 8 μm, P of 8 μm, and W of 17 μm is used, and the determination value J is 2.13, the state C is obtained when the average flow velocity V 17  of the ink flow  17  is set to 50 times or more the average evaporation flow velocity V 12  from the ink boundary  13   a . Therefore, in a liquid ejection head having H of 8 μm or less, P of 8 μm or less, and W of 17 μm or more, the state C can be obtained when the average flow velocity V 17  of the ink flow  17  is set to 50 times or more the average evaporation flow velocity V 12  from the ink boundary  13   a . Thereby, ink having changed color material concentration due to evaporation may be inhibited from staying inside the ejection opening portion  13   b . As a result, it is possible to reduce occurrence of color unevenness of an image resulting from liquid evaporation from the ejection opening  13 . Similarly to the above description, when the amount of evaporation from the circular ejection opening having W of 18 μm is about 140 pl/s, a circulation flow velocity, an average of which is 0.0067 m/s or more, is necessary. 
     Similarly, in a liquid ejection head in which H is 15 μm, P is 7 μm, W is 17 μm, and the determination value J is 1.87, the state C can be generated when the average flow velocity V 17  of the ink flow  17  is set to 50 times or more the average evaporation flow velocity V 12  from the ink boundary  13   a . Therefore, in a liquid ejection head having H of 15 μm or less, P of 7 μm or less, and W of 17 μm or more, the state C can be obtained when the average flow velocity V 17  of the ink flow  17  is set to 100 times or more the average evaporation flow velocity V 12  from the ink boundary  13   a . Similarly to the above description, when the amount of evaporation from the circular ejection opening having W of 18 μm is about 140 pl/s, a circulation flow velocity, an average of which is 0.0135 m/s or more, is necessary. 
     Next, a description will be given of a configuration of a different liquid ejection head. The present liquid ejection head is a liquid ejection head having H of 14 μm or less, P of 12 μm or less, and W of 17 μm or more, and H, P, and W satisfy Expression (2). This liquid ejection head satisfies Expression (6) below such that ink having changed color material concentration due to evaporation of ink from the ejection opening is inhibited from staying in the ejection opening portion  13   b . In other words, the average flow velocity V 17  of the ink flow  17  and the average evaporation flow velocity V 12  from the ink boundary  13   a  satisfy Expression (6) below.
 
 V 17≥900× V 12  Expression (6)
 
     In a liquid ejection head having H of 12.3 μm, P of 9 μm, and W of 17 μm (the determination value J is 1.7), the state C may be obtained by setting the average flow velocity V 17  of the ink flow  17  to 900 times the average evaporation flow velocity V 12  from the ink boundary  13   a . Similarly, in a liquid ejection head having H of 10 μm, P of 10 μm, and W of 17 μm (the determination value J is 1.7), the state C may be obtained by setting the average flow velocity V 17  of the ink flow  17  to 900 times the average evaporation flow velocity V 12  from the ink boundary  13   a . Similarly, in a liquid ejection head having H of 8.3 μm, P of 11 μm, and W of 17 μm (the determination value J is 1.7), the state C may be obtained by setting the average flow velocity V 17  of the ink flow  17  to 900 times the average evaporation flow velocity V 12  from the ink boundary  13   a . Similarly, in a liquid ejection head having H of 7 μm, P of 12 μm, and W of 17 μm (the determination value J is 1.7), the state C may be obtained by setting the average flow velocity V 17  of the ink flow  17  to 900 times the average evaporation flow velocity V 12  from the ink boundary  13   a.    
     Therefore, a liquid ejection head having H of 14 μm or less, P of 12 μm or less, and W of 17 μm or more, in which H, P, and W satisfy Expression (2), obtains the state C by satisfying Expression (6). 
     With regard to the above ninth embodiment, a condition of obtaining the state C is summarized as below. 
     H is 14 μm or less, P is 12 μm or less, and W is 17 μm or more and 30 μm or less. Further, a flow velocity of liquid in a passage is 900 times or more a rate of evaporation from an ejection opening. 
     Alternatively, H is 15 μm or less, P is 7 μm or less, and W is 17 μm or more and 30 μm or less. Further, a flow velocity of liquid in a passage is 100 times or more a rate of evaporation from an ejection opening. 
     Alternatively, H is 8 μm or less, P is 8 μm or less, and W is 17 μm or more and 30 μm or less. Further, a flow velocity of liquid in a passage is 50 times or more a rate of evaporation from an ejection opening. 
     Alternatively, H is 3 μm or more and 6 μm or less, P is 3 μm or more and 6 μm or less, and W is 17 μm or more and 30 μm or less. Further, a flow velocity of liquid in a passage is 27 times or more a rate of evaporation from an ejection opening. 
     Herein, the above regulation of the flow velocity of liquid corresponds to a range in which the state C is obtained even when a most difficult shape to obtain the state C in each head shape range is used. When another shape in each head shape range is used, the state C may be obtained at a smaller flow velocity. 
     Tenth Embodiment 
       FIG.  39 A  to  FIG.  42    are diagrams for description of a liquid ejection head according to a tenth embodiment of the invention, and the present embodiment relates to a relation between two types of characteristics below and a passage shape including an ejection opening. 
     Characteristic 1) Flow mode of ink flow 
     Characteristic 2) Ejected liquid droplet ejected from ejection opening 
     In particular, the relation with the characteristics will be described using three types of ejection opening shapes below, in which an ejection amount Vd is 5 pl, as an example. 
     Passage shape A) H=14 μm, P=11 μm, W=16 μm (J=1.34) 
     Passage shape B) H=9 μm, P=11 μm, W=18 μm (J=1.79) 
     Passage shape C) H=14 μm, P=6 μm, W=18 μm (J=2.30) 
     Herein, 
     H: Height of passage  24  at upstream side in flow direction of liquid inside passage  24  (see  FIGS.  22 A to  22 C ) 
     P: Length of ejection opening portion  13   b  in direction in which liquid is ejected from ejection opening  13  (see  FIGS.  22 A to  22 C ) 
     W: Length of ejection opening portion  13   b  in flow direction of liquid inside passage  24  (see  FIGS.  22 A to  22 C ) 
     Z: Effective length of inscribed circle of ejection opening  13   
     However, since the ejection opening  13  has a circular shape (see  FIGS.  22 A to  22 C ), an effective diameter Z of the inscribed circle of the ejection opening  13  is equal to W. 
     In addition, the example in which Vd is 5 pl is used since a plurality of main droplets and sub-droplets (hereinafter also referred to as satellites) are easily generated when the ejection amount is large, and the droplets cause deterioration of image quality. 
       FIGS.  39 A to  39 C  are diagrams illustrating flow modes of three passage shapes A to C.  FIG.  40    is a contour line diagram illustrating a value of the determination value J when a diameter of an ejection opening is changed such that the ejection amount Vd corresponds to about 5 pl. In  FIG.  40   , a horizontal axis indicates H, and a vertical axis indicates P. 
     The passage shape A has the determination value J of 1.34, and generates the flow mode B as illustrated in  FIG.  39 A . A size obtained by adding H to P of the passage shape A (hereinafter also referred to as OH) is 25 μm. However, H or P needs to be set to be small, and OH needs to be decreased to increase the determination value J. When OH equals 20 μm, the passage shape B in which only H is set to be small has the determination value J of 1.79, and generates the flow mode A as illustrated in  FIG.  39 B . In addition, the passage shape C in which only P is set to be small has the determination value J of 2.30, and similarly corresponds to the flow mode A as illustrated in  FIG.  39 C . Additionally, in the passage shape C, a flow of an ink flow easily enters an inside of the ejection opening when compared to the passage shape B, and ink may be further inhibited from staying inside the ejection opening portion  13   b . Therefore, shapes below are given with regard to flow modes of an ink flow. 
     Shape characteristic (1): For the same OH, P is preferably set to be small (see  FIG.  40   ) 
     Shape characteristic (2): OH is preferably decreased (see  FIG.  40   ) 
     Meanwhile,  FIGS.  41 A to  41 C  are diagrams illustrating results of observing ejected liquid droplets of the respective three types of passage shapes A to C.  FIG.  42    is a contour line diagram illustrating a value obtained by calculating a time at which bubbles communicate with the atmosphere (hereinafter also referred to as Tth) when a diameter of an ejection opening is changed such that the ejection amount Vd corresponds to about 5 pl. In  FIG.  42   , a horizontal axis indicates H, and a vertical axis indicates P. 
       FIGS.  41 A and  41 C  illustrate a case in which two types of ejected liquid droplets corresponding to a main droplet and a satellite are generated. Meanwhile,  FIG.  41 B  illustrates a case in which a main droplet and a plurality of satellites are generated. In the passage shape A, Tth equals 5.8 us. In the passage shape C, Tth equals 4.5 us. On the other hand, in the passage shape B, Tth equals 3.8 us, and Tth becomes small (see  FIG.  42   ). In general, a plurality of satellites are generated when the ejection amount Vd is large as in the present embodiment, and when Tth is small since an elongated tail (tailing) is easily generated, and a lot of nodes resulting from the unstable tail are generated when Tth is small, that is, communication with the atmosphere is facilitated. As a result, the number of elongated tails may not be reduced to one, and a plurality of satellites are generated as illustrated in  FIG.  41 B . Therefore, restraints below may be imposed with regard to the satellites. 
     Shape characteristic (3): For the same OH, P is preferably set to be small (see  FIG.  42   ) 
     Shape characteristic (4): OH is preferably increased (see  FIG.  42   ) 
     Accordingly, to increase the determination value J necessary to inhibit ink from staying inside the ejection opening portion  13   b,    
     Shape characteristic A) OH is decreased, and 
     Shape characteristic B) P is set to be smaller than H for the same OH. 
     In addition, to increase the determination value Tth necessary to suppress the main droplet and the satellite, 
     Shape characteristic C) OH is increased, and 
     Shape characteristic D) P is set to be smaller than H for the same OH. Since Shape characteristic A) and Shape characteristic C) indicate conflicting characteristics, it is desirable to satisfy a condition below as a compatible solution. 
     Determination value J of flow mode&gt;1.7, and determination value Tth of time at which communication with atmosphere is performed &gt;4.0 μs. 
     Therefore, a range illustrated in  FIG.  42    is preferably adopted. Herein, when the determination value Tth satisfies the above condition, the determination value Tth approximates to
 
 Tth= 0.350× H+ 0.227× P− 0.100× Z  
 
in the diagram illustrated in  FIG.  42   . The above equation indicates that Tth decreases and a plurality of satellites are easily generated when H or P decreases or Z increases. In particular, H has sensitivity which is about 1.5 times as high as sensitivity of P. Thus, for the same OH, a decrease in Tth may be suppressed, and generation of satellites may be suppressed when P is set to be small. Therefore, the above condition may be represented by the following expression.
 
0.350× H+ 0.227× P− 0.100× Z&gt; 4  Expression (7)
 
     When a shape characteristic of an ejection opening falling within the above range is adopted, it is possible to achieve suppression of occurrence of satellites and circulation effect (inhibiting ink from staying inside the ejection opening portion  13   b ) when the ejection amount Vd is 5 ng. 
     According to the embodiments described above, a change in a quality of a liquid near an ejection opening can be suppressed and thus it is possible for example to suppress increase in ink viscosity due to liquid evaporation through the ejection opening and to reduce color unevenness in an image. Specifically, when Expression (2) described in the second embodiment is satisfied, it is possible to obtain the flow mode A, and to inhibit ink from staying inside the ejection opening portion  13   b . In this way, it is possible to reduce an increase in color material concentration. A flow velocity of ink flowing through the passage  24  may be appropriately set depending on the condition, the environment, etc. in which the liquid ejection head is used according to approaches described in the present embodiment. 
     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 such modifications and equivalent structures and functions. 
     This application is a divisional application of U.S. patent application Ser. No. 16/407,437, filed May 9, 2019, which is a divisional application of U.S. patent application Ser. No. 15/991,256, filed May 29, 2018, now U.S. Pat. No. 10,363,747, which is a divisional application of U.S. patent application Ser. No. 15/388,430, filed Dec. 22, 2016, now U.S. Pat. No. 10,040,290, which claims the benefit of Japanese Patent Application No. 2016-003078 filed Jan. 8, 2016, and No. 2016-238891 filed Dec. 8, 2016, which are hereby incorporated by reference herein in their entirety.