JP2017124601A - Liquid discharge head and liquid discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a pressure chamber to be quickly refilled with liquid while downsizing a recording element substrate having a plurality of recording elements formed on one surface thereof.SOLUTION: On one surface of a recording element substrate is provided a groove-shape liquid supply path common to a plurality of recording elements, and further are provided a plurality of supply ports which penetrate through the recording element substrate and communicate the liquid supply path with a pressure chamber and a supply-side opening acting as a supply port for liquid to the liquid supply path. The sum of pressure loss of liquid in the liquid supply path ranging from a given supply-side opening to a supply port at a position farthest from the supply-side opening and pressure loss of liquid at the supply port at the time of discharging liquid is set to be 5000 Pa or less.SELECTED DRAWING: Figure 32

Description

  The present invention relates to a liquid discharge head and a liquid discharge apparatus.

  In a liquid ejection apparatus that performs recording by ejecting liquid onto a recording medium, a liquid ejection head that includes a pressure chamber that communicates with an ejection port and a recording element that applies energy for ejection to the liquid in the pressure chamber is used. . Ink and other liquids ejected from the ejection port are made by adding some components to the solvent, but the viscosity of the liquid in the vicinity of the ejection port increases due to evaporation and evaporation of the solvent component from the ejection port. There is. When the viscosity of the liquid in the vicinity of the ejection port increases, the ejection characteristics are affected, and the recording quality may be deteriorated. Therefore, a technique is known in which liquid is circulated through a pressure chamber provided with an ejection port and a recording element to achieve higher quality recording (Patent Document 1). However, in order to circulate the liquid, it is necessary to form a complicated flow path in the liquid discharge head, which increases the size of the liquid discharge head. On the other hand, in order to realize high-definition recording, there is a demand for downsizing the liquid discharge head if the recording elements are arranged at a high density and the number of the recording elements is the same. In a liquid discharge head, the recording element is generally provided on one surface of a substrate, but a groove serving as a liquid flow path is provided on the other surface of the substrate and a through flow path that communicates with the groove and passes through the substrate is provided. The liquid discharge head is downsized (Patent Document 2).

Special table 2014-510649 gazette US Patent Publication No. 2005/0157033

  For example, when the liquid is circulated, a complicated flow path needs to be formed, and the liquid discharge head tends to be enlarged. On the other hand, when a liquid flow path is formed as a groove on the surface of the substrate opposite to the surface on which the recording element is provided, and a through flow path is formed to communicate this groove with the surface on which the recording element is provided, There is a problem. In other words, when the substrate is downsized, the path through which the liquid passes (the channel formed as a groove and the through channel) inevitably becomes narrow and the viscous resistance increases. When the viscous resistance is increased, the pressure loss is increased, the refilling of the liquid into the pressure chamber at the time of ejection is delayed, and the recording quality is liable to be deteriorated, for example, the amount of the liquid ejected to the recording medium becomes too small. In particular, when the liquid is circulated in the configuration in which the flow path is formed on the other surface of the substrate, since the liquid always flows, the pressure loss tends to increase particularly, and there is a concern about the deterioration of the recording quality.

  An object of the present invention is to reduce the size of the recording element substrate by forming a groove-like flow path on the other side of the substrate on which the recording element is formed on one side, and to refill the pressure chamber with liquid. It is an object of the present invention to provide a liquid discharge head capable of quickly performing the above and a liquid discharge apparatus using the liquid discharge head.

  The liquid discharge head of the present invention includes a recording element substrate on which a plurality of recording elements that generate energy for discharging a liquid are provided on a first surface, a partition wall disposed between adjacent recording elements, and the recording element A liquid ejection head having a plurality of ejection ports arranged in a line to form a ejection port array; A liquid supply path provided in a groove shape on a second surface opposite to the first surface of the recording element substrate for supplying liquid to the plurality of pressure chambers; A plurality of supply ports for supplying liquid from the liquid supply path to the pressure chamber, and a supply-side opening for supplying liquid to the liquid supply path, A lid member provided on the second surface so as to cover the liquid supply path In the process in which the pressure chamber is filled with liquid after discharging the liquid from the discharge port, the supply side opening communicates with the supply side opening and is farthest from the supply side opening. The sum P1 of the pressure loss of the liquid in the liquid supply path to the supply port at the position and the pressure loss of the liquid at the supply port at the most distant position is 5000 Pa or less. .

  A liquid ejection apparatus according to the present invention includes the liquid ejection head according to the present invention, a storage unit that stores the liquid, and a unit that supplies the liquid from the storage unit to the liquid supply path through the supply side opening. .

  According to the present invention, it is possible to reduce the size of a recording element substrate having a plurality of recording elements while suppressing pressure loss in the flow path.

It is a figure which shows schematic structure of the liquid discharge apparatus of a 1st structural example. It is a figure explaining the 1st circulation form. It is a figure explaining the 2nd circulation form. It is a figure explaining the 3rd circulation form. It is a perspective view which shows the structure of a liquid discharge head. It is an exploded perspective view showing a liquid discharge head. It is a figure which shows the structure of the surface and back surface of each flow path member. It is a perspective view which shows the connection relation of each flow path. It is sectional drawing which shows a flow-path structural member and a discharge module. It is a figure explaining a discharge module. It is a figure which shows the structure of a recording element board | substrate. 2 is a partially broken perspective view showing a recording element substrate. FIG. FIG. 6 is a plan view showing adjacent recording element substrates. It is a figure explaining another liquid discharge device of the 1st example of composition. It is a perspective view which shows the structure of a liquid discharge head. FIG. 3 is an exploded perspective view illustrating a configuration of a liquid discharge head. It is a perspective view which shows the connection relation of each flow path. It is a figure which shows schematic structure of the liquid discharge apparatus of a 2nd structural example. It is a perspective view which shows the structure of a liquid discharge head. It is an exploded perspective view showing a liquid discharge head. It is a figure which shows the structure of each flow path member. It is a perspective view which shows the connection relation of each flow path. It is sectional drawing which shows a flow-path structural member and a discharge module. It is a figure explaining a discharge module. It is a figure which shows the structure of a recording element board | substrate. It is a figure which shows schematic structure of the liquid discharge apparatus of a 3rd structural example. It is a figure explaining the 4th circulation form. It is a perspective view which shows the structure of a liquid discharge head. It is a figure explaining the structure of a liquid discharge head. It is a figure explaining the liquid discharge head of the 1st Embodiment of this invention. FIG. 3 is a diagram illustrating a recording element substrate of the liquid discharge head according to the first embodiment. FIG. 3 is a diagram illustrating a recording element substrate of the liquid discharge head according to the first embodiment. FIG. 3 is a diagram illustrating a recording element substrate of the liquid discharge head according to the first embodiment. It is a graph which shows the relationship between a pressure loss and recording quality. FIG. 10 is a diagram illustrating a recording element substrate of a liquid ejection head according to a third embodiment. FIG. 10 is a diagram illustrating a recording element substrate of a liquid ejection head according to a fourth embodiment. FIG. 10 is a diagram illustrating a recording element substrate of a liquid ejection head according to a fifth embodiment. FIG. 10 is a diagram illustrating a recording element substrate of a liquid ejection head according to a fifth embodiment.

  Hereinafter, each configuration example and each exemplary embodiment to which the present invention can be applied will be described with reference to the drawings. However, the following description does not limit the scope of the present invention. As an example, in the following description, a so-called thermal-type liquid discharge in which a heating element is used as a recording element that generates energy for discharging a liquid, and bubbles are generated in the liquid in the pressure chamber by heat to discharge the liquid from the discharge port. The head will be described as an example. However, the liquid discharge head to which the present invention can be applied is not limited to the thermal type, and the present invention is also applied to a liquid discharge head that employs a piezoelectric method using a piezoelectric element and other various liquid discharge methods. Can be applied. The liquid discharge head of the present invention that discharges a liquid such as ink and the liquid discharge apparatus equipped with the liquid discharge head can be applied to apparatuses such as a printer, a copying machine, a facsimile having a communication system, and a word processor having a printer unit. Furthermore, the present invention can be applied to an industrial recording apparatus combined with various processing apparatuses. For example, it can be used for applications such as biochip fabrication, electronic circuit printing, and semiconductor substrate fabrication.

  In the following description, a liquid discharge head used in a liquid discharge apparatus that circulates a liquid such as a recording liquid (for example, ink) between a tank and a liquid discharge head will be described. However, the liquid discharge head according to the present invention is used. The liquid ejection device is not limited to this. A tank is provided on each of the upstream side and the downstream side without circulating the liquid, and the liquid flows in the pressure chamber of the liquid discharge head by flowing the liquid from one tank to the other tank via the liquid discharge head. The present invention can also be applied to a liquid ejection device.

  Furthermore, in the following description, it is assumed that the liquid discharge head is configured as a so-called line type (page wide type) head having a length corresponding to the width of the recording medium. However, the present invention can also be applied to a so-called serial type liquid discharge head that completes recording on a recording medium by scanning in the main scanning direction and the sub-scanning direction. As a serial type liquid discharge head, for example, there is a configuration in which one recording element substrate for black recording liquid and one for color recording liquid are mounted, but the present invention is not limited to this. The serial type liquid ejection head creates a line head with a length shorter than the width of the recording medium, with several recording element substrates arranged so that the ejection ports overlap in the direction of the ejection port array, and this is recorded It may be configured to scan the medium.

(Description of Liquid Discharge Device of First Configuration Example)
First, an ink jet recording apparatus 1000 (hereinafter also referred to as a recording apparatus) that performs recording on a recording medium by discharging a recording liquid as a liquid from an ejection port will be described as an example of a liquid ejecting apparatus according to the present invention. FIG. 1 shows a schematic configuration of a recording apparatus 1000 which is a liquid ejection apparatus of a first configuration example. The recording apparatus 1000 includes a transport unit 1 that transports the recording medium 2, and a line-type liquid ejection head 3 that is disposed substantially orthogonal to the transport direction of the recording medium 2, and includes a plurality of recording media 2. This is a line type recording apparatus that performs continuous recording in one pass while conveying continuously or intermittently. The recording medium 2 is, for example, cut paper, but may be continuous roll paper in addition to the cut paper. The liquid discharge head 3 can perform full-color recording with recording liquids of cyan (C), magenta (M), yellow (Y), and black (K) (hereinafter, these colors are collectively referred to as CMYK). Is something. As will be described later, the liquid discharge head 3 is fluidly connected to liquid supply means, a main tank, and a buffer tank (see FIG. 2), which are supply paths for supplying liquid to the liquid discharge head 3. As shown in FIG. 2 described later, the liquid discharge head 3 is roughly configured by a liquid supply unit 220, a negative pressure control unit 230, and a liquid discharge unit 300. The liquid ejection unit 300 is provided with a plurality of recording element substrates 10, a common supply channel 211, and a common recovery channel 212, and each recording element substrate 10 is provided with a plurality of recording elements. In the liquid discharge head 300, the recording liquid is supplied from the common supply channel 211 to each recording element substrate 10 as indicated by the arrow in the figure, and this recording liquid is recovered through the common recovery channel 212. ing. The liquid ejection head 3 is electrically connected to an electric control unit that transmits electric power and ejection control signals to the liquid ejection head 3. Details of the liquid path and the electric signal path in the liquid discharge head 3 will be described later.

(Description of the first circulation mode)
FIG. 2 shows a first circulation form which is one form of a circulation path configuration applied to the liquid ejection apparatus according to the present invention. In the first circulation mode, the liquid discharge head 3 is fluidly connected to the first circulation pump 1001 on the high pressure side, the first circulation pump 1002 on the low pressure side, the buffer tank 1003, and the like. In FIG. 2, for the sake of simplicity, only the path through which one color of the recording liquid of each color of CMYK flows is shown, but in reality, the circulation path for four colors is the liquid ejection head 3. And provided in the recording apparatus main body. A buffer tank 1003 as a sub tank connected to the main tank 1006 functions as a storage means for storing a recording liquid, and has an air communication port (not shown) that communicates the inside and outside of the tank, and is a recording medium. It is possible to discharge bubbles in the liquid to the outside. The buffer tank 1003 is also connected to a refill pump 1005. The replenishment pump 1005 is consumed when liquid is consumed by the liquid ejection head 3 by ejecting (discharging) the recording liquid from the ejection port of the liquid ejection head, such as recording by discharging the recording liquid and suction recovery. The recorded liquid is transferred from the main tank 1006 to the buffer tank 1003.

  The two first circulation pumps 1001 and 1002 have a role of drawing the liquid from the liquid connection portion 111 of the liquid discharge head 3 and flowing it to the buffer tank 1003. As the first circulation pumps 1001 and 1002, it is preferable to use positive displacement pumps having a quantitative liquid feeding capacity. Specific examples include tube pumps, gear pumps, diaphragm pumps, syringe pumps, and the like. For example, a general constant flow valve or relief valve is arranged at the pump outlet to ensure a constant flow rate. be able to. When the liquid discharge head 300 is driven, the recording liquid flows through the common supply channel 211 and the common recovery channel 212 at a certain flow rate by the first circulation pump 1001 on the high pressure side and the first circulation pump 1002 on the low pressure side, respectively. This flow rate is preferably set to a level that does not affect the recording quality on the recording medium 2 by the temperature difference between the recording element substrates 10 in the liquid ejection head 3. However, if an excessively large flow rate is set, the negative pressure difference is excessively increased in each recording element substrate 10 due to the influence of the pressure loss of the flow path in the liquid ejection unit 300, resulting in density unevenness in the recorded image. For this reason, it is preferable to set the flow rate in consideration of the temperature difference and the negative pressure difference between the recording element substrates 10. Of the paths through which the recording liquid circulates, the path that includes the first circulation pump 1001 on the high-pressure side constitutes the first circulation system in the liquid discharge device, and the path that includes the first circulation pump 1002 on the low-pressure side. The path constitutes a second circulation system in the liquid ejection device.

  A second circulation pump 1004 is provided in a path for supplying the recording liquid from the buffer tank 1003 toward the liquid ejection head 3. The negative pressure control unit 230 is provided in a path between the second circulation pump 1004 and the liquid discharge unit 300. Even when the flow rate of the circulation system fluctuates due to a difference in duty when performing recording, the negative pressure control unit 230 is a constant pressure that presets the pressure downstream of the negative pressure control unit 230 (that is, the liquid discharge unit 300 side). It has a function to maintain. The negative pressure control unit 230 includes two pressure adjustment mechanisms each having a different control pressure. As these two pressure adjusting mechanisms, any mechanism may be used as long as the pressure downstream of itself can be controlled with a fluctuation within a certain range around a desired set pressure. As an example, a mechanism similar to a so-called decompression regulator can be employed. When a pressure reduction regulator is used as the pressure adjustment mechanism, it is preferable to pressurize the upstream side of the negative pressure control unit 230 by the second circulation pump 1004 via the liquid supply unit 220 as shown in FIG. In this way, the influence of the water head pressure on the liquid discharge head 3 of the buffer tank 1003 can be suppressed, so that the layout flexibility of the buffer tank 1003 in the recording apparatus 1000 can be increased. The second circulation pump 1004 may be any pump that has a head pressure higher than a certain pressure within the range of the circulation flow rate of the recording liquid used when the liquid discharge head 3 is driven. Can be used. Specifically, a diaphragm pump or the like can be used. Further, instead of the second circulation pump 1004, for example, a water head tank arranged with a certain water head difference with respect to the negative pressure control unit 230 can be provided.

  Of the two pressure adjustment mechanisms in the negative pressure control unit 230, the pressure adjustment mechanism (indicated by H in FIG. 2) for which a relatively high pressure is set passes through the liquid supply unit 220 and the liquid discharge unit 300. It is connected to the common supply flow path 211 inside. Similarly, a pressure adjustment mechanism (indicated by L in FIG. 2) for which a relatively low pressure is set is connected to the common recovery flow path 212 in the liquid discharge unit 300 via the liquid supply unit 220. In addition to the common supply channel 211 and the common recovery channel 212, the liquid discharge unit 300 is provided with an individual supply channel 213 and an individual recovery channel 214 that communicate with the respective recording element substrates 10. The individual supply channel 213 and the individual recovery channel 214 provided for each recording element substrate are collectively referred to as individual channels. The individual flow paths are provided so as to branch from the common supply flow path 211 and join the common recovery flow path 212 and communicate with them. Therefore, a flow (a white arrow in FIG. 2) is generated in which a part of the liquid such as the recording liquid passes from the common supply channel 211 to the common recovery channel 212 through the internal channel of the recording element substrate 10. This is because the high pressure side pressure adjustment mechanism H is connected to the common supply flow path 211 and the low pressure side pressure adjustment mechanism L is connected to the common recovery flow path 212. This is because a differential pressure is generated between the paths 212.

  In this way, in the liquid discharge unit 300, a part of the liquid passes through each recording element substrate 10 while flowing the liquid so as to pass through the common supply flow path 211 and the common recovery flow path 212. Flow occurs. For this reason, the heat generated in each recording element substrate 10 can be discharged to the outside of the recording element substrate 10 through the flow of the common supply channel 211 and the common recovery channel 212. When recording is performed by the liquid discharge head 3, the recording liquid can be caused to flow also in the discharge port and the pressure chamber where recording is not performed. Therefore, the recording liquid is caused to evaporate at the portion. Thus, the increase in the viscosity of the recording liquid can be suppressed. Further, the thickened recording liquid and the foreign matter in the recording liquid can be discharged to the common recovery channel 212. For this reason, it is possible to perform high-speed and high-quality recording by using the liquid discharge head 3 described above.

(Description of second circulation mode)
FIG. 3 shows a second circulation form, which is a circulation form different from the first circulation form described above, among the circulation path configurations applied to the liquid ejection apparatus according to the present invention. The main difference between the second circulation mode and the first circulation mode is that the two pressure adjustment mechanisms constituting the negative pressure control unit 230 both have a pressure upstream of the negative pressure control unit 230. It is a mechanism that controls with a fluctuation within a certain range around a desired set pressure. Such a pressure adjustment mechanism can be configured as a mechanism component having the same action as a so-called back pressure regulator. The second circulation pump 1004 acts as a negative pressure source for reducing the downstream side of the negative pressure control unit 230, and the first circulation pumps 1001 and 1002 on the high pressure side and the low pressure side are arranged on the upstream side of the liquid discharge head 3. ing. Accordingly, the negative pressure control unit 230 is arranged on the downstream side of the liquid discharge head 3.

  In the second circulation mode, the negative pressure control unit 230 presets the pressure fluctuation on the upstream side of the negative pressure control unit 230 even when there is a fluctuation in the flow rate caused by the change in the recording duty when the liquid ejection head 3 performs the recording. Operates to stabilize within a certain range around pressure. Here, the upstream side of the negative pressure control unit 230 is the liquid discharge unit 300 side. As shown in FIG. 3, it is preferable to pressurize the downstream side of the negative pressure control unit 230 through the liquid supply unit 220 by the second circulation pump 1004. In this way, since the influence of the water head pressure of the buffer tank 1003 on the liquid discharge head 3 can be suppressed, the selection range of the layout of the buffer tank 1003 in the recording apparatus 1000 can be widened. Instead of the second circulation pump 1004, for example, a water head tank disposed with a predetermined water head difference with respect to the negative pressure control unit 230 may be provided.

  As in the case of the first circulation mode, as shown in FIG. 3, the negative pressure control unit 230 includes two pressure adjustment mechanisms each set with a different control pressure. The high pressure setting side (denoted as H in FIG. 3) and the pressure adjusting mechanism (denoted as L in FIG. 3) on the low pressure setting side are respectively connected to the common supply flow path in the liquid discharge unit 300 via the liquid supply unit 220. 211 and the common recovery channel 212. By making the pressure of the common supply channel 211 relatively higher than the pressure of the common recovery channel 212 by these two pressure adjusting mechanisms, the individual channels and the internal channels of each recording element substrate 10 are transferred from the common supply channel 211. A flow of the recording liquid flowing to the common recovery flow path 212 is generated via the. The flow of the recording liquid is indicated by white arrows in FIG. As described above, in the second circulation mode, the recording liquid flow state similar to that in the first circulation mode can be obtained in the liquid discharge unit 300, but there are two advantages different from the case of the first circulation path.

  The first advantage is that, in the second circulation mode, the negative pressure control unit 230 is arranged on the downstream side of the liquid discharge head 3, so that dust and foreign matters generated from the negative pressure control unit 230 flow into the liquid discharge head 3. There is little concern to do.

  The second advantage is that in the second circulation mode, the maximum value of the required flow rate supplied from the buffer tank 1003 to the liquid discharge head 3 is smaller than in the first circulation mode. The reason is as follows. A is the sum of the flow rates in the common supply channel 211 and the common recovery channel 212 when circulating during recording standby. The value A is defined as the minimum flow rate required to bring the temperature difference in the liquid discharge unit 300 within a desired range when the temperature of the liquid discharge head 3 is adjusted during recording standby. Further, F is defined as an ejection flow rate when the recording liquid is ejected from all ejection ports of the liquid ejection unit 300 (when all ejection is performed). Then, in the case of the first circulation form shown in FIG. 2 (FIG. 2), the set flow rates of the first circulation pump (high-pressure side) 1001 and the first circulation pump (low-pressure side) 1002 are A. The maximum value of the required liquid supply amount to the liquid discharge head 3 is A + F. On the other hand, in the second circulation mode shown in FIG. 3, the liquid supply amount to the liquid ejection head 3 required during recording standby is the flow rate A. The amount of supply to the liquid discharge head 3 required for full ejection is the flow rate F. Then, in the case of the second circulation mode, the total value of the set flow rates of the first circulation pumps 1001 and 1002 on the high-pressure side and the low-pressure side, that is, the maximum value of the necessary supply flow rate is the larger value of A or F. Therefore, as long as the liquid discharge unit 300 having the same configuration is used, the maximum value (A or F) of the necessary supply amount in the second circulation mode is greater than the maximum value (A + F) of the necessary supply flow rate in the first circulation mode. Will always be smaller. Therefore, in the case of the second circulation mode, the degree of freedom of the applicable circulation pump is increased. For example, a low-cost circulation pump having a simple configuration or a load of a cooler (not shown) installed in the main body side path is used. And the cost of the recording apparatus main body can be reduced. This advantage becomes larger as the line type head has a relatively large value of A or F, and among the line type heads, a head that is long in the longitudinal direction is more beneficial.

  On the other hand, however, the first circulation mode is advantageous over the second circulation mode. In the second circulation mode, since the flow rate flowing through the liquid ejection unit 300 is the maximum during recording standby, the lower the recording duty, the higher the negative pressure applied to each ejection port. For this reason, especially when the flow path width of the common supply flow path 211 and the common recovery flow path 212 is reduced to reduce the head width, a high negative pressure is applied to the discharge port in a low-duty image in which unevenness is easily visible. There is a risk that the effect of satellite droplets will increase. Here, the channel widths of the common supply channel 211 and the common recovery channel 212 are the lengths in the direction perpendicular to the liquid flow direction, and the head width is the length of the liquid ejection head 3 in the short direction. It is. On the other hand, in the case of the first circulation mode, since a high negative pressure is applied to the discharge port during high duty image formation, even if satellite droplets are generated, it is difficult to visually recognize the recorded image, and to the image. The effect of this is small. In selecting these two circulation modes, a preferable one may be selected in light of the specifications of the liquid discharge head 3 and the recording apparatus main body (discharge flow rate F, minimum circulation flow rate A, and flow path resistance in the liquid discharge head 3). .

(Description of third circulation mode)
FIG. 4 is a schematic diagram showing a third circulation form which is a further form of the circulation path applied to the recording apparatus of the present configuration example. A description of functions and configurations similar to those of the first and second circulation modes will be omitted, and different points will be mainly described.

  In this circulation mode, the liquid is supplied into the liquid discharge head 3 from two places in the center in the longitudinal direction of the liquid discharge head 3 and three places on one end side in the longitudinal direction of the liquid discharge head 3. The liquid passes through the pressure chambers 23 from the common supply flow path 211 and is then recovered in the common recovery flow path 212 and is recovered to the outside from the recovery opening at the other end of the liquid discharge head 3. In the example shown here, the common liquid channel 211 is divided into two in the longitudinal direction of the liquid ejection head 3, and the liquid is supplied from the pressure adjustment mechanism H to each of them. The individual supply channel 213 and the individual recovery channel 214 communicate with the common supply channel 211 and the common recovery channel 212, respectively. A recording element substrate 10 and a pressure chamber 23 disposed in the recording element substrate are provided in a path connecting the individual supply channel 213 and the individual recovery channel 214. Accordingly, a part of the liquid flowing through the first circulation pump 1002 flows from the common supply flow path 211 through the pressure chamber 23 of the recording element substrate 10 to the common recovery flow path 212 (FIG. 4). Arrow). This is because a pressure difference is provided between the pressure adjustment mechanism H connected to the common supply flow path 211 and the pressure adjustment mechanism L connected to the common recovery flow path 212, so that the first circulation pump 1002 can perform the common recovery flow. This is because it is connected only to the path 212.

  In this way, in the liquid discharge unit 300 of this circulation form, the liquid flows so as to pass through the common recovery flow path 212, and passes through the pressure chambers 23 in the respective recording element substrates 10 from the common supply flow path 211. A flow is generated in the common recovery channel 212. Therefore, heat generated in each recording element substrate 10 can be discharged to the outside of the recording element substrate 10 by the flow from the common supply channel 211 to the common recovery channel 212 while suppressing an increase in pressure loss. Further, according to the present circulation mode, it is possible to reduce the number of pumps that are liquid transporting means as compared with the first and second circulation modes.

(Description of liquid discharge head configuration)
Next, the configuration of the liquid ejection head 3 will be described with reference to FIG. FIG. 5A is a perspective view as seen from the side of the liquid ejection head 3 where the ejection openings are formed, and FIG. 5B is a perspective view as seen from the opposite direction to FIG. The liquid discharge head 3 includes 15 recording element substrates 10 that are capable of discharging recording liquids of four colors of cyan (C), magenta (M), yellow (Y), and black (K). This is a line-type liquid discharge head arranged in the above. As shown in FIG. 5A, the liquid discharge head 3 includes 15 recording element substrates 10, a flexible wiring substrate 40, and an electric wiring substrate 90. The electric wiring board 90 is provided with a signal input terminal 91 and a power supply terminal 92, and the signal input terminal 91 and the power supply terminal 92 are connected to each recording element substrate 10 via the electric wiring board 90 and the flexible wiring board 40. Electrically connected. The signal input terminal 91 and the power supply terminal 92 are electrically connected to the control circuit of the printing apparatus 1000, and supply the ejection drive signal and the power required for ejection to the printing element substrate 10, respectively. By consolidating the wiring by the electric circuit in the electric wiring board 90, the number of signal output terminals 91 and power supply terminals 92 can be reduced as compared with the number of recording element boards 10. Thereby, it is possible to reduce the number of electrical connection portions that need to be removed when the liquid discharge head 3 is assembled to the recording apparatus 1000 or when the liquid discharge head is replaced. As shown in FIG. 5B, the liquid connection portions 111 provided at both ends in the longitudinal direction of the liquid discharge head 3 are connected to the liquid supply system of the recording apparatus 1000 as shown in FIG. 2 or FIG. Is done. As a result, the recording liquid of each color of CMYK is supplied from the supply system of the recording apparatus 1000 to the liquid ejection head 3, and the recording liquid that has passed through the liquid ejection head 3 is recovered to the supply system of the recording apparatus 1000. Yes. As described above, the recording liquid of each color can be circulated through the path of the recording apparatus 1000 and the path of the liquid discharge head 3.

  FIG. 6 shows each component or unit constituting the liquid discharge head 3 divided by function. The liquid ejection head 3 includes a housing 80, and the liquid ejection unit 300, the liquid supply unit 220, and the electric wiring substrate 90 are attached to the housing 80. The liquid supply unit 220 is provided with a liquid connection portion 111 (see FIGS. 2 to 4). Inside the liquid supply unit 220, filters 221 (see FIGS. 2 and 3) for each color communicating with the respective openings of the liquid connection unit 111 are provided in order to remove foreign matters in the supplied recording liquid. In the illustrated example, two liquid supply units 220 and two negative pressure control units 230 are provided for one liquid discharge head. Two liquid supply units 220 are each provided with filters 221 for two colors. The recording liquid that has passed through the filter 221 is supplied to the negative pressure control unit 230 disposed on the supply unit 220 corresponding to each color. The negative pressure control unit 230 has a pressure adjustment mechanism, and the inside of the supply system of the recording apparatus 1000 (liquid ejection head) generated by the fluctuation of the liquid flow rate by the action of a valve, a spring member, or the like provided in the pressure adjustment mechanism. 3, the pressure loss change in the upstream supply system) can be greatly attenuated. Thus, the negative pressure control unit 230 can stabilize the negative pressure change on the downstream side (liquid discharge unit 300 side) from the pressure control unit within a certain range. As described above, in the negative pressure control unit 230, two pressure adjustment mechanisms are provided for each color, and the control pressures of the two pressure adjustment mechanisms for each color are set to different values. The high pressure side pressure adjustment mechanism communicates with the common supply flow path 211 in the liquid discharge unit 300, and the low pressure side pressure adjustment mechanism communicates with the common recovery flow path 212.

  The casing 80 includes a liquid discharge unit support part 81 and an electric wiring board support part 82, supports the liquid discharge unit 300 and the electric wiring board 90, and ensures the rigidity of the liquid discharge head 3. The electric wiring board support part 82 is for supporting the electric wiring board 90 and is fixed to the liquid discharge unit support part 81 by screws. The liquid discharge unit support 81 has a role of correcting the warp and deformation of the liquid discharge unit 300 and ensuring the relative positional accuracy of the plurality of recording element substrates 10, thereby suppressing streaks and unevenness in the recorded matter. Therefore, it is preferable that the liquid discharge unit support portion 81 has sufficient rigidity, and the material is preferably a metal material such as stainless steel (SUS) or aluminum, or a ceramic such as alumina. Openings 83 and 84 into which the joint rubber 100 is inserted are provided at both ends in the longitudinal direction of the liquid discharge unit support portion 81. A liquid such as a recording liquid supplied from the liquid supply unit 220 is guided to a third flow path member 70 (described later) constituting the liquid discharge unit 300 via the joint rubber 100.

  The liquid discharge unit 300 includes a plurality of discharge modules 200 and a flow path component 210 that supports the plurality of discharge modules 200, and a cover member 130 is attached to the surface of the liquid discharge unit 300 on the recording medium side. As shown in FIG. 6, the cover member 130 is a member having a frame-like surface provided with a long opening 131, and from the opening 131, the recording element substrate 10 and the sealing material 110 ( Is exposed). The frame portion around the opening 131 has a function as a contact surface of a cap member that caps the surface on which the discharge port of the liquid discharge head 3 is formed during recording standby. For this reason, a closed space is formed at the time of capping by applying an adhesive, a sealing material, a filler, or the like along the periphery of the opening 131 and filling the irregularities and gaps on the discharge port forming surface of the liquid discharge unit 300. It is preferable to do so.

  Next, the configuration of the flow path component member 210 included in the liquid discharge unit 300 will be described. The flow path component 210 distributes the liquid such as the recording liquid supplied from the liquid supply unit 220 to each discharge module 200 and returns the liquid refluxed from the discharge module 200 to the liquid supply unit 220. is there. As shown in FIG. 6, the flow path component 210 is formed by stacking the first flow path member 50, the second flow path member 60, and the third flow path member 70 in this order, and the liquid discharge unit support portion 81. It is fixed with screws. Thereby, the curvature and deformation | transformation of the flow-path structural member 210 are suppressed.

  7A to 7F show the front and back surfaces of the first to third flow path members 50, 60, and 70. FIG. FIG. 7A shows the surface of the first flow path member 50 on the side where the discharge module 200 is mounted, while FIG. 7F shows the liquid discharge unit of the third flow path member 70. The surface on the side in contact with the support portion 81 is shown. FIG. 7B shows the contact surface of the first flow path member 50 with the second flow path member 60, and correspondingly, FIG. 7C shows the second flow path member 60 of the second flow path member 60. A contact surface with one flow path member 50 is shown. Similarly, FIG. 7D shows a contact surface of the second flow path member 60 with the third flow path member 70, and FIG. 7E shows the second flow path of the third flow path member 70. The contact surface with the member 60 is shown. Common flow channel grooves formed in the respective flow channel members 60 and 70 by joining the second flow channel member 60 and the third flow channel member 70 on the surfaces shown in FIGS. 7 (d) and (e). Eight common flow paths extending in the longitudinal direction of the flow path members 60 and 70 are formed by 62 and 71. As a result, a set of the common supply channel 211 and the common recovery channel 212 for each color of CMYK is formed in the channel constituting member 210 (see FIG. 8). The communication port 72 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. A plurality of communication ports 61 are formed in the bottom surface of the common flow channel 62 of the second flow channel member 60 and communicate with one end of the individual flow channel 52 of the first flow channel member 50. A communication port 51 is formed at the other end of the individual flow channel 52 of the first flow channel member 50, and is in fluid communication with the plurality of discharge modules 200 via the communication port 51. The individual flow channel 52 allows the flow channels to be concentrated on the center side in the short direction of the first flow channel member 50. In the following description, when the common supply flow path 211 is shown separately for each color of the recording liquid, the reference numerals 211a to 211d are used instead of the reference numeral 211, and when the common recovery flow path 212 is shown separately for each color. Reference numerals 212 a to 212 d are used instead of reference numeral 212. Similarly, reference numerals 213a to 213d are used instead of reference numeral 213 when the individual supply channels 213 are shown separately for each color of the recording liquid, and reference numeral 214 is shown when the common recovery channel 214 is shown separately for each color. Instead, reference numerals 214a to 214d are used.

  The first to third flow path members 50, 60, and 70 constituting the flow path forming member 210 are preferably made of a material having corrosion resistance against a liquid such as a recording liquid and a low linear expansion coefficient. As the material, for example, alumina, LCP (liquid crystal polymer), PPS (polyphenyl sulfide), PSF (polysulfone), and a composite material in which inorganic fillers such as silica fine particles and fibers are added as a base material. (Resin material) can be suitably used. As a method of forming the flow path component 210, the three flow path members 50, 60, and 70 may be laminated and bonded to each other. When a resin composite resin material is selected as the material, a bonding method by welding May be used.

  Next, the connection relationship of each flow path in the flow path constituting member 210 will be described with reference to FIG. In FIG. 8, the discharge module 200 of the first flow path member 50 is mounted on the flow path inside the flow path forming member 210 formed by joining the first to third flow path members 50, 60, 70. It is the perspective view which expanded a part from the surface side to be measured. In FIG. 8, a region surrounded by an alternate long and short dash line corresponds to the arrangement position of the recording element substrate 10. The channel constituting member 210 is provided with common supply channels 211a to 211d and common recovery channels 212a to 212d extending in the longitudinal direction of the liquid ejection head 3 for each color. A plurality of individual supply channels 213a to 213d formed by the individual channel grooves 52 are connected to the common supply channels 211a to 211d of the respective colors via the communication ports 61, respectively. A plurality of individual recovery channels 214 a to 214 d formed by the individual channel grooves 52 are connected to the common recovery channels 212 a to 212 d of the respective colors via the communication ports 61. With such a flow path configuration, the recording liquid is concentrated on the recording element substrate 10 provided corresponding to the central portion of the flow path forming member 210 from each common supply flow path 211 via the individual supply flow path 213. can do. Further, the recording liquid can be recovered from the recording element substrate 10 to each common recovery channel 212 via the individual recovery channel 214.

  FIG. 9 shows a cross-sectional configuration of the flow path component 210 and the discharge module 200 along the line EE in FIG. As shown in the figure, the individual recovery channels 214 a and 214 c communicate with the discharge module 200 through the communication port 51. Although only the individual recovery channels 214a and 214c are shown in FIG. 9, in another cross section, the individual supply channel 213 and the discharge module 200 are communicated with each other as shown in FIG. In order to supply the recording liquid from the first flow path member 50 to the recording element 15 (see FIG. 11) provided on the recording element substrate 10 to the support member 30 and the recording element substrate 10 included in each ejection module 200. The flow path is formed. Further, the support member 30 and the recording element substrate 10 are also provided with a flow path for collecting (refluxing) part or all of the liquid supplied to the recording element 15 to the first flow path member 50. The common supply channel 211 for each color is connected to the pressure adjustment mechanism on the high pressure side of the negative pressure control unit 230 for the corresponding color via the liquid supply unit 220. Similarly, the common recovery flow channel 212 is connected to the pressure adjustment mechanism on the low pressure side of the negative pressure control unit 230 of the corresponding color via the liquid supply unit 220. By these pressure adjustment mechanisms in the negative pressure control unit 230, a differential pressure (pressure difference) is generated between the common supply flow path 211 and the common recovery flow path 212. For this reason, as shown in FIGS. 8 and 9, in the liquid discharge head 3 to which each flow path is connected, for each color, the common supply flow path 211 → the individual supply flow path 213 → the printing element substrate 10 → the individual recovery flow. A flow that flows in order from the channel 214 to the common recovery channel 212 is generated.

(Description of discharge module)
Next, the discharge module 200 will be described. FIG. 10A is a perspective view of the discharge module 200, and FIG. 10B is an exploded view thereof. As a manufacturing method of the discharge module 200, first, the recording element substrate 10 and the flexible wiring substrate 40 are bonded onto the support member 30 provided with the liquid communication port 31 in advance. Thereafter, the terminals 16 on the recording element substrate 10 and the terminals 41 on the flexible wiring substrate 40 are electrically connected by wire bonding, and then the wire bonding portion (electrical connection portion) is covered with a sealing material 110 and sealed. Stop. A terminal 42 of the flexible wiring board 40 opposite to the recording element substrate 10 is electrically connected to a connection terminal 93 (see FIG. 6) of the electric wiring board 90. Since the support member 30 is a support body that supports the recording element substrate 10 and is a flow path communication member that fluidly communicates the recording element substrate 10 and the flow path constituent member 210, the flatness is high and sufficient. In particular, those that can be bonded to the recording element substrate with high reliability are preferable. As a material of the support member 30, for example, alumina or a resin material is preferable.

(Description of structure of recording element substrate)
Next, the configuration of the recording element substrate 10 will be described. FIG. 11A is a plan view of the surface of the recording element substrate 10 on the side where the discharge ports 13 are formed, and FIG. 11B is an enlarged view of a portion indicated by A in FIG. FIG.11 (c) is a top view of the side which hits the back surface of Fig.11 (a). As shown in FIG. 11A, the recording element substrate 10 has a discharge port forming member 12 in which a plurality of discharge ports 13 are formed in a row. The discharge port forming member 12 is formed with four rows of discharge port rows corresponding to the four colors CMYK which are the colors of the recording liquid. Note that when a plurality of ejection port arrays are provided, the number is not limited to four, and can be appropriately increased or decreased according to the type of recording liquid, for example. Hereinafter, the direction in which the discharge port array in which the plurality of discharge ports 13 are arranged is referred to as “discharge port array direction”. As shown in FIG. 11B, recording elements 15 that are heat generating elements for foaming the liquid by thermal energy are arranged at positions corresponding to the respective ejection ports 13. A partition 22 defines a pressure chamber 23 having the recording element 15 therein. The recording element 15 is electrically connected to a terminal 16 shown in FIG. 11A by electrical wiring (not shown) provided on the recording element substrate 10. The recording element 15 generates heat based on a pulse signal input from the control circuit of the recording apparatus 1000 via the electric wiring board 90 (FIG. 6) and the flexible wiring board 40 (FIG. 10), and the liquid in the pressure chamber 23 is boiled. Then, the liquid is discharged from the discharge port 13 by the foaming force due to the boiling. As shown in FIG. 11B, along each discharge port array, 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 extending in the direction of the discharge port array provided in the recording element substrate 10, and communicate with the discharge port 13 through the supply port 17a and the recovery port 17b, respectively. Yes. That is, the liquid supply path 18 and the liquid recovery path 19 are provided in parallel to the extending direction of the ejection port array. Since the supply port 17a and the recovery port 17b are provided through the substrate body 11, they are collectively referred to as a through channel.

  As shown in FIGS. 11C and 12, a sheet-like lid member 20 is laminated on the back surface of the recording element substrate 10 on which the ejection port 13 is formed. A plurality of openings 21 communicating with the liquid supply path 18 and the liquid recovery path 19 are provided. In the example shown here, the lid member 20 is provided with three openings 21 for one liquid supply path 18 and two openings 21 for one liquid recovery path 19. As shown in FIG. 11B, each opening 21 of the lid member 20 communicates with a plurality of communication ports 51 shown in FIG. As shown in FIG. 12, the lid member 20 has a function as a lid that forms part of the walls of the liquid supply path 18 and the liquid recovery path 19 formed on the substrate 11 of the recording element substrate 10. The lid member 20 is preferably made of a material having sufficient corrosion resistance against a liquid such as a recording liquid. From the viewpoint of preventing color mixing, the opening shape and the opening position of the opening 21 are highly accurate. Is required. For this reason, it is preferable to use a photosensitive resin material or a silicon plate as the material of the lid member 20 and provide the opening 21 by a photolithography process. As described above, the lid member 20 converts the pitch of the flow path by the openings 21, and it is desirable that the thickness is thin in consideration of pressure loss. The lid member 20 is formed of a film-like member, particularly a resin film having photosensitivity. It is desirable.

  Next, the flow of liquid in the recording element substrate 10 will be described. FIG. 12 shows a cross section of the recording element substrate 10 and the lid member 20 on the BB plane in FIG. In the recording element substrate 10, a substrate body 11 formed of a silicon (Si) substrate and a discharge port forming member 12 formed of a photosensitive resin are laminated, and a lid member 20 is disposed on the back surface of the substrate body 11. It is joined. A recording element 15 is formed on one surface side of the substrate body 11 (see FIG. 11), and a liquid supply path 18 and a liquid recovery path 19 extending along the ejection port array are formed on the back surface side thereof. Grooves are formed. The liquid supply path 18 and the liquid recovery path 19 formed by the substrate body 11 and the lid member 20 are connected to the common supply path 211 and the common recovery path 212 in the flow path component 210, respectively. A differential pressure is generated between the supply path 18 and the liquid recovery path 19. An individual supply channel 213 and an individual recovery channel 214 are formed in the first channel member 50, but the individual supply channel 213 connects the liquid supply channel 18 and the common supply channel 211, The channel 214 connects the liquid recovery channel 19 and the common recovery channel 212. In the discharge ports that are not performing the discharge operation when the liquid is discharged from the plurality of discharge ports 13 of the liquid discharge head 3 and recording is performed, the liquid in the liquid supply path 18 is supplied to the supply port 17a by this differential pressure. → Pressure chamber 23 → Flows into the liquid recovery path 19 via the recovery port 17b. This flow is indicated by arrow C in FIG. By this flow, in the ejection port 13 and the pressure chamber 23 where recording is paused, the thickened recording liquid generated by the vaporization of the solvent from the ejection port 13, bubbles, foreign matters, and the like are collected in the liquid recovery path 19. Can do. Further, it is possible to suppress the increase in the viscosity of the recording liquid at the discharge port 13 and the pressure chamber 23. The liquid such as the recording liquid recovered in the liquid recovery path 19 passes through the opening 21 of the lid member 20 and the liquid communication port 31 of the support member 30 (see FIG. 10B). The individual collection channel 214 and the common collection channel 212 are collected in this order. The recovered liquid is finally recovered to the supply path of the recording apparatus 1000.

  After all, the liquid such as the recording liquid supplied from the main body of the recording apparatus 1000 to the liquid discharge head 3 flows in the following order, and is supplied and recovered. The liquid first flows into the liquid ejection head 3 from the liquid connection part 111 of the liquid supply unit 220. And this liquid is the joint rubber 100, the communication port 72 and the common channel groove 71 provided in the third channel member 70, the common channel groove 62 and the communication port 61 provided in the second channel member 60, the first The individual flow channel grooves 52 and the communication port 51 provided in one flow channel member are supplied in this order. Thereafter, the liquid enters the pressure chamber 23 through the liquid communication port 31 provided in the support member 30, the opening 21 provided in the lid member 20, the liquid supply path 18 provided in the substrate body 11 and the supply port 17 a in this order. Supplied. Of the liquid supplied to the pressure chamber 23, the liquid that has not been discharged from the discharge port 13 is the recovery port 17 b and the liquid recovery path 19 provided in the substrate body 11, the opening 21 provided in the lid member 20, and the support member. 30 sequentially flows through the liquid communication port 31 provided at 30. Thereafter, the liquid flows into the communication port 51 and the individual flow channel 52 provided in the first flow channel member, the communication port 61 and the common flow channel 62 provided in the second flow channel member, and the third flow channel member 70. The common channel groove 71, the communication port 72, and the joint rubber 100 that are provided flow in this order. Then, the liquid flows from the liquid connection part 111 provided in the liquid supply unit 220 to the outside of the liquid discharge head 3. When the first circulation form shown in FIG. 2 is adopted, the liquid flowing in from the liquid connecting portion 111 is supplied to the joint rubber 100 after passing through the negative pressure control unit 230. On the other hand, when the second circulation form shown in FIG. 3 is adopted, the liquid recovered from the pressure chamber 23 passes through the joint rubber 100 and then passes through the negative pressure control unit 230 and then from the liquid connection portion 111. It flows to the outside of the discharge head 3.

  Note that not all liquids that have flowed from one end of the common supply channel 211 of the liquid discharge unit 300 are supplied to the pressure chamber 23 via the individual supply channel 213a. As shown in FIGS. 2 and 3, there is also a liquid that flows from the other end of the common supply channel 211 to the liquid supply unit 220 without flowing into the individual supply channel 213a. By providing a path that flows without going through the recording element substrate 10 in this way, even if the recording element substrate 10 is provided with a flow path that is fine and has a high flow resistance, the backflow of the liquid circulation flow is suppressed. can do. In this manner, the liquid ejection head 3 can suppress the increase in the viscosity of the liquid in the pressure chamber and the vicinity of the ejection port, so that it is possible to suppress ejection irregularity and ejection failure, and as a result, high-quality recording can be performed.

(Description of positional relationship between recording element substrates)
As described above, the liquid ejection head 3 includes a plurality of ejection modules 200. FIG. 13 is a partially enlarged view of the adjacent portion of the recording element substrate 10 in two adjacent ejection modules 200. As shown in FIG. 11, a recording element substrate 10 having a substantially parallelogram is used here. As shown in FIG. 13, each of the ejection port arrays 14 a to 14 d in which the ejection ports 13 are arranged in each recording element substrate 10 is arranged so as to be inclined at a certain angle with respect to the conveyance direction L of the recording medium. As a result, at least one ejection port in the ejection port array in the adjacent portion between the recording element substrates 10 overlaps in the conveyance direction L of the recording medium. In the case shown in FIG. 13, the two discharge ports 13 on the line D have a relationship of overlapping each other. With such an arrangement, even if the position of the recording element substrate 10 is slightly deviated from the predetermined position, the black streaks and white spots in the recorded image are conspicuous by the drive control of the overlapping discharge ports. Can be eliminated. Even when a plurality of recording element substrates 10 are arranged in-line instead of in a staggered arrangement, the configuration as shown in FIG. 13 suppresses an increase in the length of the liquid ejection head 3 in the conveyance direction of the recording medium, and suppresses the recording element substrate 10. It is possible to take measures against black streaks and white spots at the connecting portions. Here, the outline shape of the recording element substrate 10 is a substantially parallelogram, but is not limited to this. For example, even when the recording element substrate 10 having a rectangular shape, a trapezoidal shape, or the like is used, the configuration of the present invention. Can be preferably applied.

(Description of Modification of Liquid Discharge Head of First Configuration Example)
Next, a modification of the above-described liquid discharge head configuration will be described with reference to FIGS. A description of the same configuration and function as those in the above-described example will be omitted, and different points will be mainly described. FIG. 14 shows a liquid ejection apparatus similar to that shown in FIG. 1, but includes a liquid ejection head 3 according to this modification. 15 and 16 are a perspective view and an exploded perspective view of a liquid discharge head according to this modification.

  In the liquid ejection head 3 of this modification, a plurality of liquid connection portions 111 that are liquid connection portions between the liquid ejection head 3 and the outside are collectively arranged on one end side in the longitudinal direction of the liquid ejection head 3. . A plurality of negative pressure control units 230 are collectively arranged on the other end side of the liquid discharge head 3 (FIG. 16). In this modification, the liquid supply unit 220 included in the liquid discharge head 3 is configured as a long unit corresponding to the length of the liquid discharge head 3, and a flow path and a filter corresponding to the four colors of liquid to be supplied. 221. As shown in FIG. 16, the openings 83 to 86 provided in the support portion 81 of the liquid discharge unit 220 are also provided at positions different from the liquid discharge head 3 described above.

  FIG. 17 shows a stacked state of the flow path members 50, 60, and 70 in the liquid discharge head 3 of the modification, and corresponds to FIG. 8 relating to the liquid discharge head described above. A plurality of recording element substrates 10 are linearly arranged on the upper surface of the channel member 50 which is the uppermost layer among the plurality of channel members 50, 60, 70. The flow paths communicating with the openings 21 (FIG. 24) formed on the back side of each recording element substrate 10 are two individual supply flow paths 213 and one individual recovery flow path 214 for each liquid color. Yes. Correspondingly, the opening 21 formed in the lid member 20 provided on the back surface of the recording element substrate 10 also has two supply openings 21 and one recovery opening 21 for each liquid color. As shown in FIG. 17, common supply channels 211 and common recovery channels 212 extending along the longitudinal direction of the liquid ejection head 3 are alternately arranged in parallel.

(Description of Liquid Discharge Device of Second Configuration Example)
The liquid ejection apparatus to which the present invention can be applied is not limited to the first configuration example described above. Hereinafter, an ink jet recording apparatus 1000 (hereinafter also referred to as a recording apparatus) which is a second configuration example of the liquid ejection apparatus according to the present invention will be described. FIG. 18 shows a schematic configuration of a recording apparatus 1000 which is a liquid ejection apparatus of the second configuration example. In the following description, only the portions different from the first configuration example will be mainly described, and the description of the same portions as the first configuration example will be omitted.

  The recording apparatus 1000 shown in FIG. 18 has a first configuration example in that full-color recording is performed on the recording medium 2 by arranging four single-color liquid ejection heads 3 corresponding to CMYK colors in parallel. Is different. In the first configuration example, the number of ejection port arrays that can be used per recording liquid of one color is one, whereas in the second configuration example, a plurality of ejection port arrays that can be used per color (in the second configuration example, 20 in the example shown in FIG. For this reason, it is possible to perform very high-speed recording by appropriately recording the recording data to a plurality of ejection port arrays. Furthermore, even if there is a discharge port that does not discharge, the reliability is achieved by performing the discharge in an interpolated manner from the discharge ports in other rows that are located in the position corresponding to the recording medium conveyance direction L with respect to the discharge port. Will improve. Therefore, the recording apparatus 1000 of the second configuration example is suitable for use in a field such as commercial printing. Similar to the first configuration example, the supply system of the recording apparatus 1000, the buffer tank 1003, and the main tank 1006 are fluidly connected to each liquid ejection head 3. Each liquid discharge head 3 is electrically connected to an electric control unit that transmits power and a discharge control signal to the liquid discharge head 3. In the second configuration example, as in the first configuration example, any of the first and second circulation forms shown in FIGS. 2 and 3 can be used.

(Description of liquid discharge head structure)
The structure of the liquid ejection head 3 in the second configuration example will be described with reference to FIG. FIG. 19A is a perspective view of the liquid discharge head 3 viewed from the side where the discharge ports are formed, and FIG. 19B is a perspective view of the liquid discharge head 3 viewed from the opposite direction to FIG. The liquid discharge head 3 includes 16 recording element substrates 10 arranged in a straight line in the longitudinal direction thereof, and is an ink jet type liquid discharge head capable of recording with a single color recording liquid. is there. The liquid ejection head 3 includes a liquid connection portion 111, a signal input terminal 91, and a power supply terminal 92, as in the first configuration example. However, since the liquid discharge head 3 has more discharge port arrays than the first configuration example, the signal output terminal 91 and the power supply terminal 92 are disposed on both sides of the liquid discharge head 3. This is to reduce voltage drop and signal transmission delay that occur in the wiring portion provided on the recording element substrate 10.

  FIG. 20 shows each component or unit constituting the liquid ejection head 3 of the second configuration example divided for each function. The role of each unit and member and the order of the liquid distribution in the liquid discharge head 3 are basically the same as those in the first configuration example, but the rigidity of the liquid discharge head 3 in the second configuration example. The functions that secure the security are different. In the first configuration example, the liquid discharge head support portion 81 mainly secures the liquid discharge head rigidity. However, in the liquid discharge head of the second configuration example, the second flow path member 60 included in the liquid discharge unit 300 is used. The rigidity of the liquid discharge head is guaranteed. The liquid discharge unit support portion 81 in the second configuration example is connected to both end portions of the second flow path member 60, and the liquid discharge unit 300 is mechanically coupled to the carriage of the recording apparatus 1000, The liquid ejection head 3 is positioned. The liquid supply unit 220 including the negative pressure control unit 230 and the electric wiring board 90 are coupled to the liquid discharge unit support portion 81. Each of the two liquid supply units 220 includes a filter (not shown). In the second configuration example, two types of pressure control are not performed for each negative pressure control unit 230. One of the two negative pressure control units 230 is set so as to control the pressure with a relatively high negative pressure as a high pressure side negative pressure control unit, and the other as a low pressure side negative pressure control unit. It is set to control the pressure with a low negative pressure. As shown in FIG. 20, when the negative pressure control units 230 on the high pressure side and the low pressure side are installed at both ends in the longitudinal direction of the liquid discharge head 3, a common supply flow extending in the longitudinal direction of the liquid discharge head 3. The liquid flows in the channel 211 and the common recovery channel 212 face each other. In this way, heat exchange between the common supply channel 211 and the common recovery channel 212 is promoted, and a temperature difference in these common channels is reduced. Therefore, there is an advantage that a temperature difference in each of the recording element substrates 10 provided along the common supply flow path 211 and the common recovery flow path 212 is less likely to occur, and recording unevenness due to the temperature difference is less likely to occur.

  Next, details of the flow path component 210 of the liquid discharge unit 300 will be described. As shown in FIG. 20, the flow path component 210 is a laminate of the first flow path member 50 and the second flow path member 60, and the liquid such as the recording liquid supplied from the liquid supply unit 220 is discharged to each discharge module. Distribute to 200. Further, the flow path component 210 functions as a recovery flow path member for returning the liquid refluxed from the discharge module 200 to the liquid supply unit 220. The second flow path member 60 of the flow path constituting member 210 is a member in which a common supply flow path 211 and a common recovery flow path 212 are formed, and has a function of mainly responsible for the rigidity of the liquid ejection head 3. . For this reason, the material of the second flow path member 60 is preferably a material having sufficient corrosion resistance against liquids such as recording liquid and high mechanical strength, and specifically, stainless steel, titanium (Ti), alumina, or the like is preferably used. be able to.

  Next, details of the first flow path member 50 and the second flow path member 60 will be described with reference to FIG. FIG. 21A shows the surface of the first flow path member 50 on the side where the discharge module 200 is attached, and FIG. 21B is the back surface thereof, which is in contact with the second flow path member 60. The surface on the side is shown. Unlike the first configuration example, the first flow path member 50 in the second configuration example has a plurality of members corresponding to each discharge module 200 arranged adjacent to each other. By adopting such a divided structure, it is possible to correspond to the length required for the liquid discharge head 3 by arranging a plurality of such modules. This configuration can be particularly suitably applied to, for example, a relatively long liquid discharge head having a length corresponding to a JIS (Japanese Industrial Standards) B2 size or larger. As shown in FIG. 21 (a), the communication port 51 of the first flow path member 50 is in fluid communication with the discharge module 200. As shown in FIG. 21 (b), the individual communication of the first flow path member 50 is performed. The port 53 is in fluid communication with the communication port 61 of the second flow path member 60. FIG. 21C shows the surface of the second flow path member 60 on the side in contact with the first flow path member 50, and FIG. 21D shows the center part in the thickness direction of the second flow path member 60. FIG. 21E shows the surface of the second flow path member 60 on the side in contact with the liquid supply unit 220. The functions of the flow path and communication port of the second flow path member 60 are the same as those for the recording liquid for one color in the first configuration example. One of the common flow channel grooves 71 of the second flow channel member 60 is a common supply flow channel 211 shown in FIG. 22, and the other is a common recovery flow channel 212, respectively, along the longitudinal direction of the liquid ejection head 3. Thus, the liquid is supplied from one end side to the other end side. In this configuration example, unlike the first configuration example, the liquid flowing directions in the common supply channel 211 and the common recovery channel 212 are opposite to each other along the longitudinal direction of the liquid ejection head 3.

  FIG. 22 shows the connection relationship of each flow path between the recording element substrate 10 and the flow path constituting member 210. As described with reference to FIG. 21, a pair of common supply channel 211 and common recovery channel 212 extending in the longitudinal direction of the liquid ejection head 3 are provided in the channel constituent member 210. The communication port 61 of the second flow path member 60 is connected in alignment with the individual communication port 53 of each first flow path member 50, and is connected to the common supply flow path from the communication port 72 of the second flow path member 60. A liquid supply flow path that communicates with the communication port 51 of the first flow path member 50 via 211 is formed. Similarly, a liquid supply channel that communicates from the communication port 72 of the second channel member 60 to the communication port 51 of the first channel member 50 via the common recovery channel 212 is also formed.

  FIG. 23 shows a cross section taken along line FF in FIG. As shown in this figure, the common supply channel 211 is connected to the discharge module 200 via the communication port 61, the individual communication port 53, and the communication port 51. Although not shown in FIG. 23, in another cross section, it is apparent with reference to FIG. 22 that the common recovery channel 212 is connected to the discharge module 200 through a similar route. Similarly to the first configuration example, each ejection module 200 and the recording element substrate 10 are formed with flow paths communicating with the pressure chambers 23 where the ejection ports 13 are formed. A part or all of the supplied liquid can be recirculated through the pressure chamber 23 corresponding to the discharge port 13 where the discharge operation is stopped by this flow path. Similarly to the first configuration example, the common supply channel 211 is connected to the high-pressure side negative pressure control unit 230, and the common recovery channel 212 is connected to the low-pressure side negative pressure control unit 230 via the liquid supply unit 220. It is connected. For this reason, the differential pressure generated by these negative pressure control units 230 generates a flow that flows from the common supply channel 211 to the common recovery channel 212 through the pressure chamber 23 of the recording element substrate 10.

(Description of discharge module)
Next, the discharge module 200 in the second configuration example will be described. 24A is a perspective view of the discharge module 200, and FIG. 24B is an exploded view thereof. The difference from the first configuration example is that a plurality of terminals 16 are respectively arranged on both sides (each long side of the recording element substrate 10) along the plurality of ejection port array directions of the recording element substrate 10, and electrically connected thereto. Two flexible wiring boards 40 are also arranged per recording element board 10. This is because the number of ejection port arrays provided on the recording element substrate 10 is, for example, 20 arrays, which is significantly larger than the 4 arrays in the first configuration example. That is, the object is to reduce the voltage drop and signal transmission delay that occur in the wiring portion in the recording element substrate 10 by suppressing the maximum distance from the terminal 16 to the recording element 15 provided corresponding to the ejection port array. It is said. Further, the liquid communication port 31 of the support member 30 is opened so as to straddle all the ejection port arrays provided in the recording element substrate 10. Other points are the same as those in the first configuration example.

(Description of structure of recording element substrate)
Next, the configuration of the recording element substrate 10 in the second configuration example will be described. FIG. 25A is a plan view of the surface of the recording element substrate 10 on the side where the discharge ports 13 are formed, and FIG. 25B shows a portion where the liquid supply path 18 and the liquid recovery path 19 are formed. FIG. 25 (c) is a plan view of the side corresponding to the back surface of FIG. 25 (a). Here, FIG. 25B shows a state in which the lid member 20 provided on the back surface side of the recording element substrate 10 in FIG. 25C is removed. As shown in FIG. 25B, the liquid supply paths 18 and the liquid recovery paths 19 are alternately provided on the back surface side of the recording element substrate 10 along the discharge port array direction. Although the number of ejection port arrays is significantly increased as compared with the first configuration example, the essential difference from the first configuration example is that the terminals 16 are arranged in the ejection port array direction of the recording element substrate 10 as described above. It is arranged on both sides along. One set of the liquid supply path 18 and the liquid recovery path 19 is provided for each discharge port array, and the opening 21 that communicates with the liquid communication port 31 of the support member 30 is provided in the lid member 20. The basic configuration is the same as that of the first configuration example.

(Description of third configuration example)
An ink jet recording apparatus which is a liquid ejecting apparatus according to a third configuration example of the present invention and a structure of a liquid ejecting head 3 provided with the recording apparatus will be described. In the third configuration example, the liquid ejection head 3 is a page-wide type that performs recording in one scan on a JIS B2 size recording medium. Since the third configuration example is similar in many respects to the second configuration example, in the following description, parts different from the second configuration example will be mainly described, and the same parts as the second configuration example will be described. Will not be described.

(Description of inkjet recording apparatus)
FIG. 26 shows a schematic diagram of the ink jet recording apparatus of this configuration example. The recording apparatus 1000 does not perform direct recording on the recording medium from the liquid ejection head 3, and once the liquid is ejected onto the intermediate transfer body (intermediate transfer drum 1007) to form an image, the image is recorded on the recording medium 2. This is a configuration for transferring. In the recording apparatus 1000, four single-color liquid ejection heads 3 respectively corresponding to four types of CMYK recording liquids are arranged in an arc along the intermediate transfer drum 1007. As a result, full-color recording is performed on the intermediate transfer member, and the recorded image is appropriately dried on the intermediate transfer member and then transferred to the recording medium 2 conveyed by the paper conveying roller 1009 in the transfer unit 1008. Transcribed. The transfer unit 1008 is provided with a pressing roller 1020 biased against the intermediate transfer drum 1007, and the recording medium 2 is conveyed while being sandwiched between the intermediate transfer drum 1007 and the pressing roller 1020, thereby transferring the recording medium. Done. The transport system of the recording medium 2 in the second configuration example is a horizontal transport mainly intended for cut paper, whereas in this configuration example, continuous paper supplied from a main body roll (not shown) is also used. It is possible. In such a drum transport system, it is easy to transport the paper, which is a recording medium, while applying a constant tension. Therefore, there is little transport jam even during high-speed recording. For this reason, the reliability of the apparatus is improved and it is suitable for commercial printing and the like. As in the first and second configuration examples, the supply system of the recording apparatus 1000, the buffer tank 1003, and the main tank 1006 are fluidly connected to each liquid ejection head 3. Each liquid discharge head 3 is electrically connected to an electric control unit that transmits power and a discharge control signal to the liquid discharge head 3.

(Explanation of fourth circulation mode)
In the third configuration example, as in the second configuration example, the liquid circulation form between the tank of the recording apparatus 1000 and the liquid discharge head 3 is the first and second configurations shown in FIG. 2 or FIG. Although the circulation form 2 is also applicable, it is preferable to use the circulation form shown in FIG. The main difference between the fourth circulation mode shown in FIG. 27 and the second circulation mode shown in FIG. 3 is that each of the first circulation pumps 1001, 1002 and the second circulation pump 1004 has an outlet of the circulation pump. And a bypass valve 1010 for short-circuiting the inlet is added. The bypass valve 1010 is configured to open a valve that exceeds a preset pressure, and has a function of reducing the pressure on the upstream side of the bypass valve 1010 (first function). The bypass valve 1010 also has a function (second function) for opening and closing the valve at an arbitrary timing based on a signal from the control board of the recording apparatus main body.

  By the first function of the bypass valve 1010, it is possible to suppress an excessive or excessive pressure from being applied to the flow path on the downstream side of the first circulation pumps 1001 and 1002 or the upstream side of the second circulation pump 1004. For example, when troubles occur in the functions of the first circulation pumps 1001 and 1002, an excessive flow rate or pressure may be applied to the liquid discharge head 3. As a result, liquid may leak from the discharge port of the liquid discharge head 3 or the joints in the liquid discharge head 3 may be broken. However, when the bypass valve 1010 is added to the first circulation pumps 1001 and 1002 as in the present configuration example, when the excessive pressure is generated, the bypass valve 1010 is opened, so that the liquid flows to the upstream side of each circulation pump. Since the route is opened, the above trouble can be suppressed.

  When the circulation is stopped by the second function, all the bypass valves 1010 are quickly opened based on a control signal from the main body side after the first circulation pumps 1001 and 1002 and the second circulation pump 1004 are stopped. be able to. Thereby, a high negative pressure state (for example, several to several tens of kPa) in the downstream portion (between the negative pressure control unit 230 and the second circulation pump 1004) of the liquid discharge head 3 can be released in a short time. . When a positive displacement pump such as a diaphragm pump is used as the circulation pump, a check valve is usually built in the pump. However, by opening the bypass valve 1010, the pressure in the downstream portion of the liquid discharge head 3 can be released also from the buffer tank 1003 side on the downstream side. Although the pressure in the downstream portion of the liquid discharge head 3 can be released only from the upstream side, there is a pressure loss in the upstream flow path of the liquid discharge head 3 and the flow path inside the liquid discharge head 3. For this reason, it takes time to release the pressure, and the pressure in the common flow path in the liquid discharge head 3 may drop excessively, and the meniscus of the recording liquid formed in the discharge port 13 may be destroyed. By opening the bypass valve 1010 on the downstream side of the liquid discharge head 3, the pressure release on the downstream side of the liquid discharge head is promoted, so that the risk of meniscus destruction of the discharge port is reduced.

(Description of liquid discharge head structure)
The structure of the liquid ejection head 3 in the third configuration example will be described with reference to FIGS. 28A and 28B are a perspective view and an exploded perspective view of the liquid discharge head 3, respectively. The liquid discharge head 3 is an ink-jet page-wide recording head that includes 36 recording element substrates 10 arranged in a straight line (in-line) in the longitudinal direction and performs recording with one color liquid. Similar to the second configuration example, the liquid ejection head 3 includes a signal input terminal 91 and a power supply terminal 92, and a shield plate 132 that protects the longitudinal side surface of the head.

  In FIG. 28B, each component or unit constituting the liquid ejection head 3 is divided and displayed for each function (however, the shield plate 132 is not shown). The role of each unit and each member and the order of liquid circulation in the liquid discharge head 3 are the same as in the second configuration example. The main differences from the second configuration example are that the electrical wiring board 90 is divided and arranged, the position of the negative pressure control unit 230, and the shape of the first flow path member 50. For example, in the case of the liquid discharge head 3 having a length corresponding to a recording medium of JIS B2 size as in this configuration example, since the power consumption of the liquid discharge head 3 is large, eight electric wiring boards 90 are provided. . Each of the electrical wiring boards 90 is attached to each side surface of the long electrical wiring board support part 82 attached to the liquid discharge unit support part 81 by four.

  FIG. 29A is a side view of the liquid discharge head 3 including the liquid discharge unit 300, the liquid supply unit 220, and the negative pressure control unit 230. FIG. 29B is a schematic view illustrating the flow of the liquid. FIG. 30 c is a perspective view showing a cross section taken along line GG in FIG. In order to facilitate understanding, some configurations are simplified. In FIG. 29B, the recording element substrate 10 is drawn downward, but in FIG. 29C, the recording element substrate 10 is drawn upward.

  A liquid connection unit 111 and a filter 221 are provided in the liquid supply unit 220, and a negative pressure control unit 230 is integrally formed below the liquid supply unit 220. As a result, the distance in the height direction between the negative pressure control unit 230 and the recording element substrate 10 is shorter than that in the second configuration example. This configuration has the advantage that not only the number of flow path connection portions in the liquid supply unit 220 is reduced and the reliability against leakage of the recording liquid is improved, but also the number of parts and the number of assembly steps can be reduced. Further, since the water head difference between the negative pressure control unit 230 and the surface on which the discharge port is formed becomes relatively small, a recording apparatus in which the inclination angle with respect to the horizontal plane is different for each liquid discharge head 3 as shown in FIG. It can be suitably adapted. Since the water head difference can be reduced, even if the plurality of liquid discharge heads 3 are used at different inclination angles, the negative pressure difference applied to the discharge ports of the respective recording element substrates 10 can be reduced. In addition, since the distance between the negative pressure control unit 230 and the recording element substrate 10 is reduced, the flow resistance therebetween is also reduced, so that the pressure loss difference due to the change in the flow rate of the liquid is reduced, and a more stable negative pressure is obtained. It is also preferable in that control can be performed.

  In FIG. 27, the flow of the common supply flow path 211 and the common recovery flow path 212 are shown in the same direction for the sake of simplicity, but FIG. 29B shows the flow in each component of the liquid ejection head 3. The actual liquid flow is shown. A pair of common supply channel 211 and common recovery channel 212 extending in the longitudinal direction of the liquid discharge head 3 are provided in the long second channel member 60. The common supply flow channel 211 and the common recovery flow channel 212 are configured such that liquid flows in directions opposite to each other, and a filter 221 is provided on the upstream side of each flow channel, and foreign matter entering from the connection portion 111 or the like. Trap. In this way, it is preferable to cause the liquid to flow through the common supply flow path 211 and the common recovery flow path 212 in a direction opposite to each other in terms of reducing a temperature gradient in the longitudinal direction in the liquid discharge head 3.

  Negative pressure control units 230 are connected to the downstream sides of the common supply channel 211 and the common recovery channel 212, respectively. Further, there are branches to the plurality of individual supply channels 213 in the middle of the common supply channel 211, and there are branches to the plurality of individual recovery channels 214 in the middle of the common recovery channel 212. Each of the individual supply channel 213 and the individual recovery channel 214 is formed inside each of the plurality of first channel members 50, and the opening 21 of the lid member 20 provided on the back surface of the recording element substrate 10. (See FIG. 25 (c)).

  The negative pressure control units 230 indicated by H and L in FIG. 29B are relatively high (H) and low (L) negative pressures, respectively, and are upstream of the negative pressure control unit 230. It is constituted by a back pressure type pressure adjusting mechanism set so as to control. The common supply flow path 211 is connected to the negative pressure control unit 230 (high pressure side), and the common recovery flow path 212 is connected to the negative pressure control unit 230 (low pressure side), whereby the common supply flow path 211 and the common recovery flow path are shared. A differential pressure is generated between the flow paths 212. Due to this differential pressure, a liquid such as a recording liquid passes through the common supply channel 211, the individual supply channel 213, the discharge port 13 (pressure chamber 23) in the recording element substrate 10, and the individual recovery channel 2134 in order. It flows to the recovery channel 212.

  As shown in FIG. 29 (c), in the present configuration example, each discharge module 200 includes the first flow path member 50, the recording element substrate 10, and the flexible wiring substrate 40. In this configuration example, the support member 30 (FIG. 23) described in the second configuration example is not provided, and the recording element substrate 10 including the lid member 20 is directly joined to the first flow path member 50. Yes. The common supply flow channel 211 provided in the second flow channel member is connected to the individual supply flow channel from the communication port 61 formed on the upper surface thereof through the individual communication port 53 formed on the lower surface of the first flow channel member 50. 213 is supplied. Thereafter, the liquid is recovered to the common recovery channel 212 via the pressure chamber 23 and the individual recovery channel 214, the individual communication port 53, and the communication port 61 in this order.

  Here, unlike the second configuration example shown in FIG. 23, the individual communication port 53 on the lower surface (the surface on the second flow channel member 60 side) of the first flow channel member 50 is provided on the second flow channel member 50. The opening is sufficiently large with respect to the communication port 61 formed on the upper surface of the. This configuration ensures fluid communication between the first flow path member 50 and the second flow path member 60 even when the position is shifted when the discharge module 200 is mounted on the second flow path member 60. As a result, the yield in manufacturing the head is improved and the cost is reduced.

(First embodiment)
Hereinafter, in the liquid discharge apparatus or the liquid discharge head as described above, a configuration based on the present invention that can quickly refill a pressure chamber with a liquid will be described. FIG. 30 shows the configuration of the liquid discharge head according to the first embodiment of the present invention. FIG. 30A shows the relationship between the recording medium 2 and the liquid discharge head 3, and FIG. FIG. 4 is an enlarged perspective view of the recording element substrate 10 in a portion surrounded by a broken line in FIG. In the liquid ejection head 3 shown in FIG. 30, the flow path component 210 in the configuration shown in FIGS. 1 to 29 has a length corresponding to the entire length (length in the X direction in the drawing) of the liquid ejection head 3. It is comprised as a formed member. Then, four recording element substrates 10 on which a plurality of recording elements that generate energy for ejecting liquid are arranged at high density are disposed on the flow path component member 210 via a support member 30 (not shown in FIG. 30). Thus, the liquid ejection heads 3 are arranged in the longitudinal direction while being alternately shifted in the lateral direction. Thus, one long liquid discharge head is configured. An overlapping area is provided between two adjacent recording element substrates 10, and by providing this area, the discharge ports are arranged without gaps from the viewpoint of recording on the recording medium 2. ing. By moving the recording medium 2 relative to the liquid ejection head 3 in a direction perpendicular to the longitudinal direction of the liquid ejection head 3, recording such as an image can be formed on the recording medium 2. Yes. Here, the recording element substrates 10 are arranged alternately, but the present invention is also applied to a liquid discharge head in which a plurality of recording element substrates 10 are arranged in a straight line as shown in FIGS. Can do. A plurality of ejection port arrays 14 are formed on the surface of the recording element substrate 10, and the direction in which each ejection port array 14 extends is the longitudinal direction of the liquid ejection head 3. Although not shown in FIG. 30, the liquid discharge head 3 is also provided with a liquid supply unit and a negative pressure control unit, similar to those shown in FIGS.

  FIG. 31 is a diagram showing the recording element substrate 10 in the liquid ejection head 3 of the first embodiment, and particularly shows the formation region of the ejection port 13 and the recording element 15 in detail. 31A is an enlarged perspective plan view of the recording element substrate 10, and FIG. 31B is a cross-sectional view taken along line A-A ′ of FIG. Here, for the sake of explanation, the configuration in the vicinity of the end portion of one discharge port array 14 is shown. 1 to 29, the discharge port forming member 12 has a plurality of discharge ports 13 formed in a row as through-holes on one surface of the substrate body 11 of the recording element substrate 10. The recording elements 15 are provided so as to face the discharge ports 13 corresponding to the respective discharge ports 13. A plurality of recording elements 15 are provided on the substrate body 11, but a partition wall 22 longer than the recording elements 15 is provided between adjacent recording elements 15. A space surrounded by the partition wall 22 adjacent to each other, the surface of the substrate body 11 and the discharge port forming member 12 is a flow channel, and a portion of the flow channel surrounded by the recording element 15 and the discharge port 13. Is the pressure chamber 23. Therefore, one recording element 15 and one ejection port 13 correspond to one pressure chamber 23. The recording element 15 is, for example, a heater that generates bubbles by heating a liquid. In the liquid discharge head 3, recording can be performed by discharging a liquid such as a recording liquid from the discharge port 13 and landing on the recording medium 2 by the impact of bubbles generated by heating by the heater.

  In the configuration shown in FIG. 31, the plurality of pressure chambers 23 are arranged in a line along the direction of the discharge port array 14. A supply port 17a communicating with the liquid supply path 18 formed on the surface is provided. Similarly, on the left side of the row of the pressure chambers 23 in the drawing, a recovery port 17 b that communicates with the liquid recovery path 19 formed on the other surface of the substrate body 11 is provided. Each of the supply port 17 a and the recovery port 17 b is a through channel that penetrates the substrate body 11, and a plurality of supply ports 17 a and recovery ports 17 b are arranged in the direction of the discharge port array at a rate of one per two pressure chambers 23. In FIG. 31, among the flow paths formed by being surrounded by the partition walls 22 adjacent to each other, the surface of the substrate body 11 and the discharge port forming member 12, the portion on the supply port 17a side as viewed from the pressure chamber 23 is denoted by reference numeral 27a. The portion on the recovery port 17b side when viewed from the pressure chamber 23 is indicated by reference numeral 27b.

  32A and 32B are diagrams for explaining the overall configuration of the recording element substrate 10, where FIG. 32A is a perspective plan view of the recording element substrate 10, and FIG. 32B is a cross-sectional view taken along line AA ′ in FIG. (C) is sectional drawing in the BB 'line of (a). FIG. 33 is a diagram for explaining the substrate body 11 and the lid member 20, where (a) is a side view of the substrate body 11 and the lid member 20, and (b) is a plan view of the first surface of the substrate body 11, (C) is an arrow view in the AA 'line of (a), (d) is the top view seen from the cover member 20 side. In addition, in FIG.32 (b), the discharge port formation member 12 is not shown for description. Also in the liquid ejection head 3 of the present embodiment, the surface of the substrate body 11 of the recording element substrate 10 on which the recording element 15 is formed, that is, the surface opposite to the first surface 36 (like the above-described one). A liquid supply path 18 and a liquid recovery path 19 are provided on the second surface. The liquid supply path 18 and the liquid recovery path 19 extend in the direction of the ejection port array 14 and are formed in a groove shape on the second surface of the substrate body 11. Further, a lid member 20 is attached to the second surface of the substrate body 11, and the liquid supply path 18 and the liquid recovery path 19 are covered by the lid member 20. Similarly to those shown in FIGS. 1 to 29, an opening is provided for supplying the liquid to the liquid supply path 18 via a support member (not shown) and recovering the liquid from the liquid recovery path 19. Here, of these openings, the opening communicating with the liquid supply path 18 is referred to as a supply side opening 21a, and the opening communicating with the liquid recovery path 19 is referred to as a recovery side opening 21b. A plurality of supply side openings 21 a and recovery side openings 21 b are provided for the liquid supply path 18 and the liquid recovery path 19, respectively. In this example, four rows of recording elements 15 are provided, and correspondingly, four liquid supply paths 18 and four liquid recovery paths 19 are alternately arranged in the substrate body 11. doing. The number of supply side openings 21 a provided in each liquid supply path 18 is smaller than the number of supply ports 17 a communicating with the liquid supply path 18. Similarly, the number of recovery side openings 21 b provided in the liquid recovery path 19 is smaller than the number of recovery ports 17 b communicating with the liquid recovery path 19. Further, the positions of the supply side opening 21 a and the recovery side opening 21 b are both inside the ends of the liquid supply path 18 and the liquid recovery path 19 in the discharge port array direction. It is possible to reduce the size. More specifically, the supply side opening 21a is closer to the center in the longitudinal direction of the liquid supply path 18 than the supply ports 17a respectively corresponding to both ends in the extending direction of the discharge port array in the liquid supply path 18. Is provided. The same applies to the position of the collection side opening 21b.

  Next, the flow of a liquid such as a recording liquid in the liquid discharge head 3 will be described. Similar to those shown in FIGS. 1 to 29, a common supply channel 211 and a common recovery channel 212 are provided in the channel component 210. The liquid diverted from the common supply flow path 211 enters the liquid supply path 18 from the liquid communication port 31 of the support member 30 through the supply side opening 21a, and flows through the liquid supply path 18 in the direction of the discharge port array. It enters the pressure chamber 23 through the supply port 17a and the flow path 27a which are paths. Since the number of the supply side openings 21a is smaller than the number of the supply ports 17a, the liquid is supplied from one supply side opening 21a to the plurality of supply ports 17a through the liquid supply path 18. The liquid that has not been discharged in the pressure chamber 23 enters the liquid recovery path 19 through the flow path 27b and the recovery port 17b that is a through flow path. In the liquid recovery path 19, the liquids from the plurality of recovery ports 17 b merge, and the merged liquid merges from the recovery side opening 21 b through the liquid communication port 31 to the common recovery channel 212. The liquid flow is indicated by arrows in FIG. The liquid discharge head 3 is also configured to circulate a liquid such as a recording liquid between the liquid discharge apparatus and suppresses the increase in the viscosity of the liquid accompanying the vaporization of the solvent from the discharge port 13, thereby reducing the recording quality. Can be prevented.

  In the liquid ejection head 3 as described above, when droplets are ejected continuously from a large number of ejection ports 13, a large amount of liquid flows through the liquid supply path 18 formed on the second surface of the substrate body 11. It will be. Thereby, pressure loss occurs in the liquid supply path 18 and the supply port 17a which is a through-flow path. When discharging from the discharge port 13, the liquid corresponding to the discharged amount must be filled into the pressure chamber 23. If the pressure loss described here is large, the pressure chamber 23 is refilled. The speed is slow. If the refilling is slow, the volume of discharged droplets per discharge is reduced when continuous discharge is performed, and a large number of minute droplets called mist are generated. As a result, the density of recording formed on the recording medium 2 becomes thin, or the inside of the liquid ejecting apparatus is contaminated with mist. As described below, according to the considerations of the present inventors, when the pressure loss exceeds 5000 Pa, the recording density is low when recording such as an image is formed on the surface of the recording medium 2 by discharging the recording liquid. Has become noticeable. The pressure loss referred to here is a pressure loss in a state where there is a flow of recording liquid due to ejection. That is, it indicates a pressure loss in a state where the liquid in the liquid supply path 18 is flowing in the process in which the liquid is filled in the pressure chamber 23 after the liquid is discharged from the discharge port 13. More specifically, it is the sum P1 of the pressure loss at the liquid supply path 18 and the pressure loss at the supply port 17a, that is, the combined pressure loss. The pressure loss in the liquid supply path 18 refers to the liquid from the supply side opening 21a formed in the lid member 20 to the farthest supply port 17a that is to be supplied from the supply side opening 21a. This is a pressure loss in the supply path 18. Since a plurality of supply side openings 21a are provided, the combined pressure loss referred to here may differ for each supply side opening 21a. In this case, the largest one of these combined pressure losses is considered.

  The inventors conducted experiments on the relationship between the combined pressure loss and the recording quality. When the width of the liquid supply path 18 formed as a groove in the substrate main body 11 is changed, the pressure loss changes. Therefore, a plurality of recording element substrates 10 having different widths of the liquid supply path 18 are created, and these recording element substrates 10 are formed. The liquid discharge head 3 was produced using this. Then, using these liquid discharge heads 3, the recording element 15 is driven to discharge the droplets at different frequencies, that is, the discharge frequencies are discharged to form a record on the recording medium 2, and the recording quality is evaluated. . The results are shown in FIG. In FIG. 34, “◯” indicates a condition in which the recording density is not thinned, and “x” indicates a condition in which the image density is significantly thinned. Although it depends on the ejection frequency, it has been found that the recording density is significantly diminished when the combined pressure loss exceeds 5000 Pa. Therefore, in the present embodiment, the combined pressure loss, which is the sum of the pressure loss in the liquid supply path 18 and the pressure loss in the supply port 17a, which is a through flow path when discharging liquid, is suppressed to 5000 Pa or less. The pressure loss in the liquid supply path 18 can change according to the positional relationship between the supply side opening 21a and the supply port 17a. Therefore, more specifically, the pressure loss of the liquid in the liquid supply path 18 from the arbitrary supply side opening 21a to the supply port 17a farthest from the supply side opening 21a, and the liquid at the supply port 17a. The sum P1 of the pressure loss is set to 5000 Pa or less. Thereby, refilling of the liquid such as the recording liquid into the pressure chamber 23 can be performed quickly, and the deterioration of the recording quality can be prevented. The combined pressure loss is preferably suppressed to 4000 Pa or less, more preferably 3000 Pa or less.

  In order to suppress the combined pressure loss to 5000 Pa or less, the cross-sectional areas of the liquid supply path 18 and the supply port 17a may be increased. However, if these cross-sectional areas are increased unnecessarily, the size of the recording element substrate 10 increases, which causes an increase in cost. In particular, when the width of the liquid supply path 18 is increased, the width of the recording element substrate 10 in the direction orthogonal to the direction of the ejection port array is increased. Therefore, by increasing the depth of the liquid supply path 18 formed as a groove with respect to the substrate body 11, the cross-sectional area of the liquid supply path 18 can be increased while suppressing an increase in the substrate size. For example, it is possible to achieve both reduction of pressure loss and suppression of increase in substrate size by making the depth at least a part of the width of the liquid supply path 18 in at least a part of the liquid supply path 18. it can. In order to reduce the combined pressure loss, it is preferable to set the depth D of the liquid supply path 18 to 300 μm or more in at least a part of the liquid supply path 18, and the distance L between the adjacent supply ports 17a. Is preferably 100 μm or less. The thickness of the lid member 20 is preferably 0.1 μm or more and 100 μm or less.

  Here, the pressure loss in the liquid discharge head 3 configured so that the recording liquid circulates has been described. However, even in a liquid discharge head configured so that the recording liquid does not circulate, the combined pressure loss at the time of full ejection is required for good recording. It shall be 5000 Pa or less. Further, in the liquid discharge head 3 configured to circulate the recording liquid described here, the recording liquid is filled into the pressure chamber 23 from the liquid recovery path 19 via the recovery port 17b when the recording liquid is discharged from the discharge port. May be. Therefore, the sum P2 of the pressure loss in the liquid recovery path 19 and the pressure loss at the recovery port 17b is also preferably set to 5000 Pa or less. The pressure loss in the liquid recovery path 19 refers to the farthest recovery port 17b from which the recording liquid flows into the recovery side opening 21b when viewed from the recovery side opening 21b formed in the lid member 20. The pressure loss in the liquid recovery path 19 up to the recovery side opening 21b. Further, in the liquid discharge head configured to circulate the recording liquid, the sum of the above-described combined pressure loss when discharging the recording liquid and the combined pressure loss in the standby state where the recording liquid is not discharged may be 5000 Pa or less. preferable.

As an example of the combined pressure loss of the liquid supply path 18 and the supply port 17a of 5000 Pa or less, the cross section of the liquid supply path 18 is rectangular and the planar shape of the supply port 17a is also rectangular in the one shown in FIGS. It is said. The liquid recovery path 19 has the same shape as the liquid supply path 18, and the recovery port 17b has the same shape as the supply port 17a. The supply port 17a and the recovery port 17b are arranged at equal intervals in the liquid supply path 18 and the liquid recovery path 19, respectively. The width W of the liquid supply path 18 is 190 μm, the depth D is 425 μm, and the distance L between adjacent supply ports 17a is 85 μm. The supply port 17a formed as a through channel has a width w ₁ of 40 μm, a width w ₂ of 45 μm and a length d of 160 μm in the shape of the opening. The viscosity η of the recording liquid that is the liquid to be discharged is 6 mPa · s, and the flow rate Q that flows through the supply port 17a when continuously discharged from all the discharge ports is 90000 pl / s. The maximum number n among the number of supply ports included in the section from the supply side opening 21a formed in the lid member 20 to the supply port 17a farthest away is set to 92. The supply port 17a farthest from any supply-side opening 21a formed in the lid member 20 is the discharge port 17a formed at the end of the recording element substrate 10 in the direction of the discharge port array. At this time, the combined pressure loss ΔP when the flow rate of the recording liquid is Q is determined by the equation (1).

式(1)において右辺第１項は、供給側開口２１ａからその最も離れた供給口１７ａまでの圧力損失であり、右辺第２項は、供給口１７ａにおける圧力損失である。ここでＲは、隣り合う供給口１７ａ間における液体供給路１８を流れる液体の粘性抵抗であり、式(2)によって求められる。また、ｒは、供給口１７ａにおける粘性抵抗であり、式(3)によって求められる。式(2)及び式(3)は断面が長方形である液体流路において一般的に成り立つ式である。

In equation (1), the first term on the right side is the pressure loss from the supply side opening 21a to the furthest away supply port 17a, and the second term on the right side is the pressure loss at the supply port 17a. Here, R is the viscous resistance of the liquid flowing in the liquid supply path 18 between the adjacent supply ports 17a, and is obtained by the equation (2). Further, r is a viscous resistance at the supply port 17a and is obtained by the equation (3). Expressions (2) and (3) are expressions that generally hold in a liquid channel having a rectangular cross section.

ここで説明した例では、吐出によって発生する流量Ｑが９００００ｐｌ／ｓとしたときに、蓋部材２０の任意の供給側開口２１ａから最も離れた供給口１７ａまでの圧力損失は、約２０００Ｐａである。この値は５０００Ｐａを下回っているため、全吐出口から連続吐出させても画像品位を維持できる。また、ここで示した液体吐出ヘッド３では、非吐出時においても記録液は液体供給路１８及び供給口１７ａを流れ続ける。ここで非吐出時に供給口１７ａを流れる記録液の流量Ｑを４８００ｐｌ／ｓとすると、合成圧力損失ΔＰは約１００Ｐａとなる。このとき、非吐出時と全吐出時の圧力損失の差が５０００Ｐａ以下であり、非吐出時と全吐出時の圧力損失の和も５０００Ｐａ以下であるので、全吐出口から連続吐出させても画像品位を維持できる。ここで述べた例では、液体吐出ヘッド３から吐出される液体は記録液であるとしたが、記録液以外の液体を吐出する場合にも本発明が適用できることは言うまでもない。

In the example described here, when the flow rate Q generated by the discharge is 90000 pl / s, the pressure loss from the arbitrary supply side opening 21a of the lid member 20 to the supply port 17a farthest is about 2000 Pa. Since this value is less than 5000 Pa, the image quality can be maintained even if the discharge is continuously performed from all the discharge ports. Further, in the liquid discharge head 3 shown here, the recording liquid continues to flow through the liquid supply path 18 and the supply port 17a even during non-discharge. Here, if the flow rate Q of the recording liquid flowing through the supply port 17a during non-ejection is 4800 pl / s, the combined pressure loss ΔP is about 100 Pa. At this time, the difference in pressure loss between non-discharge and full discharge is 5000 Pa or less, and the sum of the pressure loss between non-discharge and full discharge is 5000 Pa or less. Maintains quality. In the example described here, the liquid ejected from the liquid ejection head 3 is the recording liquid. However, it goes without saying that the present invention can also be applied to the case of ejecting a liquid other than the recording liquid.

In the example described above, the supply ports 17a and the recovery ports 17b are evenly arranged with respect to the liquid supply path 18 and the liquid recovery path 19, respectively, but the supply ports 17a and the recovery ports 17b are non-uniformly arranged. Also good. In that case, the distance between the i-th supply port 17a and the (i + 1) -th supply port 17a as viewed from the supply-side opening 21a of the cover member 20 and L _i. Further, q is the flow rate of the recording liquid flowing through the supply side opening 21a. At this time, the combined pressure loss ΔP is expressed by equation (1a) instead of equation (1).

式(1a)におけるＲ_iは、式(2a)に示すように、蓋部材２０の供給側開口２１ａから見てｉ番目の供給口１７ａとｉ＋１番目の供給口１７ａとの間の区間（距離Ｌ_i）での液体供給路１８における液体の粘性抵抗である。供給口１７ａが不均一に配置されている場合においても、式(1a)によって示される合成圧力損失ΔＰを５０００Ｐａとすることにより、圧力室２３への記録液の再充填を速やかに行うことができて、記録品位の低下を防止することができる。

R _i in the equation (1a) is a section (distance L) between the i-th supply port 17a and the i + 1-th supply port 17a when viewed from the supply-side opening 21a of the lid member 20, as shown in the equation (2a). _i ) is the viscous resistance of the liquid in the liquid supply path 18. Even when the supply ports 17a are non-uniformly arranged, the recording liquid into the pressure chamber 23 can be quickly refilled by setting the combined pressure loss ΔP represented by the equation (1a) to 5000 Pa. Thus, it is possible to prevent the recording quality from deteriorating.

(Second Embodiment)
The configuration of the liquid discharge head 3 to which the present invention is applied is not limited to that shown in the first embodiment. Even if the dimensions of the liquid supply path 18 and the supply port 17a are changed, if the combined pressure loss ΔP is 5000 Pa or less, the pressure chamber 23 can be quickly refilled with the recording liquid, and the recording quality is lowered. Can be prevented. As a specific example, the liquid discharge head 3 of the second embodiment has a basic configuration similar to that of the first embodiment, and the width W of the liquid supply path 18 is 100 μm and the depth D is 625 μm, which are adjacent to each other. The distance L between the supply ports 17a is 85 μm. The supply port 17a is a square having a side of 35 μm as the shape of the opening (that is, w ₁ = 35 μm, w ₂ = 35 μm), and the length d of the supply port 17a as a through channel is 100 μm. The viscosity η of the recording liquid that is the liquid to be discharged is 6 mPa · s, and the flow rate Q that flows through the supply port 17a when continuously discharged from all the discharge ports is 90000 pl / s. The maximum number n among the number of supply ports included in the section from the supply side opening 21a formed in the lid member 20 to the supply port 17a farthest away (the supply port 17a at the end of the recording element substrate 10) is 92. And The combined pressure loss ΔP at this time is about 4500 Pa, which is less than 5000 Pa. Therefore, even in the liquid discharge head 3 of the second embodiment, the recording quality can be maintained even when the liquid discharge head 3 is continuously discharged from all the discharge ports. In this configuration, since the width of the liquid supply path 18 is narrower than that of the first embodiment, the size of the recording element substrate 10 can be further reduced.

(Third embodiment)
FIG. 35 shows the configuration of the recording element substrate 10 in the liquid ejection head 3 of the third embodiment. 35A is a side view of the substrate body 11 and the lid member 20, FIG. 35B is a plan view of the first surface of the substrate body 11, and FIG. 35C is a line AA ′ in FIG. An arrow view and (d) are top views seen from the lid member 20 side. The liquid discharge head 3 of this embodiment is the same as that of the first embodiment, but the width W of the liquid supply path 18 and the liquid recovery path 19 changes along the direction of the discharge port array. This is different from the first embodiment. At the time of all ejections in which ejection is performed from all ejection ports, the recording liquid having an equal flow rate flows through all the supply ports 17a. At this time, since the number of the supply side openings 21a of the lid member 20 is smaller than the number of the supply ports 17a, the flow rate flowing through the liquid supply path 18 increases as the position is closer to the supply side openings 21a. If the flow path cross-sectional area is the same, the larger the flow rate, the greater the pressure loss, so in this embodiment, by widening the width of the liquid supply path 18 at the position where the flow rate is large, The pressure loss is suppressed. On the other hand, since the flow rate is relatively small at a position away from the supply side opening 21a, even if the width of the liquid supply path 18 is reduced, it is difficult to increase the pressure loss. In the present embodiment, the supply-side opening 21a and the collection-side opening 21b are arranged in a staggered manner in the lid member 20, thereby expanding the width of the liquid supply path 18 at the position of the supply-side opening 21a and moving away from that position. As the width gradually decreases. Similarly, the width of the liquid recovery path 19 also increases at the position of the recovery side opening 21b and gradually decreases as the distance from this increases. In this configuration, the cross-sectional area of the liquid supply path 18 is maximal at the position of the supply side opening 21a, and decreases as the distance from the position of the supply side opening 21a increases.

As an example, the width of the liquid supply path 18 in the vicinity of the supply-side opening 21a is 220 μm, the width at the position farthest from the supply-side opening 21a is 128 μm, and the width of the liquid supply path 18 changes linearly during this period. And Other dimensions are the same as in the first embodiment. The depth D of the liquid supply path 18 is 425 μm, the distance L between adjacent supply ports 17a is 85 μm, and the width of one side at the opening of the supply path 17a. Assume that w ₁ is 40 μm, the width w ₂ of the other side is 45 μm, and the length d of the supply port 17a is 160 μm. The viscosity η of the recording liquid to be ejected is 6 mPa · s, the flow rate Q flowing through each through-flow path at the time of all ejections is 90000 pl / s, and the supply port 17a farthest from the supply side opening 21a (at the end of the recording element substrate 10). The maximum through-channel number n included in the section up to the supply port 17a) is set to 92. At this time, the maximum value of the pressure loss from the supply side opening 21a to the furthest supply port 17a is about 1900 Pa, and even if the pressure loss at the supply port 17a itself is taken into account, the combined pressure loss is less than 5000 Pa. The recording quality can be maintained even if it is continuously discharged from the discharge port. In the present embodiment, the supply-side openings 21a and the collection-side openings 21b are arranged in a staggered manner, so that a low pressure loss can be maintained even if the width of the recording element substrate 10 is made narrower.

(Fourth embodiment)
In each embodiment described above, the cross-sectional shape of the liquid supply path 18 is rectangular, but the cross-sectional shape of the liquid supply path 18 is not limited to a rectangle. FIG. 36 is a diagram for explaining the overall configuration of the recording element substrate 10 in the liquid ejection head 3 according to the fourth embodiment. FIG. 36A is a perspective plan view of the recording element substrate 10, and FIG. ) Is a cross-sectional view taken along line AA ′, and FIG. 8C is a cross-sectional view taken along line BB ′ in FIG. As shown in FIG. 36, in the fourth embodiment, the cross-sectional shapes of the liquid supply path 18 and the liquid recovery path 19 in the first embodiment are such that a part of a rectangular corner is rounded. . The cross-sectional shapes and dimensions of the liquid supply path 18 and the liquid recovery path 19 are the same. For example, the width W ₁ of the upper bottom side (side contacting the lid member 20) of the liquid supply path 18 is 200 μm, the width W ₂ of the lower base side (supply port 17a side) is 180 μm, and the depth D of the liquid supply path 18 is 425 μm. The corner formed by the lower base and the side wall of the liquid supply path 18 is rounded, and the width W ₂ on the lower base side is the width of only the flat part not including this rounded part. Represents. The distance L between adjacent supply ports 17a is 85 μm, the width w ₁ of _one side at the opening of the supply path 17a is 40 μm, the width w ₂ of the other side is 45 μm, and the length d of the supply port 17a is 160 μm. To do. The viscosity η of the recording liquid to be ejected is 6 mPa · s, the flow rate Q flowing through each through-flow path at the time of all ejections is 90000 pl / s, and the supply port 17a farthest from the supply side opening 21a (at the end of the recording element substrate 10). The maximum through-channel number n included in the section up to the supply port 17a) is set to 92. At this time, the maximum value of the pressure loss from the supply-side opening 21a to the furthest supply port 17a is about 2000 Pa, and even if the pressure loss at the supply port 17a itself is taken into account, the combined pressure loss is less than 5000 Pa. The recording quality can be maintained even if it is continuously discharged from the discharge port. In the present embodiment, in the substrate body 11, the base side of the wall portion that separates the adjacent liquid supply path 18 and liquid recovery path 19 is formed thick, so that the strength of the recording element substrate 10 is improved. can get.

(Fifth embodiment)
In each of the embodiments described above, the depth D of the liquid supply path 18 is constant, but the depth of the liquid supply path 18 need not be constant. FIGS. 37A and 37B are diagrams illustrating the entire configuration of the recording element substrate 10 in the liquid ejection head 3 according to the fifth embodiment. FIG. 37A is a perspective plan view of the recording element substrate 10, and FIG. ) Is a cross-sectional view taken along line AA ′, and FIG. 8C is a cross-sectional view taken along line BB ′ in FIG. In the present embodiment, the depth D of the liquid supply path 18 is not constant, and the depth D of the liquid supply path 18 decreases as the distance from the supply-side opening 21a formed in the lid member 20 decreases. The liquid supply path 18 is shallow. Therefore, the cross-sectional area of the liquid supply path 18 decreases as the distance from the supply side opening 21a increases. For example, the depth D ₁ of the liquid supply path 18 at the position where the supply side opening 21a is formed is 425 μm, and the supply port 17a is located farthest from the supply side opening 21a (the supply port 17a at the end of the recording element substrate 10). It is assumed that the depth D ₂ of the liquid supply path 18 at the formation position is 333 μm. Here, the lower bottom of the liquid supply path 18 approaches the upper bottom side with a constant gradient. The width W of the liquid supply path 18 is 190 μm, the width w ₁ of _one side at the opening of the supply path 17a is 40 μm, and the width w ₂ of the other side is 45 μm. The viscosity η of the recording liquid to be ejected is 6 mPa · s, the flow rate Q flowing through each through-flow path at the time of all ejections is 90000 pl / s, and the supply port 17a farthest from the supply side opening 21a (at the end of the recording element substrate 10). The maximum through-channel number n included in the section up to the supply port 17a) is set to 92. The length of the supply port 17a as the through flow path is a value obtained by subtracting the depth of the liquid supply path 18 from the thickness of the substrate body 11. For this reason, the length d ₁ in the depth direction of the supply port 17a in the vicinity of the formation position of the supply side opening 21a is 160 μm, and the length in the depth direction of the supply port 17a in the vicinity of the end of the recording element substrate 10 is 333 μm. . At this time, the maximum value of the pressure loss from the supply side opening 21a to the furthest supply port 17a is about 3000 Pa, and even if the pressure loss at the supply port 17a itself is taken into account, the combined pressure loss is less than 5000 Pa. The recording quality can be maintained even if it is continuously discharged from the discharge port. In this configuration, since the liquid supply path 18 is formed shallower toward the end of the recording element substrate 10 in the direction of the ejection port array, the strength of the recording element substrate 10 is improved.

FIG. 38 is a diagram illustrating the overall configuration of the recording element substrate 10 in another example of the liquid ejection head 3 according to the fifth embodiment. FIG. 38A is a perspective plan view of the recording element substrate 10. ) Is a cross-sectional view taken along line AA ′ in FIG. 5A, and FIG. 5C is a cross-sectional view taken along line BB ′ in FIG. The one shown in FIG. 38 differs from the one shown in FIG. 37 in that the depth of the liquid supply path 18 changes only at the end portion in the discharge port array direction. For example, the depth D ₂ of the liquid supply path 18 at the end portion is 380 μm, and the depth of the liquid supply path 18 changes linearly within a range from the end to a distance A of, for example, 200 μm, and the position of the distance A a constant depth D ₁ at 425μm in the supply-side opening 21a side from. Also in this case, since the substantial thickness of the substrate body 11 increases at the end in the direction of the ejection port array, the strength of the recording element substrate 10 can be expected to be improved.

DESCRIPTION OF SYMBOLS 3 Liquid discharge head 10 Recording element board | substrate 13 Discharge port 15 Recording element 17a Supply port 18 Liquid supply path 20 Lid member 21a Supply side opening 22 Partition 23 Pressure chamber

Claims (18)

A recording element substrate having a plurality of recording elements that generate energy for discharging a liquid provided on the first surface, a partition wall disposed between adjacent recording elements, and an ejection provided corresponding to the recording element. A liquid discharge head having an outlet and a pressure chamber partitioned by the partition and including the recording element therein, wherein the plurality of discharge ports are arranged in a row to form a discharge port array;
A liquid supply path provided in a groove shape on a second surface opposite to the first surface of the recording element substrate, for supplying liquid to the plurality of pressure chambers;
A plurality of supply ports that communicate between the first surface and the liquid supply path, and supply liquid from the liquid supply path to the pressure chamber;
A lid member provided on the second surface so as to cover the liquid supply path, including a supply side opening for supplying liquid to the liquid supply path;
Have
The supply at the position farthest from the supply-side opening, communicating with the supply-side opening from any supply-side opening in the process of filling the pressure chamber with the liquid after discharging the liquid from the discharge port The liquid discharge head according to claim 1, wherein a sum P1 of a pressure loss of the liquid in the liquid supply path to the mouth and a pressure loss of the liquid in the supply port located farthest is 5000 Pa or less. The viscosity resistance of the liquid flowing through the liquid supply path between the i-th supply port and the (i + 1) -th supply port from the position of the supply-side opening is R _i , and the viscosity resistance of the fluid flowing through the supply port is r, Q is the flow rate of the liquid flowing through each of the supply ports, q is the amount of liquid flowing through the supply side opening, and the section is from the supply side opening to the supply port at the most distant position from the supply side opening. Assuming that the number of the supply ports included is n, the combined pressure loss ΔP is

The liquid discharge head according to claim 1, wherein the combined pressure loss ΔP is 5000 Pa or less. A plurality of the supply ports are arranged, R is a viscous resistance of the liquid flowing through the liquid supply path communicating between the adjacent supply ports, r is a viscous resistance of the fluid flowing through the supply port, and the supply The combined pressure loss ΔP is defined as Q, where Q is the flow rate of the liquid flowing through each of the ports, and n is the number of the supply ports included in the section from the supply side opening to the supply port located farthest from the supply side opening.

The liquid discharge head according to claim 1, wherein the combined pressure loss ΔP is 5000 Pa or less.   The cross section of the liquid supply path in a direction orthogonal to the fluid flow direction is rectangular, and the depth of the liquid supply path with respect to the width of the liquid supply path in at least a portion of the liquid supply path 4. The liquid discharge head according to claim 1, wherein the ratio is two times or more. 5.   5. The liquid ejection head according to claim 1, wherein a cross-sectional area of the liquid supply path in a direction orthogonal to a fluid flow direction decreases with increasing distance from the position of the supply side opening.   The liquid discharge head according to claim 1, comprising a plurality of the discharge port arrays.   7. The liquid discharge head according to claim 1, wherein the liquid supply path is provided in parallel to an extending direction of the discharge port array.   The supply side opening is provided on the center side in the extending direction with respect to the extending direction of the liquid supply path, rather than the supply ports provided on both ends of the liquid supply path. The liquid discharge head according to any one of the above. A liquid recovery path provided in a groove shape on the second surface for recovering liquid from the plurality of pressure chambers;
A plurality of recovery ports that communicate between the first surface and the liquid recovery path and recover liquid from the pressure chamber to the liquid recovery path;
A recovery side opening provided in the lid member for recovering the liquid from the liquid recovery path;
The liquid discharge head according to claim 1, further comprising:   After the liquid is discharged from the discharge port, in the process of filling the pressure chamber with the liquid, the recovery is located at a position farthest from the recovery side opening, communicating with the recovery side opening from any recovery side opening. 10. The liquid according to claim 9, wherein a sum P <b> 2 of a pressure loss of the liquid in the liquid recovery path to the mouth and a pressure loss of the liquid at the recovery port located farthest is 5000 Pa or less. Discharge head. A sum P1 of the pressure loss;
The liquid supply path from any supply-side opening to the supply-side opening that is in the standby state in which no liquid is discharged from the discharge-port, to the supply port that is farthest from the supply-side opening The sum of the pressure loss of the liquid at and the pressure loss of the liquid at the farthest supply port;
The liquid discharge head according to claim 9, wherein the sum of the values is 5000 Pa or less. The recovery port located at the position farthest from the recovery side opening, communicating with the recovery side opening from any recovery side opening in the process of filling the pressure chamber with the liquid after discharging the liquid from the discharge port The sum of the pressure loss of the liquid in the liquid recovery path up to and the pressure loss of the liquid at the most distant recovery port;
In the standby state in which liquid is not discharged from the discharge port, the liquid recovery path from any of the recovery side openings to the recovery port that is in communication with the recovery side opening and is farthest from the recovery side opening The sum of the pressure loss of the liquid at and the pressure loss of the liquid at the farthest recovery port;
The liquid discharge head according to claim 9, wherein the sum of the values is 5000 Pa or less.   The liquid discharge head according to claim 1, wherein the lid member is made of a photosensitive resin film. A page-wide liquid ejection head,
The liquid discharge head according to claim 1, further comprising a support member that supports the plurality of recording element substrates.   The support member includes a common supply channel for supplying liquid to the plurality of recording element substrates, and a common recovery channel for recovering liquid from the plurality of recording element substrates. The liquid discharge head described.   The liquid discharge head according to claim 1, wherein the liquid in the pressure chamber is circulated between the pressure chamber and the outside. A liquid discharge head according to any one of claims 1 to 8,
Storage means for storing the liquid;
Means for supplying the liquid to the liquid supply path from the storage means via the supply side opening;
A liquid ejection apparatus comprising: A liquid discharge head according to any one of claims 9 to 12,
Storage means for storing the liquid;
A first circulation system for circulating the liquid from the storage means;
A second circulation system for circulating the liquid from the storage means at a lower pressure than the first circulation system;
The liquid supply path is in communication with the first circulation system, and the liquid recovery path is in communication with the second circulation system.

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