JP6964975B2 - Liquid discharge head and liquid discharge device - Google Patents

Description

The present invention relates to a liquid discharge head and a liquid discharge device capable of discharging a liquid such as ink from a discharge port.

In the inkjet field where liquids such as ink are ejected for recording, recording applications have been diversified in recent years, and the demand for high-definition and high-quality recording is further increasing. For high-definition recording, a method of increasing the resolution of recording by arranging a plurality of discharge ports at high density is known. Further, in order to realize higher quality recording, it is necessary to suppress thickening of ink due to evaporation of water from the ejection port, which causes a decrease in the ejection speed of droplets and a modulation of the color material concentration. There is.

As a method of suppressing thickening of ink due to evaporation of water from the ejection port, the thickened ink staying in the pressure chamber is removed by forcibly flowing the ink in the pressure chamber where the ejection port is arranged. The method of spilling is known. However, if the variation in the circulation flow rate of the ink flowing in each pressure chamber becomes large or the variation in the pressure in each pressure chamber becomes large, there is a problem that the difference in ejection characteristics and colorant concentration between the ejection ports becomes large. was there. In response to this problem, Patent Document 1 describes the flow path resistance of the pressure chamber, the flow path resistance of the flow path for supplying ink to the pressure chamber, and the flow path of the flow path for discharging ink from the pressure chamber. A method of keeping the resistance at 1/100 or less is described.

Japanese Unexamined Patent Publication No. 2009-179049

However, in order to arrange a plurality of discharge ports at high density, if the number of discharge ports constituting the discharge port rows is increased or the distance between the discharge port rows is narrowed, there is a problem in the method of Patent Document 1. I found a certain point. That is, it has been found that it may be difficult to suppress the variation in the circulation flow rate of the ink flowing in each pressure chamber and the variation in the pressure in each pressure chamber. As the number of discharge ports forming the discharge port row increases, the distribution of discharge ports in the row direction of the discharge port row (the direction in which the discharge ports are arranged) becomes wider. Therefore, variations in the circulation flow rate of ink flowing in each pressure chamber and variations in pressure in each pressure chamber are likely to occur among a plurality of pressure chambers arranged in the row direction of the discharge port row. Further, when a plurality of discharge port rows are arranged at high density, the width of the flow path extending in the row direction of the discharge port rows (the length in the direction in which the plurality of discharge port rows are lined up) in relation to the adjacent flow paths. It becomes difficult to increase. Therefore, the influence of the pressure loss becomes large, and the circulation flow rate of the ink flowing in each pressure chamber and the pressure of each pressure chamber may vary among a plurality of pressure chambers arranged in the row direction of the discharge port row. be.

Therefore, in view of the above problems, it is an object of the present invention to suppress variations in the circulation flow rate and pressure of the liquid flowing in the flow path of the liquid discharge head in which a plurality of discharge ports are arranged at high density.

In the liquid discharge head of the present invention, a pressure at which a row of discharge ports in which a plurality of discharge ports for discharging liquid are arranged in the first direction and a recording element for generating energy used for discharging the liquid are arranged. A chamber, a flow path communicating with the pressure chamber, and a plurality of supply ports extending in a second direction intersecting the surface on which the recording element is arranged to supply a liquid to the flow path are provided. A row of supply ports arranged along the first direction and a plurality of collection ports extending in the second direction for collecting the liquid in the flow path are provided along the first direction. A collection port row to be arranged, a first common supply flow path extending in the first direction to supply liquid to the supply port row, and a liquid extending from the collection port row extending in the first direction. The first common recovery flow path to be collected, the first communication port on the supply side extending in the second direction and supplying the liquid to the first common supply flow path, and the first communication channel extending in the second direction. (1) A collection-side first communication port for collecting liquid from a common recovery flow path is provided, and at least one of the supply-side first communication port and the recovery-side first communication port is provided.

According to the present invention, it is possible to suppress variations in the circulating flow rate and pressure of the liquid flowing in the liquid discharge head.

It is a figure which showed the schematic structure of the liquid discharge device which discharges a liquid. It is a schematic diagram which shows the 1st circulation form of the circulation path applied to a recording apparatus. It is a schematic diagram which shows the 2nd circulation form of the circulation path applied to a recording apparatus. It is the schematic which showed the difference of the inflow amount of ink to a liquid ejection head. It is a perspective view which showed the liquid discharge head. It is an exploded perspective view which showed each component or unit which constitutes a liquid discharge head. It is a figure which showed the front surface and the back surface of each flow path member of the 1st to 3rd flow path members. FIG. 7 is a perspective view shown from the surface on which the discharge module of the α portion of FIG. 7A is mounted. It is a figure which showed the cross section in IX-IX of FIG. It is a perspective view and the exploded view which showed one discharge module. It is a figure which showed the recording element substrate. It is a perspective view which shows the cross section of a recording element substrate and a lid member. It is a top view which shows the adjacent part of the recording element substrate partially enlarged. It is a perspective view which showed the liquid discharge head. It is a perspective exploded view which showed the liquid discharge head. It is a figure which showed the 1st flow path member. It is a perspective view which showed the connection relationship of the liquid between a recording element substrate and a flow path member. It is a figure which showed the cross section in XVIII-XVIII of FIG. It is a perspective view and the exploded view which showed one discharge module. It is a schematic diagram which shows the recording element substrate. It is a figure which showed the inkjet recording apparatus which discharges a liquid and records. It is an exploded view of the main part of the liquid discharge head in the 1st Embodiment of this invention. It is an exploded view which cut out a part of the liquid discharge head in 1st Embodiment. It is sectional drawing which cut out a part of the liquid discharge head in 1st Embodiment. It is an equivalent circuit diagram which cut out a part of the liquid discharge head in 1st Embodiment. It is the equivalent circuit diagram which cut out a part of the liquid discharge head in 1st Embodiment, and is the figure explaining the pressure distribution in a flow path. It is a top view of the recording element substrate in 1st Embodiment. It is a top surface transmission view of a part of the liquid discharge head in the first embodiment. It is an exploded view of the main part of the liquid discharge head in the 2nd Embodiment of this invention. It is a top view of the recording element substrate in the 2nd Embodiment. It is a top surface transmission view of a part of the liquid discharge head in the second embodiment. It is a figure explaining the variation of the circulation flow rate in the 2nd Embodiment. It is an exploded view of the main part of the liquid discharge head in the 3rd Embodiment of this invention. It is an exploded view of the main part of the liquid discharge head in 4th Embodiment of this invention. It is an overall view of the liquid discharge head to which this invention is applied. It is a conceptual diagram explaining one example of the ink supply system of this invention. It is a figure explaining the influence of the variation of the flow rate of the ink circulation flow. It is a figure which shows an example of the manufacturing process of the liquid discharge head of this invention. It is a figure explaining the temperature distribution of the recording element substrate in 2nd Embodiment. It is the schematic explanatory drawing of the liquid discharge device in application example 1. FIG. It is a figure explaining the 3rd circulation form. It is a figure explaining the liquid discharge head in application example 1. FIG. It is a figure explaining the liquid discharge head in application example 1. FIG. It is a figure explaining the liquid discharge head in application example 1. FIG. It is the schematic explanatory drawing of the liquid discharge device in application example 3. It is a figure explaining the 4th circulation form. It is a figure explaining the liquid discharge head in application example 3. It is a figure explaining the liquid discharge head in application example 3.

Hereinafter, the liquid discharge head and the liquid discharge device according to the embodiment of the present invention will be described with reference to the drawings.

The liquid discharge head and the liquid discharge device of the present invention may be used in devices such as printers, copiers, facsimiles having a communication system, word processors having a printer unit, and industrial recording devices combined with various processing devices. Applicable. The liquid discharge head and liquid discharge device of the present invention can also be used, for example, in applications such as biochip fabrication and electronic circuit printing.

Further, since each application example and each embodiment described below are appropriate specific examples of the present invention, various technically preferable restrictions are attached. However, the present embodiment is not limited to the embodiment of the present specification and other specific methods as long as it is in line with the idea of the present invention.

Hereinafter, each application example to which the present invention can be applied will be described.

(Application example 1)
(Explanation of inkjet recording device)
FIG. 1 is a diagram showing a schematic configuration of a liquid ejection device of the present invention, particularly an inkjet recording apparatus (hereinafter, also referred to as a recording apparatus) 1000 that ejects ink to perform recording. The recording device 1000 includes a transport unit 1 for transporting the recording medium 2 and a line-type (page-wide type) liquid discharge head 3 arranged substantially orthogonal to the transport direction of the recording medium 2, and a plurality of recording media. This is a line-type recording device that continuously or intermittently conveys 2 and continuously records in one pass. The liquid discharge head 3 supplies and discharges ink to the negative pressure control unit 230 that controls the pressure (negative pressure) in the circulation path, the liquid supply unit 220 that communicates with the negative pressure control unit 230, and the liquid supply unit 220. A liquid connecting portion 111 serving as an outlet and a housing 80 are provided. The recording medium 2 is not limited to cut paper, and may be a continuous roll medium. The liquid discharge head 3 is capable of full-color recording with cyan C, magenta M, yellow Y, and black K inks, and is a liquid supply means, a main tank, and a buffer tank which are supply channels for supplying the liquid to the liquid discharge head 3. (See FIG. 2 below) are fluidly connected. Further, an electric control unit that transmits electric power and a discharge control signal to the liquid discharge head 3 is electrically connected to the liquid discharge head 3. The liquid path and the electric signal path in the liquid discharge head 3 will be described later.

The recording device 1000 is an inkjet recording device in a form in which a liquid such as ink is circulated between a tank described later and a liquid discharge head 3. The circulation form is a first circulation form in which two circulation pumps (for high pressure and low pressure) are moved on the downstream side of the liquid discharge head 3 and two circulation pumps on the upstream side of the liquid discharge head 3. There is a second circulation mode in which circulation is performed by moving (for high pressure and low pressure). Hereinafter, the first circulation form and the second circulation form of this circulation will be described.

(Explanation of the first circulation form)
FIG. 2 is a schematic diagram showing a first circulation mode of a circulation path applied to the recording device 1000 of this application example. The liquid discharge head 3 is fluidly connected to the first circulation pump (high pressure side) 1001, the first circulation pump (low pressure side) 1002, the buffer tank 1003, and the like. In FIG. 2, for simplification of the explanation, only the path through which one color of the cyan C, magenta M, yellow Y, and black K inks flows is shown, but in reality, four colors are shown. Circulation paths are provided in the liquid discharge head 3 and the recording device main body.

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

The buffer tank 1003, which is a sub tank, is connected to the main tank 1006 and has an air communication port (not shown) that communicates the inside and the outside of the tank, so that air bubbles in the ink can be discharged to the outside. A replenishment pump 1005 is provided between the buffer tank 1003 and the main tank 1006. The replenishment pump 1005 transfers the ink consumed by ejecting (discharging) the ink from the ejection port of the liquid ejection head 3 from the main tank 1006 to the buffer tank 1003, such as recording by ejecting the ink and recovering suction.

The two first circulation pumps 1001 and 1002 draw liquid from the liquid connection portion 111 of the liquid discharge head 3 and flow it into the buffer tank 1003. As the first circulation pump, a positive displacement pump having a quantitative liquid feeding capacity is preferable. Specific examples thereof include a tube pump, a gear pump, a diaphragm pump, a syringe pump, and the like. For example, a general constant flow rate valve or relief valve may be arranged at the pump outlet to secure a constant flow rate. When the liquid discharge head 3 is driven, the first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) 1002 are operated so that the common supply flow path 211 and the common recovery flow path 212 have a predetermined flow rate, respectively. Ink flows. By flowing the ink in this way, the temperature of the liquid ejection head 3 at the time of recording is maintained at the optimum temperature. The predetermined flow rate when the liquid discharge head 3 is driven is preferably set to a flow rate that can be maintained to such an extent that the temperature difference between the recording element substrates 10 in the liquid discharge head 3 does not affect the recording image quality. However, if the flow rate is set too large, the negative pressure difference between the recording element substrates 10 becomes large due to the influence of the pressure loss of the flow path in the liquid discharge unit 300, and the density unevenness of the image occurs. Therefore, it is preferable to set the flow rate while considering the temperature difference and the negative pressure difference between the recording element substrates 10.

The negative pressure control unit 230 is provided in the path between the second circulation pump 1004 and the liquid discharge unit 300. This negative pressure control unit 230 keeps the pressure on the downstream side (that is, the liquid discharge unit 300 side) of the negative pressure control unit 230 even when the flow rate of ink in the circulation system fluctuates due to the difference in the discharge amount per unit area or the like. It operates to maintain a preset constant pressure. As the two negative pressure control mechanisms constituting the negative pressure control unit 230, if the pressure downstream of the negative pressure control unit 230 can be controlled within a certain range around a desired set pressure, as long as it can be controlled. Any mechanism may be used. As an example, a mechanism similar to a so-called "decompression regulator" can be adopted. In the circulation flow path in this application example, the upstream side of the negative pressure control unit 230 is pressurized by the second circulation pump 1004 via the liquid supply unit 220. By doing so, the influence of the head pressure on the liquid discharge head 3 of the buffer tank 1003 can be suppressed, so that the degree of freedom in the layout of the buffer tank 1003 in the recording device 1000 can be expanded.

The second circulation pump 1004 may be a pump having a lift pressure equal to or higher than a certain pressure within the range of the ink circulation flow rate used when driving the liquid discharge head 3, and a turbo type pump, a positive displacement pump, or the like can be used. Specifically, a diaphragm pump or the like can be applied. Further, instead of the second circulation pump 1004, for example, a head tank arranged with a certain head difference with respect to the negative pressure control unit 230 can also be applied. As shown in FIG. 2, the negative pressure control unit 230 includes two negative pressure adjusting mechanisms in which different control pressures are set. Of the two negative pressure adjustment mechanisms, the relatively high pressure setting side (denoted as H in FIG. 2) and the relatively low pressure setting side (denoted as L in FIG. 2) pass through the inside of the liquid supply unit 220, respectively. Therefore, it is connected to the common supply flow path 211 and the common recovery flow path 212 in the liquid discharge unit 300. The liquid discharge unit 300 is provided with a common supply flow path 211, a common recovery flow path 212, and an individual flow path 215 (individual supply flow path 213, individual recovery flow path 214) communicating with each recording element substrate. A negative pressure control mechanism H is connected to the common supply flow path 211, and a negative pressure control mechanism L is connected to the common recovery flow path 212, and a differential pressure is generated between the two common flow paths. Since the individual flow path 215 communicates with the common supply flow path 211 and the common recovery flow path 212, a part of the liquid passes through the internal flow path of the recording element substrate 10 from the common supply flow path 211. A flow (arrow in FIG. 2) flowing into the common recovery flow path 212 is generated.

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, respectively. A flow occurs. Therefore, the heat generated in each recording element substrate 10 can be discharged to the outside of the recording element substrate 10 by the ink flowing through the common supply flow path 211 and the common recovery flow path 212. Further, with such a configuration, when recording is performed by the liquid discharge head 3, it is possible to generate an ink flow even in a discharge port or a pressure chamber where the liquid is not discharged. As a result, the thickening of the ink can be suppressed by reducing the viscosity of the thickened ink in the ejection port. In addition, the thickened ink and foreign matter in the ink can be discharged to the common recovery flow path 212. Therefore, the liquid discharge head 3 of this application example enables high-speed and high-quality recording.

(Explanation of the second circulation form)
FIG. 3 is a schematic diagram showing a second circulation mode, which is a circulation mode different from the first circulation mode described above, among the circulation paths applied to the recording device of this application example. The main difference from the first circulation mode described above is that the two negative pressure control mechanisms constituting the negative pressure control unit 230 both set the pressure on the upstream side of the negative pressure control unit 230 at the desired set pressure. It is a point to control by fluctuation within a certain range. Further, the difference from the first circulation mode is that the second circulation pump 1004 acts as a negative pressure source for reducing the pressure on the downstream side of the negative pressure control unit 230. Further, the first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) 1002 are arranged on the upstream side of the liquid discharge head 3, and the negative pressure control unit 230 is arranged on the downstream side of the liquid discharge head 3. There is also a difference.

In the second circulation mode, the ink in the main tank 1006 is supplied to the buffer tank 1003 by the replenishment pump 1005. After that, the ink is divided into two flow paths, and the ink is circulated in the two flow paths on the high pressure side and the low pressure side by the action of the negative pressure control unit 230 provided in the liquid discharge head 3. The ink divided into the two flow paths of the high pressure side and the low pressure side is the liquid discharge head 3 via the liquid connection portion 111 by the action of the first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) 1002. Is supplied to. After that, the ink circulated in the liquid discharge head by the action of the first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) 1002 passes through the negative pressure control unit 230 and the liquid via the liquid connection portion 111. It is discharged from the discharge head 3. The discharged ink is returned to the buffer tank 1003 by the second circulation pump 1004.

In the second circulation mode, the negative pressure control unit 230 has a pressure fluctuation on the upstream side (that is, the liquid discharge unit 300 side) of the negative pressure control unit 230 even if there is a fluctuation in the flow rate caused by a change in the discharge amount per unit area or the like. Is stabilized within a certain range around a preset pressure. In the circulation flow path of this application example, the downstream side of the negative pressure control unit 230 is pressurized by the second circulation pump 1004 via the liquid supply unit 220. In this way, the influence of the head pressure of the buffer tank 1003 on the liquid discharge head 3 can be suppressed, so that the layout selection range of the buffer tank 1003 in the recording device 1000 can be widened. Instead of the second circulation pump 1004, for example, a head tank arranged with a predetermined head difference with respect to the negative pressure control unit 230 can be applied. The second circulation mode is the same as the first circulation mode, and the negative pressure control unit 230 includes two negative pressure control mechanisms in which control pressures different from each other are set. Of the two negative pressure adjusting mechanisms, the high pressure setting side (denoted as H in FIG. 3) and the low pressure setting side (denoted as L in FIG. 3) pass through the liquid supply unit 220 and enter the liquid discharge unit 300, respectively. It is connected to the common supply flow path 211 or the common recovery flow path 212. By making the pressure of the common supply flow path 211 relatively higher than the pressure of the common recovery flow path 212 by the two negative pressure adjusting mechanisms, the individual flow path 215 and the inside of each recording element substrate 10 are formed from the common supply flow path 211. A flow of liquid is generated through the flow path to the common recovery flow path 212.

In such a second circulation mode, the same liquid flow state as in the first circulation mode can be obtained in the liquid discharge unit 300, but there are two advantages different from those in the first circulation mode. 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 matter generated from the negative pressure control unit 230 flow into the liquid discharge head 3. There is little concern about doing so. 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 case of the first circulation mode. The reason is as follows.

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

FIG. 4 is a schematic view showing the difference in the amount of ink flowing into the liquid ejection head 3 between the first circulation mode and the second circulation mode. FIG. 4 (a) shows the standby time in the first circulation mode, and FIG. 4 (b) shows the total discharge time in the first circulation mode. 4 (c) to 4 (f) show the second circulation flow path, and when the flow rates F <flow rate A are shown in FIGS. 4 (c) and 4 (d), FIGS. 4 (e) and 4 (f). ) Is the case where the flow rate F> the flow rate A, and indicates the flow rates during standby and during full discharge, respectively.

In the case of the first circulation mode in which the first circulation pump 1001 and the first circulation pump 1002 having a quantitative liquid feeding capacity are arranged on the downstream side of the liquid discharge head 3 (FIGS. 4A and 4B). The total set flow rate of the first circulation pump 1001 and the first circulation pump 1002 is the flow rate A. With this flow rate A, it is possible to control the temperature inside the liquid discharge unit 300 during standby. When the liquid discharge head 3 is used for full discharge, the total set flow rates of the first circulation pump 1001 and the first circulation pump 1002 remain at the flow rate A. However, the maximum flow rate supplied to the liquid discharge head 3 is affected by the negative pressure generated by the discharge at the liquid discharge head 3, and the flow rate F for the total discharge is added to the flow rate A of the total set flow rate. Therefore, the maximum value of the supply amount to the liquid discharge head 3 is the flow rate A + the flow rate F because the flow rate F is added to the flow rate A (FIG. 4B).

On the other hand, in the case of the second circulation mode in which the first circulation pump 1001 and the first circulation pump 1002 are arranged on the upstream side of the liquid discharge head 3 (FIGS. 4 (c) to 4 (f)), recording standby is performed. The amount of supply to the liquid discharge head 3 that is sometimes required is the flow rate A as in the first circulation mode. Therefore, in the second circulation mode in which the first circulation pump 1001 and the first circulation pump 1002 are arranged on the upstream side of the liquid discharge head 3, the flow rate A is larger than the flow rate F (FIGS. 4C and 4d). )), The flow rate A is sufficient for the supply amount to the liquid discharge head 3 even at the time of full discharge. At that time, the discharge flow rate from the liquid discharge head 3 becomes the flow rate A − the flow rate F (FIG. 4 (d)). However, when the flow rate F is larger than the flow rate A (FIGS. 4 (e) and 4 (f)), if the supply flow rate to the liquid discharge head 3 is set to the flow rate A at the time of full discharge, the flow rate becomes insufficient. Therefore, when the flow rate F is larger than the flow rate A, it is necessary to set the supply amount to the liquid discharge head 3 as the flow rate F. At that time, when all the discharges are performed, the liquid discharge head 3 consumes the flow rate F, so that the discharge flow rate from the liquid discharge head 3 is hardly discharged (FIG. 4 (f)). When the flow rate F is larger than the flow rate A and the discharge is performed but not all discharges, the amount obtained by subtracting the amount consumed by the discharge from the flow rate F is discharged from the liquid discharge head 3. Further, when the flow rate A and the flow rate F are equal, the flow rate A (or the flow rate F) is supplied to the liquid discharge head 3, and the flow rate F is consumed by the liquid discharge head 3, so that the liquid discharge head 3 consumes the flow rate F. The discharge flow rate of is almost not discharged.

As described above, in the case of the second circulation mode, the total value of the set flow rates of the first circulation pump 1001 and the first circulation pump 1002, that is, the maximum value of the required supply flow rate is the larger value of the flow rate A or the flow rate F. .. Therefore, as long as the liquid discharge unit 300 having the same configuration is used, the maximum value of the required supply amount (flow rate A or flow rate F) in the second circulation mode is the maximum value of the required supply flow rate (flow rate A + flow rate) in the first circulation mode. It is smaller than F).

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 can be used, or a load of a cooler (not shown) installed in the main body side path can be applied. There is an advantage that it can be reduced and the cost of the recording device can be reduced. This advantage increases as the value of the flow rate A or the flow rate F becomes relatively large, and is more beneficial for the line head having a longer length in the longitudinal direction.

However, on the other hand, there is also a point that the first circulation form is more advantageous than the second circulation form. That is, in the second circulation mode, since the flow rate flowing through the liquid discharge unit 300 during the recording standby is the maximum, the smaller the discharge amount per unit area (hereinafter, also referred to as a low Duty image), the more the discharge port has. A high negative pressure is applied. For this reason, when the flow path width is narrow and the negative pressure is high, a high negative pressure is applied to the ejection port in a low Duty image in which unevenness is easily visible, so that many so-called satellite droplets are ejected along with the main droplet of ink. It may occur and the recording quality may deteriorate.

On the other hand, in the case of the first circulation mode, a high negative pressure is applied to the discharge port when an image having a large discharge amount per unit area (hereinafter, also referred to as a high duty image) is formed, so that satellite droplets are tentatively generated. However, it has the advantage that it is difficult to see and the effect on the image is small. The selection of these two circulation modes can be made in light of the specifications of the liquid discharge head and the recording device main body (discharge flow rate F, minimum circulation flow rate A, and flow path resistance in the head).

(Explanation of the third circulation form)
FIG. 41 is a schematic diagram showing a third circulation form, which is one form of the circulation path applied to the recording device of the present embodiment. The same functions and configurations as those of the first and second circulation modes will be omitted, and the differences will be mainly described.

In this circulation mode, the liquid is supplied into the liquid discharge head 3 from two places in the center of the liquid discharge head 3 and a total of three places on one end side of the liquid discharge head 3. The liquid is collected from the common supply flow path 211 through each pressure chamber 23 and then into the common recovery flow path 212, and is collected to the outside through the recovery opening at the other end of the liquid discharge head 3. The individual flow path 213 communicates with the common supply flow path 211 and the common recovery flow path 212, and a recording element substrate 10 and a pressure chamber 23 arranged in the recording element substrate are provided in the path of each individual flow path 213. Has been done. Therefore, a part of the liquid flowing by the first circulation pump 1002 passes through the pressure chamber 23 of the recording element substrate 10 from the supply flow path 211 and flows to the common recovery flow path 212 (arrow in FIG. 41). This is because a pressure difference is provided between the pressure adjusting mechanism H connected to the common supply flow path 211 and the pressure adjusting mechanism L connected to the common recovery flow path 212, and the first circulation pump 1002 is used for the common recovery flow. This is because it is connected only to the road 212.

In this way, in the liquid discharge unit 300, the liquid flow that passes through the common recovery flow path 212 and the common recovery flow path that passes through the pressure chamber 23 in each recording element substrate 10 from the common supply flow path 211. A flow occurs at 212. Therefore, the 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 flow path 211 to the common recovery flow path 212 while suppressing the increase in pressure loss. Further, according to this circulation path, it is possible to reduce the number of pumps, which are means for transporting liquid, as compared with the first and second circulation paths.

(Explanation of liquid discharge head configuration)
The configuration of the liquid discharge head 3 according to Application Example 1 will be described. 5 (a) and 5 (b) are perspective views showing the liquid discharge head 3 according to this application example. In the liquid ejection head 3, 15 recording element substrates 10 capable of ejecting four color inks of cyan C / magenta M / yellow Y / black K on one recording element substrate 10 are arranged in a straight line (arranged in-line). This is a line-type liquid discharge head.

As shown in FIG. 5A, the liquid discharge head 3 has each recording element board 10, a signal input terminal 91 and a power supply terminal 92 electrically connected via the flexible wiring board 40 and the electric wiring board 90. Be prepared. The signal input terminal 91 and the power supply terminal 92 are electrically connected to the control unit of the recording device 1000, and supply the discharge drive signal and the power required for discharge to the recording element substrate 10, respectively. By consolidating the wiring by the electric circuit in the electric wiring board 90, the number of signal input terminals 91 and power supply terminals 92 can be reduced as compared with the number of recording element boards 10. As a result, the number of electrical connections that need to be removed when assembling the liquid discharge head 3 to the recording device 1000 or when replacing the liquid discharge head can be reduced.

As shown in FIG. 5B, the liquid connection portions 111 provided at both ends of the liquid discharge head 3 are connected to the liquid supply system of the recording device 1000. As a result, cyan C / magenta M / yellow Y / black K4 color ink is supplied from the supply system of the recording device 1000 to the liquid ejection head 3, and the ink that has passed through the liquid ejection head 3 is supplied to the supply system of the recording device 1000. It is supposed to be collected. In this way, the inks of each color can be circulated through the path of the recording device 1000 and the path of the liquid ejection head 3.

FIG. 6 is an exploded perspective view showing each component or unit constituting the liquid discharge head 3. The liquid discharge unit 300, the liquid supply unit 220, and the electrical wiring board 90 are attached to the housing 80. The liquid supply unit 220 is provided with a liquid connection portion 111 (see FIG. 3), and the inside of the liquid supply unit 220 communicates with each opening of the liquid connection portion 111 in order to remove foreign substances in the supplied ink. Filters 221 for each color (see FIGS. 2 and 3) are provided. The two liquid supply units 220 are each provided with a filter 221 for two colors. The liquid that has passed through the filter 221 is supplied to the negative pressure control unit 230 arranged on the liquid supply unit 220 corresponding to each color. The negative pressure control unit 230 is a unit composed of negative pressure control valves for each color, and is provided in the supply system of the recording device 1000, which is generated by the action of valves and spring members provided inside the negative pressure control unit 230 as the liquid flow rate fluctuates. The pressure loss change of (the supply system on the upstream side of the liquid discharge head 3) is greatly attenuated. As a result, the negative pressure control unit 230 can stabilize the negative pressure change on the downstream side (liquid discharge unit 300 side) of the negative pressure control unit within a certain range. As described with reference to FIG. 2, two negative pressure control valves for each color are built in the negative pressure control unit 230 for each color. The two negative pressure control valves are set to different control pressures, and the high pressure side is the common supply flow path 211 (see FIG. 2) in the liquid discharge unit 300, and the low pressure side is the common recovery flow path 212 (see FIG. 2) and the liquid supply. It communicates through the unit 220.

The housing 80 is composed of a liquid discharge unit support portion 81 and an electric wiring board support portion 82, supports the liquid discharge unit 300 and the electric wiring board 90, and secures the rigidity of the liquid discharge head 3. The electric wiring board support portion 82 is for supporting the electric wiring board 90, and is fixed to the liquid discharge unit support portion 81 by screwing. The liquid discharge unit support portion 81 has a role of correcting the warp and deformation of the liquid discharge unit 300 to ensure the relative position accuracy of the plurality of recording element substrates 10, thereby suppressing streaks and unevenness in the recorded material. .. Therefore, the liquid discharge unit support portion 81 preferably has sufficient rigidity, and as the material, a metal material such as SUS or aluminum, or a ceramic such as alumina is preferable. The liquid discharge unit support portion 81 is provided with openings 83 and 84 into which the joint rubber 100 is inserted. The liquid supplied from the liquid supply unit 220 is guided to the third flow path member 70 constituting the liquid discharge unit 300 via the joint rubber.

The liquid discharge unit 300 includes a plurality of discharge modules 200 and a flow path member 210, and a cover member 130 is attached to the surface of the liquid discharge unit 300 on the recording medium side. Here, the cover member 130 is a member having a frame-like surface provided with a long opening 131 as shown in FIG. 6, and the recording element substrate 10 and the sealing included in the discharge module 200 are sealed from the opening 131. The stop member 110 (see FIG. 10 described later) is exposed. The frame portion around the opening 131 has a function as a contact surface of a cap member that caps the liquid discharge head 3 during recording standby. Therefore, an adhesive, a sealing material, a filler, or the like is applied along the periphery of the opening 131 to fill the irregularities and gaps on the discharge port surface of the liquid discharge unit 300, so that a closed space is formed at the time of capping. It is preferable to do so.

Next, the configuration of the flow path member 210 included in the liquid discharge unit 300 will be described. As shown in FIG. 6, the flow path member 210 is a stack of the first flow path member 50, the second flow path member 60, and the third flow path member 70, and the liquid supplied from the liquid supply unit 220 is supplied. Distribute to each discharge module 200. Further, the flow path member 210 is a flow path member for returning the liquid recirculated from the discharge module 200 to the liquid supply unit 220. The flow path member 210 is fixed to the liquid discharge unit support portion 81 with screws, whereby warpage and deformation of the flow path member 210 are suppressed.

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

The first to third flow path members are preferably made of a material having corrosion resistance to liquid and having a low coefficient of linear expansion. As the material, for example, alumina can be used. Further, a composite material (resin material) using LCP (liquid crystal polymer), PPS (polyphenyl sulfide), PSF (polysulfone) or modified PPE (polyphenylene ether) as a base material and adding an inorganic filler such as silica fine particles or fibers is preferable. Can be used. As a method for forming the flow path member 210, three flow path members may be laminated and bonded to each other, or when a resin composite resin material is selected as the material, a joining method by welding may be used.

FIG. 8 shows the α portion of FIG. 7A, and the flow path in the flow path member 210 formed by joining the first to third flow path members is the flow path of the first flow path member 50. It is a perspective view showing a part enlarged from the surface side on which the discharge module 200 is mounted. In the common supply flow path 211 and the common recovery flow path 212, the common supply flow path 211 and the common recovery flow path 212 are alternately arranged from the flow paths at both ends. Here, the connection relationship of each flow path in the flow path member 210 will be described.

The flow path member 210 is provided with a common supply flow path 211 (211a, 211b, 211c, 211d) and a common recovery flow path 212 (212a, 212b, 212c, 212d) extending in the longitudinal direction of the liquid discharge head 3 for each color. Has been done. A plurality of individual supply flow paths 213 (213a, 213b, 213c, 213d) formed by the individual flow path grooves 52 are connected to the common supply flow path 211 of each color via a communication port 61. Further, a plurality of individual recovery channels 214 (214a, 214b, 214c, 214d) formed by the individual channel grooves 52 are connected to the common recovery channel 212 of each color via a communication port 61. With such a flow path configuration, ink can be concentrated on the recording element substrate 10 located at the center of the flow path member from each common supply flow path 211 via the individual supply flow path 213. Ink can be recovered from the recording element substrate 10 to each common recovery flow path 212 via the individual recovery flow path 214.

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

Here, the common supply flow path 211 of each color is connected to the negative pressure control unit 230 (high pressure side) of the corresponding color via the liquid supply unit 220, and the common recovery flow path 212 is the negative pressure control unit 230. It is connected to (low pressure side) via a liquid supply unit 220. The negative pressure control unit 230 creates a differential pressure (pressure difference) between the common supply flow path 211 and the common recovery flow path 212. Therefore, as shown in FIGS. 8 and 9, in the liquid discharge head of the present application example in which each flow path is connected, the common supply flow path 211 to the individual supply flow path 213 to the recording element substrate 10 to each color are individually used. A flow is generated in order from the recovery flow path 214 to the common recovery flow path 212.

(Explanation of discharge module)
FIG. 10A is a perspective view showing one discharge module 200, and FIG. 10B is an exploded view thereof. As a method of manufacturing the discharge module 200, first, the recording element substrate 10 and the flexible wiring substrate 40 are adhered to a support member 30 provided with a liquid communication port 31 in advance. After that, the terminal 16 on the recording element substrate 10 and the terminal 41 on the flexible wiring board 40 are electrically connected by wire bonding, and then the wire bonding portion (electrical connection portion) is covered with the sealing member 110 and sealed. .. The terminal 42 on the side of the flexible wiring board 40 opposite to the recording element board 10 is electrically connected to the connection terminal 93 (see FIG. 6) of the electrical wiring board 90. Since the support member 30 is a support that supports the recording element substrate 10 and is a flow path member that fluidly communicates the recording element substrate 10 and the flow path member 210, the flatness is high and sufficiently high. Those that can be reliably bonded to the recording element substrate are preferable. As the material, for example, alumina or a resin material is preferable.

(Explanation of the structure of the recording element substrate)
FIG. 11A shows a plan view of the surface of the recording element substrate 10 on the side where the discharge port 13 is formed, and FIG. 11B shows an enlarged view of the portion shown by A in FIG. 11A. 11 (c) shows a plan view of the back surface of FIG. 11 (a). Here, the configuration of the recording element substrate 10 in this application example will be described. As shown in FIG. 11A, the ejection port forming member 12 of the recording element substrate 10 is formed with four rows of ejection ports corresponding to each ink color. Hereinafter, the direction in which the discharge port row in which the plurality of discharge ports 13 are arranged extends is referred to as the "row direction of the discharge port row". As shown in FIG. 11B, a recording element 15 which is a heat generating element for foaming a liquid by heat energy is arranged at a position corresponding to each discharge port 13. The partition wall 22 partitions the pressure chamber 23 including the recording element 15 inside. The recording element 15 is electrically connected to the terminal 16 by an electric wiring (not shown) provided on the recording element substrate 10. Then, the recording element 15 generates heat based on a pulse signal input from the control circuit of the recording device 1000 via the electric wiring board 90 (see FIG. 6) and the flexible wiring board 40 (see FIG. 10) to boil the liquid. Let me. The liquid is discharged from the discharge port 13 by the force of foaming due to this boiling. As shown in FIG. 11B, a liquid supply flow path 18 extends on one side and a liquid recovery flow path 19 extends on the other side along each discharge port row. The liquid supply flow path 18 and the liquid recovery flow path 19 are flow paths extending in the row direction of the discharge port rows provided on the recording element substrate 10, and communicate with the discharge port 13 via the supply port 17a and the recovery port 17b, respectively. doing.

As shown in FIG. 11C, a sheet-shaped lid member 20 is laminated on the back surface of the surface of the recording element substrate 10 on which the discharge port 13 is formed, and the lid member 20 has a liquid supply flow path. A plurality of openings 21 communicating with the 18 and the liquid recovery flow path 19 are provided. In this application example, the lid member 20 is provided with three openings 21 for one liquid supply flow path 18 and two openings 21 for one liquid recovery flow path 19. As shown in FIG. 11B, each opening 21 of the lid member 20 communicates with the plurality of communication ports 51 shown in FIG. 7A. The lid member 20 preferably has sufficient corrosion resistance against a liquid, and from the viewpoint of preventing color mixing, the opening shape and opening position of the opening 21 are required to have high accuracy. Therefore, it is preferable to use a photosensitive resin material or a silicon plate as the material of the lid member 20 and to provide the opening 21 by a photolithography process. As described above, the lid member 20 changes the pitch of the flow path by the opening 21, and it is desirable that the lid member 20 is thin in consideration of the pressure loss, and it is desirable that the lid member 20 is made of a film-like member.

FIG. 12 is a perspective view showing a cross section of the recording element substrate 10 and the lid member 20 in XII-XII in FIG. 11A. Here, the flow of the liquid in the recording element substrate 10 will be described. The lid member 20 has a function as a lid that forms a part of the walls of the liquid supply flow path 18 and the liquid recovery flow path 19 formed on the substrate 11 of the recording element substrate 10. The recording element substrate 10 is formed by laminating a substrate 11 formed of Si and a discharge port forming member 12 formed of a photosensitive resin, and a lid member 20 is bonded to the back surface of the substrate 11. A recording element 15 is formed on one surface side of the substrate 11 (see FIG. 11), and on the back surface side thereof, a liquid supply flow path 19 and a liquid recovery flow path 18 extending along a discharge port row are formed. A groove is formed to form a structure. The liquid supply flow path 18 and the liquid recovery flow path 19 formed by the substrate 11 and the lid member 20 are connected to the common supply flow path 211 and the common recovery flow path 212 in the flow path member 210, respectively, and supply liquid. A differential pressure is generated between the flow path 18 and the liquid recovery flow path 19. When the liquid is discharged from the discharge port 13 and recorded, at the discharge port where the liquid is not discharged, the liquid in the liquid supply flow path 18 provided in the substrate 11 due to this differential pressure is discharged from the supply port 17a. , Flows into the liquid recovery flow path 19 via the pressure chamber 23 and the recovery port 17b (arrow C in FIG. 12). By this flow, in the discharge port 13 and the pressure chamber 23 where recording is suspended, thickening ink, bubbles, foreign substances and the like generated by evaporation from the discharge port 13 can be collected in the liquid recovery flow path 19. Further, it is possible to prevent the ink in the discharge port 13 and the pressure chamber 23 from thickening. The liquid collected in the liquid recovery flow path 19 is common to the communication port 51 in the flow path member 210 and the individual recovery flow path 214 through the opening 21 of the lid member 20 and the liquid communication port 31 (FIG. 10b) of the support member 30. It is collected in the order of the collection flow path 212, and is collected in the collection path of the recording device 1000. That is, the liquid supplied from the recording device main body to the liquid discharge head 3 flows in the following order, and is supplied and recovered.

The liquid first flows into the inside of the liquid discharge head 3 from the liquid connection portion 111 of the liquid supply unit 220. The liquid is the joint rubber 100, the communication port 72 and the common flow path groove 71 provided in the third flow path member, the common flow path groove 62 and the communication port 61 provided in the second flow path member, and the first flow path. It is supplied in the order of the individual flow path groove 52 and the communication port 51 provided in the member. After that, the liquid is supplied to the pressure chamber 23 through the liquid communication port 31 provided in the support member 30, the opening 21 provided in the lid member 20, the liquid supply flow path 18 provided in the substrate 11, and the supply port 17a in this order. .. Of the liquids supplied to the pressure chamber 23, the liquids not discharged from the discharge port 13 are the recovery port 17b provided on the substrate 11, the liquid recovery flow path 19, the opening 21 provided in the lid member 20, and the support member. The liquid communication port 31 provided in 30 flows in order. After that, the liquid is provided in the communication port 51 and the individual flow path groove 52 provided in the first flow path member, the communication port 61 and the common flow path groove 62 provided in the second flow path member, and the third flow path member 70. The common flow path groove 71, the communication port 72, and the joint rubber 100 flow in this order. Then, the liquid flows from the liquid connection portion 111 provided in the liquid supply unit 220 to the outside of the liquid discharge head 3.

In the first circulation mode shown in FIG. 2, the liquid flowing in from the liquid connection portion 111 is supplied to the joint rubber 100 after passing through the negative pressure control unit 230. Further, in the second circulation mode shown in FIG. 3, the liquid recovered from the pressure chamber 23 passes through the joint rubber 100 and then passes from the liquid connection portion 111 to the outside of the liquid discharge head via the negative pressure control unit 230. Flow to. Further, not all the liquid that has flowed in from one end of the common supply flow path 211 of the liquid discharge unit 300 is supplied to the pressure chamber 23 via the individual supply flow path 213a. That is, there is also a liquid that has flowed in from one end of the common supply flow path 211 and flows into the liquid supply unit 220 from the other end of the common supply flow path 211 without flowing into the individual supply flow path 213a. In this way, by providing the path for flowing without passing through the recording element substrate 10, even when the recording element substrate 10 having a fine flow path having a large flow resistance as in this application example is provided, the liquid is provided. It is possible to suppress the backflow of the circulating flow. As described above, in the liquid discharge head 3 of the present application example, the thickening of the liquid in the pressure chamber 23 and the vicinity of the discharge port can be suppressed, so that the discharge twist and non-discharge can be suppressed, and as a result, the discharge can be suppressed. High-quality recording can be performed.

(Explanation of positional relationship between recording element substrates)
FIG. 13 is a plan view showing a partially enlarged view of an adjacent portion of the recording element substrate in two adjacent discharge modules. In this application example, a substantially parallelogram recording element substrate is used. The discharge port rows (14a to 14d) in which the discharge ports 13 of the recording element substrates 10 are arranged are arranged so as to be inclined at a constant angle with respect to the longitudinal direction of the liquid discharge head 3. Then, in the discharge port row in the adjacent portion between the recording element substrates 10, at least one discharge port overlaps in the transport direction of the recording medium. In FIG. 13, the two discharge ports on the line D overlap each other. With such an arrangement, even if the position of the recording element substrate 10 deviates slightly from the predetermined position, black streaks and white spots in the recorded image can be made inconspicuous by the drive control of the overlapping discharge ports. Even when a plurality of recording element substrates 10 are arranged in a straight line (in-line) instead of in a staggered arrangement, the recording element is suppressed from increasing in length in the transport direction of the recording medium of the liquid discharge head 10 by the configuration as shown in FIG. It is possible to take measures against black streaks and white spots at the joints between the substrates 10. In this application example, the main plane of the recording element substrate is a parallelogram, but the present invention is not limited to this, and the configuration of the present invention is preferable even when a recording element substrate having a rectangular shape, a trapezoidal shape, or another shape is used. Can be applied.

(Explanation of a modified example of the liquid discharge head configuration)
A modified example of the configuration of the liquid discharge head will be described with reference to FIGS. 40 and 42 to 44. The same configuration and function as the above-mentioned example will be omitted, and the differences will be mainly described. In this modification, as shown in FIGS. 40 and 42, the plurality of liquid connection portions 111, which are the liquid connection portions between the liquid discharge head 3 and the outside, are integrated on one end side in the longitudinal direction of the liquid discharge head. Have been placed. A plurality of negative pressure control units 230 are collectively arranged on the other end side of the liquid discharge head 3 (FIG. 43). 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 includes a flow path and a filter 221 corresponding to the four colors of liquid to be supplied. Further, as shown in FIG. 43, the openings 83 to 86 provided in the liquid discharge unit support portion 81 are provided at positions different from those of the liquid discharge head 3 described above.

FIG. 44 shows the laminated state of the flow path members 50, 60, and 70. A plurality of recording element substrates 10 are linearly arranged on the upper surface of the flow path member 50, which is the uppermost layer of the plurality of flow path members 50, 60, 70. The flow path communicating with the opening 21 (FIG. 19) formed on the back surface side of each recording element substrate 10 has two individual supply flow paths 213 and one individual recovery flow path 214 for each color of the liquid. There is. Correspondingly, the openings 21 formed in the lid member 20 provided on the back surface of the recording element substrate 10 also have two supply openings 21 and one recovery opening 21 for each color of the liquid. As shown in FIG. 44, the common supply flow path 211 and the common recovery flow path 212 extending along the longitudinal direction of the liquid discharge head 3 are alternately arranged in parallel.

(Application example 2)
Hereinafter, the configurations of the inkjet recording apparatus 2000 and the liquid discharge head 2003 according to the second application example of the present invention will be described with reference to the drawings. In the following description, only the parts different from the application example 1 will be mainly described, and the description of the parts similar to the application example 1 will be omitted.

(Explanation of inkjet recording device)
FIG. 21 is a diagram showing an inkjet recording apparatus 2000 that discharges and records a liquid to which this application example can be applied. The recording device 2000 of this application example performs full-color recording on a recording medium by arranging four liquid ejection heads 2003 for single colors corresponding to each ink of cyan C, magenta M, yellow Y, and black K in parallel. Is different from Application Example 1. In the first application example, the number of discharge port rows that can be used per color is one, whereas in this application example, the number of discharge port rows that can be used per color is 20 rows. Therefore, by appropriately allocating the recorded data to a plurality of discharge port rows and recording the data, very high-speed recording becomes possible. Further, even if there is a discharge port that does not discharge, reliability is improved by performing complementary discharge from a discharge port in another row located at a position corresponding to the discharge port in the transport direction of the recording medium. However, it is suitable for commercial records. Similar to Application Example 1, for each liquid discharge head 2003, the supply system of the recording device 2000, the buffer tank 1003 (see FIGS. 2 and 3) and the main tank 1006 (see FIGS. 2 and 3) are fluidized. It is connected. Further, each liquid discharge head 2003 is electrically connected to an electric control unit that transmits electric power and a discharge control signal to the liquid discharge head 2003.

(Explanation of circulation route)
Similar to Application Example 1, as the liquid circulation mode between the recording device 2000 and the liquid discharge head 2003, the first and second circulation modes shown in FIG. 2 or 3 can be used.

(Explanation of liquid discharge head structure)
14 (a) and 14 (b) are perspective views showing the liquid discharge head 2003 according to this application example. Here, the structure of the liquid discharge head 2003 according to this application example will be described. The liquid discharge head 2003 is an inkjet line-type recording head that includes 16 recording element substrates 2010 that are linearly arranged in the longitudinal direction of the liquid discharge head 2003 and can record with one type of liquid. Similar to Application Example 1, the liquid discharge head 2003 includes a liquid connection portion 111, a signal input terminal 91, and a power supply terminal 92. However, since the liquid discharge head 2003 of this application example has more discharge port rows than the first application example, signal output terminals 91 and power supply terminals 92 are arranged on both sides of the liquid discharge head 2003. This is to reduce the voltage drop and signal transmission delay that occur in the wiring portion provided on the recording element substrate 2010.

FIG. 15 is a perspective exploded view showing the liquid discharge head 2003, and each component or unit constituting the liquid discharge head 2003 is divided and shown for each function. The roles of each unit and member and the order of liquid flow in the liquid discharge head are basically the same as those in Application Example 1, but the functions for ensuring the rigidity of the liquid discharge head are different. In Application Example 1, the rigidity of the liquid discharge head was mainly secured by the liquid discharge unit support portion 81, but in the liquid discharge head 2003 of Application Example 2, the liquid discharge head is provided by the second flow path member 2060 included in the liquid discharge unit 2300. Rigidity is guaranteed. The liquid discharge unit support portion 81 in this application example is connected to both ends of the second flow path member 2060, and the liquid discharge unit 2300 is mechanically coupled to the carriage of the recording device 2000 to be mechanically coupled to the liquid discharge head 2003. Positioning. The liquid supply unit 2220 including the negative pressure control unit 2230 and the electrical wiring board 90 are coupled to the liquid discharge unit support portion 81. A filter (not shown) is built in each of the two liquid supply units 2220.

The two negative pressure control units 2230 are set to control the pressure with different, relatively high and low negative pressures. Further, when the negative pressure control units 2230 on the high pressure side and the low pressure side are installed at both ends of the liquid discharge head 2003, the liquid in the common supply flow path and the common recovery flow path extending in the longitudinal direction of the liquid discharge head 2003, respectively. Flows face each other in the extending direction. The configuration is illustrated in FIGS. 14 and 15. In such a configuration, heat exchange is promoted between the common supply flow path and the common recovery flow path, and the temperature difference between the two common flow paths is reduced. This has the advantage that the temperature difference between the plurality of recording element substrates 2010 provided along the common flow path is reduced, and recording unevenness due to the temperature difference is less likely to occur.

Next, the details of the flow path member 2210 of the liquid discharge unit 2300 will be described. As shown in FIG. 15, the flow path member 2210 is a stack of the first flow path member 2050 and the second flow path member 2060, and distributes the liquid supplied from the liquid supply unit 2220 to each discharge module 2200. do. Further, the flow path member 2210 functions as a flow path member for returning the liquid recirculated from the discharge module 2200 to the liquid supply unit 2220. The second flow path member 2060 of the flow path member 2210 is a flow path member in which a common supply flow path and a common recovery flow path are formed therein, and has a function of mainly carrying the rigidity of the liquid discharge head 2003. Therefore, as the material of the second flow path member 2060, a material having sufficient corrosion resistance against liquid and high mechanical strength is preferable. Specifically, SUS, Ti, alumina and the like can be used.

FIG. 16A is a view showing the surface of the first flow path member 2050 on which the discharge module 2200 is mounted, and FIG. 16B shows the back surface thereof, and FIG. 16B shows the back surface of the first flow path member 2060. It is a figure which showed the surface which comes into contact with. Unlike the first application example, the first flow path member 2050 in this application example is an array of a plurality of members corresponding to each discharge module 2200 adjacent to each other. By adopting the divided structure in this way, a plurality of modules can be arranged to correspond to the length of the liquid discharge head 2003, so that a relatively long scale corresponding to, for example, B2 size or longer can be used. It can be particularly preferably applied to the liquid discharge head of the above. As shown in FIG. 16A, the communication port 51 of the first flow path member 2050 fluidly communicates with the discharge module 2200, and as shown in FIG. 16B, the first flow path member 2050 is individually connected. The communication port 53 fluidly communicates with the communication port 61 of the second flow path member 2060. FIG. 16 (c) shows the surface of the second flow path member 60 that comes into contact with the first flow path member 2050, and FIG. 16 (d) shows a cross section of the second flow path member 60 at the center in the thickness direction. 16 (e) is a view showing a surface of the second flow path member 2060 that comes into contact with the liquid supply unit 2220. The functions of the flow path and the communication port of the second flow path member 2060 are the same as those for one color of Application Example 1. One of the common flow path grooves 71 of the second flow path member 2060 is the common supply flow path 2211 shown in FIG. 17, which will be described later, and the other is the common recovery flow path 2212, respectively, in the longitudinal direction of the liquid discharge head 2003. The liquid is supplied from one end side to the other end side. This application example is different from the application example 1, and the liquid flows of the common supply flow path 2211 and the common recovery flow path 2212 are opposite to each other.

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

FIG. 18 is a view showing a cross section of XVIII-XVIII of FIG. The common supply flow path 2211 is connected to the discharge module 2200 via a communication port 61, an individual communication port 53, and a communication port 51. Although not shown in FIG. 18, in another cross section, it is clear with reference to FIG. 17 that the common recovery channel 2212 is connected to the discharge module 2200 by a similar path. Similar to Application Example 1, each discharge module 2200 and the recording element substrate 2010 are formed with a flow path communicating with each discharge port, and a part or all of the supplied liquid is inactive in the discharge operation. It can be recirculated through the discharge port. Further, as in Application Example 1, the common supply flow path 2211 is connected to the negative pressure control unit 2230 (high pressure side), and the common recovery flow path 2212 is connected to the negative pressure control unit 2230 (low pressure side) via the liquid supply unit 2220. Has been done. Therefore, due to the differential pressure, a flow is generated from the common supply flow path 2211 through the pressure chamber of the recording element substrate 2010 to the common recovery flow path 2212.

(Explanation of discharge module)
FIG. 19A is a perspective view showing one discharge module 2200, and FIG. 19B is an exploded view thereof. The difference from Application Example 1 is that a plurality of terminals 16 are arranged on both side portions (each long side portion of the recording element substrate 2010) along the row direction of a plurality of discharge port rows of the recording element substrate 2010. be. Along with this, two flexible wiring boards 40 that are electrically connected to the recording element substrate 2010 are also arranged with respect to one recording element substrate 2010. This is because the number of discharge port rows provided on the recording element substrate 2010 is 20 rows, which is significantly larger than the 8 rows of Application Example 1, and the maximum distance from the terminal 16 to the recording element is shortened for recording. This is to reduce the voltage drop and signal delay that occur in the wiring portion in the element substrate 2010. Further, the liquid communication port 31 of the support member 2030 is provided on the recording element substrate 2010 and opens so as to straddle all the discharge port rows. Other points are the same as in Application Example 1.

(Explanation of the structure of the recording element substrate)
20 (a) is a schematic view of a surface on which the discharge port 13 of the recording element substrate 2010 is arranged, and FIG. 20 (c) is a schematic view showing the back surface of the surface of FIG. 20 (a). FIG. 20 (b) is a schematic view showing the surface of the recording element substrate 2010 when the lid member 2020 provided on the back surface side of the recording element substrate 2010 is removed in FIG. 20 (c). As shown in FIG. 20B, the liquid supply flow path 18 and the liquid recovery flow path 19 are alternately provided on the back surface of the recording element substrate 2010 along the row direction of the discharge port row. Although the number of discharge port rows is significantly increased as compared with Application Example 1, the essential difference from Application Example 1 is that the terminals 16 are along the row direction of the discharge port rows of the recording element substrate as described above. It is arranged on both sides. A set of liquid supply flow path 18 and liquid recovery flow path 19 is provided for each discharge port row, and the lid member 2020 is provided with an opening 21 that communicates with the liquid communication port 31 of the support member 2030. The basic configuration is the same as that of Application Example 1.

(Application example 3)
The configuration of the inkjet recording apparatus 1000 and the liquid ejection head 3 according to the third application of the present invention will be described. The liquid discharge head of Application Example 3 is a page-wide type that records on a B2 size recording medium in one scan. Since the application example 3 has many similarities to the application example 2, the parts different from the second application example will be mainly described in the following description, and the description of the parts similar to the second application example will be omitted.

(Explanation of inkjet recording device)
FIG. 45 shows a schematic view of the inkjet recording device of this application example. The recording device 1000 does not directly record on the recording medium from the liquid discharge head 3, but once discharges the liquid to the intermediate transfer body (intermediate transfer drum 1007) to form an image, and then transfers the image to the recording medium 2. It is a configuration to be transferred. In the recording device 1000, four liquid ejection heads 3 for single colors corresponding to each of the four types of CMYK inks are arranged in an arc shape along the intermediate transfer drum 1007. As a result, full-color recording is performed on the intermediate transfer body, and the recorded image is appropriately dried on the intermediate transfer body and then transferred to the recording medium 2 conveyed by the paper transfer roller 1009 by the transfer unit 1008. Transferred. While the paper transport system of Application Example 2 was horizontal transport mainly intended for cut paper, in this application example, continuous paper supplied from a main body roll (not shown) can also be supported. In such a drum transport system, it is easy to transport the paper while applying a constant tension, so that there is little transport jam even during high-speed recording. Therefore, the reliability of the apparatus is improved, and it is suitable for commercial printing and the like. Similar to the first and second application examples, the supply system of the recording device 1000, the buffer tank 1003, and the main tank 1006 are fluidly connected to each liquid discharge head 3. Further, an electric control unit that transmits electric power and a discharge control signal to the liquid discharge head 3 is electrically connected to each liquid discharge head 3.

(Explanation of the fourth circulation form)
Similar to Application Example 2, as the liquid circulation path between the tank of the recording device 1000 and the liquid discharge head 3, the first and second circulation paths shown in FIG. 2 or 3 can also be applied. The circulation route shown in FIG. 46 is suitable. The main difference from the second circulation path in FIG. 3 is that a bypass valve 1010 communicating with the flow path of each of the first circulation pumps 1001 and 1002 and the second circulation pump 1004 is added. The bypass valve 1010 has a function (first function) of lowering the pressure on the upstream side of the bypass valve 1010 by opening the valve when the preset pressure is exceeded. It also has a function (second function) of opening and closing the valve at an arbitrary timing by a signal from the control board of the recording device main body.

The first function can prevent excessive or underpressure 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 the functions of the first circulation pumps 1001 and 1002 are disturbed, an excessive flow rate or pressure may be applied to the liquid discharge head 3. As a result, there is a risk that the liquid may leak from the discharge port of the liquid discharge head 3 or that each joint in the liquid discharge head 3 may break. However, when bypass valves are added to the first circulation pumps 1001 and 1002 as in this application example, even if excessive pressure is generated, the bypass valve 1010 opens and the liquid path to the upstream side of each circulation pump. Is released, so that the above troubles can be suppressed.

Further, by the second function, when the circulation drive is stopped, after the first circulation pumps 1001, 1002 and the second circulation pump 1004 are stopped, all the bypass valves 1010 are promptly opened based on the control signal from the main body side. As a result, the high negative pressure (for example, several to several tens of kPa) in the downstream portion of the liquid discharge head 3 (between the negative pressure control unit 230 and the second circulation pump 1004) can be released in a short time. When a positive displacement pump such as a diaphragm pump is used as a circulation pump, a check valve is usually built in the pump. However, by opening the bypass valve, the pressure in the downstream portion of the liquid discharge head 3 can be released from the buffer tank 1003 side on the downstream side as well. 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 flow path on the upstream side of the liquid discharge head and the flow path in the liquid discharge head. Therefore, it takes time to release the pressure, and the pressure in the common flow path in the liquid discharge head 3 is transiently lowered too much, which may destroy the meniscus of the discharge port. 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 at the discharge port is reduced.

(Explanation of liquid discharge head structure)
The structure of the liquid discharge head 3 according to the third application example of the present invention will be described. FIG. 47 (a) is a perspective view of the liquid discharge head 3 according to this application example, and FIG. 47 (b) is an exploded perspective view thereof. The liquid discharge head 3 is an inkjet page-wide type recording head provided with 36 recording element substrates 10 arranged linearly (in-line) in the longitudinal direction of the liquid discharge head 3 and recording with one color liquid. be. Similar to Application Example 2, the liquid discharge head 3 includes a signal input terminal 91 and a power supply terminal 92, and is also provided with a shield plate 132 that protects the longitudinal side surface of the head.

FIG. 47B is a perspective exploded view of the liquid discharge head 3, and each component or unit constituting the liquid discharge head 3 is divided and displayed according to its function (shield plate 132 is not shown). The roles of each unit and each member and the order of liquid flow in the liquid discharge head 3 are the same as in Application Example 2. The main differences from Application Example 2 are the positions of the electrical wiring board 90, the negative pressure control unit 230, and the shape of the first flow path member, which are arranged in a plurality of divisions. In the case of the liquid discharge head 3 having a length corresponding to, for example, a B2 size recording medium as in this application example, eight electric wiring boards 90 are provided because the power consumption of the liquid discharge head 3 is large. Four of each of the electric wiring boards 90 are attached to both side surfaces of the long electric wiring board support portion 82 attached to the liquid discharge unit support portion 81.

48 (a) 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, and FIG. 48 (b) is a schematic view showing the flow of the liquid, FIG. 48 (c). ) Is a perspective view showing a cross section of the GG line portion of FIG. 48 (a). Some configurations have been simplified for ease of understanding.

A liquid connection portion 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 between the negative pressure control unit 230 and the recording element substrate 10 in the height direction is shorter than that in Application Example 2. This configuration has the advantage that the number of flow path connection portions in the liquid supply unit 220 is reduced, the reliability against leakage of the recorded liquid is improved, and the number of parts and the number of assembly steps can be reduced.

Further, since the head difference between the negative pressure control unit 230 and the surface on which the discharge port is formed becomes relatively small, the inclination angle of the liquid discharge head 3 as shown in FIG. 45 is different for each liquid discharge head. It can be suitably adapted to various recording devices. This is because the water arithmetic progression can be reduced, so that 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 can be reduced. Further, as the distance between the negative pressure control unit 230 and the recording element substrate 10 becomes smaller, the flow resistance between them becomes smaller, so that the pressure loss difference due to the change in the flow rate of the liquid becomes smaller, which is also preferable in that more stable negative pressure control can be performed. ..

FIG. 48B is a schematic view showing the flow of the recorded liquid inside the liquid discharge head 3. Although the circuit is the same as that of the circulation path shown in FIG. 46, FIG. 48B shows the actual flow of liquid in each component of the liquid discharge head 3. A set of a common supply flow path 211 and a common recovery flow path 212 extending in the longitudinal direction of the liquid discharge head 3 are provided in the long second flow path member 60. The common supply flow path 211 and the common recovery flow path 212 are configured so that liquid flows in directions facing each other, and a filter 221 is provided on the upstream side of each flow path to allow foreign matter to enter from the connection portion 111 or the like. To trap. As described above, the common supply flow path 211 and the common recovery flow path 212 are preferable in that the temperature gradient in the longitudinal direction in the liquid discharge head 3 is reduced by flowing the liquid in the directions facing each other. In FIG. 46, the flows of the common supply flow path 211 and the common recovery flow path 212 are shown in the same direction for the sake of simplification of the description.

Negative pressure control units 230 are connected to the downstream sides of the common supply flow path 211 and the common recovery flow path 212, respectively. Further, in the middle of the common supply flow path 211, there is a branch portion to a plurality of individual supply flow paths 213a, and in the middle of the common recovery flow path 212, there is a branch portion to a plurality of individual recovery flow paths 213b. The individual supply flow path 213a and the individual recovery flow path 213b are formed in a plurality of first flow path members 50, and each individual flow path is an opening 21 of a lid member 20 provided on the back surface of the recording element substrate 10. (See FIG. 19 (c)).

The negative pressure control unit 230 shown by H and L in FIG. 48 (b) has a high pressure side (H) and a low pressure side (L) as units. Each negative pressure control unit 230 is a back pressure type pressure adjusting mechanism set to control the pressure on the upstream side of the negative pressure control unit 230 with relatively high (H) and low (L) negative pressures. Is. 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), thereby being common with the common supply flow path 211. A differential pressure is generated between the flow paths 212. Due to the differential pressure, the liquid passes from the common supply flow path 211 through the individual supply flow path 213a, the discharge port 13 (pressure chamber 23) in the recording element substrate 10, and the individual recovery flow path 213b in this order, and the common recovery flow path 212. Flow to.

FIG. 48 (c) is a perspective view showing a cross section taken along line GG of FIG. 48 (a). In this application example, each discharge module 200 is composed of a first flow path member 50, a recording element substrate 10, and a flexible wiring board 40. In the present embodiment, there is no support member 30 (FIG. 18) described in Application Example 2, and the recording element substrate 10 provided with the lid member 20 is directly joined to the first flow path member 50. The common supply flow path 211 provided in the second flow path member is an individual supply flow path from the communication port 61 formed on the upper surface thereof via the individual communication port 53 formed on the lower surface of the first flow path member 50. It is supplied to 213a. After that, the liquid is recovered to the common recovery flow path 212 via the individual recovery flow path 213b, the individual communication port 53, and the communication port 61 via the pressure chamber 23 in this order.

Here, unlike Application Example 2 shown in FIG. 15, the individual communication port 53 on the lower surface of the first flow path member 50 (the surface on the second flow path member 60 side) is the upper surface of the second flow path member 50. The opening is sufficiently large with respect to the communication port 61 formed in. With this configuration, even if the position of the discharge module 200 is displaced when it is mounted on the second flow path member 60, fluid communication is reliably performed between the first flow path member and the second flow path member. Therefore, the yield at the time of head manufacturing is improved and the cost can be reduced.

The description of the above application example does not limit the scope of the present invention. As an example, in this application example, a thermal method in which bubbles are generated by a heat generating element to discharge a liquid has been described, but the present invention is also applied to a liquid discharge head in which a piezo method and various other liquid discharge methods are adopted. be able to.

Although this application example has described an inkjet recording device (recording device) in which a liquid such as ink is circulated between the tank and the liquid ejection head, other forms may be used. In another form, for example, two tanks are provided on the upstream side and the downstream side of the liquid discharge head without circulating the ink, and the ink flows from one tank to the other tank to flow the ink in the pressure chamber. It may be.

Further, in this application example, an example of using a so-called line type head having a length corresponding to the width of the recording medium has been described, but a so-called serial type liquid discharge head that records while scanning the recording medium. The present invention can also be applied to. Examples of the serial type liquid ejection head include, but are not limited to, a configuration in which one recording element substrate for ejecting black ink and one recording element substrate for ejecting color ink are mounted. That is, a short liquid discharge head shorter than the width of the recording medium is created in which a plurality of recording element substrates are arranged so that the discharge ports overlap in the row direction of the discharge port row, and the liquid discharge head is scanned against the recording medium. It may be in the form of causing.

Each embodiment showing the features of the present invention will be described below.

(First Embodiment)
The liquid discharge head according to the first embodiment of the present invention will be described with reference to FIGS. 22 to 28. The liquid supply flow path in the above-mentioned application example corresponds to the first common supply flow path in the embodiment. Similarly, the liquid recovery flow path corresponds to the first common recovery flow path, the first communication port corresponds to the opening, the common supply flow path corresponds to the third common supply flow path, and the common recovery flow path corresponds to the third common recovery flow path.

FIG. 22 is an exploded view of a main part of the liquid discharge head according to the embodiment of the present invention. 22 (a) to (g) are perspective views of the disassembled components, and FIGS. 22 (h) to (m) are disassembled components from FIGS. 22 (b) to (g). It is a corresponding plan view. FIG. 23 is a diagram schematically showing the structure of one of the plurality of discharge port rows 3024 shown in FIG. 22 (a), focusing on the discharge port row 3024. 23 (a) to (d) are perspective views corresponding to FIGS. 22 (a) to 22 (d), and FIGS. 23 (e) to (g) correspond to FIGS. 22 (h) to (j). It is a plan view. Further, FIG. 24 (a) is a cross-sectional view taken along the line XXIVa-XXIVa of FIGS. 23 (e) to (g), and FIG. 24 (b) is a cross-sectional view taken along the line XXIVb-XXIVb. FIG. 25 is an equivalent circuit diagram obtained by cutting out a part of the liquid discharge head of the present embodiment. FIG. 26 is a diagram illustrating an equivalent circuit diagram obtained by cutting out a part of the liquid discharge head of the present embodiment and a pressure distribution in the flow path. FIG. 27 is a top view illustrating the shape of the recording element substrate of the present embodiment. FIG. 28 is a schematic transmission diagram illustrating an end portion of the discharge port row.

As shown in FIGS. 22 to 24, the liquid discharge head of the present embodiment has a discharge port forming member 3012, a first flow path layer 3011, a second flow path layer 3050, a third flow path layer 3060, and a fourth flow path layer 3070. , A fifth channel layer 3080, and a sixth channel layer 3090.

The discharge port forming member 3012 is provided with a plurality of discharge port rows 3024 in which a plurality of discharge ports 3013 are arranged in a row. The first flow path layer 3011 is provided with a recording element 3015 that generates energy used for discharging the liquid at a position corresponding to the discharge port 3013. The discharge port forming member 3012 and the first flow path layer 3011 are laminated so that a space serving as a pressure chamber 3023 and a flow path 3310 (FIG. 24) is formed between them. The liquid discharge head can discharge a liquid such as ink in the pressure chamber 3023 (inside the flow path 3310) from the discharge port 3013 by the energy generated by the recording element 3015. The static pressure of the flow path 3310 and the pressure chamber 3023 is maintained at a negative pressure so that the meniscus of the liquid (ink) is stretched at the discharge port 3013. If the pressure in the pressure chamber varies, the discharge characteristics such as the discharge speed of the liquid and the volume of the discharged droplets will be affected.

As shown in FIG. 22, in the present embodiment, the plurality of discharge port rows 3024 are arranged at a high density of 600 dpi. In the second flow path layer 3050, a first common supply flow path 3313 and a first common recovery flow path 3314 are formed along the main surface thereof. The first communication port 3315a (supply side communication port) and the first communication port 3315b (recovery side communication port) are formed in the third flow path layer 3060. The first flow path layer 3011 is formed with a row of recording elements in which the recording elements 3015 are arranged and a row of through holes in which the through holes 3017 for supplying / recovering the liquid are arranged. As shown in FIG. 24, these through holes 3017 include a supply port 3017a and a recovery port 3017b. The plurality of supply ports 3017a extend in a direction (second direction) intersecting the surface on which the recording elements 3015 are arranged to form a supply flow path, and the recording elements 3015 are in the row direction of the discharge port rows. Are arranged along the arrangement direction (first direction) of the above to form a supply port row. Similarly, the plurality of collection ports 3017b extend in a direction (second direction) intersecting the surface on which the recording element 3015 is arranged to form a supply flow path, and are in the row direction of the discharge port row. The recording elements 3015 are arranged along the arrangement direction (first direction) to form a collection port row.

As shown in FIG. 24, the first common supply flow path 3313 communicates with the flow path 3310 and the pressure chamber 3023 via the supply port 3017a. Similarly, the first common recovery flow path 3314 communicates with the flow path 3310 and the pressure chamber 3023 via the recovery port 3017b. Further, the first common supply flow path 3313 receives the liquid supply from the first communication port 3315a (supply side communication port) formed in the third flow path layer 3060. Similarly, the first common recovery flow path 3314 communicates with the first communication port 3315b (recovery side communication port) formed in the third flow path layer 3060. As shown in FIGS. 22 (d) and 22 (j), the plurality of first communication ports 3315a are arranged in a direction intersecting the row direction of the discharge port row to form the first communication port row. A plurality of first communication ports 3315b are also arranged in the same direction to form a first communication port row.

A second common supply flow path 3331 and a second common recovery flow path 3332 are formed in the fourth flow path layer 3070. A second communication port 3333a (supply side communication port) and a second communication port 3333b (recovery side communication port) are formed in the fifth flow path layer 3080. A third common supply flow path 3335 and a third common recovery flow path 3336 are formed in the sixth flow path layer 3090.

The first common supply flow path 3313 of the second flow path layer 3050 communicates with a plurality of supply ports 3017a on one surface side and communicates with the first communication port 3315a on the other surface side. Similarly, the first common recovery flow path 3314 of the second flow path layer 3050 communicates with the plurality of recovery ports 3017b on one surface side and communicates with the first communication port 3315b on the other surface side. Further, the second common supply flow path 3331 of the fourth flow path layer 3070 communicates with the first communication port 3315a on one surface side and communicates with a plurality of second communication ports 3333a on the other surface side. Similarly, the second common recovery flow path 3332 of the fourth flow path layer 3070 communicates with the first communication port 3315b on one surface side and communicates with the second communication port 3333b on the other surface side. Here, at least one of the first communication port 3315a and the first communication port 3315b is plural. Further, the third common supply flow path 3336 of the sixth flow path layer 3090 communicates with a plurality of second communication ports 3333a. Similarly, the third common recovery flow path 3336 of the sixth flow path layer 3090 communicates with a plurality of second communication ports 3333b.

The plurality of first communication ports 3315a (supply side first communication port) are arranged along the direction (third direction) intersecting the row direction (first direction) of the discharge port row, and the supply side first communication port 3315a (supply side first communication port). It forms a communication port row. The plurality of first communication ports 3315b (collection side first communication port) are arranged along the direction (third direction) intersecting the row direction (first direction) of the discharge port row, and the collection side first communication port 3315b (collection side first communication port) is arranged. It forms a communication port row.

The plurality of second communication ports 3333a (supply-side second communication ports) are arranged along the row direction (first direction) of the discharge port rows to form a supply-side second communication port row. The plurality of second communication ports 3333b (recovery side second communication ports) are arranged along the row direction (first direction) of the discharge port rows to form a recovery side second communication port row.

The arrangement density of the plurality of second communication ports 3333a and the arrangement density of the plurality of second communication ports 3333b are smaller than the arrangement density of the plurality of first communication ports 3315a and the arrangement density of the plurality of first communication ports 3315b. Further, the arrangement densities of the plurality of first communication ports 3315a and the arrangement densities of the plurality of first communication ports 3315b are smaller than the arrangement densities of the plurality of supply ports 3017a and the arrangement densities of the plurality of collection ports 3017b. Each of the first common supply flow path 3313 and the first common recovery flow path 3314 extends in the first direction, and the first common supply flow path 3313 and the first common recovery flow path 3314 are the first. They are alternately arranged in a third direction that intersects with the direction of. The second common supply flow path 3331 and the second common recovery flow path 3332 extend along a third direction that intersects the first direction, and the second common supply flow path 3331 and the second common recovery flow path 3331 and the second common recovery flow flow. Roads 3332 are alternately arranged in parallel in the first direction. The third common supply flow path 3335 and the third common recovery flow path 3336 extend along the first direction.

The liquid discharge head of the present embodiment has a configuration in which the density of the flow path gradually increases from the sixth flow path layer 3090 to the first flow path layer 3011 by laminating a plurality of flow path layers in this way. can do. As a result, it is possible to provide a liquid discharge head provided with a plurality of high-density discharge port rows while suppressing an increase in size of the recording element substrate and each flow path member.

The flow of the liquid (hereinafter, referred to as ink) in the liquid discharge head of the present embodiment will be described. The ink supplied from the outside flows into the liquid outflow head from the third common supply flow path 3336 as the inflow opening. The inflowing ink then passes through the second communication port 3333a, the second common supply flow path 3331, the first communication port 3315a, the first common supply flow path 3313, and the supply port 3017a in this order, and then passes through the flow path 3310 (pressure chamber 3023). ) Is supplied. The ink then flows out through the recovery port 3017b, the first common recovery flow path 3314, the first communication port 3315b, the second common recovery flow path 3332, the second communication port 3333b, and the third common recovery flow path 3336 in this order. It flows out from the third common recovery flow path 3336 as an opening.

By forcibly flowing the ink in this way, it is possible to suppress the thickening of the ink in the ejection head, and as a result, the ink ejection speed is lowered and the color material density of the recorded dots is modulated. It can be suppressed. Hereinafter, in the present specification, such a forced flow of ink is referred to as an “ink circulation flow”.

This embodiment has the following configuration so as to suppress variations in the flow rate of the ink circulating flow flowing through each pressure chamber and variations in pressure in each pressure chamber. That is, as shown in FIG. 23, the first communication port 3315a communicates with one first common supply flow path 3313. Similarly, the first communication port 3315b communicates with one first common recovery flow path 3314. Here, at least one of the first communication port 3315a and the first communication port 3315b is plural. In these first communication ports 3315a and 1st communication port 3315b, variations in the flow rate of the ink circulation flow flowing through each pressure chamber 3023 and variations in pressure in each pressure chamber are within a range that does not significantly affect the ejection characteristics. Have been placed. In particular, with respect to one discharge port row 3024, the first communication port 3315a and the first communication port 3315b are alternately arranged with respect to the row direction of the discharge port row. By arranging them alternately, the distance between the first communication port 3315a and the first communication port 3315b can be made narrower. That is, even when the flow path widths of the first common supply flow path 3313 and the first common recovery flow path 3314 are relatively narrow, the flow rate of the ink circulation flow flowing in each pressure chamber 3023 (each flow path 3310) varies and each pressure. It is possible to suppress variations in chamber pressure.

Further, the arrangement relationship between the first communication port 3315a and the first communication port 3315b is as follows. First, with respect to each of the plurality of pressure chambers 3023 (flow path 3310), the flow path of the flow path between the first common supply flow path 3313 including the pressure chamber 3023 (flow path 3310) and the first common recovery flow path 3314. Let r be the resistance. Further, in the first common supply flow path 3313, the flow path resistance of the flow path between the adjacent supply ports 3017a (that is, between the supply flow paths) is defined as R. Similarly, in the first common recovery flow path 3314, the flow path resistance of the flow path between the adjacent recovery ports 3017b (that is, between the recovery flow paths) is defined as R. Further, regarding the flow rate of the ink flowing through each flow path 3310 (pressure chamber 3023), the average flow rate thereof is set to q, and the maximum flow rate does not affect the ejection characteristics, that is, the maximum flow rate in the range where the landing position deviation and the color unevenness do not affect the image. Let Δq be the flow rate difference between and the minimum flow rate, and let X be the ratio of the two. That is, the flow rate ratio X = Δq / q. At this time, the first communication port 3315 is arranged so that the number N of the discharge ports between the first communication port 3315a and the first communication port 3315b satisfies the following equation.

By arranging the first communication port 3315a and the first communication port 3315b under such conditions, the variation in the flow rate of the ink circulation flow flowing through each pressure chamber 3023 (each flow path 3310) between the pressure chambers can be discharged. It is possible to suppress the flow rate difference that does not affect the characteristics.

The conditional expression (1) for suppressing the variation in the flow rate of the ink circulation flow flowing through each pressure chamber 3023 between the pressure chambers will be described in detail with reference to FIG. 25. FIG. 25 is an equivalent circuit in which a part between the first communication port 3315a and the first communication port 3315b that are adjacent to each other in the first direction is partially cut out. The case where N pressure chambers 3023 (flow path 3310) are included between the adjacent first communication port 3315a and the first communication port 3315b is shown.

In this case, the largest amount of ink is in the pressure chamber 3023 (pressure chamber 1 in FIG. 25) closest to the first communication port 3315a and the pressure chamber 3023 closest to the first communication port 3315b among the N pressure chambers 3023. Flows. Further, it is known that the flow rate of ink flowing into the pressure chamber 3023 located at an intermediate position between the first communication port 3315a and the first communication port 3315b among the N pressure chambers 3023 is minimized. Assuming that the maximum flow rate and the minimum flow rate are q ₁ and q ₂ , respectively, and the average value of the flow rates of the ink flowing through each pressure chamber 3023 is q, the total amount of ink Q supplied is Q = Nq.

From the first communication port 3315a, it reaches the first communication port 3315b via the pressure chamber 3023 (pressure chamber 1 in FIG. 25) closest to the first communication port 3315a and through the first common recovery flow path 3314. The pressure loss p _{1 up} to is shown below.

The first common recovery flow path from the first communication port 3315a through the first common supply flow path 3313 and via the pressure chamber (FIG. 25 pressure chamber 2) located between the first communication port 3315a and the first communication port 3315b. _{The pressure loss p 2} until reaching the first communication port 3315b through 3314 is shown below.

Since the pressure loss p ₁ and the pressure loss p ₂ are equal, from the equations (2) and (3), the flow rate difference Δq'between _{the maximum flow rate q 1} and the minimum flow rate q _{2 of the ink flowing through each pressure chamber is obtained.} The following formula holds.

Here, in order not to affect the ejection characteristics, the flow rate difference between the maximum flow rate and the minimum flow rate of the ink flowing through each pressure chamber Δq'= q ₁ −q ₂ and the average of the ink flowing through each pressure chamber. It is necessary that the ratio with the flow rate q is set to a predetermined flow rate ratio X or less. For that purpose, at least the conditions shown by the following equation are required.

Equation (5) is transformed into equation (1) by focusing on the number N of pressure chambers between the first communication port 3315a and the first communication port 3315b.

In the embodiment of the present invention, when the flow rate of the ink circulation flow is increased or decreased to a certain ratio or more, the ink recovery effect by the ink circulation flow flowing under the ejection port changes, and the ejection speed and the ejection droplet volume change. It is known that the difference in colorant density becomes large. In particular, in a non-limiting example of the present embodiment, when the flow rate is increased or decreased by about 10% with respect to a certain flow rate of the ink circulating flow, the ejection speed and the ejection droplet volume change, and the difference in the color material concentration Has grown. Further, in this example, when the ratio Δq / q of the flow rate difference between the maximum flow rate and the minimum flow rate and the average flow rate is set to a predetermined flow rate ratio X0.2 or less, the discharge characteristics and the color material concentration are greatly affected. It no longer occurs.

Next, with reference to FIG. 37, an example of the influence of the variation in the flow rate of the ink circulating flow will be described.

FIG. 37 shows the flow rate (circulation flow rate) of the ink circulation flow flowing through the lower part of each ejection port, and the ejection of the ink to be ejected to the first shot after the ink ejection is paused for a certain period of time while circulating the ink at each circulation flow rate. It is a graph which shows one non-limiting example of the relationship with speed. In this example, when the circulation flow rate is about 7,000 pl / s or more with the circulation flow rate around 7,000 pl / s as a boundary, the ink can be ejected from the first shot at an ejection speed of 90% or more of the steady ejection speed. did it. On the other hand, when the circulation flow rate was less than about 7,000 pl / s, the ejection speed of the first ink was less than about 90% of the ejection speed in the steady state. When the ink ejection speed is reduced, the position of the ejected ink when it arrives at the recording medium (at the time of landing) is displaced, and as a result, the image quality is deteriorated.

Therefore, in order to prevent deterioration of image quality due to positional deviation at the time of landing, it is effective to increase the circulation flow rate to some extent so as to suppress a decrease in the ink ejection speed after a certain period of pause.

Here, FIG. 36 shows an example of an ink supply system applicable to the liquid ejection head of the present invention. In FIG. 36, the liquid discharge head 3003 communicates with the first liquid tank 3044 on the upstream side and the second liquid tank 3045 on the downstream side, respectively. The first liquid tank 3044 supplies ink to the third common supply flow path 3335. The supplied ink is supplied to the pressure chamber 3023 (flow path 3310) through the second common supply flow path 3331 and the first common supply flow path 3313 via each communication port. Further, from the pressure chamber 3023 (flow path 3310), the first common recovery flow path 3314 and the second common recovery flow path 3332 pass through each communication port, and the third common recovery flow path 3336 to the second liquid It is collected in tank 3045. In such a structure, as a means for generating an ink circulation flow, there is a method of using the head difference between the first liquid tank 3044 and the second liquid tank 3045. Another method is to control the pressure between the first liquid tank 3044 and the second liquid tank 3045 and use the pressure difference between the first liquid tank 3044 and the second liquid tank 3045. There is also a method of generating a flow with a pump or the like.

However, when the pressure difference between the first liquid tank 3044 and the second liquid tank 3045 is increased or a large flow rate is flowed by a pump or the like in order to increase the circulation flow rate, it tends to be difficult to control the pressure at the lower part of the discharge port. There is. Therefore, the circulation flow rate should be as small as possible so that the ejection speed does not decrease too much in consideration of both the deterioration of the image quality due to the positional deviation of the ink at the time of landing and the difficulty of pressure control.

As described above, in the present embodiment, the first common supply flow path 3313 and the first common supply flow path 3313 so that at least one of the first communication port 3315a and the first communication port 3315b is plural so as to satisfy the equation (1). 1 It is arranged in the common recovery flow path 3314, respectively. As a result, the value of the ratio (flow rate ratio) X between the flow rate difference between the maximum flow rate and the minimum flow rate and the average flow rate can be reduced while the fluid resistance ratio r / R is fixed. That is, without widening the width of the first common supply flow path 3313 and the first common recovery flow path 3314, the variation of the flow rate of the ink circulation flow flowing through each pressure chamber 3023 between the pressure chambers is suppressed. can do. Therefore, it is possible to suppress a decrease in the ejection speed of the droplet due to evaporation of water from the ejection port 3013 and a modulation of the color material density, so that a higher-definition and high-quality image can be formed.

Similarly, in the present embodiment, it is possible to suppress variations in the pressure of each pressure chamber 3023 between pressure chambers. The pressure loss that occurs in the first common supply flow path 3313 and the first common recovery flow path 3314 is a variation in the pressure of each pressure chamber in the row direction of the discharge port row among the pressure chambers. That is, if the pressure variation is ΔP, the following equation holds.

Here, assuming that the maximum allowable pressure variation within a range that does not affect the discharge characteristics is ΔPm, the number of discharge ports N between the first communication port 3315a and the first communication port 3315b satisfies the following equation. It is located in.

As described above, in the present embodiment, the plurality of first communication ports 3315a and the plurality of first communication ports 3315b are arranged in the first common supply flow path 3313 and the first common recovery flow path 3314 so as to satisfy the equation (7). Place each in. As a result, it is possible to suppress variations in the pressure of each pressure chamber between pressure chambers without widening the width of the flow paths of the first common supply flow path 3313 and the first common recovery flow path 3314. Therefore, it is possible to suppress variations in the ink ejection speed and the volume of the ejected ink droplets, so that higher-definition and higher-quality images can be formed.

Further, in the present embodiment, the flow rate of the ink circulation flow flowing through each pressure chamber corresponding to the discharge port 3013 arranged at high density varies between pressure chambers and the pressure of each pressure chamber varies between pressure chambers. It should be as follows so as to suppress it. That is, as shown in FIG. 22, the second common supply flow path 3331 extends in a direction (third direction) intersecting the row direction (first direction) of the discharge port row 3024, and extends in a third direction. It communicates with a plurality of first communication ports 3315a arranged in. Similarly, the second common recovery flow path 3332 extends in a third direction intersecting the row direction (first direction) of the discharge port row 3024, and a plurality of first communication lines arranged in the third direction. It communicates with the mouth 3315b. Further, the plurality of second common supply flow paths 3331 are combined into one flow path as the third common supply flow path 3336 via the second communication port 3333a. Similarly, the plurality of second common third common recovery flow paths 3332 are combined into one flow path as the third common recovery flow path 3336 via the second communication port 3333b.

As described above, in the present embodiment, with respect to the discharge port forming member 3012, the first flow path layer 3011, the second flow path layer 3050, the third flow path layer 3060, the fourth flow path layer 3070, and the fifth flow path The flow paths are connected by a six-layer structure consisting of a layer 3080 and a sixth flow path layer 3090. As a result, a plurality of first common supply flow paths 3313 arranged at a narrow pitch with respect to the plurality of discharge port rows 3024 arranged at high density are arranged with the first communication port 3315a so as to satisfy the equation (1). However, it can be combined into one. Similarly, a plurality of first common recovery flow paths 3314 arranged at a narrow pitch with respect to a plurality of discharge port rows 3024 arranged at high density, and a first communication port 3315b are arranged so as to satisfy the equation (1). However, it can be combined into one. That is, a high-density discharge port row can be formed without widening the flow path widths of the first common supply flow path 3313 and the first common recovery flow path 3314. Further, variations in the flow rate of the ink circulation flow flowing in each pressure chamber 23 (flow path 3310) corresponding to the discharge ports 3013 of the plurality of discharge port rows 3024 arranged at high density among the pressure chambers and the pressure of each pressure chamber. It is possible to suppress variations between pressure chambers. Further, for the discharge ports 3013 arranged at high density, the ink from the liquid tank is suppressed while suppressing the variation in the flow rate of the ink circulation flow in each pressure chamber 3023 (flow path 3310) and the variation in the pressure in each pressure chamber. And the ink can be easily collected in the liquid tank. This has the advantage that not only the liquid discharge head is made compact, but also the entire system of the liquid discharge device provided with the liquid discharge head is made compact.

In this embodiment, the number of pressure chambers 3023 arranged in each discharge port row 3024 is large (for example, 100 or more), and the arrangement density of a plurality of discharge port rows 3024 (the discharge port rows in the direction intersecting the discharge port rows). It is effective when the arrangement density) is high (for example, 50 dpi or more). In such a case, even if the ratio (r / R) of the flow path resistance between the pressure chamber and the flow path is small (for example, about 1/1000), the variation in the flow rate of the ink circulating flow tends to be large. .. That is, when the number of discharge ports constituting the discharge port rows is further increased or the distance between the discharge port rows is narrowed, the flow rate of the ink circulation flow in each pressure chamber may vary or the pressure chambers may have different flow rates. The configuration of the present invention is effective in suppressing pressure variation. Therefore, it is particularly effective for a line head which is a liquid discharge head having a length corresponding to the width of the recording medium, and a liquid discharge head having a discharge port arrangement density of 600 dpi or more.

Next, in the present embodiment, a case where ink is ejected from a large number of ejection ports 3013 will be described. In this embodiment, when ink is ejected from a large number of ejection ports 3013, it is preferable that the ink circulation flow is as follows so as to suppress variations in the flow rate of the ink circulating flow flowing into the resting pressure chamber 3023. Let I be the flow rate of the ink ejected from each ejection port 3013 by ejection. At this time, the first communication port 3315a and the first communication port 3315b are arranged so that the number N of the discharge ports 3013 between them satisfies the following equation.

In the present embodiment, the first communication port 3315a and the first communication port 3315b are arranged under such conditions. As a result, when ink is ejected from a large number of ejection ports 3013, the variation in the flow rate of the ink circulation flow flowing through each of the resting pressure chambers 3023 between the pressure chambers is suppressed to a flow rate difference that does not affect the ejection characteristics. It becomes possible to do.

FIG. 26 will be described in detail of the conditional expression (8) for suppressing the variation in the flow rate of the ink circulating flow flowing into the resting pressure chamber 3023 when ink is ejected from a large number of ejection ports 3013.

When the ink circulation flow is applied at a flow rate sufficient to suppress the influence of water evaporation from the ejection port 3013, the ejection amount when ejecting ink from a large number of ejection ports 3013 is larger than the flow rate of the ink circulation flow. May increase. In such a case, as shown in FIG. 26A, the ink in the first common recovery flow path 3314 will flow backward. That is, in FIG. 26A, in the first common supply flow path 3313, the ink flows in the direction from the first communication port 3315a to the first communication port 3315b, as indicated by the arrows. Further, in a large number of pressure chambers 3023, ink is discharged from the discharge port at a flow rate I, respectively. Along with this, in the first common recovery flow path 3314, the ink is flowing in the direction from the first communication port 3315b to the first communication port 3315a.

FIG. 26B is a graph showing the relationship between the pressure distributions of the first common supply flow path 3313 and the first common recovery flow path 3314 at this time. The horizontal axis of the graph indicates the relative position L from the adjacent first communication port 3315a to the first communication port 3315b, and the vertical axis indicates the pressure P. When the ink ejection from the pressure chamber 3023 is stopped in the state shown in FIG. 26 (a), the first common supply flow path 3313 side and the first common recovery flow path 3314 side are used for each pressure chamber. The ratio of the amount of ink supplied is t: 1-t. At this time, assuming that the pressure loss generated in the first common supply flow path 3313 is ΔPin1 and the pressure loss generated in the first common recovery flow path 3314 is ΔPout1, the following two equations are established.

Further, for each pressure chamber, the pressure generated on the first common supply flow path 3313 side is defined as Pin, the pressure generated on the first common recovery flow path 3314 side is defined as Pout, and the maximum value of the pressure variation in each pressure chamber is ΔPmax. And the minimum value is ΔPmin. At this time, since ΔPmax = Pin-Pout + ΔPout1 and ΔPmin = Pin-Pout-ΔPin1, the variation Δq'of the flow rate of the ink circulating flow is expressed by the following equation.

In order to set the variation Δq'of the flow rate of the ink circulating flow to a predetermined flow rate ratio X or less, the conditions shown by the following equation are required.

Equation (12) is transformed into equation (8) by focusing on the number N of pressure chambers between the first communication port 3315a and the first communication port 3315b.

Here, in the present embodiment, as a non-limiting example of the present invention, the flow path width of the first common supply flow path 3313 and the first common recovery flow path 3314 of the liquid discharge head is 200 μm, and the flow path height is 500 μm. And said. Further, the discharge ports 3013 in the discharge port row 3024 are arranged so as to be lined up at a density of 600 dpi, and the shape of the flow path 3310 under the discharge port 3013 is such that the flow path width is 30 μm, the flow path height is 14 μm, and the flow path length. The height was set to 100 μm. In this liquid ejection head, a case was examined in which the flow velocity of the ink circulating flow at the lower part of the ejection port was 0.01 m / s, and the ink was ejected at an ejection amount of 5 pl and a drive frequency of 10 kHz. In this case, by reducing the number N of the number N of the discharge ports between the first communication port 3315a and the first communication port 3315b to about 65 or less, the influence of the variation in the flow rate could be suppressed.

As described above, in the present embodiment, at least one of the first communication port 3315a and the first communication port 3315b is a plurality of the first communication port 3315a and the first communication port 3315b so as to satisfy the equation (8), and the first common supply flow path 3313 and the first common recovery flow path 3314. Place each in. As a result, the value of the flow rate ratio X can be reduced while the ratio r / R of the flow path resistance is fixed. That is, in the case of ejecting ink from a large number of ejection ports without widening the flow path widths of the first common supply flow path 3313 and the first common recovery flow path 3314, the pressure chamber 3023 (flow rate) is stationary. It is possible to suppress variations in the flow rate of the ink circulating flow flowing through the path 3310). Therefore, it is possible to suppress a decrease in the ejection speed of ink droplets due to evaporation of water from the ejection port 3013 and modulation of the color material density, so that higher-definition and higher-quality images can be formed.

Further, the present embodiment preferably has the following configuration so as to suppress variations in the flow rate of the ink circulating flow flowing through each pressure chamber and variations in pressure in each pressure chamber. That is, the first communication port 3315a or the first communication port 3315b arranged on both end sides in the row direction of the discharge port row 3024 is from the first communication port 3315a or the first communication port 3315b arranged on other than both ends side. Also has a small shape (opening area).

When viewed from the first communication port 3315a or the first communication port 3315b arranged on both end sides, the discharge port 3013 is arranged on only one side in the row direction of the discharge port row. Therefore, the total amount of ink Q passing through the first communication port 3315a or the first communication port 3315b is the first communication port 3315a or the first communication port arranged at a location different from both ends in the row direction of the ejection port row. It is less than the total amount of ink passing through 3315b. Therefore, the first communication port 3315a or the first communication port 3315b on both ends side is made smaller than the central part side to increase the flow path resistance, so that the first communication port is arranged at a place different from the end side. The pressure loss that occurs at 3315a or the first communication port 3315b can be approached. Therefore, the flow of the ink circulation flow through the pressure chamber communicating with the first communication port 3315a or the first communication port 3315b on both ends side and the pressure chamber communicating with the first communication port 3315a or the first communication port 3315b different from the flow of the ink circulation flow. The difference in the flow of the ink circulation flow through the communication can be reduced. As a result, it becomes possible to further suppress the flow rate variation of the ink circulation flow flowing in each pressure chamber.

A further aspect of this embodiment will be described with reference to FIGS. 27 and 28. This embodiment is as follows so as to suppress the flow rate variation of the ink circulation flow flowing through each pressure chamber 3023.

FIG. 27 is a top view of the recording element substrate of the liquid discharge head of the present embodiment. As shown in FIG. 27, in the recording element substrate 3010 of the present embodiment, the region between the end portion of the discharge port row 3024 and the end portion of the recording element substrate 3010 is large. For example, in this region, a pad for transmitting and receiving an electric signal to and from the recording element substrate 3010 and a circuit for driving are arranged.

FIG. 28 is a schematic upper surface transmission view in which a part of one discharge port row 3024 of the liquid discharge head of the present embodiment is cut out. In FIG. 28, the arrow indicates the direction of the ink circulation flow. In the case of the recording element substrate 3010 as shown in FIG. 27, as shown in FIGS. 28 (a) and 28 (b), the first communication port 3315b overlaps the discharge port 3013 at the end of the discharge port row 3024. Have been placed. On the other hand, FIG. 28 (c) shows an example of an arrangement in which the first communication port 3315b does not overlap the end portion of the discharge port 3013. According to the configurations of FIGS. 28 (a) and 28 (b), as compared with the configuration of FIG. 28 (c), the first communication port from the first communication port 3315a at the end of the discharge port row 3024 passes through the pressure chamber 3023 to the first communication port. The length of ink flowing can be shortened to 3315b. That is, by arranging as shown in FIGS. 28A and 28B, the maximum pressure loss generated in the first common supply flow path 3313 and the first common recovery flow path 3314 near the end of the discharge port row 3024 can be reduced. It can be made smaller. Therefore, it is possible to suppress the flow rate variation of the ink circulation flow flowing in each pressure chamber 3023. It should be noted that a configuration in which the first communication port 3315a is arranged so as to overlap the discharge port at the end of the discharge port row 24 instead of the first communication port 3315b is also applicable.

A further aspect of this embodiment will be described with reference to FIG. This embodiment is as follows in order to suppress the temperature distribution in the chip (recording element substrate 3010). That is, as shown in FIGS. 22 (d) and 22 (j), the first communication ports 3315 on both end sides of the discharge port row 3024 in the row direction are both the first communication ports 3315b.

When the ink in each pressure chamber is forcibly convected as in the configuration of the present embodiment, the liquid (ink) normally recovers the heat generated from the recording element 3015 or the like, so that the recovery side flows out from the pressure chamber. The temperature of the ink becomes high. Further, even if the ink circulation flow is flowing at a flow rate sufficient to suppress the influence of water evaporation from the ejection port 3013, the ejection amount when ejecting ink from a large number of ejection ports 3013 may be larger. be. In that case, ink is also supplied from the first communication port 3315b through the third common recovery flow path 3336. That is, when ejecting ink from a large number of ejection ports 3013, high-temperature ink may be supplied from the first communication port 3315b. As a result, the temperature near the first communication port 3315b becomes higher than that near the first communication port 3315a, and the water is discharged between the discharge port 3013 near the first communication port 3315a and the discharge port 3013 near the first communication port 3315b. There is a difference in speed. Therefore, when different types of first communication ports 3315 on both ends of the discharge port row 3024 are arranged, such as one end side is the first communication port 3315a and the other end side is the first communication port 3315b, the discharge port is arranged. When looking at the entire row 3024, there is an inclination of the heat distribution in the row direction. Therefore, the heat distribution width of the entire chip becomes large, and as a result, the ejection characteristics of the entire chip vary. That is, by setting both ends of the discharge port row 3024 in the row direction as the first communication port 3315b, which is the same type of flow path, such an inclination of the heat distribution can be suppressed, so that the discharge characteristics vary. Can be suppressed.

In FIGS. 22 (d) and 22 (j), both the both ends are the first communication port 3315b, but even if both the both ends are the first communication port 3315a, the effect of suppressing the inclination of the heat distribution is similarly suppressed. There is. However, as shown in FIGS. 22 (d) and 22 (j), it is preferable that both ends of the discharge port row 3024 in the row direction are the first communication ports 3315b. The recording element substrate 3010 of the present embodiment has a large region in which the ejection port 3013 is not arranged between both ends of the ejection port row 3024 and the end portion of the recording element substrate 3010, and the heat generated during ink ejection is in this region. Heat is dissipated from. Therefore, when ink is ejected from a large number of ejection ports 3013, the temperature tends to be lower at both ends of the ejection port row 3024 in the row direction than at other portions. On the other hand, by setting both both ends as the first communication port 3315b, high temperature ink can be supplied to both ends, the temperature of both ends can be raised, and the temperature of both ends can be raised. The temperature difference can be reduced. That is, since the heat distribution width of the entire chip can be reduced, it is possible to suppress variations in discharge characteristics.

In the present embodiment, a plurality of first communication ports 3315a and a plurality of first communication ports 3315 have been described, but the present invention includes a plurality of at least one of the first communication port 3315a and the first communication port 3315. All you need is. That is, the present invention also includes a configuration in which at least one of the first communication port 3315a and the first communication port 3315b is provided to suppress variations in discharge characteristics. For example, the present invention also includes a configuration including two first communication ports 3315a and one first communication port 3315b. As another example, the present invention also includes a configuration including one first communication port 3315a and two first communication ports 3315b.

Further, the relationship between each flow path layer and the member configuration in each embodiment of the present invention does not limit the present invention. In each layer configuration of the discharge port forming member and the first flow path layer to the sixth flow path layer, different members may be laminated to form a liquid discharge head, or a plurality of layers may be integrally molded. A liquid discharge head may be configured as a member. As an example, the following two configuration examples can be given. In one configuration example, the first flow path layer 3011 and the second flow path layer 3050 are integrally formed as the recording element substrate 10 in the above-mentioned application example. Specifically, a supply port 3017a, a recovery port 2017b, a first common supply flow path 3313, and a first common recovery flow path 3314 are formed on a Si substrate provided with a recording element 3015. The third flow path layer 3060 is formed on the lid member 20 or 2020, and a part of the fourth flow path layer 3070 is formed on the support member 30 of FIG. The other part of the fourth flow path layer 3070 is formed on the first flow path member 50 in FIG. 7, and a part of the fifth flow path layer 3080 and the sixth flow path layer 3090 is the second flow path member 60. To form. The other part of the sixth flow path layer 3090 is formed on the third flow path member 70. In the second configuration example, the first flow path layer 3011 and the second flow path layer 3050 are formed on the recording element substrate 10 in the above-described application example. The third flow path layer 3060 is formed on the lid member 20 or 2020, and a part of the fourth flow path layer 3070 is formed on the support member 2030. The other part of the fourth flow path layer 3070 and the fifth flow path layer 3080 are formed on the first flow path member 2050, and the sixth flow path layer 3090 is formed on the second flow path member 2060. Further, the first flow path layer 3011 may be formed on the recording element substrate 10, and the second flow path layer 3050 may be formed on the second substrate.

(Making process of liquid discharge head)
FIG. 38 shows an example of a manufacturing process of the liquid discharge head of the present embodiment. As shown in FIG. 38, in this example, first, in step S91, the discharge port forming member 3012 is arranged on the recording element substrate 3010 on which the recording element 3015 and necessary circuits are already formed, and the discharge port is discharged. (Discharge port forming step). Next, in step S92, the supply port 3017a and the recovery port 3017b are formed on the back surface of the recording element substrate 3010, which is the surface opposite to the discharge port forming surface (back surface supply / recovery flow path forming step). Next, in step S93, the lid member 20 is formed on the back surface of the recording element substrate 10 so as to cover the supply port 3017a and the recovery port 3017b (cover member forming step). Next, in step S94, the outer shape of the recording element substrate 10 having the laminated structure obtained in step S93 is processed from the wafer form to the chip form (cutting step). Further, in step S95, the chip-shaped recording element substrate 10 obtained in step S94 is joined to the support member 30 (joining step).

As described above, in this example, the third flow path layer 3060 (cover member 20) is placed on the back surface of the recording element substrate 3010 (recording element substrate 10) by the lid member forming step (S93) before the joining step (S95). To form. Thereby, the first communication port 3315a and the first communication port 3315b can be formed in the wafer process of processing the substrate in the form of a wafer. By forming the lid member 20 in the wafer process, the shape accuracy of the member is improved as compared with the case where the member is manufactured by machining or molding. Therefore, it is possible to form finer holes at a higher density. Further, the lid member 20 can be made thinner. Therefore, the discharge ports can be arranged at a high density. Further, the flow path resistance of the first communication port 3315a and the first communication port 3315b can be reduced, and the variation thereof can be reduced. Therefore, it is possible to stabilize the differential pressure that generates the ink circulating flow rate, and it is possible to reduce the variation in the circulating flow rate.

Here, from the viewpoint of the manufacturing process, the lid member 20 may be made of a silicon substrate. That is, since the lid member 20 made of the silicon substrate in the wafer form can be bonded to the recording element substrate 10 in the wafer form, the number of steps can be reduced as compared with joining the cover member 20 for each chip obtained by cutting the wafer. It will be possible.

Alternatively, the lid member 20 may be made of a resin film. Since the lid member 20 can be joined by laminating a film-shaped resin on the wafer-shaped recording element substrate 10 as in the case of being made of a silicon substrate, the process is more than joining the lid member for each chip. Can be reduced.

Here, the process order and the content of the process shown in the present embodiment are examples of the present invention, and do not limit the present invention. That is, the order of the discharge port forming step, the back surface supply / recovery flow path forming step, the lid member forming step, and the cutting step does not limit the present invention, and is before the joining step (S95). It suffices if there is a lid member forming step (S93).

(Second Embodiment)
The liquid discharge head according to the second embodiment of the present invention will be described with reference to FIGS. 29 to 32. The same parts as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted.

FIG. 29 is an exploded view of a main part of the liquid discharge head according to the embodiment of the present invention. 29 (a) to (g) are perspective views of the disassembled components, and FIGS. 29 (h) to (m) are plan views of the disassembled components.

FIG. 30 is a top view illustrating the shape of the recording element substrate of the liquid discharge head of the present embodiment. FIG. 31 is a schematic transmission diagram of a liquid discharge head for explaining the end of the discharge port row. FIG. 32 is a diagram for explaining the variation in the circulating flow rate of the present embodiment. 32 (a) and 32 (b) show the top transmission view of the recording element substrate, and FIGS. 32 (c) and 32 (d) show the pressure distribution in the first common supply flow path and the first common recovery flow path. It is an image diagram.

As shown in FIG. 30, the recording element substrate 4010 in the present embodiment has a parallelogram shape, and is the end of the discharge port row 3024 as compared with the configuration of the recording element substrate 3010 in the first embodiment shown in FIG. 27. The area between the portion and the end of the recording element substrate 4010 is small. In such a case, the pad and the driving circuit formed on the recording element substrate 4010 for transmitting and receiving the electric signal to and from the outside are arranged on the long side side of the recording element substrate 4010. In this embodiment, such a recording element substrate 4010 is used. As a result, even in a line head in which a plurality of recording element substrates 4010 are arranged substantially in a row instead of in a staggered pattern, the discharge port rows of adjacent recording element substrates 4010 are located adjacent to each other in the recording element substrates 4010. Can be easily superimposed with respect to the scanning direction. Here, the scanning direction refers to the direction of movement of the liquid discharge head with respect to the medium when recording is performed on the medium by the liquid discharge head. Further, substantially one row means that the adjacent recording element substrates 4010 are arranged so as to partially overlap each other in both the long direction (arrangement direction of the recording element substrates) and the scanning direction of the liquid discharge head. It means that it is.

As shown in FIG. 30, in the second embodiment, the discharge port 3013 is arranged near the end of the recording element substrate 4010. As described with reference to FIGS. 28 (a) and 28 (b), in the first embodiment, the first communication port 3315a and the first communication port 3315b are provided at positions overlapping the ends of the discharge port rows of the recording element substrate 3010. It was placed. However, in the second embodiment, unlike the first embodiment, the first communication port 3315a and the first communication port 3315b are arranged at positions overlapping with the end of the discharge port row of the recording element substrate 4010. This is difficult in forming a member. Therefore, as shown in FIG. 31, the first communication port 3315a and the first communication port 3315b are arranged at positions separated from the end of the discharge port row 3024 toward the center side in the row direction of the discharge port row.

In this embodiment, in order to suppress the variation in the flow rate of the ink circulating flow flowing between the pressure chambers (between the flow paths), the variation in the pressure in each pressure chamber (flow path), and the temperature distribution in the recording element substrate 4010, It is as follows. That is, as shown in FIG. 29, the first communication port 3315a is arranged on both end sides of the discharge port row 3024 in the row direction.

FIG. 32 is a diagram showing an example of a state in which liquid is discharged from a large number of discharge ports. In FIGS. 32 (a) and 32 (b), the arrows indicate the direction of ink flow, and ΔPin2, ΔPout2, ΔPin3, and ΔPout3 indicate the pressure loss generated in each flow path. 32 (c) shows the pressure distribution corresponding to the state of FIG. 32 (a), and FIG. 32 (d) shows the pressure distribution corresponding to the state of FIG. 32 (b). In FIGS. 32 (c) and 32 (d), the solid line shows the pressure in the first common supply flow path 3313, and the alternate long and short dash line shows the pressure in the first common recovery flow path 3314.

As shown in FIG. 32 (a), when the first communication port 3315 at the end of the discharge port row in the row direction is the first communication port 3315a, the first common at the end of the discharge port row 3024. Let ΔP2 be the differential pressure between the supply flow path 3313 and the first common recovery flow path 3314. Similarly, as shown in FIG. 32 (b), when the first communication port 3315 at the end of the discharge port row in the row direction is the communication port 3315b, the first at the end of the discharge port row 3024. Let ΔP3 be the differential pressure between the common supply flow path 3313 and the first common recovery flow path 3314. At this time, each formula is as follows.
ΔP2 = (Pin−ΔPin2) − (Pout−ΔPout2) = (Pin−Pout) + (ΔPout2-ΔPin2) ・ ・ ・ Equation (13)
ΔP3 = (Pin−ΔPin3) − (Pout−ΔPout3) = (Pin−Pout) − (ΔPin3-ΔPout3) ・ ・ ・ Equation (14)

Here, due to the positional relationship between the end of the discharge port row and the first communication port 3315 (first communication port 3315a and first communication port 3315b), the pressure loss is ΔPout2> ΔPin2 and ΔPin3> ΔPout3. .. As a result, the differential pressure ΔP2 becomes larger than the initial differential pressure (Pin-Pout) when the initial discharge is not performed, and the differential pressure ΔP3 becomes smaller than the initial differential pressure. When the differential pressure becomes small, the ink circulation flow becomes small, and the effect of suppressing the decrease in the ejection speed of droplets due to the evaporation of water from the ejection port and the modulation of the color material concentration becomes small, so the effect is smaller than when the differential pressure becomes large. Is big. Therefore, by arranging the first communication ports 3315a at both ends of the discharge port row 3024 in the row direction, the influence of the flow rate variation can be reduced.

Further, the pressure of the first communication port 3315a is set to be higher than that of the first communication port 3315b in order to generate an ink circulation flow, which makes it easier to supply ink at the time of ink ejection. The first communication port 3315a, which is easy to supply ink, is arranged near the end of the discharge port row 3024. As a result, the pressure loss that occurs in the first common supply flow path 3313 and the first common recovery flow path 3314 when ink is ejected from a large number of ejection ports is reduced by moving the ink communication port 3315b near the end of the ejection port row 24. It can be made smaller than when it is placed.

Further, as shown in FIG. 30, in the present embodiment, unlike the first embodiment, in the recording element substrate 4010, between both ends in the row direction of the discharge port row 3024 and the end portion of the recording element substrate 4010. However, the area without a discharge port (no recording element) is small.

With such a structure, heat dissipated from this region of heat generated during discharge is limited. On the contrary, the lengths of the first common supply flow path 3313 and the first common recovery flow path 3314 from the first communication port 3315a or the first communication port 3315b to the end of the discharge port row 3024 in the row direction become long. The ink flowing through the long flow path easily receives heat from the recording element substrate 4010, and when the ink is ejected from a large number of ejection ports 3013, the temperature at both ends of the ejection port row 3024 in the row direction becomes higher than that of other parts. Tend. Further, due to the length of the flow path, the pressure loss generated in each flow path during discharge tends to be large, and the pressure variation at the end of the discharge port row 3024 tends to be large.

On the other hand, in the present embodiment, the first communication port 3315a is arranged on both ends of the discharge port row 3024. As a result, from the first communication port 3315a, which is the first communication port 3315 arranged closer to the discharge port 3013 near the end of the discharge port row 3024 in the row direction, than from the first communication port 3315b. A lot of ink will be supplied. Therefore, when the ink is ejected from a large number of ejection ports 3013, the amount of high-temperature ink supplied from the first communication port 3315b is reduced, so that the temperature rise at the end of the ejection port row 3024 can be reduced. ..

As described above, in the present embodiment, by setting both both ends of the discharge port row 3024 in the row direction as the first communication port 3315a, the influence of the variation in the flow rate, the variation in the pressure, and the temperature distribution in the chip are reduced. be able to. Therefore, it is possible to suppress a decrease in the ejection speed of droplets due to evaporation of water from the ejection port, a modulation of the color material concentration, and a variation in ejection characteristics, so that higher definition and higher quality image formation can be achieved. It will be possible.

Next, the temperature distribution of the entire recording element substrate 4010 in the present embodiment will be described with reference to FIG. 39. FIG. 39 is a graph showing the temperature distribution when discharging from all the discharge ports in the row direction of the discharge port row 3024. The recording element substrate 4010 is in a state where the temperature is controlled at 50 degrees Celsius.

A case where the flow rate of the ink discharged from the ejection port by the ejection is larger than the flow rate of the ink circulating flow will be described. The direction of the ink circulation flow at the first communication port 3315a and the first communication port 3315b is toward the discharge port 3013. Further, the flow rate of ink in the first communication port 3315a and the first communication port 3315b tends to be higher in the first communication port 3315a.

39 (a) and 39 (b) are graphs showing the relationship between the positions of the first communication port 3315a and the first communication port 3315b and the temperature in one discharge port row 3024.

FIG. 39A shows, as a comparative example, the temperature distribution when one first communication port 3315a and one first communication port 3315b are arranged for one discharge port row 3024. Since the ink flowing through the first common supply flow path 3313 and the first common recovery flow path 3314 receives heat from the recording element substrate 4010, the temperature at the center of the flow path away from the communication port is high. Further, when comparing the temperatures of the first communication port 3315a and the first communication port 3315b, the temperature of the first communication port 3315a is lower because the flow rate of the ink circulation flow is larger.

Even under the condition that the ink does not flow back toward the discharge port 3013 at the first communication port 3315b, the ink that has received heat from the recording element substrate flows through the flow path through the first communication port 3315b. Therefore, the temperature of the first communication port 3315a tends to be lower.

FIG. 39B shows the temperature distribution in the present embodiment when a plurality of first communication ports 3315a and a plurality of first communication ports 3315b are alternately arranged for one discharge port row.

In the present embodiment, a plurality of first communication ports 3315a and a plurality of first communication ports 3315b are arranged. Therefore, the distance between the adjacent first communication port 3315a and the first communication port 3315b is shorter than that of the comparative example of FIG. 39 (a). Therefore, the length of the ink flowing through the first common supply flow path 3313 and the first common recovery flow path 3314 is shortened, and the temperature rise of the ink due to receiving heat from the recording element substrate while flowing through the flow paths is small. It has become. In this example, in particular, the temperature of the first communication port 3315b is the same as the temperature of the first communication port 3315a.

Further, in the present embodiment, since the first communication port 3315a and the first communication port 3315b are alternately arranged with respect to the row direction of the discharge port row, the ink is supplied to the first common supply flow path 3313 and the first common recovery flow. The maximum length flowing through the road 3314 is shortened. For this reason as well, the temperature rise of the ink due to receiving heat from the recording element substrate while flowing through the flow path is reduced.

As described above, in the present embodiment, a plurality of first communication ports 3315a and a plurality of first communication ports 3315b are alternately arranged for one discharge port row, which is shown in FIG. 39 (a). Compared with the comparative example, the temperature difference in the recording element substrate 4010 can be reduced. Therefore, since the variation in the ejection characteristics can be suppressed, it is possible to form a higher-definition and higher-quality image.

FIG. 39C shows a case where the first communication port 3315a and the first communication port 3315b for the plurality of discharge port rows 3024 are arranged so as to be offset from each other according to the contour of the parallelogram of the recording element substrate 4010. The distribution of the temperature of the communication port in the discharge port row 3024 is shown. In the figure, the discharge port forming member and the discharge port are omitted.

Although there is a difference in the absolute value of the temperature of each discharge port row itself depending on the position of the discharge port row, the positions of the first communication port 3315a and the first communication port 3315b in the row direction of the discharge port row among the plurality of discharge port rows. It can be seen that the high temperature position and the low temperature position are displaced according to the deviation.

FIG. 39 (d) is a graph obtained by averaging the temperature distribution of FIG. 39 (c) with respect to the direction in which the rows of the plurality of discharge port rows 3024 are arranged. Since the high temperature position and the low temperature position in each discharge port row are deviated from each other, the temperature difference in the recording element substrate 4010 on average is the temperature when all the discharge port rows in FIG. 39 (c) are considered individually. It is smaller than the difference. Therefore, assuming that the scanning direction of the recording medium (the relative scanning direction between the liquid discharge head and the recording medium) intersects the direction of the row direction of the discharge port row 3024 (particularly, the vertical direction), the discharge characteristics due to the temperature difference The effects of variability can be averaged.

As described above, in the present embodiment, the positions of the first communication port 3315a and the first communication port 3315b in the row direction with respect to the plurality of discharge port rows are shifted between the discharge port rows. Thereby, the temperature difference due to the arrangement position of the first communication port 3315a and the first communication port 3315b can be averaged. Therefore, since the variation in the ejection characteristics can be suppressed, it is possible to form a higher-definition and higher-quality image.

(Third Embodiment)
FIG. 33 is a diagram for explaining the liquid discharge head according to the third embodiment of the present invention, and the same parts as those of the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted. FIG. 33 is an exploded view of a main part of the liquid discharge head according to the embodiment of the present invention. 33 (a) to (f) are perspective views, and FIGS. 33 (g) to (l) are plan views.

In this embodiment, as shown in FIG. 33, one first common supply flow path 5313 communicates with a pressure chamber 3023 arranged in two discharge port rows 3024. Similarly, one first common recovery flow path 5314 communicates with the pressure chambers 3023 arranged in the two discharge port rows 3024. That is, as shown in FIGS. 33 (g) and 33 (h), one first common supply flow path 5313 or one first common recovery flow path 5314 is positioned between two adjacent discharge port rows 3024. Has been done.

This embodiment is preferable in the following points in addition to the effects of the first embodiment. That is, by sharing the first common supply flow path 5313 and the first common recovery flow path 5314 of the two adjacent discharge port rows, the number of partition walls between the flow paths can be reduced. Further, since the flow path resistance is proportional to the square of the flow path width, in the case of the same number of discharge ports N, two of the first common supply flow path 3313 or the first common recovery flow path 3314 in the first embodiment Eq. (1) can be established for two discharge port rows with a flow path width smaller than the flow path width of. Further, in the case of the same discharge port row spacing, the flow path resistance R of the first common supply flow path 5313 or the first common recovery flow path 5314 of the formula (1) for one discharge port row can be reduced, and the discharge can be performed. The number of words N can be increased.

As a result, the discharge port rows 3024 are arranged at a higher density than in the above-described embodiment while further suppressing the variation in the flow rate of the ink circulation flow flowing through each pressure chamber and the variation in the pressure in each pressure chamber. Can be done. Therefore, it is possible to reduce the size (chip size) of the recording element substrate. Further, when the density of the discharge port rows 3024 is the same, the variation of the flow rate of the ink circulation flow flowing through each pressure chamber between the pressure chambers and the variation of the pressure of each pressure chamber between the pressure chambers are further suppressed. However, the number of the first communication port 3315a and the first communication port 3315b can be reduced. Therefore, the flow path structure of the liquid discharge head can be made simpler.

(Fourth Embodiment)
FIG. 34 is a diagram illustrating a liquid discharge head according to a fourth embodiment of the present invention, and the same parts as those of the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted. FIG. 34 is an exploded view of a main part of the liquid discharge head according to the embodiment of the present invention. 34 (a) to (g) are perspective views, and FIGS. 34 (h) to (m) are plan views.

As shown in FIG. 34, in the present embodiment, an ejection port 6051 for ink 1 and an ejection port 6061 for ink 2 for ejecting different colors or different types of ink are arranged in one liquid ejection head. There is. The first flow path member 3050 includes a first common supply flow path 6052 for ink 1, a first common supply flow path 6062 for ink 2, a first common recovery flow path 6053 for ink 1, and a first common flow path for ink 2. 1 Common recovery flow path 6063 is formed. Further, the second communication port member 3060 has a first communication port 6054a for ink 1, a first communication port 6064a for ink 2, a first communication port 6054b for ink 1, and a first communication port 6064b for ink 2. Is formed. Further, the third flow path member 3070 includes a second common supply flow path 6056 for ink 1, a second common supply flow path 6066 for ink 2, a second common recovery flow path 6057 for ink 1, and ink 2. The second common recovery flow path 6067 is formed. Further, in the fourth flow path member 3080, a second communication port 6058a for ink 1, a second communication port 6068a for ink 2, a second communication port 6058b for ink 1, and a second communication port for ink 2 are provided. 6068b is formed. The fifth common flow path member 3090 includes a third common supply flow path 6070 for ink 1, a third common supply flow path 6080 for ink 2, a third common recovery flow path 6071 for ink 2, and ink 2. A third common recovery channel 6081 for use is formed. For each of the inks 1 and 2, as in the third embodiment, the ink supplied from the third common supply flow paths 6070 and 6080 passes through the pressure chamber 3024 (flow path 3310) and the third common recovery flow path 6071. , 6081 so that it flows out.

It should be noted that, as in the third embodiment, one first common supply flow path may communicate with the pressure chambers arranged in the two discharge port rows. Similarly, one first common recovery flow path may be in communication with pressure chambers arranged in two discharge port rows.

Further, the third common supply flow path 6070 and the third common recovery flow path 6071 for the ink 1 and the third common supply flow path 6080 and the third common recovery flow path 6081 for the ink 2 are formed in the sixth flow path layer. The size of the 3090 may be larger than that of the recording element substrate 3010. That is, the sixth flow path layer 3090 may take a form of widening, for example, in a direction intersecting the direction of the discharge port row 3024 row (for example, a vertical direction).

Further, when liquids of different colors are discharged by one liquid discharge head as in the present embodiment, the liquid discharge head can be miniaturized while suppressing color mixing by adopting the following configuration. Specifically, in FIGS. 34 (c) and 34 (i), the distance between the first common supply flow path 6052 for supplying the liquid of the same color and the first common recovery flow path 6053 (thickness of the wall separating both flow paths) is set. It is preferable that the distance between the flow paths for supplying liquids of different colors (thickness of the wall separating the two flow paths) is smaller than that. More specifically, the interval between the flow paths of the same color is set between the first common supply flow path 6052 for supplying the liquid for ink 1 and the first common recovery flow path for collecting the liquid for ink 2 adjacent thereto. Make it smaller than the distance from 6053.

In this way, even in the liquid ejection head for multicolor ink or multitype ink, the ink flowing between the pressure chambers without widening the width of the first common supply flow path and the first common recovery flow path. It is possible to suppress variations in the circulation amount and pressure variations in each pressure chamber. Therefore, it is possible to suppress a decrease in the ejection speed of droplets due to evaporation of water from the ejection port and modulation of the color material density, so that higher-definition and higher-quality images can be formed.

(Fifth Embodiment)
FIG. 35 is an external perspective view showing an example of various liquid discharge heads to which the present invention can be applied.

FIG. 35A shows an example of a liquid discharge head in the form of a single recording element substrate to which the present invention can be applied. This liquid discharge head records while repeating reciprocating movement with respect to the recording medium. The fifth flow path layer 7080 is arranged on the sixth flow path layer 7090, and the fourth flow path layer 7070 is arranged on the fifth flow path layer 7080. Further, the recording element substrate 7010 including the third flow path layer 7060 and the second flow path layer 7050 is arranged on the support member 7030.

35 (b) and 35 (c) show an example of a liquid discharge head in the form of a line head in which a plurality of recording element substrates 7010 are arranged in a staggered pattern. In FIG. 35B, each recording element substrate 7010 is arranged on a common support member 7032. Further, in FIG. 35 (c), each recording element substrate 7010 is arranged on an individual support member 7034.

35 (d) and 35 (e) show an example of a liquid discharge head in the form of a line head in which a plurality of recording element substrates 7010 are arranged in a row. In FIG. 35 (d), each recording element substrate 7010 is arranged on a common support member 7032. Further, in FIG. 35 (e), each recording element substrate 7010 is arranged on an individual support member 7034. The recording element substrate 7010 in this case may have a shape similar to that of the recording element substrate 4010 in the fourth embodiment.

Such various liquid ejection heads of the present embodiment can generate the ink circulation flow described above. As a result, it is possible to suppress variations in the amount of ink circulating between the pressure chambers and pressure variations in the pressure chambers. Therefore, it is possible to suppress a decrease in the ejection speed of droplets due to evaporation of water from the ejection port and modulation of the color material density, so that higher-definition and higher-quality images can be formed.

3003 Liquid discharge head 3010 Recording element substrate 3011 First flow path layer 3012 Discharge port forming member 3013 Discharge port 3015 Recording element 3310 Flow path 3315a First communication port (supply side)
3315b 1st communication port (collection side)
3017a Supply port 3017b Recovery port 3023 Pressure chamber 3050 Second flow path layer 3060 Third flow path layer 3070 Fourth flow path layer 3080 Fifth flow path layer 3090 Sixth flow path layer

Claims (35)

A row of discharge ports in which a plurality of discharge ports for discharging liquid are arranged in the first direction,
A pressure chamber in which a recording element that generates energy used to discharge liquid is arranged,
A flow path communicating with the pressure chamber and
A plurality of supply ports extending in a second direction intersecting the surface on which the recording element is arranged and for supplying liquid to the flow path are arranged along the first direction. Columns and
A plurality of collection ports extending in the second direction for collecting the liquid in the flow path are arranged along the first direction, and a collection port row.
A first common supply channel extending in the first direction and supplying a liquid to the supply port row,
A first common collection channel extending in the first direction and collecting liquid from the collection port row,
A supply-side first communication port extending in the second direction and supplying a liquid to the first common supply flow path,
A recovery-side first communication port extending in the second direction and recovering the liquid from the first common recovery flow path is provided.
A liquid discharge head including at least one of the first communication port on the supply side and the first communication port on the collection side. The first aspect of claim 1, wherein a plurality of supply-side first communication ports are provided, and a supply-side first communication port row in which the plurality of supply-side first communication ports are arranged extends in the first direction. Liquid discharge head. Claim 1 or 2 in which a plurality of collection-side first communication ports are provided, and the collection-side first communication port row in which the plurality of collection-side first communication ports are arranged extends in the first direction. The liquid discharge head described in. The liquid according to claim 2, wherein the arrangement density of the plurality of supply-side first communication ports included in the supply-side first communication port row is smaller than the arrangement density of the plurality of supply ports included in the supply port row. Discharge head. The liquid according to claim 3, wherein the arrangement density of the plurality of collection-side first communication ports included in the collection-side first communication port row is smaller than the arrangement density of the plurality of collection ports included in the collection port row. Discharge head. The liquid discharge head according to any one of claims 1 to 5, wherein the supply port, the first common supply flow path, and the supply side first communication port are formed on different substrates. Claims 1 to 6, further comprising a second common supply flow path extending in the first direction and a third direction intersecting the second direction and communicating with the plurality of supply-side first communication ports. The liquid discharge head according to any one of the items. Claims 1 to 7, further comprising a second common recovery flow path extending in the first direction and a third direction intersecting the second direction and communicating with the plurality of collection-side first communication ports. The liquid discharge head according to any one of the items. The liquid discharge head according to claim 7, further comprising a plurality of supply-side second communication ports extending in the second direction and supplying the liquid to the second common supply flow path. The liquid discharge head according to claim 8, further comprising a plurality of recovery-side second communication ports extending in the second direction and recovering the liquid from the second common recovery flow path. The liquid discharge head according to claim 9, further comprising a third common supply flow path extending in the first direction and supplying the liquid to the plurality of supply-side second communication ports. The liquid discharge head according to claim 10, further comprising a third common recovery flow path extending in the first direction and collecting the liquid from the plurality of second communication ports on the recovery side. The liquid discharge head according to claim 9, wherein the supply-side second communication port row in which the plurality of supply-side second communication ports are arranged extends in the first direction. The liquid discharge head according to claim 10, wherein the collection side second communication port row in which the plurality of collection side second communication ports are arranged extends in the first direction. The array density of the supply-side second communication port included in the supply-side second communication port row is such that the plurality of the supply-side first communication ports included in the supply-side first communication port row in which the plurality of the supply-side first communication ports are arranged. The liquid discharge head according to claim 13, which is smaller than the arrangement density of the first communication port on the supply side. The arrangement density of the collection-side second communication port included in the collection-side second communication port row is such that the plurality of the collection-side first communication ports included in the collection-side first communication port row in which the plurality of collection-side first communication ports are arranged. The liquid discharge head according to claim 14, which is smaller than the arrangement density of the first communication port on the collection side. The liquid discharge head according to any one of claims 1 to 16, wherein the supply-side first communication port and the collection-side first communication port are alternately arranged with respect to the first direction. Let r be the flow path resistance of the flow path communicating the supply port and the recovery port, and the flow path resistance between the supply ports communicating with the first common supply flow path and the first common recovery flow path. Let R be the flow path resistance between each of the recovery ports communicating with the flow path, and let q be the average flow rate of the liquid flowing through the flow path. When the difference is Δq, the ratio Δq / q between the q and the Δq is X, and the number of discharge ports between the adjacent first communication port on the supply side and the first communication port on the recovery side is N. ,

The liquid discharge head according to any one of claims 1 to 17, which satisfies the above conditions. The liquid discharge head according to claim 18, wherein the value of X is 0.2 or less. From claim 1, the supply-side first communication port and the collection-side first communication port are provided with the supply-side first communication port on both ends of the liquid discharge head in the first direction. 19. The liquid discharge head according to any one of 19. From claim 1, the first communication port on the collection side is arranged on both ends of the liquid discharge head in the first direction with respect to the first communication port on the supply side and the first communication port on the collection side. 19. The liquid discharge head according to any one of 19. The flow path resistance of the first communication port on the recovery side arranged on both ends is higher than the flow path resistance of the first communication port on the recovery side arranged on the central side of the liquid discharge head in the first direction. The large liquid discharge head according to claim 21. The liquid discharge head according to any one of claims 1 to 22, the liquid is supplied to the supply side first communication port, the first common supply flow path, the pressure chamber, and the first common recovery flow path. A liquid discharge device having a supply means for supplying the liquid in the order of the first communication port on the collection side. A liquid discharge head having a discharge port for discharging liquid.
A pressure chamber internally provided with a plurality of recording elements that generate energy used for discharging the liquid, a plurality of supply ports that are through holes for supplying the liquid to the pressure chamber, and a liquid from the pressure chamber. A first substrate provided with a plurality of collection ports, which are through holes for collecting energy, and
A first common supply flow path that communicates with a plurality of the supply ports and extends in a direction along a surface of the first substrate on which the recording element is provided, and communicates with the plurality of collection ports and extends in the direction. A second substrate comprising a first common recovery flow path and
A first communication port on the supply side, which is a through hole for supplying liquid to the first common supply flow path, and a first communication port on the recovery side, which is a through hole for collecting liquid from the first common recovery flow path. And, with a lid member,
A liquid discharge head including at least one of the first communication port on the supply side and the first communication port on the collection side. A liquid discharge head having a discharge port for discharging liquid.
A pressure chamber internally provided with a plurality of recording elements that generate energy used for discharging the liquid, a plurality of supply ports that are through holes for supplying the liquid to the pressure chamber, and a liquid from the pressure chamber. A plurality of collection ports that are through holes for collecting the data, a first common supply flow path that communicates with the plurality of supply ports and extends in a direction along a surface on which the recording element is provided, and a plurality of the above. A recording element substrate including a first common recovery flow path that communicates with the recovery port and extends in the above direction.
A first communication port on the supply side, which is a through hole for supplying liquid to the first common supply flow path, and a first communication port on the recovery side, which is a through hole for collecting liquid from the first common recovery flow path. A liquid discharge head comprising, and a plurality of at least one of a supply side first communication port and a collection side first communication port. The recording element array includes a recording element array in which the recording elements are arranged in the first direction.
The liquid discharge head according to claim 24 or 25, wherein both the first common supply flow path and the first common recovery flow path extend along the first direction. The recording element array includes a recording element array in which the recording elements are arranged in the first direction.
A supply port row in which the plurality of supply ports are arranged in the first direction, and
The liquid discharge head according to any one of claims 24 to 26, comprising a collection port row in which the plurality of collection ports are arranged in the first direction. The recording element array includes a recording element array in which the recording elements are arranged in the first direction.
A supply-side first communication port row in which a plurality of the supply-side first communication ports are arranged in the first direction,
The liquid discharge head according to any one of claims 24 to 27, comprising a collection-side first communication port row in which a plurality of the collection-side first communication ports are arranged in the first direction. The array density of the plurality of supply-side first communication ports included in the supply-side first communication port row is such that the plurality of supply ports included in the supply port row in which the plurality of supply ports are arranged in the first direction. The array density of the plurality of collection-side first communication ports, which is smaller than the array density of the supply port and is included in the collection-side first communication port row, is such that the plurality of collection ports are arranged in the first direction. 28. The liquid discharge head according to claim 28, which is smaller than the arrangement density of the plurality of collection ports included in the collection port row. A second extending in a direction along the surface on which the recording element is provided and in a direction intersecting the extending direction of the first common supply flow path, which supplies the liquid to the plurality of first communication ports on the supply side. A direction along the common supply flow path and a surface on which the recording element is provided for collecting liquid from the plurality of first communication ports on the recovery side, and a direction intersecting the extending direction of the first common recovery flow path. The liquid discharge head according to any one of claims 24 to 29, comprising a support member comprising a second common recovery flow path extending in. A plurality of supply-side second communication ports that are through holes for supplying liquid to the second common supply flow path, and a plurality of recovery-side second communication ports that are through holes for collecting liquid from the second common recovery flow path. The liquid discharge head according to claim 30, further comprising a first flow path member comprising Liquid is supplied from the plurality of third common supply channels extending in the direction along the surface provided with the recording element, which supplies the liquid to the plurality of second communication ports on the supply side, and the plurality of second communication ports on the collection side. The liquid discharge head according to claim 31, further comprising a second flow path member including a third common recovery flow path extending in a direction along a surface on which the recording element is provided for recovery. The first common supply channel includes a first common supply channel for supplying a first type of liquid and a first common supply channel for supplying a second type of liquid.
The first common recovery flow path includes a first common recovery flow path for collecting the first type of liquid and a first common recovery flow path for collecting the second type of liquid. The liquid discharge head according to any one of 1 to 22 and 24 to 32. The distance between the first common supply flow path for supplying the first type of liquid and the first common recovery flow path for collecting the first type of liquid is such that the first type of liquid is supplied. The liquid discharge head according to claim 33, which is smaller than the distance between the common supply flow path and the first common recovery flow path for collecting the second type of liquid. The liquid discharge head according to any one of claims 1 to 22 and 24 to 34, wherein the liquid in the pressure chamber is circulated to and from the outside of the pressure chamber.

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