JP7707260B2 - LIQUID DISCHARGE UNIT AND LIQUID DISCHARGE APPARATUS - Google Patents

Description

The present invention relates to a liquid ejection unit and a liquid ejection device that ejects liquid from an ejection port.

In recent years, the recording applications of recording devices have become more diverse, and the demand for high-definition, high-quality recording is increasing. To achieve even higher definition recording, liquid ejection heads that can selectively eject liquid from multiple ejection ports are required to have ejection ports arranged at higher densities. In addition, to achieve even higher quality recording, there is a demand for ejection of droplets of uniform size.

In order to arrange the ejection ports at a high density, it is necessary to miniaturize the liquid supply flow paths for supplying liquid to the ejection ports. Patent Document 1 describes a method in which a sealing film integrated in the longitudinal direction of the line head is used as a member for supplying ink to the element substrate, and after laminating it onto the head support member, a supply opening is machined with a laser. The recording element substrate is then mounted on the sealing film with the supply opening formed therein.

U.S. Pat. No. 7,347,534

However, in the method described in Patent Document 1, after processing a supply opening in a sealing film that is a support member for the recording element substrate, the recording element substrate is mounted on the sealing film while positioning it to correspond to the formed supply opening. With this type of configuration, from the viewpoint of the positioning accuracy between the flow path on the back side of the recording element substrate and the supply opening of the sealing film, it is difficult to further miniaturize or increase the density of the flow path and supply opening on the back side of the recording element substrate.

The present invention aims to provide a liquid ejection unit and a liquid ejection device that can accommodate further miniaturization and higher density of the flow path configuration on the back side of the recording element substrate.

Therefore, the liquid ejection unit of the present invention is a liquid ejection unit comprising: an element substrate including an ejection port array in which a plurality of ejection ports are arranged in an arrangement direction for ejecting liquid, a plurality of elements corresponding to each of the ejection ports and generating energy for ejecting liquid from the ejection ports, and a plurality of pressure chambers each having the element therein; and a back surface member provided on the back surface of the element substrate on the side on which the ejection ports are formed, wherein a supply path for supplying liquid to the plurality of pressure chambers is formed by the back surface of the element substrate and the back surface member, and the back surface member is provided with a supply opening for supplying liquid to the supply path, when the liquid ejection unit is viewed from a direction perpendicular to the element substrate, the outer shape of the back surface member is located inside the outer shape of the element substrate at the end side in the arrangement direction , and a plurality of the supply openings are provided which communicate with one of the supply paths, and adjacent element substrates of the plurality of element substrates are arranged so as to partially overlap each other in the longitudinal direction of the liquid ejection head .

The present invention makes it possible to realize a liquid ejection unit and a liquid ejection device that can suppress pressure variations in the pressure chambers.

FIG. 1 is a diagram illustrating a schematic configuration of a liquid ejection device that ejects liquid. FIG. 2 is a schematic diagram showing a first circulation mode of a circulation path applied to the recording apparatus; FIG. 13 is a schematic diagram showing a second circulation mode of the circulation path applied to the recording apparatus. 5A and 5B are schematic diagrams showing differences in the amount of ink flowing into a liquid ejection head. FIG. 2 is a perspective view showing a liquid ejection head. FIG. 2 is an exploded perspective view showing each part or unit that constitutes the liquid ejection head. 3A to 3C are diagrams showing the front and back surfaces of the first to third flow path members. 7( a ) is a perspective view showing the surface on which the ejection module is mounted in the α portion of FIG. 7( a ). 9 is a cross-sectional view taken along line IX-IX in FIG. 8. 1A and 1B are perspective and exploded views showing one dispensing module; FIG. 2 is a diagram showing a recording element substrate. FIG. 2 is a perspective view showing a cross section of a recording element substrate and a cover member. 4 is a partially enlarged plan view showing an adjacent portion of the recording element substrate; FIG. FIG. 2 is a perspective view showing a liquid ejection head. FIG. 2 is an exploded perspective view showing a liquid ejection head. FIG. 4 is a diagram showing a first flow path member. 5 is a perspective view showing a liquid connection relationship between a recording element substrate and a flow path member. FIG. 18 is a cross-sectional view taken along line XVIII-XVIII in FIG. 17. 1A and 1B are perspective and exploded views showing one dispensing module; FIG. 2 is a schematic diagram showing a recording element substrate. FIG. 1 is a diagram showing an inkjet recording apparatus that performs recording by ejecting liquid. FIG. 2 is a diagram illustrating a recording element substrate and a cover member. FIG. 2 is a perspective view showing a liquid ejection head. 1 is a diagram showing an overview of a liquid ejection recording apparatus and a flow path configuration. FIG. 2 is an exploded perspective view showing the liquid ejection unit. FIG. 2 is an exploded perspective view showing the liquid ejection unit. FIG. 4 is a diagram showing an enlarged view of a part of a first flow path layer with ejection ports superimposed thereon. 5 is a cross-sectional view showing a liquid supply path and a liquid recovery path of a second flow path layer. FIG. 13 is a perspective view showing a liquid supply path and a liquid recovery path of a second flow path layer. FIG. 4 is a flowchart showing an example of a manufacturing process of a liquid ejection head. FIG. 2 is a diagram showing a recording element substrate. This is a cross-sectional view taken along line XXXII-XXXII in Figure 31. This is a cross-sectional view taken along line XXXII-XXXII in Figure 31. 13 is a diagram showing the positional relationship between a liquid supply opening and a liquid supply path. FIG. 1 is a graph showing the relationship between the width of the supply opening and the pressure loss and the circulation flow rate and the variation. 4 is a diagram showing the relationship between the outer shape of an element substrate and a lid member. FIG. 4 is a diagram showing the positions of a recording element substrate, a liquid supply opening, and a liquid recovery opening. FIG. FIG. 2 is a diagram showing a liquid ejection unit. FIG. 2 is a diagram showing a liquid ejection unit. FIG. 2 is a diagram showing a liquid ejection unit. FIG. 2 is a diagram showing a liquid ejection unit. FIG. 2 is a diagram showing a liquid ejection unit. 11 is a graph showing the temperature distribution of the recording element substrate when ejection is performed from all ejection ports. 13 is a graph showing a temperature distribution of a recording element substrate. 13A to 13C are diagrams showing modified examples regarding the shape of the liquid supply opening. 10A and 10B are diagrams showing an example of the configuration of a gap between adjacent recording element substrates. 10A and 10B are diagrams showing an example of the configuration of a gap between adjacent recording element substrates. 1A and 1B are diagrams showing an example of the configuration of a gap between adjacent substrates. 1A and 1B are diagrams showing an example of the configuration of a gap between adjacent substrates. FIG. 2 is an exploded perspective view of the liquid ejection unit. FIG. 2 is an exploded plan view of the liquid ejection unit. FIG. 2 is a diagram showing a liquid ejection unit. FIG. 2 is a diagram showing a liquid ejection unit. FIG. 4 is a diagram showing the arrangement relationship of flow paths of a first ink and a second ink.

The following describes various application examples and embodiments to which the present invention can be suitably applied, with reference to the drawings. The liquid ejection head of the present invention that ejects liquid such as ink and the liquid ejection device equipped with the liquid ejection head can be applied to devices such as printers, copiers, facsimiles with communication systems, and word processors with printer units. Furthermore, it can be applied to industrial recording devices that are combined in a complex manner with various processing devices. For example, it can also be used in applications such as biochip production, electronic circuit printing, and semiconductor substrate production.

In addition, each application example and embodiment described below is a suitable specific example of the present invention, and therefore includes various technically preferable limitations. However, as long as it is in line with the concept of the present invention, the application examples and embodiments are not limited to the application examples, embodiments, or other specific methods described in this specification.

(First Application Example)
(Description of Liquid Ejection Recording Apparatus)
1 is a diagram showing a schematic configuration of a liquid ejection device for ejecting liquid according to the present invention, in particular a liquid ejection recording device (hereinafter also referred to as a recording device) 1000 that ejects ink to perform recording. The recording device 1000 is a line-type recording device that includes a conveying section 1 for conveying a recording medium 2 and a line-type (page-wide type) liquid ejection head 3 arranged approximately perpendicular to the conveying direction of the recording medium 2, and performs continuous recording in one pass while conveying multiple recording media 2 continuously or intermittently. The liquid ejection head 3 includes a negative pressure control unit 230 for controlling the pressure (negative pressure) in the circulation path, a liquid supply unit 220 fluidly connected to the negative pressure control unit 230, a liquid connection section 111 that serves as a supply and discharge port for ink to the liquid supply unit 220, and a housing 80. The recording medium 2 is not limited to cut paper, and may be a continuous roll medium. The liquid ejection head 3 is capable of full-color recording using cyan C, magenta M, yellow Y, and black K inks, and is fluidly connected to a liquid supply means, which is a supply path for supplying liquid to the liquid ejection head 3, a main tank, and a buffer tank (see FIG. 2, which will be described later). In addition, an electrical control unit that transmits power and ejection control signals to the liquid ejection head 3 is electrically connected to the liquid ejection head 3. The liquid paths and electrical signal paths within the liquid ejection head 3 will be described later.

The recording device 1000 is a liquid ejection recording device that circulates liquid such as ink between a tank (described later) and the liquid ejection head 3. There are two types of circulation: a first circulation type in which the liquid is circulated by operating two circulation pumps (one for high pressure, one for low pressure) downstream of the liquid ejection head 3, and a second circulation type in which the liquid is circulated by operating two circulation pumps (one for high pressure, one for low pressure) upstream of the liquid ejection head 3. The first and second circulation types are described below.

(Explanation of the first circulation mode)
Fig. 2 is a schematic diagram showing a first circulation form of the circulation path applied to the recording device 1000 of this application example. The liquid ejection head 3 is fluidly connected to a first circulation pump (high pressure side) 1001, a first circulation pump (low pressure side) 1002, a buffer tank 1003, etc. Note that in Fig. 2, for the sake of simplicity, only a path through which one color of ink flows out of cyan C, magenta M, yellow Y, and black K is shown, but in reality, circulation paths for all four colors are provided in the liquid ejection head 3 and the recording device main body.

In the first circulation mode, the ink in the main tank 1006 is supplied to the buffer tank 1003 by the refill pump 1005, and then supplied to the liquid supply unit 220 of the liquid ejection head 3 via the liquid connection part 111 by the second circulation pump 1004. After that, the ink, which is adjusted to two different negative pressures (high pressure and low pressure) by the negative pressure control unit 230 connected to the liquid supply unit 220, is divided into two flow paths, the high pressure side and the low pressure side, and circulates. The ink in the liquid ejection head 3 is circulated within the liquid ejection head by the action of the first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) 1002 downstream of the liquid ejection head 3, and is discharged from the liquid ejection head 3 via the liquid connection part 111 and returned to the buffer tank 1003.

The buffer tank 1003, which is a sub-tank, is connected to the main tank 1006 and has an air communication port (not shown) that connects the inside of the tank to the outside, making it possible to discharge air bubbles in the ink to the outside. A refill pump 1005 is provided between the buffer tank 1003 and the main tank 1006. The refill pump 1005 transfers ink consumed by discharging (discharging) ink from the discharge ports of the liquid discharge head 3, such as for recording by discharging ink or for suction recovery, from the main tank 1006 to the buffer tank 1005.

The two first circulation pumps 1001 and 1002 draw liquid from the liquid connection 111 of the liquid ejection head 3 and flow it to the buffer tank 1003. As the first circulation pump, a volumetric pump having a quantitative liquid delivery capacity is preferable. Specifically, a tube pump, a gear pump, a diaphragm pump, a syringe pump, etc. can be mentioned, but for example, a general constant flow valve or a relief valve may be arranged at the pump outlet to ensure a constant flow rate. When the liquid ejection head 3 is driven, a predetermined flow rate of ink flows in the common supply flow path 211 and the common recovery flow path 212 by operating the first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) 1002. By flowing the ink in this way, the temperature of the liquid ejection head 3 during recording is maintained at an optimal temperature. It is preferable that the predetermined flow rate when the liquid ejection head 3 is driven is set to a flow rate that can be maintained to a degree that the temperature difference between each recording element substrate 10 in the liquid ejection head 3 does not affect the recording image quality. However, if the flow rate is set too high, the negative pressure difference between the recording element substrates 10 will increase due to the pressure loss in the flow paths within the liquid ejection unit 300, resulting in uneven density in the image. For this reason, it is preferable to set the flow rate while taking into account the temperature difference and negative pressure difference between the recording element substrates 10.

The negative pressure control unit 230 is provided in the path between the second circulation pump 1004 and the liquid ejection unit 300. This negative pressure control unit 230 operates to maintain the pressure downstream of the negative pressure control unit 230 (i.e., the liquid ejection unit 300 side) at a preset constant pressure even if the flow rate of ink in the circulation system fluctuates due to differences in the ejection amount per unit area, etc. As the two negative pressure control mechanisms constituting the negative pressure control unit 230, any mechanism may be used as long as it can control the pressure downstream of the negative pressure control unit 230 to fluctuate within a certain range centered on the desired set pressure. As an example, a mechanism similar to a so-called "pressure reducing regulator" can be adopted. In the circulation flow path in this application example, the second circulation pump 1004 pressurizes the upstream side of the negative pressure control unit 230 via the liquid supply unit 220. In this way, the effect of the head pressure of the buffer tank 1003 on the liquid ejection head 3 can be suppressed, so that the degree of freedom of the layout of the buffer tank 1003 in the recording device 1000 can be increased.

The second circulation pump 1004 may be any pump having a head pressure equal to or greater than a certain pressure within the range of the ink circulation flow rate used when driving the liquid ejection head 3, and may be a turbo pump or a volumetric pump. Specifically, a diaphragm pump or the like may be used. In place of the second circulation pump 1004, for example, a head tank arranged with a certain head difference relative to the negative pressure control unit 230 may also be used. As shown in FIG. 2, the negative pressure control unit 230 has two negative pressure adjustment mechanisms, each of which has a different control pressure. Of the two negative pressure adjustment mechanisms, the relatively high pressure setting side (H in FIG. 2) and the relatively low pressure setting side (L in FIG. 2) are connected to the common supply flow path 211 and the common recovery flow path 212 in the liquid ejection unit 300 via the liquid supply unit 220, respectively. The liquid ejection unit 300 is provided with a common supply flow path 211, a common recovery flow path 212, and individual flow paths 215 (individual supply flow paths 213, individual recovery flow paths 214) that communicate with each recording element substrate. A negative pressure control mechanism H is connected to the common supply flow path 211, and a negative pressure control mechanism L is connected to the common recovery flow path 212, and a pressure difference is generated between the two common flow paths. Since the individual flow paths 215 communicate with the common supply flow path 211 and the common recovery flow path 212, a flow (arrow in FIG. 2) occurs in which a portion of the liquid flows from the common supply flow path 211 through the internal flow path of the recording element substrate 10 to the common recovery flow path 212.

In this way, in the liquid ejection unit 300, a flow occurs in which liquid flows through the common supply flow path 211 and the common recovery flow path 212, while a portion of the liquid passes through each recording element substrate 10. Therefore, heat generated in each recording element substrate 10 can be discharged to the outside of the recording element substrate 10 by the ink flowing through the common supply flow path 211 and the common recovery flow path 212. In addition, with this configuration, when recording is performed with the liquid ejection head 3, ink flow can be generated even in ejection ports and pressure chambers that are not ejecting. This reduces the viscosity of the ink that has thickened in the ejection port, thereby suppressing the thickening of the ink. In addition, thickened ink and foreign matter in the ink can be discharged to the common recovery flow path 212. Therefore, the liquid ejection head 3 of this application example is capable of high-speed, high-quality recording.

(Explanation of the second circulation mode)
3 is a schematic diagram showing a second circulation form, which is a circulation form different from the first circulation form described above, among the circulation paths applied to the recording apparatus of this application example. The main difference from the first circulation form described above is that both of the two negative pressure control mechanisms constituting the negative pressure control unit 230 control the pressure upstream of the negative pressure control unit 230 to fluctuate within a certain range centered on a desired set pressure. Another difference from the first circulation form is that the second circulation pump 1004 acts as a negative pressure source that reduces the pressure downstream of the negative pressure control unit 230. Another difference is that the first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) 1002 are arranged upstream of the liquid ejection head 3, and the negative pressure control unit 230 is arranged downstream of the liquid ejection head 3.

In the second circulation mode, the ink in the main tank 1006 is supplied to the buffer tank 1003 by the refill pump 1005. The ink is then divided into two flow paths, and circulated in two flow paths, 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 divided into the two flow paths, the high pressure side and the low pressure side, is supplied to the liquid ejection head 3 through the liquid connection part 111 by the action of the first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) 1002. The ink circulated in the liquid ejection head by the action of the first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) 1002 is then discharged from the liquid ejection head 3 through the liquid connection part 111 via 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 form, the negative pressure control unit 230 stabilizes the pressure fluctuations on the upstream side of the negative pressure control unit 230 (i.e., the liquid ejection unit 300 side) within a certain range centered on a preset pressure, even if there is a fluctuation in the flow rate caused by a change in the ejection amount per unit area, etc. In the circulation flow path of this application example, the second circulation pump 1004 pressurizes the downstream side of the negative pressure control unit 230 via the liquid supply unit 220. In this way, the influence of the head pressure of the buffer tank 1003 on the liquid ejection head 3 can be suppressed, so that the range of options for the layout of the buffer tank 1003 in the recording device 1000 can be expanded. Instead of the second circulation pump 1004, for example, a head tank arranged with a predetermined head difference with respect to the negative pressure control unit 230 can also be applied. In the second circulation form, like the first circulation form, the negative pressure control unit 230 has two negative pressure control mechanisms, each of which has a different control pressure set. Of the two negative pressure adjustment mechanisms, the high pressure setting side (indicated as H in FIG. 3) and the low pressure setting side (indicated as L in FIG. 3) are connected to the common supply flow path 211 or the common recovery flow path 212 in the liquid ejection unit 300 via the liquid supply unit 220. By making the pressure of the common supply flow path 211 relatively higher than the pressure of the common recovery flow path 212 by the two negative pressure adjustment mechanisms, a flow of liquid is generated that flows from the common supply flow path 211 to the common recovery flow path 212 via the individual flow paths 215 and the internal flow paths of each recording element substrate 10.

In this second circulation mode, the same liquid flow state is obtained within the liquid ejection unit 300 as in the first circulation mode, but there are two advantages that differ from the first circulation mode. The first advantage is that in the second circulation mode, the negative pressure control unit 230 is disposed downstream of the liquid ejection head 3, so there is less concern that dust or foreign matter generated from the negative pressure control unit 230 will flow into the liquid ejection head 3. The second advantage is that in the second circulation mode, the maximum flow rate required to supply liquid from the buffer tank 1003 to the liquid ejection head 3 is smaller than in the first circulation mode. The reasons for this are as follows.

The total flow rate in the common supply flow path 211 and the common recovery flow path 212 when circulating during standby for recording is defined as flow rate A. The value of flow rate A is defined as the minimum flow rate required to keep the temperature difference in the liquid ejection unit 300 within the desired range when adjusting the temperature of the liquid ejection head 3 during standby for recording. In addition, the ejection flow rate when ink is ejected from all the ejection ports of the liquid ejection unit 300 (during full ejection) is defined as flow rate F (ejection amount per ejection port x ejection frequency per unit time x number of ejection ports).

Figure 4 is a schematic diagram showing the difference in the amount of ink flowing into the liquid ejection head 3 in the first and second circulation modes. Figure 4(a) shows the first circulation mode during standby, and Figure 4(b) shows the first circulation mode during full ejection. Figures 4(c) to 4(f) show the second circulation flow path, with Figures 4(c) and (d) showing the case where flow rate F < flow rate A, and Figures 4(e) and (f) showing the case where flow rate F > flow rate A, and showing the flow rates during standby and full ejection, respectively.

In the case of the first circulation configuration in which the first circulation pump 1001 and the first circulation pump 1002, which have a quantitative liquid delivery capacity, are arranged downstream of the liquid ejection head 3 (FIGS. 4A and 4B), the total set flow rate of the first circulation pump 1001 and the first circulation pump 1002 is flow rate A. This flow rate A enables temperature management within the liquid ejection unit 300 during standby. When full ejection is performed by the liquid ejection head 3, the total set flow rate of the first circulation pump 1001 and the first circulation pump 1002 remains at flow rate A. However, the maximum flow rate supplied to the liquid ejection head 3 is the total set flow rate A plus the flow rate F consumed by full ejection due to the negative pressure generated by the ejection in the liquid ejection head 3. Therefore, the maximum value of the supply amount to the liquid ejection head 3 is flow rate A + flow rate F, since flow rate F is added to flow rate A (FIG. 4B).

On the other hand, in the case of the second circulation form in which the first circulation pump 1001 and the first circulation pump 1002 are disposed upstream of the liquid ejection head 3 (FIGS. 4(c) to 4(f)), the supply amount to the liquid ejection head 3 required during recording standby is the flow rate A, as in the first circulation form. Therefore, in the second circulation form in which the first circulation pump 1001 and the first circulation pump 1002 are disposed upstream of the liquid ejection head 3, when the flow rate A is greater than the flow rate F (FIGS. 4(c) and 4(d)), the supply amount to the liquid ejection head 3 is sufficient even during full ejection. In that case, the discharge flow rate from the liquid ejection head 3 is the flow rate A minus the flow rate F (FIG. 4(d)). However, when the flow rate F is greater than the flow rate A (FIGS. 4(e) and 4(f)), if the supply flow rate to the liquid ejection head 3 is set to the flow rate A during full ejection, the flow rate will be insufficient. Therefore, when the flow rate F is greater than the flow rate A, the supply amount to the liquid ejection head 3 needs to be set to the flow rate F. In this case, when full ejection is performed, the flow rate F is consumed in the liquid ejection head 3, so the discharge flow rate from the liquid ejection head 3 is almost not discharged (FIG. 4(f)). Note that when the flow rate F is greater than the flow rate A and ejection is performed but not full ejection, the amount of liquid discharged from the liquid ejection head 3 is the flow rate F minus the amount consumed in ejection. Also, when the flow rates A and F are equal, the flow rate A (or flow rate F) is supplied to the liquid ejection head 3 and the flow rate F is consumed in the liquid ejection head 3, so the discharge flow rate from the liquid ejection head 3 is almost not discharged.

In this way, in the case of the second circulation mode, the sum of the set flow rates of the first circulation pump 1001 and the first circulation pump 1002, i.e., the maximum required supply flow rate, is the larger of flow rate A or flow rate F. Therefore, as long as the same configuration of the liquid ejection unit 300 is used, the maximum required supply flow rate in the second circulation mode (flow rate A or flow rate F) will be smaller than the maximum required supply flow rate in the first circulation mode (flow rate A + flow rate F).

Therefore, in the case of the second circulation mode, the degree of freedom in the applicable circulation pump is increased, and for example, it is possible to use a low-cost circulation pump with a simple configuration, and to reduce the load on the cooler (not shown) installed in the main body side path, which has the advantage of reducing the cost of the recording device. This advantage is greater for line heads with relatively large values of flow rate A or flow rate F, and is more beneficial for line heads with longer longitudinal lengths.

However, on the other hand, the first circulation mode also has some advantages over the second circulation mode. That is, in the second circulation mode, the flow rate through the liquid ejection unit 300 is at its maximum when waiting to print, so the lower the ejection volume per unit area of the image (hereinafter also referred to as a low-duty image), the higher the negative pressure applied to each ejection port. For this reason, when the flow path width is narrow and the negative pressure is high, a high negative pressure is applied to the ejection port in a low-duty image where unevenness is easily visible, and this can result in the generation of many so-called satellite droplets that are ejected along with the main droplets of ink, which can degrade the printing quality.

On the other hand, in the case of the first circulation mode, a high negative pressure is applied to the ejection port when forming an image with a large ejection volume per unit area (hereinafter also referred to as a high duty image), so even if satellite droplets are generated, they are difficult to see and have little effect on the image, which is an advantage. The choice between these two circulation modes can be made based on the specifications of the liquid ejection head and the recording device body (ejection flow rate F, minimum circulation flow rate A, and flow path resistance within the head).

(Description of Liquid Ejection Head Configuration)
The configuration of the liquid ejection head 3 according to the first application example will be described. Fig. 5(a) and Fig. 5(b) are perspective views showing the liquid ejection head 3 according to this application example. The liquid ejection head 3 is a line-type liquid ejection head in which 15 recording element substrates 10 capable of ejecting four colors of ink, cyan C/magenta M/yellow Y/black K, are linearly arranged (arranged in-line). As shown in Fig. 5(a), the liquid ejection head 3 includes each recording element substrate 10, a signal input terminal 91 electrically connected via a flexible wiring substrate 40 and an electric wiring substrate 90, and a power supply terminal 92. The signal input terminal 91 and the power supply terminal 92 are electrically connected to the control unit of the recording device 1000, and supply the ejection drive signal and the power required for ejection to the recording element substrate 10, respectively. By consolidating the wiring by the electric circuit in the electric wiring substrate 90, the number of the signal input terminals 91 and the power supply terminals 92 can be reduced compared to the number of the recording element substrates 10. This reduces the number of electrical connections that need to be removed when assembling the liquid ejection head 3 to the recording apparatus 1000 or when replacing the liquid ejection head. As shown in Fig. 5B, liquid connections 111 provided at both ends of the liquid ejection head 3 are connected to a liquid supply system of the recording apparatus 1000. This allows four colors of ink, cyan C/magenta M/yellow Y/black K, to be supplied from the supply system of the recording apparatus 1000 to the liquid ejection head 3, and the ink that has passed through the liquid ejection head 3 is collected back into the supply system of the recording apparatus 1000. In this way, the inks of each color can circulate through the paths of the recording apparatus 1000 and the paths of the liquid ejection head 3.

Figure 6 is an exploded perspective view showing each part or unit that constitutes the liquid ejection head 3. The liquid ejection unit 300, the liquid supply unit 220, and the electrical wiring board 90 are attached to the housing 80. The liquid supply unit 220 is provided with a liquid connection section 111 (see Figure 3), and inside the liquid supply unit 220, filters 221 (see Figures 2 and 3) for each color that communicate with each opening of the liquid connection section 111 are provided to remove foreign matter from the ink being supplied. Each of the two liquid supply units 220 is provided with filters 221 for two colors. The liquid that passes through the filters 221 is supplied to the negative pressure control units 230 arranged on the liquid supply unit 220 corresponding to each color. The negative pressure control unit 230 is a unit consisting of negative pressure control valves for each color, and the valves and spring members provided inside each unit greatly attenuate the pressure loss change in the supply system of the recording device 1000 (the supply system upstream of the liquid ejection head 3) that occurs with the fluctuation of the liquid flow rate. This allows the negative pressure control unit 230 to stabilize the negative pressure change downstream of the negative pressure control unit (the liquid ejection unit 300 side) within a certain range. As described in FIG. 2, two negative pressure control valves are built into the negative pressure control unit 230 for each color. The two negative pressure control valves are set to different control pressures, and the high pressure side is connected to the common supply flow path 211 (see FIG. 2) in the liquid ejection unit 300, and the low pressure side is connected to the common recovery flow path 212 (see FIG. 2) via the liquid supply unit 220.

The housing 80 is composed of a liquid ejection unit support part 81 and an electric wiring board support part 82, and supports the liquid ejection unit 300 and the electric wiring board 90 while ensuring the rigidity of the liquid ejection head 3. The electric wiring board support part 82 is for supporting the electric wiring board 90, and is fixed to the liquid ejection unit support part 81 by screwing. The liquid ejection unit support part 81 has a role of correcting warping and deformation of the liquid ejection unit 300 and ensuring the relative position accuracy of the multiple recording element boards 10, thereby suppressing streaks and unevenness in the recorded matter. For this reason, it is preferable that the liquid ejection unit support part 81 has sufficient rigidity, and the material is preferably a metal material such as SUS or aluminum, or a ceramic such as alumina. The liquid ejection unit support part 81 is provided with openings 83 and 84 into which the joint rubber 100 is inserted. The liquid supplied from the liquid supply unit 220 is led to the third flow path member 70 constituting the liquid ejection unit 300 via the joint rubber.

The liquid ejection unit 300 is composed of a plurality of ejection modules 200 and a flow path member 210, and a cover member 130 is attached to the recording medium side surface of the liquid ejection unit 300. Here, the cover member 130 is a member having a frame-like surface with a long opening 131 as shown in FIG. 6, and the recording element substrate 10 and the sealing member 110 (see FIG. 10 described later) included in the ejection module 200 are exposed from the opening 131. The frame portion around the opening 131 functions as a contact surface of the cap member that caps the liquid ejection head 3 when waiting to print. For this reason, it is preferable to apply an adhesive, a sealant, a filler, or the like along the periphery of the opening 131 to fill the unevenness and gaps on the ejection port surface of the liquid ejection unit 300 so that a closed space is formed when capped.

Next, the configuration of the flow path member 210 included in the liquid ejection unit 300 will be described. As shown in FIG. 6, the flow path member 210 is a laminate of a first flow path member 50, a second flow path member 60, and a third flow path member 70, and distributes the liquid supplied from the liquid supply unit 220 to each ejection module 200. The flow path member 210 is also a flow path member for returning the liquid circulating from the ejection module 200 to the liquid supply unit 220. The flow path member 210 is fixed to the liquid ejection unit support part 81 with screws, which suppresses warping and deformation of the flow path member 210.

Figures 7(a) to (f) are diagrams showing the front and back surfaces of each of the first to third flow path members. Figure 7(a) shows the surface of the first flow path member 50 on which the ejection module 200 is mounted, and Figure 7(f) shows the surface of the third flow path member 70 that abuts against the liquid ejection unit support part 81. The first flow path member 50 and the second flow path member 60 are joined so that the abutment surfaces of the respective flow path members in Figures 7(b) and 7(c) face each other, and the second flow path member and the third flow path member are joined so that the abutment surfaces of the respective flow path members in Figures 7(d) and 7(e) face each other. By joining the second flow path member 60 and the third flow path member 70, eight common flow paths (211a, 211b, 211c, 211d, 212a, 212b, 212c, 212d) extending in the longitudinal direction of the flow path member are formed from the common flow path grooves 62, 71 formed in each flow path member. As a result, a set of a common supply flow path 211 and a common recovery flow path 212 is formed for each color in the flow path member 210. Ink is supplied from the common supply flow path 211 to the liquid ejection head 3, and the ink supplied to the liquid ejection head 3 is recovered by the common recovery flow path 212. The communication port 72 (see FIG. 7(f)) of the third flow path member 70 communicates with each hole of the joint rubber 100, and is in fluid communication with the liquid supply unit 220 (see FIG. 6). A plurality of communication ports 61 (communication port 61-1 communicating with the common supply flow path 211, and communication port 61-2 communicating with the common recovery flow path 212) are formed on the bottom surface of the common flow path groove 62 of the second flow path member 60, and communicate with one end of the individual flow path groove 52 of the first flow path member 50. A communication port 51 is formed on the other end of the individual flow path groove 52 of the first flow path member 50, and is fluidly connected to a plurality of ejection modules 200 via the communication port 51. This individual flow path groove 52 makes it possible to aggregate the flow paths toward the center side of the flow path member.

The first to third flow path members are preferably made of a material that is resistant to corrosion by liquids and has a low linear expansion coefficient. Suitable materials include alumina, LCP (liquid crystal polymer), PPS (polyphenyl sulfide), and PSF (polysulfone) as a base material, and composite materials (resin materials) with inorganic fillers such as silica particles and fibers added thereto. The flow path member 210 may be formed by laminating the three flow path members and bonding them together, or, if a resin composite resin material is selected as the material, a joining method by welding may be used.

Figure 8 shows the α portion of Figure 7(a), and is a perspective view showing an enlarged portion of the flow paths in the flow path member 210 formed by joining the first to third flow path members, viewed from the side of the first flow path member 50 on which the ejection module 200 is mounted. The common supply flow path 211 and the common recovery flow path 212 are arranged alternately from the flow paths at both ends. Here, the connection relationship of each flow path in the flow path member 210 will be described.

The flow path member 210 is provided with common supply flow paths 211 (211a, 211b, 211c, 211d) and common recovery flow paths 212 (212a, 212b, 212c, 212d) that extend in the longitudinal direction of the liquid ejection head 3 for each color. A plurality of individual supply flow paths 213 (213a, 213b, 213c, 213d) formed by the individual flow path grooves 52 are connected to the common supply flow paths 211 of each color via the communication port 61. In addition, a plurality of individual recovery flow paths 214 (214a, 214b, 214c, 214d) formed by the individual flow path grooves 52 are connected to the common recovery flow paths 212 of each color via the communication port 61. With this flow path configuration, ink can be collected from each common supply flow path 211 through the individual supply flow paths 213 to the recording element substrate 10 located in the center of the flow path member. Ink can also be recovered from the recording element substrate 10 to each common recovery flow path 212 via the individual recovery flow paths 214.

Figure 9 is a diagram showing a cross section at IX-IX in Figure 8. Each individual recovery flow path (214a, 214c) communicates with the ejection module 200 via the communication port 51. Although only the individual recovery flow paths (214a, 214c) are shown in Figure 9, in another cross section, the individual supply flow paths 213 communicate with the ejection module 200 as shown in Figure 8. The support member 30 and the recording element substrate 10 included in each ejection module 200 are formed with a flow path for supplying ink from the first flow path member 50 to the recording element 15 provided on the recording element substrate 10. Furthermore, the support member 30 and the recording element substrate 10 are formed with a flow path for recovering (circulating) part or all of the liquid supplied to the recording element 15 to the first flow path member 50.

Here, the common supply flow path 211 of each color is connected to the negative pressure control unit 230 (high pressure side) of the corresponding color via the liquid supply unit 220, and the common recovery flow path 212 is connected to the negative pressure control unit 230 (low pressure side) via the liquid supply unit 220. This negative pressure control unit 230 creates a pressure difference between the common supply flow path 211 and the common recovery flow path 212. For this reason, as shown in Figures 8 and 9, in the liquid ejection head of this application example in which each flow path is connected, a flow is generated for each color that flows in order from the common supply flow path 211 to the individual supply flow path 213 to the recording element substrate 10 to the individual recovery flow path 214 to the common recovery flow path 212.

(Description of the Discharge Module)
FIG. 10(a) is a perspective view showing one ejection module 200, and FIG. 10(b) is an exploded view thereof. In the manufacturing method of the ejection module 200, first, the recording element substrate 10 and the flexible wiring substrate 40 are bonded to a support member 30 in which a liquid communication port 31 is provided in advance. Then, the terminal 16 on the recording element substrate 10 and the terminal 41 on the flexible wiring substrate 40 are electrically connected by wire bonding, and then the wire bonding portion (electrical connection portion) is covered and sealed with a sealing member 110. The terminal 42 on the flexible wiring substrate 40 opposite to the recording element substrate 10 is electrically connected to the connection terminal 93 (see FIG. 6) of the electrical wiring substrate 90. The support member 30 is a support body that supports the recording element substrate 10 and is also a flow path member that fluidly communicates the recording element substrate 10 and the flow path member 210, so it is preferable that the support member 30 has a high flatness and can be joined to the recording element substrate with sufficiently high reliability. For example, alumina or a resin material is preferable as the material.

(Description of the structure of the recording element substrate)
FIG. 11(a) shows a plan view of the surface of the recording element substrate 10 on which the ejection ports 13 are formed, FIG. 11(b) shows an enlarged view of the portion indicated by A in FIG. 11(a), and FIG. 11(c) shows a plan view of the back surface of FIG. 11(a). Here, the configuration of the recording element substrate 10 in this application example will be described. As shown in FIG. 11(a), four ejection port arrays corresponding to each ink color are formed in the ejection port forming member 12 of the recording element substrate 10. Hereinafter, the direction in which the ejection port array in which the multiple ejection ports 13 are arranged extends will be referred to as the "ejection port array direction". As shown in FIG. 11(b), a recording element 15, which is a heat generating element for foaming the liquid by thermal energy, is arranged at a position corresponding to each ejection port 13. A pressure chamber 23 having the recording element 15 therein is partitioned by a partition wall 22. The recording element 15 is electrically connected to a terminal 16 by an electric wiring (not shown) provided on the recording element substrate 10. The recording elements 15 generate heat based on pulse signals input from the control circuit of the recording device 1000 via the electric wiring board 90 (see FIG. 6) and the flexible wiring board 40 (see FIG. 10) to boil the liquid. The liquid is ejected from the ejection ports 13 by the bubbling force caused by this boiling. As shown in FIG. 11B, along each ejection port row, a liquid supply path 18 extends on one side, and a liquid recovery path 19 extends on the other side. The liquid supply path 18 and the liquid recovery path 19 are flow paths that extend in the ejection port row direction provided on the recording element substrate 10, and communicate with the ejection ports 13 via the supply port 17a and the recovery port 17b, which are liquid paths, respectively.

As shown in FIG. 11C, a sheet-like resin cover member (resin film) 20 is laminated on the back surface of the recording element substrate 10, on which the ejection ports 13 are formed, and the cover member 20 is provided with a plurality of openings 21 that communicate with the liquid supply path 18 and the liquid recovery path 19. In this application example, the cover member 20 is provided with three openings 21 for each liquid supply path 18, which is a common flow path extending along the longitudinal direction of the recording element substrate 10, and two openings 21 for each liquid recovery path 19, which is a supply and recovery path also extending along the longitudinal direction. In the present invention, the number of openings 21 is not limited to this. For example, a configuration may be used in which two supply side openings 21 are provided for each liquid supply path 18 and one recovery side opening 21 is provided for each liquid recovery path 19. Considering the pressure loss in the flow path portion, a configuration in which at least two or more openings are provided in either the liquid supply path 18 or the liquid recovery path 19 is preferable.

As shown in FIG. 11(b), each opening 21 of the lid member 20 communicates with the multiple communication ports 51 shown in FIG. 7(a). The lid member 20 is preferably made of a material that has sufficient corrosion resistance against liquids, and from the viewpoint of preventing color mixing, high precision is required for the shape and position of the openings 21. For this reason, it is preferable to use a photosensitive resin material or a silicon plate as the material for the lid member 20, and to provide the openings 21 by a photolithography process. In this way, the lid member 20 changes the pitch of the flow path with the openings 21, and it is preferable that the thickness of the lid member 20 is thin considering pressure loss, and that the lid member 20 is preferably made of a photosensitive resin film.

Figure 12 is a perspective view showing a cross section of the recording element substrate 10 and the lid member 20 at XII-XII in Figure 11 (a). Here, the flow of liquid in the recording element substrate 10 will be described. The lid member 20 functions as a lid that forms part of the wall of the liquid supply path 18 and the liquid recovery path 19 formed in the substrate 11 of the recording element substrate 10. The recording element substrate 10 is formed by laminating the substrate 11 made of Si and the ejection port forming member 12 made of photosensitive resin, and the lid member 20 is bonded to the back surface of the substrate 11. On one surface of the substrate 11, the recording elements 15 are formed (see Figure 11), and on the back surface thereof, grooves that form the liquid supply path 19 and the liquid recovery path 18 extending along the ejection port row are formed. The liquid supply path 18 and the liquid recovery path 19 formed by the substrate 11 and the cover member 20 are connected to a common supply path 211 and a common recovery path 212 in the flow path member 210, respectively, and a pressure difference is generated between the liquid supply path 18 and the liquid recovery path 19. When liquid is discharged from the ejection port 13 to perform recording, the liquid in the liquid supply path 18 provided in the substrate 11 flows to the liquid recovery path 19 via the supply port 17a, the pressure chamber 23, and the recovery port 17b at the ejection port not performing ejection due to this pressure difference (arrow C in FIG. 12). This flow allows the ink, bubbles, and foreign matter, etc., which have been caused by evaporation from the ejection port 13, to be recovered to the liquid recovery path 19 at the ejection port 13 and the pressure chamber 23 where recording is paused. Also, the ink in the ejection port 13 and the pressure chamber 23 can be prevented from becoming viscous. The liquid recovered to the liquid recovery path 19 passes through the opening 21 of the cover member 20 and the liquid communication port 31 of the support member 30 (see FIG. 10b), and is then recovered to the communication port 51 in the flow path member 210, the individual recovery flow path 214, and the common recovery flow path 212, in that order, and is then recovered to the recovery path of the recording device 1000. In other words, the liquid supplied from the recording device body to the liquid ejection head 3 flows, is supplied, and is recovered in the following order:

The liquid first flows into the liquid ejection head 3 from the liquid connection part 111 of the liquid supply unit 220. The liquid is then supplied in the order of the joint rubber 100, the communication port 72 and the common flow channel 71 provided in the third flow channel member, the common flow channel 62 and the communication port 61 provided in the second flow channel member, and the individual flow channel 52 and the communication port 51 provided in the first flow channel member. After that, the liquid is supplied to the pressure chamber 23 through the liquid communication port 31 provided in the support member 30, the opening 21 provided in the cover member 20, the liquid supply path 18 and the supply port 17a provided in the substrate 11, in that order. The liquid supplied to the pressure chamber 23 that is not ejected from the ejection port 13 flows in the order of the recovery port 17b and the liquid recovery path 19 provided in the substrate 11, the opening 21 provided in the cover member 20, and the liquid communication port 31 provided in the support member 30. The liquid then flows in sequence through the communication port 51 and individual flow channel 52 provided in the first flow channel member, the communication port 61 and common flow channel 62 provided in the second flow channel member, the common flow channel 71 and communication port 72 provided in the third flow channel member 70, and the joint rubber 100. The liquid then 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 form shown in FIG. 2, the liquid flowing in from the liquid connection part 111 is supplied to the joint rubber 100 after passing through the negative pressure control unit 230. In the second circulation form shown in FIG. 3, the liquid recovered from the pressure chamber 23 flows from the liquid connection part 111 to the outside of the liquid ejection head through the negative pressure control unit 230 after passing through the joint rubber 100. Also, not all of the liquid flowing in from one end of the common supply flow path 211 of the liquid ejection unit 300 is supplied to the pressure chamber 23 via the individual supply flow path 213a. In other words, some of the liquid flowing in from one end of the common supply flow path 211 flows from the other end of the common supply flow path 211 to the liquid supply unit 220 without flowing into the individual supply flow path 213a. In this way, by providing a path that flows without passing through the recording element substrate 10, it is possible to suppress the backflow of the circulating flow of the liquid even in the case of providing a recording element substrate 10 having a fine flow path with a large flow resistance as in this application example. In this way, the liquid ejection head 3 of this application example can suppress thickening of the liquid in the pressure chamber 23 and in the vicinity of the ejection port, thereby suppressing ejection distortion and ejection failure, and as a result, high-quality recording can be performed.

(Description of the Positional Relationship Between Printing Element Substrates)
FIG. 13 is a partially enlarged plan view showing adjacent portions of the recording element substrates in two adjacent ejection modules. In this application example, a recording element substrate of a substantially parallelogram shape is used. The parallelogram shown in FIG. 13 is particularly suitable for application to a parallelogram in which the angle between adjacent sides is not 90 degrees. Each ejection port array (14a to 14d) in which the ejection ports 13 in each recording element substrate 10 are arranged at a certain angle with respect to the longitudinal direction of the liquid ejection head 3. The ejection port arrays in the adjacent portions of the recording element substrates 10 are arranged so that at least one ejection port overlaps in the conveying direction of the recording medium. In FIG. 13, two ejection ports on the line D are in an overlapping relationship with each other. With this arrangement, even if the position of the recording element substrate 10 is slightly deviated from the predetermined position, black streaks and white spots in the recorded image can be made less noticeable by driving control of the overlapping ejection ports. 13, it is possible to prevent black streaks and white spots at the joints between the recording element substrates 10 while suppressing an increase in the length of the liquid ejection head 10 in the recording medium transport direction. Note that, although the main plane of the recording element substrate 10 in this application example is a parallelogram, this is not limiting, and the configuration of the present invention can be preferably applied even when a recording element substrate having a rectangular, trapezoidal, or other shape is used.

(Second Application Example)
Hereinafter, the configuration of a liquid ejection recording apparatus 2000 and a liquid ejection head 2003 according to a second application example of the present invention will be described with reference to the drawings. In the following explanation, only the parts that are different from the first application example will be mainly described, and the explanation of the parts that are the same as the first application example will be omitted.

(Description of Liquid Ejection Recording Apparatus)
FIG. 21 is a diagram showing a liquid ejection recording apparatus 2000 that performs recording by ejecting liquid, to which this application example can be applied. The recording apparatus 2000 of this application example is different from the first application example in that full-color recording is performed on a recording medium by arranging four single-color liquid ejection heads 2003 corresponding to each ink of cyan C, magenta M, yellow Y, and black K in parallel. In the first application example, the number of ejection port rows that can be used per color is one row, whereas in this application example, the number of ejection port rows that can be used per color is 20 rows. Therefore, by appropriately allocating the recording data to a plurality of ejection port rows and performing recording, very high-speed recording is possible. Furthermore, even if there is an ejection port that does not eject, reliability is improved by performing complementary ejection from ejection ports in other rows that are located at positions corresponding to the ejection port in the conveying direction of the recording medium, which is suitable for commercial recording, etc. As in the first application example, the supply system, buffer tank 1003 (see FIGS. 2 and 3), and main tank 1006 (see FIGS. 2 and 3) of the recording apparatus 2000 are fluidly connected to each liquid ejection head 2003. In addition, each liquid ejection head 2003 is electrically connected to an electric control unit that transmits power and ejection control signals to the liquid ejection head 2003.

(Explanation of the circulation route)
As in the first application example, the first and second circulation modes shown in FIG. 2 or FIG. 3 can be used as the circulation mode of the liquid between the recording apparatus 2000 and the liquid ejection head 2003.

(Description of Liquid Ejection Head Structure)
14A and 14B are perspective views showing a liquid ejection head 2003 according to this application example. Here, the structure of the liquid ejection head 2003 according to this application example will be described. The liquid ejection head 2003 is a line-type liquid ejection head that includes 16 recording element substrates 2010 arranged in a straight line in the longitudinal direction of the liquid ejection head 2003 and is capable of printing with one type of liquid. The liquid ejection head 2003 includes a liquid connection portion 111, a signal input terminal 91, and a power supply terminal 92, as in the first application example. However, the liquid ejection head 2003 of this application example has more ejection port rows than the first application example, so that the signal output terminal 91 and the power supply terminal 92 are arranged on both sides of the liquid ejection head 2003. This is to reduce voltage drops and signal transmission delays that occur in the wiring portions provided on the recording element substrate 2010.

Figure 15 is an exploded perspective view showing the liquid ejection head 2003, and shows each part or unit constituting the liquid ejection head 2003 divided by its function. The role of each unit and member and the order of liquid flow in the liquid ejection head are basically the same as in the first application example, but the function of ensuring the rigidity of the liquid ejection head is different. In the first application example, the rigidity of the liquid ejection head is mainly ensured by the liquid ejection unit support part 81, but in the liquid ejection head 2003 of the second application example, the rigidity of the liquid ejection head is ensured by the second flow path member 2060 included in the liquid ejection unit 2300. The liquid ejection unit support part 81 in this application example is connected to both ends of the second flow path member 2060, and this liquid ejection unit 2300 is mechanically connected to the carriage of the recording device 2000 to position the liquid ejection head 2003. The liquid supply unit 2220 equipped with the negative pressure control unit 2230 and the electric wiring board 90 are connected to the liquid ejection unit support part 81. Each of the two liquid supply units 2220 has a built-in filter (not shown).

The two negative pressure control units 2230 are set to control pressure at different, relatively high and low negative pressures. Also, as shown in Figures 14 and 15, when the high-pressure and low-pressure negative pressure control units 2230 are installed at both ends of the liquid ejection head 2003, the liquid flows in the common supply flow path and the common recovery flow path extending in the longitudinal direction of the liquid ejection head 2003 face each other. In this configuration, heat exchange is promoted between the common supply flow path and the common recovery flow path, reducing the temperature difference in the two common flow paths. This has the advantage of reducing the temperature difference in each of the multiple recording element substrates 2010 provided along the common flow path, making it less likely that recording unevenness due to temperature differences will occur.

Next, the flow path member 2210 of the liquid ejection unit 2300 will be described in detail. As shown in FIG. 15, the flow path member 2210 is a laminate of a first flow path member 2050 and a second flow path member 2060, and distributes the liquid supplied from the liquid supply unit 2220 to each ejection module 2200. The flow path member 2210 also functions as a flow path member for returning the liquid circulating from the ejection module 2200 to the liquid supply unit 2220. The second flow path member 2060 of the flow path member 2210 is a flow path member in which a common supply flow path and a common recovery flow path are formed, and also has the function of mainly providing the rigidity of the liquid ejection head 2003. For this reason, the material of the second flow path member 2060 is preferably one that has sufficient corrosion resistance against liquid and high mechanical strength. Specifically, SUS, Ti, alumina, etc. can be used.

16(a) is a diagram showing the surface of the first flow path member 2050 on which the ejection module 2200 is mounted, and FIG. 16(b) is a diagram showing the back surface thereof, which is a surface that abuts against the second flow path member 2060. Unlike the first application example, the first flow path member 2050 in this application example is an arrangement of multiple members corresponding to each ejection module 2200 adjacent to each other. By adopting such a divided structure, multiple modules can be arranged to correspond to the length of the liquid ejection head 2003, so that it can be particularly suitably applied to a relatively long-scale liquid ejection head corresponding to, for example, B2 size or longer. As shown in FIG. 16(a), the communication port 51 of the first flow path member 2050 is fluidically connected to the ejection module 2200, and as shown in FIG. 16(b), the individual communication port 53 of the first flow path member 2050 is fluidically connected to the communication port 61 of the second flow path member 2060. FIG. 16C shows the surface of the second flow path member 60 that comes into contact with the first flow path member 2050, FIG. 16D shows a cross section of the center of the thickness direction of the second flow path member 60, and FIG. 16E shows the surface of the second flow path member 2060 that comes into contact with the liquid supply unit 2220. The functions of the flow paths and communication ports of the second flow path member 2060 are the same as those of one color in the first application example. The common flow path groove 71 of the second flow path member 2060 is a common supply flow path 2211 shown in FIG. 17 described later on one side, and a common recovery flow path 2212 on the other side, each of which is provided along the longitudinal direction of the liquid ejection head 2003, and liquid is supplied from one end side to the other end side. This application example is different from the first application example, and the liquid flows in the common supply flow path 2211 and the common recovery flow path 2212 in opposite directions.

Figure 17 is a perspective view showing the liquid connection relationship between the recording element substrate 2010 and the flow path member 2210. A set of common supply flow path 2211 and common recovery flow path 2212 extending in the longitudinal direction of the liquid ejection head 2003 is provided in the flow path member 2210. The communication port 61 of the second flow path member 2060 is aligned and connected to the individual communication port 53 of the first flow path member 2050, and a liquid supply flow path is formed that communicates from the common supply flow path 2211 of the second flow path member 2060 to the communication port 51 of the first flow path member 2050 via the communication port 61. Similarly, a liquid supply path is also formed that communicates from the communication port 72 of the second flow path member 2060 to the communication port 51 of the first flow path member 2050 via the common recovery flow path 2212.

Figure 18 is a diagram showing a cross section at XVIII-XVIII in Figure 17. The common supply flow path 2211 is connected to the ejection module 2200 via the communication port 61, the individual communication port 53, and the communication port 51. Although not shown in Figure 18, it is clear from Figure 17 that the common recovery flow path 2212 is connected to the ejection module 2200 by a similar route in another cross section. As in the first application example, each ejection module 2200 and the recording element substrate 2010 are formed with a flow path communicating with each ejection port, so that a part or all of the supplied liquid can be circulated through the ejection port that is not ejecting. Also, as in the first application example, the common supply flow path 2211 is connected to the negative pressure control unit 2230 (high pressure side), and the common recovery flow path 2212 is connected to the negative pressure control unit 2230 (low pressure side) via the liquid supply unit 2220. Therefore, this pressure difference generates a flow that passes from the common supply flow path 2211 through the pressure chamber of the recording element substrate 2010 and into the common recovery flow path 2212.

(Description of the Discharge Module)
FIG. 19A is a perspective view showing one ejection module 2200, and FIG. 19B is an exploded view thereof. The difference from the first application example is that a plurality of terminals 16 are arranged on both sides (each long side of the recording element substrate 2010) along the direction of the plurality of ejection port arrays of the recording element substrate 2010. Accordingly, two flexible wiring substrates 40 electrically connected to the recording element substrate 2010 are also arranged for one recording element substrate 2010. This is because the number of ejection port arrays provided on the recording element substrate 2010 is 20, which is significantly increased from the eight arrays in the first application example, and this is to reduce the maximum distance from the terminals 16 to the recording elements and reduce the voltage drop and signal delay that occur in the wiring portion in the recording element substrate 2010. In addition, the liquid communication port 31 of the support member 2030 is provided on the recording element substrate 2010 and opens so as to straddle all the ejection port arrays. Other points are the same as those of the first application example.

(Description of the structure of the recording element substrate)
Fig. 20(a) is a schematic diagram of the surface of the recording element substrate 2010 on which the ejection ports 13 are arranged, and Fig. 20(c) is a schematic diagram showing the back surface of the surface of Fig. 20(a). Fig. 20(b) is a schematic diagram showing the surface of the recording element substrate 2010 when the cover member 2020 provided on the back surface side of the recording element substrate 2010 in Fig. 20(c) is removed. As shown in Fig. 20(b), the liquid supply path 18 and the liquid recovery path 19 are alternately provided along the ejection port array direction on the back surface of the recording element substrate 2010. Although the number of ejection port arrays is significantly increased compared to the first application example, the essential difference from the first application example is that the terminals 16 are arranged on both sides of the recording element substrate along the ejection port array direction as described above. The basic configuration is the same as in the first application example, in that a set of liquid supply path 18 and liquid recovery path 19 is provided for each row of ejection ports, and an opening 21 is provided in the cover member 2020 that communicates with the liquid communication port 31 of the support member 2030.

The above description of the application example does not limit the scope of the present invention. As an example, the application example describes a thermal method in which a heating element generates bubbles to eject liquid, but the present invention can also be applied to liquid ejection heads that use a piezo method or various other liquid ejection methods.

This application example has been described as a liquid ejection recording device (recording device) in a form in which liquid such as ink is circulated between a tank and a liquid ejection head, but other forms are also possible. Other forms may be used, for example, in which, instead of circulating ink, two tanks are provided on the upstream and downstream sides of the liquid ejection head, and ink is caused to flow from one tank to the other tank, thereby causing the ink in the pressure chamber to flow.

In addition, this application example has been described as using a so-called line-type head having a length corresponding to the width of the recording medium, but the present invention can also be applied to so-called serial-type liquid ejection heads that perform printing while scanning the recording medium. An example of a serial-type liquid ejection head is a configuration that has one recording element board that ejects black ink and one recording element board that ejects color ink, but is not limited to this. In other words, a short liquid ejection head shorter than the width of the recording medium may be created by arranging multiple recording element boards so that the ejections overlap in the ejection port row direction, and the recording medium may be scanned with this.

First Embodiment
A first embodiment of the present invention will be described below with reference to the drawings. Note that since the basic configuration of this embodiment is similar to that of the above-mentioned application example, only the characteristic configuration will be described below.

The liquid ejection head and liquid ejection device according to the embodiment of the present invention will be described below with reference to the drawings. In each of the following embodiments, a liquid ejection head that ejects liquid (hereinafter also referred to as ink), a liquid ejection device, and a manufacturing method will be described in a specific configuration, but the present invention is not limited thereto. The liquid ejection head, liquid ejection device, and manufacturing method of the present invention are applicable to devices such as printers, copiers, facsimiles with communication systems, and word processors with printer units, as well as industrial recording devices that are combined in a complex with various processing devices. For example, they can also be used in applications such as biochip production and electronic circuit recording.

The embodiments described below are suitable specific examples of the present invention, and therefore include various technically preferable limitations. However, as long as they are in line with the concept of the present invention, the present embodiments are not limited to the embodiments described in this specification or other specific methods.

(Printing element substrate and cover member)
22 is a diagram showing the recording element substrate 10 and the cover member 20 in this embodiment. The cover member 20 is a member that covers the flow path formed on the back surface (the surface opposite to the surface having the ejection port forming member 12) of the recording element substrate 10, and a third flow path layer, which will be described later, is formed on the back surface. In the present invention, the recording element substrate 10 and the cover member 20 are both processed in a wafer form in a wafer process, and then divided and formed.

(Example of the configuration of a liquid ejection head)
23(a) to (e) are perspective views showing a liquid ejection head. The liquid ejection head in FIG. 23(a) includes one recording element substrate 10, and the support member 30 and the recording element substrate 10 are disposed on a first flow path member 50. This liquid ejection head is used in a so-called serial scan type liquid ejection recording device. This liquid ejection recording device records an image on a recording medium by repeating a recording scan in which ink is ejected from the ejection port while moving the liquid ejection head in the main scanning direction of the arrow X direction, and a transport operation in which the recording medium is transported in the sub-scanning direction of the arrow Y direction intersecting with the main scanning direction. The main scanning direction is a direction intersecting (in this example, perpendicular to) the first direction in which the ejection port array 14 extends.

The liquid ejection heads in Figs. 23(b) and (c) are long line heads in which multiple recording element substrates 10 are arranged in a staggered pattern. In the configuration in Fig. 23(b), the first flow path member 50 is arranged in common for multiple recording element substrates 10, while in the configuration in Fig. 23(c), the first flow path member 50 is arranged individually for each recording element substrate 10. Such liquid ejection heads are used in so-called full-line type liquid ejection recording devices. The liquid ejection recording device continuously records images on a recording medium by ejecting ink from a fixed-position liquid ejection head while continuously transporting the recording medium in the direction of arrow Y that intersects (in this example, perpendicularly) the first direction in which the ejection port array 14 extends.

The liquid ejection heads of Figures 23(d) and (e) are long line heads in which the recording element substrates 10 are arranged in a row, and are used in so-called full-line type liquid ejection recording devices. In the configuration of Figure 23(d), the first flow path member 50 is arranged in common to multiple recording element substrates 10, while in the configuration of Figure 23(e), the first flow path member 50 is arranged individually for each recording element substrate 10. It is desirable for the recording element substrate 10 in such a liquid ejection head to have a shape similar to that of the fourth embodiment described below.

(Recording device)
FIG. 24 is a diagram showing an outline of a liquid ejection recording apparatus (liquid ejection apparatus) to which the liquid ejection head of the present invention can be applied, and a flow path configuration. The recording apparatus of FIG. 24(a) is a serial scan type recording apparatus using a liquid ejection head having the configuration as shown in FIG. 23(a) as the liquid ejection head 3. The chassis 1010 is composed of a plurality of plate-shaped metal members having a predetermined rigidity, and forms the framework of the recording apparatus. The chassis 1010 is assembled with a feed unit 4, a transport unit 1, and a carriage 5 that is mounted with the liquid ejection head 3 and can move back and forth in the main scanning direction of the arrow X. The main scanning direction is a direction that intersects (in this example, perpendicular to) the direction in which the ejection port row in the liquid ejection head 3 extends. The feed unit 4 automatically feeds a sheet-shaped recording medium (not shown) into the inside of the recording apparatus, and the transport unit 1 transports the recording medium fed one by one from the feed unit 4 in the sub-scanning direction of the arrow Y. The sub-scanning direction is a direction that intersects (in this example, perpendicular to) the main scanning direction. Such a recording device records an image on a recording medium by repeating a recording scan in which ink is discharged from the discharge ports of the liquid discharge head 3 while moving the liquid discharge head 3 in the main scanning direction together with the carriage 5, and a transport operation in which the recording medium is transported in the sub-scanning direction. Ink is supplied to the liquid discharge head 3 from an ink tank (not shown).

The recording device in FIG. 24(b) is a full-line type liquid ejection head using a long liquid ejection head 3 as shown in FIG. 23(b), (c), (d), and (e) described above, and is equipped with a conveying unit 1 that continuously conveys a sheet (recording medium) 2 in the direction of the arrow Y. The conveying unit 1 may be configured to use a conveying belt as in this example, or a conveying roller or the like. In this example, the liquid ejection head 3 is equipped with four liquid ejection heads 3Y, 3M, 3C, and 3B for ejecting yellow (Y), magenta (M), cyan (C), and black (Bk) inks. The corresponding inks are supplied to the liquid ejection heads 3 (3Y, 3M, 3C, and 3B). While continuously conveying the sheet 2 in the direction of the arrow Y, ink is ejected from the liquid ejection heads 3 at fixed positions, thereby continuously recording color images on the sheet 2.

Figure 24 (c) is an explanatory diagram of an ink supply system for the liquid ejection head 3. The ink in the first ink tank 1011 is supplied to the common supply flow path 211 (see Figures 2 and 3) in the liquid ejection head 3, passes through the pressure chamber 23, and is then recovered from the common recovery flow path 212 (see Figures 2 and 3) to the second ink tank 1012. As a method for generating an ink circulation flow in the liquid ejection head 3, which will be described later, there is, for example, a method using a water head difference between the first ink tank 1011 and the second ink tank 1012. Alternatively, there is a method of controlling the pressure inside the first ink tank 1011 and the second ink tank 1012 to generate a pressure difference between the first ink tank 1011 and the second ink tank 1012. Furthermore, an ink circulation flow can also be generated using a pump or the like. The configuration of the ink supply system and the method for generating an ink circulation flow are not limited to this example and are arbitrary. In other words, all that is required is to configure a differential pressure generating section that generates the pressure difference necessary for the ink to circulate through the pressure chamber.

The method described here is merely an example and does not limit the scope of the present invention. For example, a circulation path may be formed in which the ink collected in the second liquid tank 1012 is supplied to the liquid ejection head 3 again via the first liquid tank 1011. Furthermore, the liquid ejection head may be configured with only the liquid tank 1011, and have a circulation path in which ink returns from the liquid tank 1011 to the liquid tank 1011 again via the liquid ejection head, and is then supplied to the liquid ejection head 3.

(Liquid ejection unit)
25 and 26 are exploded perspective views showing the liquid ejection unit 300. As shown in FIG. 25 and FIG. 26, the liquid ejection unit 300 of this embodiment has six laminated flow paths including an ejection port forming member 12, a first flow path layer 221, a second flow path layer 222, a third flow path layer 223, a fourth flow path layer 224, a fifth flow path layer 225, and a sixth flow path layer 226. The recording element substrate 10 includes the recording element 15, the ejection port forming member 12, and a flow path configuration (first flow path layer 221 and second flow path layer 222) described later. The recording element substrate 10 includes a substrate including the recording element 15 and an ejection port forming member 12 including the ejection port. Here, the substrate including the recording element 15 is made of a Si substrate, and a flow path for supplying liquid to the recording element 15 is formed. This flow path includes a liquid supply path 18 and a liquid recovery path 19 extending along the arrangement direction of the ejection port 13. Furthermore, this flow path includes a plurality of supply ports 17a that communicate with the liquid supply path 18 and are arranged along the liquid supply path 18, and a plurality of recovery ports 17b that communicate with the liquid recovery path 19 and are arranged along the liquid recovery path 19.

In the present invention, the substrate having the recording element 15 may be single-layered or multi-layered. In the case of a single layer as shown in FIG. 12, a liquid supply path 18, a liquid recovery path 19, a plurality of supply ports 17a, and a plurality of recovery ports 17b are formed in one Si substrate 11. In the case of a two-layered substrate having a first and second Si substrate stacked as shown in FIG. 28, a plurality of supply ports 17a and a plurality of recovery ports 17b are formed in the first Si substrate 11, and a liquid supply path 18 and a liquid recovery path 19 are formed in the second Si substrate 115. Regardless of whether the Si substrate is single-layered or multi-layered, a cover member 20 having a plurality of openings 21 is provided on the back side of the Si substrate. The openings 20 include a supply opening 20 for supplying liquid to the liquid supply path 18 and a recovery opening 20 for recovering liquid from the liquid recovery path 19. A plurality of openings 20 are arranged along the liquid supply path 18 and the liquid recovery path 19. The present invention is not limited to this example, and for example, the first flow path layer 221 may be formed from a first Si substrate, and the second flow path layer 222 may be formed from a second Si substrate. Also, there may be at least one opening 20 for the liquid supply path 18 and the liquid recovery path 19.

The recording element 15 may be an electrothermal conversion element (heater) or a piezoelectric element. When a heater is used, the heat generated by the heater causes the ink in the pressure chamber 23 to bubble, and the resulting bubble-forming energy is used to eject ink from the ejection port 13.

Figure 27 shows an enlarged view of a portion of the first flow path layer 221, with the ejection ports 13 of the ejection port forming member 12 superimposed on it. As shown in Figure 27, the ejection ports 13 are arranged at high density to form an ejection port array 14. In this example, four ejection port arrays 14 are formed in one liquid ejection unit 300.

28 is a cross-sectional view showing the liquid supply path 18 and the liquid recovery path 19 of the second flow path layer 222, and FIG. 29 is a perspective view thereof. As shown in FIG. 28, the liquid supply path 18 of the second flow path layer 222 is connected to one side (left side in FIG. 28) of each pressure chamber 23 through an individual supply port 17a corresponding to each pressure chamber 23. Similarly, the liquid recovery path 19 of the second flow path layer 222 is connected to the other side (right side in FIG. 28) of each pressure chamber 23 through an individual recovery port 17b from the pressure chamber 23. The liquid supply path 18 is connected to a liquid supply opening 2133 formed in the third flow path layer 223, which is a cover member, and ink is supplied from the liquid supply opening 2133. Similarly, the liquid recovery path 19 is connected to a liquid recovery opening 2143 formed in the third flow path layer 223. A plurality of liquid recovery ports 2143 are arranged in the arrangement direction (first direction) of the ejection ports in the ejection port array 14, forming a row of liquid supply openings 2133. Similarly, a plurality of liquid recovery openings 2143 are arranged along the same first direction as the row of liquid supply openings 2133, forming a row of liquid recovery openings 2143. In the third flow path layer 223, the row of liquid supply openings 2133 and the row of liquid recovery openings 2143 are alternately arranged.

The fourth flow path layer 224 has a common supply path 2134 and a common recovery path 2144, and the fifth flow path layer 225 has an individual supply port 2135 and an individual recovery port 2145. The sixth flow path layer 226 has a common supply flow path 211 and a common recovery flow path 212.

The liquid supply path 18 communicates with a plurality of supply ports 17a on one side (first flow path layer 221 side) in the thickness direction of the second flow path layer 222, and communicates with a plurality of liquid supply openings 2133 on the other side (third flow path layer 223 side). Similarly, the liquid recovery path 19 communicates with a plurality of recovery ports 17b on one side in the thickness direction of the second flow path layer 222, and communicates with a plurality of liquid recovery openings 2143 on the other side. The common supply path 2134 communicates with a plurality of liquid supply openings 2133 on one side in the thickness direction of the fourth flow path layer 224, and communicates with a plurality of second supply ports 2135 on the other side. Similarly, the common recovery path 2144 communicates with a liquid recovery opening 2143 on one side in the thickness direction of the fourth flow path layer 224, and communicates with an individual recovery port 2145 on the other side. In addition, the common supply flow path 211 of the sixth flow path layer 226 communicates with a plurality of individual supply ports 2135, and the common recovery flow path 212 communicates with a plurality of individual recovery ports 2145.

The arrangement density of the multiple individual supply ports 2135 and the arrangement density of the multiple individual recovery ports 2145 are lower than the arrangement density of the multiple liquid supply openings 2133 and the arrangement density of the multiple liquid recovery openings 2143. The arrangement density of the multiple liquid supply openings 2133 and the arrangement density of the multiple liquid recovery openings 2143 are also lower than the arrangement density of the multiple supply ports 17a and the arrangement density of the multiple recovery ports 17b. The liquid supply path 18 and the liquid recovery path 19 are each formed in parallel along the first direction, and the common supply path 2134 and the common recovery path 2144 are each formed in parallel along the second direction. The common supply flow path 211 and the common recovery flow path 212 are each formed in parallel along the first direction.

The liquid ejection unit 300 of this example has multiple flow path layers and is configured by stacking multiple flow path layers. The flow path formation density in these flow path layers increases in the order of the sixth flow path layer 226, the fifth flow path layer 225, the fifth flow path layer 225, the fourth flow path layer 224, the third flow path layer 223, the second flow path layer 222, and the first flow path layer 221. This makes it possible to configure a liquid ejection unit 300 that has multiple ejection port rows 14 at high density while suppressing the increase in size of the recording element substrate 10 and each flow path member. Note that each of these six flow path layers may be formed in a different member.

Also, both the first flow path layer 221 and the second flow path layer 222 are formed on the substrate 11 to form the recording element substrate 10, the third flow path layer 223 is formed on the cover member 20, and a part of the fourth flow path layer 224 is formed on the support member 30. It is also possible to form another part of the fourth flow path layer 224 on the first flow path member 50 (see FIG. 23), the fifth flow path layer 225 and a part of the sixth flow path layer 226 on the second flow path member 60 (see FIG. 23), and another part of the sixth flow path layer 226 on the third flow path member.

In addition, both the first flow path layer 221 and the second flow path layer 222 are formed on the substrate 11 to form the recording element substrate 10, and the third flow path layer 223 is formed on the cover member 20. A configuration is also possible in which a part of the fourth flow path layer 224 is formed on the support member 30, another part of the fourth flow path layer 224 and the fifth flow path layer 225 are formed on the first flow path member 50, and the sixth flow path layer 226 is formed on the second flow path member 60. In this way, the relationship between the flow path layers and the members does not limit the present invention. Furthermore, the configuration of the individual supply paths 214a, individual recovery paths 214b, individual supply ports 215a, and individual recovery ports 215b does not limit this configuration.

Ink supplied from the outside is led from the common supply flow path 211, which is connected to the ink inlet opening, through the individual supply port 2135, the common supply path 2134, the liquid supply opening 2133, the liquid supply path 18, and the supply port 17a in sequence to the pressure chamber 23. The ink in the pressure chamber 23 passes through the recovery port 17b, the liquid recovery path 19, the liquid recovery opening 2143, the common recovery path 2144, the individual recovery port 2145, and the common recovery flow path 212 in sequence, and flows out from the outflow opening connected to the common recovery flow path 212 to the outside. By circulating the ink in the pressure chamber 23 with the outside in this way, the thickened ink and air bubbles that tend to remain in the pressure chamber 23 can be discharged, thereby suppressing a decrease in the ink ejection speed from the ejection port 13 and a change in the colorant concentration in the ink. Hereinafter, such a forced flow of ink is referred to as an "ink circulation flow."

In this example, the supply port 17a and the recovery port 17b are arranged to face each other across the ejection port 13, as shown in Figures 27, 28, and 29. By configuring the pressure chamber 23 to be sandwiched between the supply port 17a and the recovery port 17b in this manner, it is possible to efficiently generate an ink circulation flow passing through the pressure chamber 23, and more efficiently suppress a decrease in the ink ejection speed and a change in the color material concentration of the ink. In addition, the supply port 17a and the recovery port 17b are formed in a plurality of parts in the first direction in which the ejection port row 14 extends so as to correspond to each of the plurality of pressure chambers 23. In this way, by forming the supply port 17a and the recovery port 17b in a plurality of parts, it is possible to arrange electrical wiring for driving the recording element 15 between adjacent supply ports 17a and between adjacent recovery ports 17b. Therefore, there is no need to provide wiring extending in the first direction between the supply port 17a and the discharge port 13, and between the recovery port 17b and the discharge port 13, and it is possible to form the gap between them smaller. The relationship between the number of supply ports 17a and the number of discharge ports 13 may be 1:1, 1:2, or 1:5, and the number of pressure chambers 23 to which the supply port 17a communicates is not limited to the 1:1 relationship between the number of supply ports 17a and the number of discharge ports 13 as in this example.

In this example, in order to generate an ink circulation flow through the pressure chamber 23 and the ejection port 13, the flow paths are formed as follows. The liquid supply path 18 extends in the first direction and communicates with a plurality of supply ports 17a, and further communicates with the pressure chamber 23 via each of the supply ports 17a. Similarly, the liquid recovery path 19 extends in the first direction and communicates with a plurality of recovery ports 17b, and further communicates with the pressure chamber 23 via each of the recovery ports 17b.

The second flow path layer 222 and the first flow path layer 221 in which the liquid supply path 18 and the liquid recovery path 19 are formed are preferably made of the same material. In this example, the first flow path layer 221 and the second flow path layer 222 are formed on the substrate 11 made of a silicon (Si) substrate. The substrate 11 on which the first flow path layer 221 made of a silicon substrate is formed and the second substrate 115 on which the second flow path layer 222 made of a silicon substrate is formed are laminated and bonded, and the liquid supply path 18 and the liquid recovery path 19 are formed on the second flow path layer 222. It is more preferable that the substrate 11 and the second substrate 115 are bonded by a method that does not use adhesive, for example, by surface activated bonding or fusion bonding. The reason for this is that when the substrate 11 and the second substrate 115 are bonded so that the ejection ports formed at high density correspond to the ink flow paths formed at high density, the effect of the adhesive overflowing is reduced. By this type of surface activation bonding or fusion bonding, the silicon substrate 11 and the second substrate 115 are integrated, and the supply port 17a, recovery port 17b, liquid supply path 18, and liquid recovery path 19 are formed inside the integrated body.

In this way, a series of ink flow paths consisting of the supply port 17a, the recovery port 17b, the liquid supply path 18, and the liquid recovery path 19 are formed in the first flow path layer 221 and the second flow path layer 222 in correspondence with the ejection port array 14. Through such ink flow paths, an ink circulation flow can be generated in the pressure chamber 23 of the first flow path layer 221 and in the ejection port 13 of the ejection port forming member 12.

28 and 29, the side walls forming the supply port 17a, the recovery port 17b, the liquid supply path 18, and the liquid recovery path 19 are substantially perpendicular to the front and back surfaces (top and bottom surfaces in the figure) of the first flow path layer 221. Here, "substantially perpendicular" includes the inclination of the tapered shape and the like that occurs when the first flow path layer 221 and the second flow path layer 222 are processed. The supply port 17a, the recovery port 17b, the liquid supply path 18, and the liquid recovery path 19 are formed, for example, by dry etching. They may also be formed by laser processing, or dry etching processing and laser processing may be combined. The depth direction (the vertical direction in FIG. 28) of the supply port 17a, the recovery port 17b, the liquid supply path 18, and the liquid recovery path 19 is substantially perpendicular to the surface of the first flow path layer 221. This allows these ink paths to be efficiently formed at high density, and ink circulation flow can be more efficiently generated in the pressure chambers 23 and the ejection ports 13 that are densely formed in the first flow path layer 221.

(Manufacturing method and shape of the cover member)
FIG. 30 is a flow chart showing an example of the manufacturing process of the liquid ejection head of this embodiment. In the ejection port forming process 2000, ejection ports are formed on the recording element substrate 10 on which the recording elements 15 and necessary circuits are formed. In the back surface supply path forming process 2001, the liquid supply path 18 and the liquid recovery path 19 are formed on the back surface of the recording element substrate 10. In addition, in the lid member forming process 2002, a lid member (third flow path layer 223) is formed on the back surface of the recording element substrate 10 so as to cover the back surface supply path. In the present invention, after the liquid supply path 18 and the liquid recovery path 19 are formed on the back surface of the Si substrate in the wafer state, the lid member 20 (223) is provided on the back surface of the Si substrate in the wafer state. In this state, a plurality of openings 21 (2133, 2143) smaller than the liquid supply path 18 and the liquid recovery path 19 are formed by patterning. After that, in the cutting process 2003, the recording element substrate 10 is processed from the wafer state to a chip form. Furthermore, in a bonding process 2004, the recording element substrate 10 is bonded to the support member 30 and the first flow path member 50. In a placement process 2005, the bonded members are placed in a predetermined position to fabricate a liquid ejection head. Although the above describes a method for manufacturing a liquid ejection head having a supply path for supplying liquid to a pressure chamber, a liquid ejection head having a liquid recovery path 19 for recovering liquid from a pressure chamber such as that shown in FIG. 29 can be similarly applied. A recording element substrate having a liquid supply path 18 and a liquid recovery path 19 is prepared on the back surface of the recording element substrate, and a film-like lid member is provided on the back surface of the recording element substrate so as to cover the liquid supply path 18 and the liquid recovery path 19 formed on the back surface of the recording element substrate. After that, a plurality of liquid supply openings 2133 communicating with the liquid supply path 18 and smaller than the liquid supply path, and a plurality of liquid recovery openings 2143 communicating with the liquid recovery path 19 and smaller than the liquid recovery path are formed in the lid member. Thereafter, a plurality of recording element substrates each having a lid member are cut from the wafer, and each recording element substrate is bonded to a support member to produce a liquid ejection head in which a plurality of recording element substrates are arranged.

In this way, in the present invention, first, the liquid supply path 18 and the liquid recovery path 19 are formed in the wafer state, and then the cover member 20 is provided to cover the liquid supply path 18 and the liquid recovery path 19. After that, the liquid supply opening 2133 that communicates with the liquid supply path 18 and the liquid recovery opening 2143 that communicates with the liquid recovery path 19 are formed. This makes it possible to form openings (liquid supply opening 2133, liquid recovery opening 2143) that are denser and have smaller opening dimensions than the liquid supply path 18 and the liquid recovery path 19 with high precision. The manufacturing method of the recording element substrate will be described in detail below.

Figure 31 shows the recording element substrate with the cover member 517 provided, and Figures 32 and 33 are cross-sectional views taken along the line XXXII-XXXII in Figure 31. Note that the manufacturing process for the recording element substrate is explained below, but in order to distinguish each component of the manufacturing process from the components of the finished product, the reference numerals for the components in the manufacturing process are changed to distinguish them from those of the finished product. Figure 32 shows a partial recording element substrate, but multiple recording element substrates are manufactured together on a wafer, which are then cut into small pieces to produce individual recording element substrates.

First, a pattern 521 that will be the mold of the flow path is provided on the surface side of a silicon substrate 511 on which a recording element and necessary circuits are formed, using a positive photosensitive resin. First, a photosensitive resin is provided on the substrate 511 by a spin coating method, a spray coating method, a method of laminating a film, or the like, and then a member that will be the flow path can be formed by patterning the shape of the ink flow path by a photolithography method or the like. As the positive photosensitive resin, for example, a main chain decomposition type photosensitive resin of a polymer mainly composed of polymethyl isopropenyl ketone or methacrylic acid ester is used. The positive photosensitive resin layer can be formed into a desired pattern by exposing it to an exposure wavelength that is optimal for the material. Next, a discharge port forming member 522 is formed on the surface side of the substrate 511 using a negative photosensitive resin layer (FIG. 32(a)). Examples of negative photosensitive resins include negative photosensitive resins that utilize a radical polymerization reaction and negative photosensitive resins that utilize a cationic polymerization reaction. The negative photosensitive resin may be used alone or in combination of two or more. Furthermore, additives and the like may be added as necessary. As the negative photosensitive resin, commercially available products such as "SU-8 series" and "KMPR-1000" (product names) manufactured by Nippon Kayaku Co., Ltd., and "TMMR S2000" and "TMMF S2000" (product names) manufactured by Tokyo Ohka Kogyo Co., Ltd. may be used.

The method for coating the negative photosensitive resin composition onto the flow path pattern is not particularly limited, and can be selected from, for example, spin coating, lamination, spray coating, etc., as appropriate, and then the ejection orifice is formed by photolithography, etc.

In addition to the ejection port forming process using a positive photosensitive resin, the ejection port forming member 522 may be formed by stacking multiple layers of a negative photosensitive resin and using a photolithography method.

Next, using photolithography and Si deep etching techniques, a common liquid chamber 513 (corresponding to the liquid supply channel 18 and liquid recovery channel 19) for supplying ink and an ink supply port 516 are formed from the back side (Figure 32 (b)). After that, a resin film that serves as a lid member is provided on the surface of the substrate 511 on which the common liquid chamber 513 is formed. If the lid member 517 is bonded with an adhesive, the adhesive may overflow into the common liquid chamber 513, adversely affecting the actual flow path shape, so it is preferable to bond it without adhesive.

When a non-photosensitive thermosetting resin is used to form the lid member 517, the non-photosensitive resin is laminated onto the base film 518 that serves as the substrate (Fig. 32(c)), and then the base film 518 is peeled off (Fig. 32(d)). After curing, the flow path mold 521 is removed (Fig. 32(e)), and the openings (corresponding to the supply opening 2133 and the recovery opening 2143) are formed by laser processing (Fig. 32(f)).

Next, a method for forming the lid member using a photolithography method will be described with reference to FIG. 33. The lid member 517 can also be formed by a photolithography method, which can avoid damage to the substrate side due to ablation during laser processing and achieve higher positional accuracy. The process is the same as that shown in FIG. 32(b) until the common liquid chamber 513 and the ink supply port 516 are formed on the back side, and then the laminate of the base film 518 and the photosensitive resin layer is transferred (FIG. 33(a)) onto the surface of the substrate 511 on which the common liquid chamber 513 is formed using a laminator device. Examples of materials for the photosensitive resin layer include negative photosensitive resins that utilize radical polymerization reactions and negative photosensitive resins that utilize cationic polymerization reactions. Negative photosensitive resins that utilize radical polymerization reactions are cured by polymerization and crosslinking between the molecules of radically polymerizable monomers and prepolymers contained in the photosensitive resin composition due to radicals generated from a photopolymerization initiator contained in the photosensitive resin composition. Examples of photopolymerization initiators include benzoins, benzophenones, thioxanthones, anthraquinones, acylphosphine oxides, titanocenes, and acridines. Examples of radically polymerizable monomers include, but are not limited to, monomers and prepolymers having an acryloyl group, a methacryloyl group, an acrylamide group, a maleic acid diester, and an allyl group. A negative photosensitive resin using a cationic polymerization reaction is cured by polymerization or crosslinking between the molecules of the cationic polymerizable monomers and prepolymers contained in the photosensitive resin due to cations generated from a photocation initiator contained in the photosensitive resin. Examples of photocation initiators include aromatic iodonium salts and aromatic sulfonium salts. Examples of cationic polymerizable monomers and prepolymers include, but are not limited to, monomers and prepolymers having an epoxy group, a vinyl ether group, or an oxetane group. The negative photosensitive resin may be used alone or in combination of two or more. Furthermore, additives may be added as necessary.

As the negative photosensitive resin, commercially available products such as "SU-8 series" and "KMPR-1000" (product names) manufactured by Nippon Kayaku Co., Ltd., and "TMMR S2000" and "TMMF S2000" (product names) manufactured by Tokyo Ohka Kogyo Co., Ltd. can also be used. The method for forming the negative photosensitive resin on the base film 518 is not particularly limited, and a spin coating method, a slit die coating method, a spray coating method, or the like can be appropriately selected. The thickness of the lid member 517 is preferably 2 to 50 μm, depending on the dimensions of the opening, the flow rate of the ink to be supplied, and the viscosity. If the thickness of the lid member 517 is less than 2 μm, the common liquid chamber 513 cannot be sufficiently covered, and ink leakage is likely to occur when ink is supplied. Furthermore, the lid member 517 is likely to be damaged by the ink supply pressure.

For example, PET, polyimide, fluorine-based film, and hydrocarbon-based film are used as the base film 518. Next, the base film 518 is peeled off (FIG. 33(b)), and exposed to light through a mask 532 (FIG. 33(c)). Next, post-baking and development are performed to form the lid member (FIG. 33(d)). In addition, in order to maintain the unevenness of the lid member 517, a process may be used in which the negative photosensitive resin is exposed and post-baked while supported by the base film 518, and then the base film 518 is peeled off and developed. Next, the flow path mold 521 is removed, and a curing process is performed. This produces a recording element substrate on the wafer (FIG. 33(e)). In addition, the process of removing the flow path mold 521 may be performed before forming the lid member 517.

Furthermore, because liquid supply opening 2133 and liquid recovery opening 2143 can be processed in cover member 517 by lithography, it is possible to improve the shape accuracy of each opening and the positioning accuracy of liquid supply path 18 and liquid recovery path 19. By using a resin film with a film thickness of 50 μm or less, it is possible to achieve a shape accuracy of ±5 μm or less and a positioning accuracy of ±5 μm or less.
Furthermore, when the film thickness is less than 25 μm, the shape precision can be further improved.
Although not shown in Figures 32 and 33, a plurality of openings are formed in cover member 517 for each of liquid supply path 18 and liquid recovery path 19, as shown in Figure 11(c).

By processing the lid member 517 in the wafer process, the shape precision is better than with mechanical processing or molding processing, so it is possible to form finer holes at a higher density, and furthermore, the lid member 517 can be made thinner. In addition, after forming the liquid supply path 18 and the liquid recovery path 19 on the surface of the substrate, a lid member is provided on the surface of the substrate on which they are formed, and then multiple openings 21 (2133, 2143) are provided in the lid member. This makes it possible to form the fine openings 21 (2133, 2143) with high precision for the liquid supply path 18 and the liquid recovery path 19. It is more preferable in terms of precision to perform this processing on the Si substrate wafer by applying a photosensitive film, which is the lid member, and forming openings in the lid member using photolithography technology.

In this way, by fabricating the cover member 517 on the element substrate in a wafer state and increasing the shape accuracy of the liquid supply opening 2133 and the liquid recovery opening 2143, it is possible to reduce the variation in flow path resistance in the liquid supply opening 2133 and the liquid recovery opening 2143. In addition, by increasing the shape accuracy and arrangement accuracy, the liquid supply opening 2133 and the liquid recovery opening 2143 can be arranged smaller and more accurately, so it is possible to arrange a flow path for the liquid supply path 18 and the liquid recovery path 19 arranged at a higher density. In other words, it is possible to form a flow path for the ejection port array 14 arranged at a higher density. In particular, as in this embodiment, in a liquid ejection head 3 that generates an ink circulation flow, it is necessary to arrange the liquid supply path 18 and the liquid recovery path 19 for each ejection port array 14, so the density becomes higher and the effect of using the present invention is large. Furthermore, it is possible to accurately form multiple openings that are denser and have smaller opening dimensions than the liquid supply path 18 and the liquid recovery path 19 for the liquid supply path 18 and the liquid recovery path 19 formed along the ejection port array.

FIG. 34 is a schematic diagram of a liquid ejection head with the lid member 20 applied to the recording element substrate 10, seen from the lid member 20 side, and shows the positional relationship between the liquid supply opening 2133 formed in the lid member 20 and the liquid supply path 18 formed in the recording element substrate 10. FIG. 34(a) shows an example in which the width of the liquid supply opening 2133 is larger than the width of the liquid supply path 18. When the shape accuracy is ±5 μm or less and the positional accuracy is also ±5 μm or less, the positional relationship shown in FIG. 34(a) does not change even when the accuracy of each varies by making the width of the liquid supply opening 2133 larger than the width of the liquid supply path 18 by 10 μm on both sides. Considering other factors of accuracy variation, it is preferable to make the width of the liquid supply opening 2133 larger than the width of the liquid supply path 18 by 15 μm on both sides. Since the positional relationship does not change in this way, it is possible to reduce the variation in the flow path resistance from the liquid supply opening 2133 to the liquid supply path 18. Similarly, as shown in FIG. 34(b), the width of the liquid supply opening 2133 may be made smaller than the width of the liquid supply path 18 by 15 μm on both sides. Also, as shown in FIG. 34(c), the width may be made larger by 15 μm on one side and smaller by 15 μm on the other side. In this way, even if the difference in width between the liquid supply path 18 and the liquid supply opening 2133 is within 30 μm, it is possible to reduce the flow path resistance variation. In such a case, for example, in the case of the relationship shown in FIG. 34(a), even if it is necessary to secure at least 50 μm for the width of the joint surface between the cover member 20 and the recording element substrate 10, the arrangement relationship does not change even if the beam width between the liquid supply path 18 and the liquid recovery path 19 is reduced to 65 μm. Also, in the case of the relationship shown in FIG. 34(b), even if it is necessary to secure 150 μm for the width of the liquid supply opening, the arrangement relationship does not change even if the width of the liquid supply path 18 is reduced to 180 μm.

Figure 35 (a) is a graph showing the relationship between the width of the liquid supply opening 2133 and the pressure loss in the supply flow path 18. The effects of the present invention will be described below. As shown in Figure 35 (a), when the width of the liquid supply opening becomes smaller, the impact on the pressure loss when the width varies becomes greater. In particular, when the width is 200 μm or less, the pressure loss becomes greater. In other words, when the liquid supply opening 2133 is made smaller by increasing the density of the ejection port row, the effect of the shape accuracy of the liquid supply opening on the flow path resistance variation becomes greater. In this way, the present invention is particularly effective in liquid ejection heads in which ejection ports are arranged at a high density, and it is possible to reduce the flow path resistance variation, that is, the variation in the pressure loss that occurs in the supply flow path during ejection, and the pressure variation at the ejection port meniscus interface can be reduced. As a result, it is possible to eject droplets of a more uniform size, and it is possible to form images with higher resolution and higher quality.

In addition, in the liquid ejection head 3 that generates an ink circulation flow as in this embodiment, by reducing the variation in flow path resistance, it is possible to further stabilize the pressure difference that generates the ink circulation flow, and the variation in the amount of ink circulation can also be reduced.

Figure 35 (b) is a graph showing an example of the effect of variation in the amount of circulating ink, showing an example of the relationship between the ink circulation flow rate flowing through the lower part (pressure chamber) of each ejection port and the ejection speed of the first droplet after a certain period of rest at each ink circulation flow rate. It can be seen that when the circulation flow rate is about 7000 pl/s or more, the first droplet can be ejected at an ejection speed of more than 90% of the steady-state ejection speed, whereas at a flow rate below that, the ejection speed of the first droplet becomes less than 90%. When the ejection speed decreases in this way, the landing time is shifted, resulting in deterioration of image quality. In addition, in order to increase the circulation flow rate, it is necessary to increase the pressure difference between the first liquid tank 1011 and the second liquid tank 1012 in Figure 24 (c) or to flow a large flow rate using a pump or the like, which requires a large ink supply system and makes it difficult to control the pressure of the ejection port. Therefore, it is better to make the circulation flow rate as small as possible so that the ejection speed does not decrease too much, and in a liquid ejection head 3 with small variations in the circulation flow rate, it is easier to reduce the circulation flow rate to a level where the ejection speed does not decrease.

In this way, the present invention can reduce the variation in flow path resistance even in liquid ejection heads with high density ejection ports, making it possible to stabilize the pressure difference that generates the ink circulation flow and reduce the variation in the circulation flow rate. As a result, ejection characteristics can be made uniform regardless of whether or not each ejection port is paused, and regardless of how long it is paused, making it possible to form images with higher resolution and quality.

(Relationship between Outer Shape of Element Substrate and Outer Shape of Lid Member)
FIG. 36 is a diagram showing the relationship between the outer shapes of the element substrate 2010 and the lid member 517 (20), and FIG. 36(a) shows the state in which the lid member 517 is formed on the element substrate 2010 in a wafer state. The liquid supply opening 2133 and the liquid recovery opening 2143 are omitted. The lid member 517 is divided into units that will eventually become one recording element substrate 10. FIG. 36(b) is a diagram showing an enlarged portion of FIG. 36(a). When dividing the element substrate 2010 in a wafer state, it is preferable to divide it in an area where the lid member 517 is not present. By dividing it in an area where the lid member 517 is not present, it is possible to suppress the shape deterioration and peeling of the lid member 517 when dividing the recording element substrate 2010. In other words, by making the outer size of the lid member smaller than the outer size of the recording element substrate to be divided by cutting, it is possible to form the lid member on the element substrate in a wafer state, and it is possible to suppress the shape deterioration and peeling of the lid member 517 during cutting.

For example, various etching and dicing methods are used to divide the element substrate 2010. When dividing by etching, it is necessary to divide the area where there is no lid member 517. When dividing by blade dicing, if there is a lid member 517 in the area to be divided, this may cause the shape of the lid member 517 to deteriorate or peel off, and may cause deterioration of the blade. When dividing by laser dicing, it is necessary to divide the area where there is no lid member 517, just as in the case of etching.

Figure 36(c) shows one recording element substrate 10 and lid member 20 after division. To divide the recording element substrate 2010 in an area without the lid member 20 as in Figures 36(a) and (b), the relationship between the outer shape of the recording element substrate 10 and the outer shape of the lid member 20 should be such that the lid member 20 fits inside the outer shape of the recording element substrate 10 as in Figure 36(c).

In this way, in this embodiment, the outer shape of the lid member is on the inside of the outer shape of the recording element substrate, which makes it possible to cut the lid member after it has been formed on the wafer-shaped recording element substrate, and prevents the lid member from deforming or peeling off. In other words, when forming a lid member on a wafer-shaped recording element substrate, it is essential to make the outer shape of the lid member smaller than the outer shape of the recording element substrate. This can also be prevented by having the lid member be at least partially on the inside without protruding from the outer shape.

(Structure for suppressing variations in ink circulation flow rate and pressure (1))
Furthermore, in this embodiment, in order to suppress variations in the ink circulation flow rate and pressure in each pressure chamber 23, the following structure is provided. That is, as shown in Figs. 25 and 26, a plurality of liquid supply openings 2133 communicate with one liquid supply path 18, and similarly, a plurality of liquid recovery openings 2143 communicate with one liquid recovery path 19. These liquid supply openings 2133 and liquid recovery openings 2143 are arranged so that the variations in the ink circulation flow rate and pressure in each pressure chamber 23 do not significantly affect the ink ejection characteristics. Specifically, the liquid supply openings 2133 and the liquid recovery openings 2143 are arranged so as to be alternately positioned in the first direction in which the ejection ports 13 are arranged in the ejection port array 14. This makes it possible to further narrow the distance between the liquid supply openings 2133 and the liquid recovery openings 2143 in the first direction. Therefore, even if the flow path width of the liquid supply path 18 and the liquid recovery path 19 is relatively narrow, it is possible to suppress variations in the ink circulation flow rate and pressure in each pressure chamber 23.

(Structure for suppressing variations in ink circulation flow rate and pressure (2))
Furthermore, in this embodiment, in order to suppress variations in the ink circulation flow rate and pressure in each pressure chamber 23, the following structure is provided. That is, as shown in Fig. 25 and Fig. 26, the common supply path 2134 extends in a second direction intersecting the arrangement direction of the ejection ports 13, and communicates with a plurality of liquid supply openings 2133 arranged in the second direction. Similarly, the common recovery path 2144 extends in the second direction, and communicates with a plurality of liquid recovery openings 2143 arranged in the second direction. Furthermore, the plurality of common supply paths 2134 are collectively connected to one common supply flow path 211 via the individual supply ports 2135. Similarly, the plurality of common recovery paths 2144 are collectively connected to one common recovery flow path 212 via the individual recovery ports 2145.

In this way, by forming the ink flow path with a six-layer structure, the multiple liquid supply paths 18 formed at a narrow pitch to match the multiple nozzle rows 14 arranged at high density are finally combined into one common supply flow path 211 through the multiple liquid supply openings 2133. Similarly, the multiple liquid recovery paths 19 formed at a narrow pitch to match the multiple nozzle rows 14 arranged at high density are finally combined into one common recovery flow path 212 through the multiple liquid recovery openings 2143. Therefore, the multiple nozzle rows 14 can be arranged at high density without widening the flow path width of the liquid supply path 18 and the liquid recovery path 19. In addition, in each pressure chamber 23 corresponding to each nozzle 13 of the multiple nozzle rows 14 arranged at high density in this way, the ink circulation flow rate and pressure variations can be suppressed. In addition, for the nozzles 13 arranged at high density, the supply of ink from an ink tank (not shown) and the outflow of ink to the ink tank can be easily realized while suppressing the ink circulation flow rate and pressure variations in the pressure chamber 23. This makes it possible to compactly configure not only the liquid ejection head and the recording device equipped with it, but also various liquid ejection heads and the entire system of the liquid ejection device equipped with them.

(Structure for suppressing variations in ink circulation flow rate and pressure (3))
In order to suppress the variation in the ink circulation flow rate and pressure in each pressure chamber 23, it is desirable to provide the following structure. That is, the liquid supply openings 2133 and/or liquid recovery openings 2143 located at both ends of the ejection port array 14 are made smaller in shape than the liquid supply openings 2133 and/or liquid recovery openings 2143 located at other ends. That is, the openings of the liquid supply openings 2133 and/or liquid recovery openings 2143 located at both ends of the ejection port array 14 are formed smaller than the openings of the liquid supply openings 2133/or liquid recovery openings 2143 other than at both ends of the ejection port array 14. The ejection ports 13 of the ejection port array 14 are located on only one side of the liquid supply openings 2133 located at both ends of the ejection port array 14. Therefore, the ink flow rate at the liquid supply openings 2133 located at both ends of the ejection port array 14 is smaller than the ink flow rate at the other liquid supply openings 2133. Similarly, the ejection ports 13 of the ejection port array 14 are located on only one side of the liquid recovery openings 2143 located at both ends of the ejection port array 14. Therefore, the ink flow rate at the liquid recovery openings 2143 located at both ends of the ejection port array 14 is smaller than the ink flow rate at the other liquid recovery openings 2143.

In this way, the shape of the liquid supply openings 2133 and/or liquid recovery openings 2143 located at both ends of the ejection port array 14 is made small to increase the flow path resistance. This makes it possible to make the pressure loss occurring in those liquid supply openings 2133 and/or liquid recovery openings 2143 closer to the pressure loss occurring in the other liquid supply openings 2133 and/or liquid recovery openings 2143. This makes it possible to reduce the difference between the ink flow rate flowing into the pressure chamber 23 through the liquid supply openings 2133 and/or liquid recovery openings 2143 at both ends and the ink flow rate flowing into the pressure chamber 23 through the other liquid supply openings 2133 and/or liquid recovery openings 2143. As a result, the variation in the ink circulation flow rate in each pressure chamber 23 can be further suppressed.

(Structure for suppressing variations in ink circulation flow rate and pressure (4))
FIG. 37 is a diagram showing the recording element substrate 10 and the positions of the liquid supply opening and the liquid recovery opening in the recording element substrate 10. In order to suppress the variation in the ink circulation flow rate and pressure in each pressure chamber 23, it is desirable for the recording element substrate 10 to have the following structure. That is, as shown in FIG. 37(a), the area a between the end of the ejection port array 14 and the end of the recording element substrate 10 is set large. The area a can be used, for example, as an arrangement space for the pad terminal 16 for transmitting and receiving an electric signal to the recording element substrate 10, and the drive circuit of the recording element 15. It is also desirable to use such area a to provide a liquid recovery port 2133 as shown in the perspective views of FIG. 37(b) and (c). That is, the liquid recovery port 2133 is provided so as to overlap the ejection port 13 located at the end of the ejection port array 14 in the first direction in which the ejection port array 14 extends. 37(b) and (c), the left end of liquid recovery path 19 is in the same position as the left end of liquid recovery opening 2143. Also, in Fig. 37(c), the left ends of liquid recovery path 19 and liquid recovery opening 2143 bulge out more to the left than recovery port 17b located at the left end.

37(b) and (c), ink passing through the pressure chamber 23 located at the end of the ejection port array 14 first enters the liquid supply path 18 and the supply port 17a from the liquid supply opening 2133 as indicated by the arrow A1. Then, as indicated by the arrow A2, the ink passes through the pressure chamber 23 located at the end of the ejection port array 14, the recovery port 17b, and the liquid recovery path 19, and then flows out of the liquid recovery opening 2143. FIG. 37(d) is a comparative example in which the liquid recovery opening 2143 is arranged so as not to overlap with the ejection port 13 located at the end of the ejection port array 14 in the first direction. In FIG. 37(d), ink passing through the pressure chamber 23 located at the end of the ejection port array 14 first enters the liquid supply path 18 and the supply port 17a from the liquid supply opening 2133 as indicated by the arrow A1. Then, as indicated by arrow A2, the liquid passes through the pressure chamber 23 and recovery port 17b located at the end of the ejection port row 14, and then flows out of the liquid recovery opening 2143 through the liquid recovery path 19 as indicated by arrow A3.

37(b) and (c), the length of the ink flow path from the liquid supply opening 2133 located at the end in the first direction through the pressure chamber 23 to the liquid recovery opening 2143 can be shortened compared to the configuration of FIG. 37(d). In other words, the maximum pressure loss occurring in the liquid supply path 18 and the liquid recovery path 19 near the end of the ejection port array 14 can be reduced, suppressing the variation in the ink circulation flow rate in each pressure chamber 23. Note that when the liquid supply opening 2133 is located at the end in the first direction instead of the liquid recovery opening 2143, the liquid supply opening 2133 can be arranged so as to overlap with the ejection port 13 located at the end of the ejection port array 14 in the first direction.

(Temperature distribution suppression structure)
In this embodiment, the following structure is provided in order to suppress the temperature distribution in the liquid ejection head 3. That is, as shown in FIG. 25 and FIG. 26, the liquid recovery openings 2143 are located at both ends of the ejection port array 14. When ink is forcibly circulated through each pressure chamber 23 as in this example, the heat generated from the recording element 15 and the like is usually recovered by the ink, so that the temperature of the ink in the flow path on the ink outflow side becomes higher than that of each pressure chamber 23. Even if a sufficient ink circulation flow rate is secured to suppress the influence of the evaporation of moisture in the ink from the ejection port 13, the ejection amount when ink is ejected simultaneously from a large number of ejection ports 13 may be greater than the ink circulation flow rate. In such a case, ink is also supplied into the pressure chamber 23 from the common recovery flow path 212. That is, ink is supplied into the pressure chamber 23 from the common recovery flow path 212 through the individual recovery port 2145, the common recovery path 2144, the liquid recovery opening 2143, the liquid recovery path 19, and the recovery port 17b. Therefore, when ink is ejected simultaneously from a large number of ejection ports 13, high-temperature ink in the liquid recovery opening 2143 may be supplied to the pressure chamber 23. In such a case, the temperature of the ink in the vicinity of the liquid recovery opening 2143 becomes higher than that in the vicinity of the liquid supply opening 2133, and there is a risk of a difference in the ink ejection speed between the ejection ports 13 in the vicinity of the liquid supply opening 2133 and the ejection ports 13 in the vicinity of the liquid recovery opening 2143. In addition, when the liquid supply opening 2133 is located on one end side of both ends of the ejection port array 14 and the liquid recovery opening 2143 is located on the other end side, a gradient in the heat distribution occurs in the arrangement direction of the ejection port array 14 as a whole, and the heat distribution width of the entire liquid ejection head becomes large. As a result, there is a risk of variation in the ink ejection characteristics of each ejection port 13.

In this embodiment, a liquid recovery opening 2143 is provided at each end of the ejection port array 14, which suppresses the inclination of the heat distribution and reduces the variation in the ink ejection characteristics. The same effect can be achieved by providing a liquid supply opening 2133 at each end of the ejection port array 14. However, it is preferable to provide a liquid recovery opening 2143 at each end of the ejection port array 14, as in this embodiment.

That is, as described above, in the recording element substrate 10, between both ends of the ejection port array 14 and the ends of the recording element substrate 10, a large area a where the ejection ports 13 are not arranged is set, and heat generated during ink ejection is dissipated from this area a. Therefore, when a large number of ejection ports 13 eject ink, the temperature at both ends of the ejection port array 14 tends to be lower than the temperature in other parts. By providing liquid recovery openings 2143 at both ends of the ejection port array 14, high-temperature ink can be supplied to both ends of the ejection port array 14 in such a case. Therefore, the temperature at both ends of the ejection port array 14 can be made higher, and the temperature difference with other parts can be reduced. As a result, the heat distribution width of the entire liquid ejection head can be reduced, and the variation in the ejection characteristics of the ink can be suppressed.

In this way, a lid member is fabricated on the element substrate in a wafer state, and then the element substrate is cut to fabricate chipped recording element substrates. This makes it possible to realize a liquid ejection head and liquid ejection device that can suppress pressure variations in the pressure chambers.

Second Embodiment
A second embodiment of the present invention will be described below with reference to the drawings. Note that since the basic configuration of this embodiment is similar to that of the first embodiment, only the characteristic configuration will be described below.

Figures 38 and 39 show a liquid ejection unit 300 in this embodiment, and parts similar to those in the previously described embodiment are given the same reference numerals and will not be described. Figure 38 is an exploded perspective view of the liquid ejection unit 300, and Figure 39 is an exploded plan view of the liquid ejection unit 300. In this embodiment, at one end of the ejection port array 14, the liquid supply path 18 communicates with the liquid supply opening 2133, and the liquid recovery path 19 communicates with the liquid recovery opening 2143. Similarly, at the other end of the ejection port array 14, the liquid supply path 18 communicates with the liquid supply opening 2133, and the liquid recovery path 19 communicates with the liquid recovery opening 2143. By arranging the liquid supply opening 2133 and the liquid recovery opening 2143 at both ends of the ejection port array 14, it is possible to suppress the variation in the ink circulation flow rate in the first direction in which the ejection port array 14 extends, and the variation in the pressure in each pressure chamber 23, more than in the first application example. Furthermore, it is only necessary to provide two each of the common supply paths 2134 and common recovery paths 2144.

In this way, in this embodiment, the number of liquid supply openings and liquid recovery openings can be reduced, simplifying the structure of the ink flow path.

Third Embodiment
Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. Note that since the basic configuration of this embodiment is similar to that of the first embodiment, only the characteristic configuration will be described below.

Figures 40 to 42 show the liquid ejection unit 600 in this embodiment, and parts similar to those in the previously described embodiments are given the same reference numerals and will not be described. Figure 40 is an exploded perspective view of the liquid ejection unit 600, and Figure 41 is an exploded plan view of the liquid ejection unit 600. Figure 42(a) is a plan view of the recording element substrate 610 in this embodiment, and Figure 42(b) is a perspective view for explaining the structure of the end of the ejection port array 14.

The recording element substrate 610 in this embodiment has a parallelogram shape, and the area a between the end of the ejection port array 14 and the end of the element substrate is smaller than that of the recording element substrate 10 in FIG. 37(a) in the first application example (see FIG. 42(a)). In this embodiment, the connection pads 16 and the driving circuits such as the recording elements 15 for transmitting and receiving electrical signals between the recording element substrate 610 and the outside are arranged on the long side of the recording element substrate 610 as shown in FIG. 42(a). The outer shape is not limited to a parallelogram, but may be rectangular. When such recording element substrates 610 are combined to form a long liquid ejection head (line head), the recording element substrates 10 are arranged substantially in a line as shown in FIG. 23(d), FIG. 23(e) and FIG. 42(a) rather than in a staggered manner. In other words, the adjacent element substrates are arranged so that they partially overlap each other in both the long and short directions of the liquid ejection head. This arrangement makes it easy to make the ends of the ejection port arrays 14 on adjacent recording element substrates 10 overlap in the second direction, which is the up-down direction in FIG. 42(a).

Here, "arranged substantially in a row" means that adjacent recording element substrates 610 are arranged to partially overlap each other in both a first direction in which the ejection ports 13 extend in the ejection port array 14, and in a second direction that intersects with the first direction, as shown in Figure 42(a).

In this manner, in this embodiment, the ejection ports 13 are arranged up to the vicinity of the end of the recording element substrate 610. In this form, it is difficult to arrange the liquid supply opening 2133 or the liquid recovery opening 2143 at a position overlapping with the end of the ejection port array 14 of the recording element substrate 610, as in Figures 37(b) and (c) in the first application example. Therefore, in this embodiment, the liquid supply opening 2133 or the liquid recovery opening 2143 is arranged at a position shifted toward the center from the end of the ejection port array 14, as in Figure 42(b).

In this embodiment, in order to suppress variations in the ink circulation flow rate and pressure in each pressure chamber 23, and further suppress temperature distribution within the recording element substrate 610, liquid supply openings 2133 are provided near both ends of the ejection port array 14, as shown in Figures 40 and 41.

When the liquid supply opening 2133 is disposed near the end of the ejection port array 14 as in this embodiment, the pressure difference between the liquid supply path 18 and the liquid recovery path 19 located at the end of the ejection port array 14 is greater during ink ejection than during ink circulation due to the initial pressure difference. On the other hand, when the liquid recovery port 2133 is disposed at the end of the ejection port array 14 as in the first application example, the pressure difference between the liquid supply path 18 and the liquid recovery path 19 at the end of the ejection port array 14 is smaller during ink ejection than during ink circulation due to the initial pressure difference. When the pressure difference between the liquid supply path 18 and the liquid recovery path 19 becomes smaller, the ink circulation flow rate decreases, and the effect of suppressing the effect of the evaporation of water in the ink from the ejection port 13, that is, the decrease in the ejection speed of the ink, and the change in the colorant concentration of the ink becomes smaller. Therefore, it is better that the pressure difference is larger. By disposing the liquid supply opening 2133 near both ends of the ejection port array 14 as in this embodiment, the effect of the variation in the ink circulation flow rate can be reduced.

The pressure inside the liquid supply opening 2133 is set higher than the pressure inside the liquid recovery opening 2143 to generate an ink circulation flow, and when ink is ejected, ink is easily supplied into the pressure chamber 23 through the liquid supply opening 2133. By arranging the liquid supply opening 2133, which makes it easier to supply ink, near the end of the ejection port row 14 in this way, it is possible to reduce pressure loss that occurs in the liquid supply path 18 and liquid recovery path 19 when ink is ejected simultaneously from multiple ejection ports 13.

In addition, in this embodiment, as described above, the area a between the end of the ejection port array 14 and the end of the element substrate is small, so the degree to which heat generated during ink ejection is dissipated from the area a is small. Because the area a is small, as shown in FIG. 42(b), the portion of the liquid supply path 18 between the liquid supply opening 2133 and the end of the ejection port array 14 becomes long, and similarly, the portion of the liquid recovery path 19 between the liquid recovery opening 2143 and the end of the ejection port array 14 becomes long. Therefore, the ink passing through those portions of the liquid supply path 18 and the liquid recovery path 19 is more likely to receive heat from the recording element substrate 610. Therefore, when ink is ejected simultaneously from a large number of ejection ports 13, the temperature at the end of the ejection port array 14 tends to be higher than the other portions. In addition, the pressure loss occurring in each ink flow path during ink ejection also becomes large, and the pressure variation at the end of the ejection port array 14 becomes large.

In addition, in this embodiment, as described above, a liquid supply opening 2133 is arranged at each end of the ejection port array 14. Therefore, a large amount of ink is supplied to the ejection ports 13 near the ends of the ejection port array 14 from the liquid supply openings 2133 arranged in the vicinity. As a result, when ink is ejected simultaneously from a large number of ejection ports 13, the amount of high-temperature ink supplied from the liquid supply openings 2133 is reduced, and the temperature rise at the ends of the ejection port array 14 can be reduced.

Specifically, ink supplied from the liquid supply opening 2133 first enters the supply port 17a from the liquid supply path 18 as indicated by arrow B1 in FIG. 42(b). The ink then passes through the pressure chamber 23 and recovery port 17b located at the end of the ejection port row 14 as indicated by arrow B2, and then flows through the liquid recovery path 19 as indicated by arrow A3 before flowing out of the liquid recovery opening 2143.

In this embodiment, by arranging the liquid supply openings 2133 at both ends of the nozzle row 14, it is possible to suppress variations in the ink circulation flow rate and pressure, and to keep the temperature distribution inside the liquid ejection head small. This suppresses the decrease in ink ejection speed due to evaporation of water in the ink from the nozzles 13, and the change in the ink colorant concentration, and also suppresses variations in the ink ejection characteristics, making it possible to record images with higher resolution and quality.

(Arrangement of Liquid Supply Opening and Liquid Recovery Opening)
FIG. 43 is a graph showing the temperature distribution of the recording element substrate 610 when ejection is performed from all ejection ports. Next, the temperature distribution of the entire recording element substrate 610 in this embodiment will be described. The recording element substrate 610 is in a state where the temperature is controlled at 50 degrees. Since the flow rate due to ejection is greater than the flow rate of the ink circulation flow, the direction of the ink flow at the liquid recovery opening 2143 is toward the ejection port. In addition, the flow rate of the liquid supply opening 2133 and the liquid recovery opening 2143 tends to be greater for the liquid supply opening 2133. FIG. 43(a) shows a temperature distribution in a comparative example in which one liquid supply opening 2133 and one liquid recovery opening 2143 are arranged for one ejection port row 14. The ink flowing through the liquid supply path 18 and the liquid recovery path 19 receives heat from the recording element substrate 610, and the temperature of the central portion is high. In addition, when the temperatures of the liquid supply opening 2133 and the liquid recovery opening 2143 are compared, the liquid supply opening 2133 has a larger flow rate, and therefore the temperature of the liquid supply opening 2133 is lower. Even when the liquid recovery opening 2143 does not flow backward, the ink that has once flowed through the recording element substrate 610 and received heat flows through the liquid recovery opening 2143, so the temperature of the liquid supply opening 2133 tends to be lower. Fig. 43B shows the temperature distribution when a plurality of liquid supply openings 2133 and liquid recovery openings 2143 are alternately arranged for one ejection port row in this embodiment. Since the distance between the liquid supply opening 2133 and the liquid recovery opening 2143 is short, the length of flow through the liquid supply path 18 and the liquid recovery path 19 is short, so the temperature rise between them is small, and in particular the temperature is similar to that of the liquid recovery opening 2143. Furthermore, since the liquid supply opening 2133 and the liquid recovery opening 2143 are alternately arranged, the maximum length of flow through the liquid supply path 18 and the liquid recovery path 19 is short, so the temperature rise is small.

In this manner, in this embodiment, by arranging multiple liquid supply openings 2133 and multiple liquid recovery openings 2143 alternately for one ejection port row, the temperature difference within the recording element substrate 610 can be reduced compared to the comparative example shown in FIG. 43(a). This makes it possible to suppress variations in ejection characteristics, enabling the formation of images with higher resolution and quality. The effect of this embodiment can be obtained if there are at least two of either the liquid supply openings 2133 or the liquid recovery openings 2143.

Figure 44(a) is a graph showing the temperature distribution in each ejection port array 14 when the liquid supply opening 2133 and the liquid recovery opening 2143 for the multiple ejection port arrays 14 are arranged in a shifted manner to match the parallelogram of the recording element substrate 610. Although the absolute temperature value of each ejection port array itself differs depending on the position of the ejection port array, it can be seen that the high temperature position and the low temperature position are shifted according to the shift of the liquid supply opening 2133 and the liquid recovery opening 2143. Figure 44(b) is a graph averaging the temperature distribution in Figure 44(a) in the row direction of the ejection port array 14. Since the high temperature position and the low temperature position in each ejection port array are shifted, when averaged, the temperature difference in the recording element substrate 610 is smaller than the temperature difference when all the ejection port arrays in Figure 44(a) are considered. Therefore, if the scanning direction of the recorded material (the relative scanning direction between the liquid ejection head and the recorded material) is perpendicular to the row direction of the ejection port array 14, the effect of the variation in the ejection characteristics due to the temperature difference on the recorded material can be averaged.

In this way, by arranging the liquid supply opening 2133 and the liquid recovery opening 2143 in an offset manner, the temperature difference caused by the arrangement of the liquid supply opening 2133 and the liquid recovery opening 2143 can be averaged. This makes it possible to suppress the variation in the ejection characteristics, thereby enabling the formation of images with higher resolution and quality.

(Modifications of the Shapes of the Liquid Supply Opening and the Liquid Recovery Opening)
FIG. 45 is a diagram showing a modified example of the shape of the liquid supply opening 2133 or the liquid supply opening 2143. FIG. 45(a) is a diagram showing the cover member 620 and the recording element substrate 610 from the side opposite to the ejection port. FIG. 45(b) is a diagram showing the details of the liquid supply opening 2133 in FIG. 45(a), and also shows the liquid supply path 18 on the recording element substrate 10. FIG. 45(c) shows a state in which the support member 30 or the first flow path member 50 having the fourth flow path layer 224 is joined to the cover member 620. As shown in FIG. 45(b), the liquid supply opening 2133 has a parallelogram shape in accordance with the outer shape of the recording element substrate 610. By forming it into a parallelogram shape in this way, the width W5 of the joining surface between the cover member 620 and the fourth flow path layer 224 in FIG. 45(c) and the cross-sectional area perpendicular to the liquid flow direction of the liquid supply opening 2133 can be made larger. In other words, in consideration of the overflow of adhesive or the like when bonding the cover member 620 and the fourth flow path layer 224, it is desirable to increase the minimum distance W6 between the outer shape of the liquid supply opening 2133 and the common supply path 2134. By forming the liquid supply opening 2133 into a parallelogram, the cross-sectional area, width W5, and distance W6 of the liquid supply opening 2133 can be increased. By using lithography processing, it is possible to process fine and complex shapes such as this shape, and it is easy to increase the cross-sectional areas of the liquid supply opening 2133 and the liquid recovery opening 2143, and the bonding surfaces between the cover member 620 and the support member 30 or the first flow path member 50.

(Linear expansion coefficient of cover member)
In a liquid ejection head in which a plurality of recording element substrates are arranged, the cover member 620 is separated for each recording element substrate, so that the deterioration of the arrangement accuracy of the recording element substrate can be suppressed. That is, in a liquid ejection head as shown in FIG. 23(d) or FIG. 24(e), when a cover member integrated in the longitudinal direction is used for a plurality of recording element substrates as in Patent Document 1, the linear expansion coefficient of the cover member may affect the arrangement accuracy of the recording element substrate due to temperature changes, and the arrangement accuracy of the recording element substrate may deteriorate. In contrast, since the cover member 620 is separated for each recording element substrate as in this embodiment, the deterioration of the arrangement accuracy of the recording element substrate due to temperature changes in the longitudinal direction of the liquid ejection head is largely due to the linear expansion coefficient of the member supporting the recording element substrate, not the linear expansion coefficient of the cover member. When a resin film is used for the cover member 620, the linear expansion coefficient is generally about 30 ppm. In contrast, for example, when alumina is used for the member supporting the plurality of recording element substrates 610, the linear expansion coefficient can be about 7 ppm, and when a resin material filled with a filler that reduces the linear expansion coefficient is used, the linear expansion coefficient can be about 20 ppm. That is, by dividing the cover member 620 into separate ones for each recording element substrate and reducing the linear expansion coefficient of the member that integrally supports the plurality of recording element substrates 610, the accuracy of arrangement of the recording element substrates can be improved.

(Gap between adjacent boards)
In this embodiment, by providing an individual lid member 620 for each recording element substrate, the misalignment width of the ejection port array at the joint between the recording element substrates 610 can be reduced. In other words, when forming a lid member across adjacent recording element substrates, adhesive may be required when bonding the recording element substrate to the lid member, and in such a case, it is necessary to widen the gap between the adjacent recording element substrates in consideration of the spread and creeping of the adhesive. In contrast, in this embodiment, by adopting the configurations (1) and (2) of the gap portion between the adjacent substrates in the fourth embodiment described later, it is possible to bring the adjacent recording element substrates closer to each other without considering the spread and creeping of the adhesive. As a result, the misalignment width between the recording element substrates in the scanning direction to the recorded material at the joint between the recording element substrates can be reduced, and the misalignment width of the ejection port array can be reduced. Therefore, defects such as unevenness in the image at the joint can be reduced, and high-quality image formation can be achieved.

(Fourth embodiment)
A fourth embodiment of the present invention will be described below with reference to the drawings. Note that since the basic configuration of this embodiment is similar to that of the first embodiment, only the characteristic configuration will be described below.

(Configuration of Gap Between Adjacent Substrates (1))
Fig. 46 and Fig. 47 are diagrams showing an example of the configuration of the gap between adjacent recording element substrates in this embodiment. Fig. 46 is a schematic diagram of the liquid ejection head of this embodiment, Fig. 46(a) is a perspective view, and Fig. 46(b) is a perspective view in an exploded state. Fig. 47 is a schematic diagram of the gap between adjacent element substrates in this embodiment, Fig. 47(a) is a top view, and Fig. 47(b) is a cross-sectional view taken along XLVIIb-XLVIIb in Fig. 47(a).

In this embodiment, a lid member 20 is disposed on the rear surface of the recording element substrate 10, and a liquid supply path 18 for supplying liquid to the ejection port 13 is located on the rear surface of the recording element substrate 10, with the lid member 20 acting as a lid for the liquid supply path 18. Furthermore, a liquid supply opening 2133 for supplying liquid to the liquid supply path 18 is provided in the lid member 20, and is connected to a supply path provided in the support member 50.

In this embodiment, the ejection port 13 is also arranged in the area of the recording element substrate 50 protruding above the groove 55 of the first flow path member 50, which is a support member, to reduce the misalignment width of the ejection port array at the joint of the recording element substrate. As shown in FIG. 47B, in the gap portion where the recording element substrates 10 are adjacent to each other, the liquid supply path 18 is also arranged in the recording element substrate 10 protruding above the groove of the first flow path member 50, and the cover member 20 serves as a cover for the liquid supply path 18. In addition, in the adjacent gap portion, the joint between the cover member 20 and the support member 50 extends inward from the outer edge of the recording element substrate. In this way, by covering the liquid supply path 18 protruding above the groove 55 with the cover member 20, it is possible to supply liquid to the ejection port 13 protruding outward from the end of the first flow path member 50 through the liquid supply path 18 arranged on the back surface of the recording element substrate 50. That is, first, the width of the groove 55 provided on the first flow path member (the length in the longitudinal direction of the first flow path member 50) is made larger than the width of the gap between the recording element substrates, thereby making it possible to reduce the gap between adjacent recording element substrates. Furthermore, by covering the liquid supply path 18 at the portion protruding above the groove 55 of the first flow path member 50 with the cover member 20, the ejection port 13 can be arranged up to the end of the recording element substrate 10, and the deviation width of the ejection port array at the joint of the recording element substrate can be further reduced. For example, a comparison is made for a case in which the distance between the recording element substrates is reduced from 0.2 mm to 0.03 mm by using this embodiment. When the ejection port at the end of the ejection port array can be arranged at a position 0.05 mm from the end of the recording element and the angle of the hypotenuse of the chip is 45 degrees, the deviation width of the ejection port array is about 0.42 mm to about 0.18 mm, and the present invention has been able to significantly reduce the deviation width of the ejection port array.

In this way, even when adhesive is used to bond the recording element substrate 10 and the first flow path member 50, it is possible to reduce the misalignment between the recording element substrates at the joints of the recording element substrates in the scanning direction of the recorded material, and to reduce the misalignment of the ejection port arrays. As a result, defects such as unevenness in the image at the joints are reduced, making it possible to form high-quality images.

In addition, in this embodiment, it is preferable that the outer shape of the lid member 20 is smaller than the outer shape of the recording element substrate 10. In other words, it is possible to bring adjacent recording element substrates closer to each other at the seams regardless of the processing accuracy of the lid member 20, and it is possible to reduce the misalignment between the recording element substrates at the seams in the scanning direction of the recorded material and to reduce the misalignment of the ejection port arrays. As a result, defects such as unevenness in the image at the seams are reduced, making it possible to form high-quality images.

(Configuration of Gap Between Adjacent Substrates (2))
Fig. 48 and Fig. 49 are diagrams showing an example of the configuration of the gap between adjacent substrates in this embodiment. Fig. 48 is a schematic diagram of a liquid ejection head of this configuration example, Fig. 48(a) is a perspective view, and Fig. 48(b) is a perspective view in an exploded state. Fig. 49 is a schematic diagram of the gap between adjacent element substrates in this embodiment, Fig. 49(a) is a top view, and Fig. 49(b) is a cross-sectional view taken along the line XLIXb-XLIXb in Fig. 49(a).

Here, a comparison is made when the distance between adjacent recording element substrates is reduced from 0.2 mm to 0.02 mm. When the ejection ports at the end of the ejection port array can be located 0.05 mm from the end of the recording element and the angle of the hypotenuse of the chip is 45 degrees, the deviation width of the ejection port array is reduced from approximately 0.42 mm to approximately 0.17 mm, and the present invention has been able to significantly reduce the deviation width of the ejection port array.
In this way, the present invention can reduce the misalignment between elements in the scanning direction of the printed material at the seams of the printing element substrate 10, and can reduce the misalignment of the ejection port arrays. As a result, defects such as unevenness in the image at the seams can be reduced, making it possible to form high-quality images.

Furthermore, as in the configuration example described above, it is possible to suppress the adhesive from creeping up onto the ejection port surface in the adjacent portion of the recording element substrate. When adhesive is used to join the cover member 20 and the first flow path member 50, as in this embodiment, the ends of the cover member 20 and the recording element substrate 10 protrude outward beyond the end of the first flow path member 50, and the protruding adhesive accumulates on the back surface of the protruding cover member 20. Therefore, compared to a configuration that does not protrude outward, it is possible to suppress the adhesive from creeping up onto the ejection port surface in the adjacent portion.

The configuration of the gap between adjacent substrates has been described using a parallelogram-shaped recording element substrate 10 as in this embodiment, but it is not limited to a parallelogram. For example, it can also be applied to a liquid ejection head in which multiple rectangular recording element substrates 10 are arranged.

Fifth Embodiment
Hereinafter, a fifth embodiment of the present invention will be described with reference to the drawings. Since the basic configuration of this embodiment is the same as that of the first embodiment, only the characteristic configuration will be described below. In this embodiment, as in each of the above-mentioned embodiments, a third flow path layer 223 is provided as a cover member.

Figures 50 and 51 show the liquid ejection unit 700 in this embodiment, and parts similar to those in the previously described embodiment are given the same reference numerals and will not be described. Figure 50 is an exploded perspective view of the liquid ejection unit 700, and Figure 51 is an exploded plan view of the liquid ejection unit 700.

In this embodiment, as shown in FIG. 50, three liquid supply paths 18 (18A, 18B, 18C) and two liquid recovery paths 19 (19A, 19B) are arranged for four ejection port rows 14 (14A, 14B, 14C, 14D). As shown in FIG. 51, a common recovery port 17b is arranged between ejection port rows 14A and 14B, and the recovery port 17b is connected to liquid recovery path 19A. A common supply port 17a is arranged between ejection port rows 14B and 14C, and the supply port 17a is connected to liquid supply path 18B. A common recovery port 17b is arranged between ejection port rows 14C and 14D, and the recovery port 17b is connected to liquid recovery path 19B. The supply ports 17a of the ejection port array 14A are connected to the liquid supply path 18A, and the supply ports 17a of the ejection port array 14D are connected to the liquid supply path 18C.

In this way, the single liquid supply path 18B communicates with the pressure chambers 23 of the two ejection port arrays 14B, 14C via a common supply port 17a for the two ejection port arrays 14B, 14C. In addition, the single liquid recovery path 19A communicates with the pressure chambers 23 of the two ejection port arrays 14A, 14B via a common recovery port 17b for the two ejection port arrays 14A, 14B. Similarly, the single liquid recovery path 19B communicates with the pressure chambers 23 of the two ejection port arrays 14C, 14D via a common recovery port 17b for the two ejection port arrays 14C, 14D.

According to this embodiment, in addition to the effects of the above-mentioned embodiment, the following effects can be achieved. That is, by sharing the liquid supply path 18 and the liquid recovery path 19 between two adjacent ejection port rows, the number of partitions between the ink flow paths and the number of ink flow paths can be reduced. Therefore, it is possible to narrow the interval between the ejection port rows 14 and increase the width of the ink flow path. As a result, the ink circulation flow rate and pressure variations in each pressure chamber 23 are further suppressed, and the ejection port rows 14 can be arranged at a higher density than in the above-mentioned embodiment, thereby reducing the size of the liquid ejection unit 700 and the liquid ejection head. In addition, when the arrangement density of the ejection port rows 14 is the same, the ink circulation flow rate and pressure variations in each pressure chamber 23 are further suppressed, and the number of liquid supply openings 2133 and liquid recovery openings 2143 can be reduced. This makes it possible to simplify the ink flow path structure in the liquid ejection unit 700.

Sixth Embodiment
Hereinafter, a sixth embodiment of the present invention will be described with reference to the drawings. Since the basic configuration of this embodiment is the same as that of the first embodiment, only the characteristic configuration will be described below. In this embodiment, as in each of the above-mentioned embodiments, a third flow path layer 223 is provided as a cover member.

Figures 52 and 53 show the liquid ejection unit 800 in this embodiment, and parts similar to those in the previously described embodiment are given the same reference numerals and will not be described. Figure 52 is an exploded perspective view of the liquid ejection unit 800, and Figure 53 is an exploded plan view of the liquid ejection unit 800.

In this embodiment, in order to eject inks of different colors or different types, a nozzle row in which nozzles 13M for the first ink are arranged and a nozzle row in which nozzles 13Y for the second ink are arranged are formed in one liquid ejection unit 800. In the second flow path layer 222, a liquid supply path 18M for the first ink, a liquid supply path 18Y for the second ink, a liquid recovery path 19M for the first ink, and a liquid recovery path 19Y for the second ink are formed. In the third flow path layer 223, a liquid supply opening 2133M for the first ink, a liquid supply opening 2133Y for the second ink, a liquid recovery opening 2143M for the first ink, and a liquid recovery opening 2143Y for the second ink are formed. In the fourth flow path layer 224, a common supply path 2134M for the first ink, a common supply path 2134Y for the second ink, a common recovery path 2144M for the first ink, and a common recovery path 2144Y for the second ink are formed. The fifth flow path layer 225 is formed with an individual supply port 2135M for the first ink, an individual supply port 2135Y for the second ink, an individual recovery port 2145M for the first ink, and an individual recovery port 2145Y for the second ink. The sixth flow path layer 226 is formed with a common supply flow path 211M for the first ink, a common supply flow path 211Y for the second ink, a common recovery flow path 212M for the first ink, and a common recovery flow path 212Y for the second ink.

As in the first application example, the first and second inks are supplied from the common supply flow paths 211M and 211Y, respectively, pass through the corresponding pressure chambers 23, and then flow out of the common recovery flow paths 212M and 212Y.

As in the fifth embodiment, one liquid supply path may be configured to be commonly connected to the pressure chambers of the two ejection port arrays, and similarly, one liquid recovery path may be configured to be commonly connected to the pressure chambers of the two ejection port arrays. In addition, the width of the sixth flow path layer 226 in the second direction may be set to be larger than the width of the recording element substrate 10 in the second direction.

In this way, even in liquid ejection heads for multiple colors or types of ink, it is possible to suppress the amount of ink circulating and the pressure variations in each pressure chamber without widening the width of the liquid supply path and the liquid recovery path. This suppresses the decrease in ink ejection speed caused by the evaporation of water in the ink from the ejection port, and the change in the ink colorant concentration, making it possible to record images with higher resolution and quality.

(Arrangement Relationship Between Flow Channels 18M, 19M, 18Y, and 19Y)
Furthermore, the positional relationship between the liquid supply path 18M and the liquid recovery path 19M for the first ink, and the liquid supply path 18Y and the liquid recovery path 19Y for the second ink may be set as follows. That is, as shown in FIG. 54, the beam width of the common outflow flow path 19M and the common supply flow path 18Y between the first ink ejection port row and the second ink ejection port row is set to beam width W4, and the beam width W4 is set to be larger than the beam width W1. By increasing the beam width W4, it is possible to suppress the occurrence of color mixing due to ink leakage between the common outflow flow path 19M and the common supply flow path 18Y. Here, the relationship between the beam width W3 and the beam width W4 may be the same width or different widths. In particular, when the beam width W3 is larger, it is possible to reduce the flow path pressure loss with respect to the ink flow, which leads to improved ejection characteristics. In this way, it is possible to suppress the occurrence of color mixing of ink while suppressing the backflow of the ink circulation flow and maintaining the pressure in the liquid supply path at a negative pressure.

Seventh Embodiment
A seventh embodiment of the present invention will be described below. Note that since the basic configuration of this embodiment is similar to that of the first embodiment, only the characteristic configuration will be described below.

In this embodiment, unlike the previously described embodiment, the liquid ejection head does not generate an ink circulation flow. Each ejection port row is connected to a supply port, a liquid supply path, a liquid supply opening, an individual supply flow path, a communication port, and a common supply port.

Even in liquid ejection heads that do not generate ink circulation flow, by increasing the shape precision and arrangement precision of the liquid supply port, it is possible to reduce the variation in flow path resistance, in other words the variation in pressure loss that occurs in the supply flow path during ejection, even in liquid ejection heads with ejection ports arranged at high density. This reduces the pressure variation at the ejection port meniscus interface and allows droplets of uniform size to be ejected, making it possible to form images with higher resolution and quality.

REFERENCE SIGNS LIST 10 recording element substrate 13 ejection port 15 recording element 18 liquid supply path 19 liquid recovery path 20 cover member 23 pressure chamber 300 liquid ejection unit 517 cover member

Claims (18)

an ejection port array in which a plurality of ejection ports are arranged in an arrangement direction for ejecting liquid;
a plurality of elements provided corresponding to each of the ejection ports and generating energy for ejecting liquid from the ejection ports;
a plurality of pressure chambers each having the element therein;
An element substrate comprising:
a back surface member provided on a back surface of the element substrate on a side on which the ejection ports are formed,
a supply path for supplying liquid to the pressure chambers is formed by the rear surface of the element substrate and the rear surface member,
the back surface member is provided with a supply opening for supplying liquid to the supply path,
when the liquid ejection unit is viewed in a direction perpendicular to the element substrate, an outer shape of the rear surface member is located inside an outer shape of the element substrate at an end side in the arrangement direction ,
A plurality of the supply openings are provided in communication with one of the supply paths,
A liquid ejection unit, comprising : a plurality of element substrates, each of which is disposed so that adjacent element substrates partially overlap each other in a longitudinal direction of the liquid ejection head . the back surface member further includes a recovery opening for recovering liquid from the pressure chamber,
a recovery path for recovering the liquid recovered from the pressure chamber of the element substrate to the recovery opening is further provided on the rear surface of the element substrate,
The liquid ejection unit according to claim 1 , wherein a part of the recovery path is formed by the rear surface member. The liquid ejection unit according to claim 2, characterized in that the supply path and the recovery path are provided in a first direction, which is a direction in which the ejection port array in which the multiple ejection ports are arranged extends, and correspond to the length of the ejection port array. The liquid ejection unit according to claim 3, characterized in that the supply paths and the recovery paths are arranged alternately in a second direction intersecting the first direction. The liquid ejection unit according to any one of claims 2 to 4, characterized in that the element substrate is provided with a plurality of supply ports for supplying the liquid in the supply path to the pressure chamber, and a plurality of recovery ports for recovering the liquid in the pressure chamber to the recovery path. The liquid ejection unit according to claim 5, characterized in that the supply port and the recovery port are liquid paths having a longitudinal direction in the thickness direction of the element substrate. The liquid ejection unit according to any one of claims 1 to 6, characterized in that the thickness of the back member is less than 25 μm. The liquid ejection unit according to any one of claims 1 to 7, characterized in that no adhesive is interposed between the element substrate and the back surface member. The liquid ejection unit according to any one of claims 1 to 8, characterized in that the outer shape of the element substrate is a parallelogram. The liquid ejection unit according to any one of claims 2 to 6, characterized in that the outer shape of the element substrate is a parallelogram, and at least one of the supply opening and the recovery opening is also shaped like a parallelogram. The liquid ejection unit according to claim 7 or 8, characterized in that it comprises a support member that supports the element substrate via the back member, and an adhesive is provided between the support member and the back member. 7. The liquid ejection unit according to claim 2, wherein the supply opening and the recovery opening are arranged alternately in a first direction, which is a direction in which the ejection port row in which the plurality of ejection ports are arranged extends. the support member supports a plurality of the element substrates,
The liquid ejection unit according to claim 11, characterized in that the support member has a groove in an adjacent portion where the element substrate is adjacent, the width of the groove is larger than the width of the gap in the element substrate, and in the adjacent portion, the joint between the rear surface member and the support member extends inward from the outer edge of the element substrate. The liquid ejection unit according to claim 11, characterized in that the linear expansion coefficient of the support member is smaller than the linear expansion coefficient of the back surface member. a plurality of the support members each supporting the element substrate;
The liquid ejection unit according to claim 11 , wherein in an adjacent portion where the element substrates are adjacent to each other, a joint between the support member and the rear surface member extends inward from an outer edge of the element substrate. 16. The liquid ejection unit according to claim 1, which is a page-wide type liquid ejection head in which a plurality of the element substrates are linearly arranged. 17. The liquid ejection unit according to claim 2, wherein the liquid in the pressure chamber is circulated between the pressure chamber and the outside of the pressure chamber. A liquid ejection apparatus comprising the liquid ejection unit according to any one of claims 1 to 17 .