JP6900179B2 - Liquid discharge head - Google Patents

Description

The present invention relates to a liquid discharge head.

In the liquid discharge head that discharges liquid such as ink from the discharge port, the volatile components in the liquid evaporate from the discharge port and the liquid thickens near the discharge port, so that the discharge rate of the discharged droplets changes. There is a problem that the landing accuracy is affected.
As one of the measures against such a liquid thickening phenomenon, a method of circulating the ink supplied to the liquid ejection head along the circulation path is known. Patent Document 1 describes a discharge port that accompanies liquid evaporation from a discharge port by circulating a liquid in a flow path formed between a member on which a discharge port is formed and a substrate on which a heat generating resistor is formed. A liquid discharge head that suppresses clogging is described.

JP-A-2002-355973

If the pause time after the discharge operation is long, the viscosity of the liquid in the vicinity of the discharge port increases remarkably, and the solid component in the liquid may stick to the vicinity of the discharge port. Therefore, at the time of the first liquid discharge after the pause, the fluid resistance when the liquid passes through the discharge port increases due to this solid component, which may cause a discharge failure.
However, in the liquid discharge head described in Patent Document 1, such discharge failure is not taken into consideration. Therefore, the image quality may be deteriorated due to the discharge defect that occurs when the first liquid is discharged after the pause.
Therefore, an object of the present invention is to provide a liquid discharge head capable of forming a higher-definition and higher-quality image.

In order to achieve the above-mentioned object, in the liquid discharge head of the present invention, the first and second discharge port rows in which the discharge ports for discharging the liquid are arranged and parallel to each other, and the first and second discharge ports are described. It is a first and second pressure chamber row provided corresponding to the outlet row, and is provided inside with a recording element that generates energy used for discharging the liquid, and is provided through the discharge port and the discharge port portion. The first and second pressure chamber rows in which the pressure chambers communicating with each other are arranged, the first liquid supply path for supplying the liquid to the first pressure chamber row, and the liquid from the first pressure chamber row. A first liquid recovery path for collecting liquid, a second liquid supply path for supplying liquid to the second pressure chamber row, and a second liquid recovery path for recovering liquid from the second pressure chamber row. A page-wide liquid discharge head provided with a plurality of recording element substrates provided with, over a length corresponding to the width of the recording medium , wherein the first liquid supply path, the first liquid recovery path, and the like. The second liquid supply path and the second liquid recovery path are provided in parallel in this order, and at the time of recording, of the plurality of the pressure chambers included in the first and second pressure chamber rows. In each case, the flow directions of the liquids in the pressure chamber flowing from the liquid supply passage to the liquid recovery passage through the pressure chamber are the same. In one aspect, the height H of the pressure chamber on the upstream side of the liquid flow direction with respect to the communicating portion with the discharge port portion, and the length P of the discharge port portion in the liquid discharge direction. The relationship between the length W of the discharge port portion in the flow direction of the liquid (H, P, W have the same length unit) and H ^−0.34 × P ^−0.66 × W> 1.7. If satisfying, the first and second plurality of flow direction of the liquid flowing within each of said pressure chamber included in the pressure chamber column of the relative of the recording medium with respect to the liquid discharge head definitive when the liquid discharge In another aspect, the height H of the pressure chamber on the upstream side in the flow direction of the liquid with respect to the communicating portion with the discharge port portion, and the discharge port portion. The length P in the liquid discharge direction and the length W of the discharge port in the liquid flow direction (H, P, W have the same length unit) are H ^−0.34 × P ^{−. When} the relationship of 0.66 × W ≦ 1.7 is satisfied, the flow direction of the liquid flowing inside each of the plurality of pressure chambers included in the first and second pressure chamber rows is the liquid flow direction at the time of liquid discharge. wherein for said liquid discharge head is a relative movement in the same direction of the recording medium.

As described above, according to the present invention, it is possible to provide a liquid discharge head capable of forming a higher-definition and higher-quality image.

It is a perspective view of the inkjet recording apparatus according to 1st Embodiment. It is a schematic diagram which shows the 1st circulation path in 1st Embodiment. It is a schematic diagram which shows the 2nd circulation path in 1st Embodiment. It is a perspective view of the liquid discharge head according to 1st Embodiment. It is an exploded perspective view of the liquid discharge head according to 1st Embodiment. It is a top view of the 1st to 3rd flow path members of 1st Embodiment. It is a perspective view which shows the part of the flow path member of 1st Embodiment in an enlarged manner. FIG. 5 is a cross-sectional view taken along the line EE of FIG. It is a perspective view and the exploded perspective view of the discharge module of 1st Embodiment. It is a top view of the recording element substrate of 1st Embodiment. 10 (a) is a perspective view showing a cross section taken along the line BB. It is a partially enlarged plan view of the adjacent part of the recording element substrate of 1st Embodiment. It is a perspective view of the liquid discharge head by 2nd Embodiment. It is an exploded perspective view of the liquid discharge head according to 2nd Embodiment. It is a top view of the 1st and 2nd flow path members of the 2nd Embodiment. It is a perspective view which shows the part of the flow path member of the 2nd Embodiment in an enlarged manner. It is sectional drawing in the FF line of FIG. It is a perspective view and the exploded perspective view of the discharge module of the 2nd Embodiment. It is a top view of the recording element substrate of the 2nd Embodiment. It is a perspective view of the inkjet recording apparatus according to 2nd Embodiment. It is a top view, a cross-sectional view, and a perspective view which show the main part of the liquid discharge head. It is an enlarged cross-sectional view near the discharge port of a liquid discharge head. It is a graph for demonstrating the relationship between a head dimension and a flow mode. It is a graph which shows the result of having confirmed the relationship between a head dimension and a flow mode. It is a figure which shows the state of the circulation flow in a discharge port part. It is a figure which shows the state of the color material density | concentration of the ink in a discharge port part. It is a graph which shows the result of having compared the color | density | density | density | density | density | density | density | density | density | density | density | color | color material density | density | density | color | recording medium. It is a figure for demonstrating the deviation of the liquid discharge direction in flow mode A. It is a figure for demonstrating the deviation of the liquid discharge direction in flow mode B. It is a top view which shows the structural example of the liquid discharge head which considered the deviation of the discharge direction. It is a top view which shows the structural example of the liquid discharge head including a plurality of recording element substrates. It is a graph which plotted the discharge rate with respect to the number of discharges after a pause. It is a figure which shows the relationship between a circulating flow and a recording medium in a flow mode A. It is a figure which shows the relationship between a circulating flow and a recording medium in a flow mode B.

Hereinafter, examples of embodiments of the present invention will be described with reference to the drawings. However, the following description does not limit the scope of the present invention. As an example, in the present embodiment, a thermal method in which bubbles are generated by a heat generating element to discharge a liquid is adopted, 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. Can be applied. The liquid discharge head of the present invention for discharging a liquid such as ink and the liquid discharge device equipped with the liquid discharge head can be applied to devices such as printers, copiers, facsimiles having a communication system, and word processors having a printer unit. is there. Furthermore, it can be applied to an industrial recording device that is combined with various processing devices. For example, it can also be used for biochip manufacturing, electronic circuit printing, semiconductor substrate manufacturing, and the like.
The present embodiment is an inkjet recording device (recording device) in which a liquid such as ink is circulated between the tank and the liquid ejection head, but other forms may be used. For example, two tanks may be provided on the upstream side and the downstream side of the liquid discharge head without circulating the ink, and the ink in the pressure chamber may be flowed by flowing the ink from one tank to the other tank. ..
Further, the present embodiment is a so-called line type (page wide type) head having a length corresponding to the width of the recording medium, but a so-called serial type liquid that records while scanning the recording medium. The present invention can also be applied to the discharge head. Examples of the serial type liquid ejection head include, but are not limited to, a configuration in which one recording element substrate for black ink and one recording element substrate for color ink are mounted. A form in which several recording element substrates are arranged so that the discharge ports overlap in the discharge port row direction, a short line head shorter than the width of the recording medium is created, and the line head is scanned against the recording medium. It may be one.

[First Embodiment]
(Explanation of inkjet recording device)
FIG. 1 shows a schematic configuration of a device for ejecting a liquid, particularly an inkjet recording apparatus 1000 (hereinafter, also referred to as a recording apparatus) for ejecting ink for recording according to the present invention. The recording device 1000 includes a transport unit 1 for transporting the recording medium 2, a line-type liquid discharge head 3 arranged substantially orthogonal to the transport direction of the recording medium 2, and a plurality of recording media 2 continuously or intermittently. It is a line-type recording device that continuously records in one pass while being conveyed to. The recording medium 2 is not limited to cut paper, and may be continuous roll paper. The liquid discharge head 3 can perform full-color printing with CMYK ink (cyan, magenta, yellow, black). As will be described later, the liquid discharge head 3 is fluidly connected to a liquid supply means, a main tank, and a buffer tank (see FIG. 2), which are supply paths for supplying the liquid to the liquid discharge head. 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 discharge head 3 will be described later.

(Explanation of the first circulation route)
FIG. 2 is a schematic diagram showing a first circulation path, which is one form of the circulation path applied to the recording device of the present embodiment. FIG. 2 shows a diagram in which 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. Note that FIG. 2 shows only the path through which one color of the CMYK ink flows for the sake of simplification of the explanation, but in reality, the circulation path for four colors is the liquid ejection head 3 and the recording device main body. It is provided in. The buffer tank 1003 as a sub tank connected to the main tank 1006 has an atmospheric communication port (not shown) that communicates the inside and the outside of the tank, and can discharge air bubbles in the ink to the outside. The buffer tank 1003 is also connected to the replenishment pump 1005. The replenishment pump 1005 discharges (discharges) ink from the discharge port of the liquid discharge head, such as recording ink discharge and suction recovery, and the consumed ink is consumed by the liquid discharge head 3. Minutes are transferred from the main tank 1006 to the buffer tank 1003.
The two first circulation pumps 1001 and 1002 have a role of drawing out the liquid from the liquid connection portion 111 of the liquid discharge head 3 and flowing it to the buffer tank 1003. As the first circulation pump, a positive displacement pump having a quantitative liquid feeding capacity is preferable. Specific examples include tube pumps, gear pumps, diaphragm pumps, syringe pumps, etc. For example, a general constant flow valve or relief valve may be placed at the pump outlet to ensure a constant flow rate. You can. When the liquid discharge unit 300 is driven, a certain amount of ink flows in the common supply path 211 and the common recovery flow path 212 by the first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) 1002, respectively. It is preferable that the flow rate is set so 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 an excessively large flow rate is set, the negative pressure difference becomes too large in each recording element substrate 10 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 between the path between the second circulation pump 1004 and the liquid discharge unit 300. The negative pressure control unit 230 maintains the pressure on the downstream side (that is, the liquid discharge unit 300 side) of the negative pressure control unit 230 at a preset constant pressure even when the flow rate of the circulation system fluctuates due to the difference in the recording duty. It has a function to operate as if it were. As the two pressure adjusting mechanisms constituting the negative pressure control unit 230, any mechanism can be used as long as the pressure downstream of itself can be controlled with fluctuations below a certain range around a desired set pressure. May be used. As an example, a mechanism similar to a so-called "decompression regulator" can be adopted. When a pressure reducing regulator is used, as shown in FIG. 2, it is preferable that the second circulation pump 1004 pressurizes the upstream side of the negative pressure control unit 230 via the liquid supply unit 220. In this way, the 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 any 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 type 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 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 side (denoted as L in FIG. 2) pass through the inside of the liquid supply unit 220, respectively. , It is connected to the common supply 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 path 211, a common recovery flow path 212, and an individual supply flow path 213a and an individual recovery flow path 213b that communicate with each recording element substrate. Since the individual flow path 213 communicates with the common supply path 211 and the common recovery flow path 212, a part of the liquid passes from the common supply flow path 211 through the internal flow path of the recording element substrate 10 to the common recovery flow path. A flow (arrow in FIG. 2) flowing to 212 is generated. This is because the pressure adjusting mechanism H is connected to the common supply flow path 211 and the pressure adjusting mechanism L is connected to the common recovery flow path 212, so that a differential pressure is generated between the two common flow paths.
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 flow of 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, ink can be caused to flow even in a discharge port or a pressure chamber where recording is not performed, so that the ink is thickened at that portion. Can be suppressed. Further, the thickened ink and foreign substances in the ink can be discharged to the common recovery flow path 212. Therefore, the liquid discharge head 3 of the present embodiment enables high-speed, high-quality recording.

(Explanation of the second circulation route)
FIG. 3 is a schematic diagram showing a second circulation path, which is a circulation form different from the above-mentioned first circulation path, among the circulation paths applied to the recording device of the present embodiment. The main difference from the first circulation path described above is that the two pressure adjusting 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 mechanism that controls by fluctuation within a certain range. This mechanism is a mechanical component having the same function as a so-called "back pressure regulator". Another difference 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, and the negative pressure control unit 230 is arranged on the downstream side of the liquid discharge head. It is a point.
In the second circulation path, the negative pressure control unit 230 operates as follows. That is, even if there is a fluctuation in the flow rate caused by a change in the recording duty when recording is performed by the liquid discharge head 3, the pressure fluctuation on the upstream side (that is, the liquid discharge unit 300 side) of the liquid discharge head 3 is centered on a preset pressure. It operates to stabilize within a certain range. As shown in FIG. 3, it is preferable that the second circulation pump 1004 pressurizes the downstream side of the negative pressure control unit 230 via the liquid supply unit 220. In this way, the influence of the head pressure of the buffer tank 1003 on the liquid 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.

Similar to the first embodiment, as shown in FIG. 3, the negative pressure control unit 230 includes two pressure adjusting mechanisms in which different control pressures are set. Of the two negative pressure adjusting mechanisms, the high pressure setting side (denoted as H in FIG. 3) and the low pressure 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 path 211 and the common recovery flow path 212. The pressure of the common supply flow path 211 is made relatively higher than the pressure of the common recovery flow path 212 by the two negative pressure adjusting mechanisms. As a result, an ink flow is generated from the common supply flow path 211 to the common recovery flow path 212 via the individual flow path 213 and the internal flow path of each recording element substrate 10 (arrow in FIG. 3). As described above, in the second circulation path, the same ink flow state as in the first circulation path can be obtained in the liquid ejection unit 300, but there are two advantages different from those in the case of the first circulation path.
The first advantage is that since the negative pressure control unit 230 is arranged on the downstream side of the liquid discharge head 3 in the second circulation path, there is a concern that dust and foreign matter generated from the negative pressure control unit 230 may flow into the head. There are few. The second advantage is that in the second circulation path, 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 path. The reason is as follows. Let A be the total flow rate in the common supply flow path 211 and the common recovery flow path 212 when circulating during the recording standby. The value of 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 the temperature of the liquid discharge head 3 is adjusted 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 total discharge) is defined as F. Then, in the case of the first circulation path (FIG. 2), the set flow rates of the first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) 1002 become A, so that the liquid discharge head required for total discharge The maximum value of the liquid supply amount to 3 is A + F.

On the other hand, in the case of the second circulation path (FIG. 3), the amount of liquid supplied to the liquid discharge head 3 required during recording standby is the flow rate A. Then, the amount of supply to the liquid discharge head 3 required at the time of total discharge is the flow rate F. Then, in the case of the second circulation path, the total value of the set flow rates of the first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) 1002, that is, the maximum value of the required supply flow rate is the larger of A or F. Is the value of. Therefore, as long as the liquid discharge unit 300 having the same configuration is used, the maximum value (A or F) of the required supply amount in the second circulation path is always higher than the maximum value (A + F) of the required supply flow rate in the first circulation path. It becomes smaller. Therefore, in the case of the second circulation path, 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 used. Can be reduced. As a result, there is an advantage that the cost of the recording device main body can be reduced. This advantage increases as the value of A or F becomes relatively large, and is more beneficial for line heads having a longer length in the longitudinal direction.
However, on the other hand, there is also a point that the first circulation path is more advantageous than the second circulation path. That is, in the second circulation path, since the flow rate flowing through the liquid discharge unit 300 during the recording standby is the maximum, the lower the recording duty of the image, the higher the negative pressure is applied to each nozzle. Therefore, in particular, the flow path width (length in the direction orthogonal to the liquid flow direction) of the common supply flow path 211 and the common recovery flow path 212 is reduced to reduce the head width (length in the lateral direction of the liquid discharge head). If the size is reduced, the effect of satellite droplets may increase. This is because a high negative pressure is applied to the nozzle in a low Duty image in which unevenness is easily visible. On the other hand, in the case of the first circulation path, since high negative pressure is applied to the nozzle at the time of forming a high duty image, even if satellites are generated, they are difficult to see and have an advantage that the influence on the image is small. .. The selection of the two circulation paths 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 liquid discharge head configuration)
The configuration of the liquid discharge head 3 according to the first embodiment will be described. 4 (a) and 4 (b) are perspective views of the liquid discharge head 3 according to the present embodiment. The liquid discharge head 3 is a line-type liquid in which 15 recording element substrates 10 capable of ejecting four colors of C / M / Y / K ink on one recording element substrate 10 are linearly arranged (arranged in-line). It is a discharge head. As shown in FIG. 4A, the liquid discharge head 3 has a recording element substrate 10, a signal input terminal 91 and a power supply terminal 92 electrically connected via the flexible wiring board 40 and the electrical wiring board 90. To be equipped. 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 output 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. 4B, 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, CMYK four-color ink is supplied from the supply system of the recording device 1000 to the liquid discharge head 3, and the ink that has passed through the liquid discharge head 3 is collected to the supply system of the recording device 1000. 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. 5 shows an exploded perspective view of 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 (FIG. 3), and inside the liquid supply unit 220, each color communicating with each opening of the liquid connection portion 111 in order to remove foreign substances in the supplied ink. Another filter 221 (FIGS. 2 and 3) is 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 supply unit 220 corresponding to each color. The negative pressure control unit 230 is a unit composed of pressure adjusting valves for each color, and is generated in the supply system of the recording device 1000 (liquid discharge) caused by fluctuations in the flow rate of the liquid due to the action of valves, spring members, etc. inside each of them. The pressure loss change of the supply system on the upstream side of the head 3) is greatly attenuated. Then, it is possible to stabilize the negative pressure change on the downstream side (liquid discharge unit 300 side) of the pressure control unit within a certain range. As described with reference to FIG. 2, two pressure adjusting valves for each color are built in the negative pressure control unit 230 for each color. These two pressure regulating valves are set to different control pressures, and the high pressure side communicates with the common supply flow path 211 in the liquid discharge unit 300, and the low pressure side communicates with the common recovery flow path 212 via the liquid supply 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 and ensuring 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, as shown in FIG. 5, the cover member 130 is a member having a frame-like surface provided with a long opening 131, and the recording element substrate 10 and the sealing included in the discharge module 200 are sealed from the opening 131. The stop material portion 110 (FIG. 9) 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. 5, the flow path member 210 is a stack of a first flow path member 50, a second flow path member 60, and a third flow path member 70. The flow path member 210 is a flow path member for distributing the liquid supplied from the liquid supply unit 220 to each discharge module 200 and 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.

6 (a) to 6 (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. 6A shows the surface of the first flow path member 50 on the side on which the discharge module 200 is mounted, and FIG. 6F 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. 6 (b) and 6 (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, FIGS. 6 (d) and 6 (e), face each other. By joining the second flow path member 60 and the third flow path member 70, eight common flow path grooves 62 and 71 formed in the respective flow path members extend in the longitudinal direction of the flow path member. Common flow path is 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 (FIG. 7). The communication port 72 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. A plurality of communication ports 61 are formed on the bottom surface of the common flow path groove 62 of the second flow path member 60, and communicate with one end of the individual flow path groove 52 of the first flow path member 50. A communication port 51 is formed 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, a composite material (resin material) using alumina, LCP (liquid crystal polymer), PPS (polyphenyl sulfide) or PSF (polysulfone) as a base material and adding an inorganic filler such as silica fine particles or fibers is preferably used. be able to. 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.

Next, the connection relationship of each flow path in the flow path member 210 will be described with reference to FIG. 7. FIG. 7 shows a part of the flow path in the flow path member 210 formed by joining the first to third flow path members from the surface side of the first flow path member 50 on which the discharge module 200 is mounted. It is an enlarged perspective view. The flow path member 210 includes a common supply flow path 211 (211a, 211b, 211c, 211d) extending in the longitudinal direction of the liquid discharge head 3 for each color, and a common recovery flow path 212 (212a, 212b, 212c, 212d). It is provided. A plurality of individual supply channels (213a, 213b, 213c, 213d) formed by the individual channel grooves 52 are connected to the common supply channel 211 of each color via a communication port 61. Further, a plurality of individual recovery channels (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. 8 is a view showing a cross section taken along the line EE of FIG. As shown in this figure, each individual collection flow path (214a, 214c) communicates with the discharge module 200 via a communication port 51. Although only the individual recovery channels (214a and 214c) are shown in FIG. 8, in another cross section, the individual supply channels 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 have a flow path for supplying ink from the first flow path member 50 to the recording element 15 (FIG. 10) provided on the recording element substrate 10. It is formed. 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 (the negative pressure control unit 230 (high pressure side). It is connected to the low pressure side) via the 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, in the liquid discharge head of the present embodiment in which each flow path is connected as shown in FIGS. 7 and 8, the common supply flow path 211 to the individual supply flow path 213a to the recording element substrate 10 to the individual recovery flow for each color. A flow is generated in order from the path 213b to the common recovery flow path 212.

(Explanation of discharge module)
FIG. 9A shows a perspective view of one discharge module 200, and FIG. 9B shows 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 a sealing material 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. 5) 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)
The configuration of the recording element substrate 10 in this embodiment will be described. FIG. 10A 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. 10B shows an enlarged view of the portion shown by A in FIG. 10A. FIG. 10 (c) shows a plan view of the back surface of FIG. 10 (a). As shown in FIG. 10A, 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 "discharge port row direction".
As shown in FIG. 10B, 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 of FIG. 10A by an electric wiring (not shown) provided on the recording element substrate 10. The recording element 15 generates heat based on a pulse signal input from the control circuit of the recording device 1000 via the electric wiring board 90 (FIG. 5) and the flexible wiring board 40 (FIG. 9) to boil the liquid. The liquid is discharged from the discharge port 13 by the force of foaming due to this boiling. As shown in FIG. 10B, a liquid supply path 18 extends on one side and a liquid recovery path 19 extends on the other side along each discharge port row. The liquid supply path 18 and the liquid recovery path 19 are flow paths extending in the discharge port row direction 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.
As shown in FIG. 10B, the first and second discharge port rows are arranged in parallel on the recording element substrate 10, and the first and second pressure chamber rows correspond to the respective discharge port rows. It is formed. Further, corresponding to each of the first and second pressure chamber rows, a supply port row in which a plurality of supply ports 17a are arranged, a collection port row in which a plurality of collection ports 17b are arranged, a liquid supply path 18, and a liquid recovery are provided. Road 19 is provided. Each of the supply port 17a and the recovery port 17b extends in a direction intersecting the surface of the substrate 11 on which the recording element 15 is provided. In the present embodiment, the liquid supply passage 18 and the liquid recovery passage 19 are alternately provided in parallel with each discharge port row. Further, each of the supply port row, the recovery port row, the liquid supply path 18, and the liquid recovery path 19 extends along the extending direction of the discharge port row.

As shown in FIGS. 10C and 11, 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 will be described later. A plurality of openings 21 communicating with the liquid supply path 18 and the liquid recovery path 19 are provided. In the present embodiment, the lid member 20 is provided with three openings 21 for one liquid supply path 18 and two openings 21 for one liquid recovery path 19. As shown in FIG. 10B, each opening 21 of the lid member 20 communicates with the plurality of communication ports 51 shown in FIG. 6A. As shown in FIG. 11, the lid member 20 has a function as a lid forming a part of the walls of the liquid supply path 18 and the liquid recovery path 19 formed on the substrate 11 of the recording element substrate 10. The lid member 20 preferably has sufficient corrosion resistance against 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 changes the pitch of the flow path by the opening 21, and it is desirable that the lid member is thin in consideration of the pressure loss, and it is desirable that the lid member is composed of a film-like member.

Next, the flow of the liquid in the recording element substrate 10 will be described. FIG. 11 is a perspective view showing a cross section of the recording element substrate 10 and the lid member 20 on the BB plane in FIG. 10A. 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 (FIG. 10), and a groove forming a liquid supply path 18 and a liquid recovery path 19 extending along the discharge port row is formed on the back surface side thereof. Is formed. The liquid supply path 18 and the liquid recovery 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 the liquid supply path 18 and A differential pressure is generated between the liquid recovery path 19 and the liquid recovery path 19. When the liquid is discharged from the plurality of discharge ports 13 of the liquid discharge head 3 and recorded, the liquid flows as follows due to this differential pressure at the discharge ports that are not performing the discharge operation. That is, the liquid in the liquid supply path 18 provided in the substrate 11 flows to the liquid recovery path 19 via the supply port 17a, the pressure chamber 23, and the recovery port 17b (the flow indicated by the arrow C in FIG. 11). .. By this flow, in the discharge port 13 and the pressure chamber 23 where recording is suspended, thickening ink, bubbles, foreign substances, etc. generated by evaporation from the discharge port 13 can be collected in the liquid recovery path 19. Further, it is possible to suppress thickening of ink in the discharge port 13 and the pressure chamber 23. The liquid collected in the liquid recovery 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 (see FIG. 9b) of the support member 30. It is collected in the order of the collection flow path 212. Finally, it is collected in the supply 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. Then, 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 member The individual flow path grooves 52 and the communication ports 51 provided are supplied in this order. 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, the liquid supply 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 supplied to the recovery port 17b and the liquid recovery path 19 provided on the substrate 11, the opening 21 provided in the lid member, and the support member 30. It flows through the provided liquid communication ports 31 in order. After that, 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 were provided. 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 to the outside of the liquid discharge head 3. In the form of the first circulation path shown in FIG. 2, the liquid flowing from the liquid connecting portion 111 is supplied to the joint rubber 100 after passing through the negative pressure control unit 230. In the form of the second circulation path 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, as shown in FIGS. 2 and 3, not all the liquid flowing 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. There is also a liquid that flows from the other end of the common supply flow path 211 to the liquid supply unit 220 without flowing into the individual supply flow path 213a. In this way, by providing 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 the present embodiment is provided, the liquid is provided. It is possible to suppress the backflow of the circulating flow. In this way, in the liquid discharge head of the present embodiment, the thickening of the liquid in the pressure chamber 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, high-quality recording can be performed. it can.

(Explanation of positional relationship between recording element substrates)
FIG. 12 is a plan view showing a partially enlarged view of an adjacent portion of the recording element substrate in two adjacent discharge modules. As shown in FIG. 10, in this embodiment, a recording element substrate having a substantially parallelogram outer shape is used. As shown in FIG. 12, each discharge port row (14a to 14d) in which the discharge ports 13 of each recording element substrate 10 are arranged is arranged so as to be inclined at a constant angle with respect to the transport direction of the recording medium. As a result, at least one ejection port of the ejection row in the adjacent portion between the recording element substrates 10 overlaps in the conveying direction of the recording medium. In FIG. 12, the two discharge ports on the D line are in an overlapping relationship with each other. With such an arrangement, even if the position of the recording element substrate 10 deviates slightly from the predetermined position, the black streaks and white spots in the recorded image can be made inconspicuous by the drive control of the overlapping discharge ports. it can. Even when the plurality of recording element substrates 10 are arranged in a straight line (in-line) instead of in a staggered arrangement, the recording element while suppressing an increase in the length of the liquid discharge head 3 in the transport direction of the recording medium by the configuration of FIG. It is possible to take measures against black streaks and white spots at the joints between the substrates 10. In the present embodiment, the main plane of the recording element substrate is a parallelogram, but the present invention is not limited to this, and even when a rectangular, trapezoidal, or other shaped recording element substrate is used, the present invention is not limited to this. The configuration can be preferably applied.

[Second Embodiment]
The configuration of the inkjet recording device 1000 and the liquid ejection head 3 according to the second embodiment of the present invention will be described. In the following description, only the parts different from the first embodiment will be mainly described, and the description of the parts similar to the first embodiment will be omitted.

(Explanation of inkjet recording device)
The inkjet recording apparatus according to the second embodiment of the present invention is shown in FIG. The recording device 1000 of the second embodiment is different from the first embodiment in that full-color recording is performed on the recording medium by arranging four liquid ejection heads 3 for single colors corresponding to each ink of CMYK in parallel. In the first embodiment, the number of discharge port rows that can be used per color is one row, whereas in the second embodiment, the number of discharge port rows that can be used per color is 20 rows (FIG. 19). (A)). 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 can be improved by interpolating the discharge from the discharge port of another row located at a position corresponding to the transport direction of the recording medium with respect to the discharge port. Improved and suitable for commercial printing and the like. Similar to the first embodiment, the supply system of the recording device 1000, the buffer tank 1003, and the main tank 1006 (FIG. 2) 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 circulation route)
As in the first embodiment, as the liquid circulation path between the recording device 1000 and the liquid discharge head 3, the first and second circulation paths shown in FIG. 2 or 3 are used as in the first embodiment. be able to.

(Explanation of liquid discharge head configuration)
The structure of the liquid discharge head 3 according to the second embodiment of the present invention will be described. 13 (a) and 13 (b) are perspective views of the liquid discharge head 3 according to the present embodiment. The liquid discharge head 3 is an inkjet type line-type recording head that includes 16 recording element substrates 10 that are linearly arranged in the longitudinal direction of the liquid discharge head 3 and can record with one color of liquid. The liquid discharge head 3 includes a liquid connection portion 111, a signal input terminal 91, and a power supply terminal 92, as in the first embodiment. However, since the liquid discharge head 3 of the present embodiment has more discharge port rows than the first embodiment, the signal output terminals 91 and the power supply terminals 92 are arranged on both sides of the liquid discharge head 3. This is to reduce the voltage drop and signal transmission delay that occur in the wiring portion provided on the recording element substrate 10.

FIG. 14 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. 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 the first embodiment, but the functions for ensuring the rigidity of the liquid discharge head are different. In the first embodiment, the rigidity of the liquid discharge head is mainly secured by the liquid discharge unit support portion 81, but in the liquid discharge head of the second embodiment, the second flow path member 60 included in the liquid discharge unit 300 is used. The rigidity of the liquid discharge head is ensured. The liquid discharge unit support portion 81 in the present embodiment is connected to both ends of the second flow path member 60, and the liquid discharge unit 300 is mechanically coupled to the carriage of the recording device 1000 to form a liquid discharge head 3. Perform positioning. The liquid supply unit 220 including the negative pressure control unit 230 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 220. The two negative pressure control units 230 are set to control the pressure with different, relatively high and low negative pressures. Further, when the negative pressure control units 230 on the high pressure side and the low pressure side are installed at both ends of the liquid discharge head 3 as shown in this figure, the common supply flow path 211 extending in the longitudinal direction of the liquid discharge head 3 The liquid flows in the common recovery flow path 212 face each other. In this way, heat exchange is promoted between the common supply flow path 211 and the common recovery flow path 212, and the temperature difference between the two common flow paths is reduced. Therefore, there is an advantage that a temperature difference is less likely to occur in each of the plurality of recording element substrates 10 provided along the common flow path, and recording unevenness due to the temperature difference is less likely to occur.

Next, the details of the flow path member 210 of the liquid discharge unit 300 will be described. As shown in FIG. 14, the flow path member 210 is a stack of the first flow path member 50 and the second flow path member 60, and distributes the liquid supplied from the liquid supply unit 220 to each discharge module 200. .. Further, the flow path member 210 functions as a flow path member for returning the liquid recirculated from the discharge module 200 to the liquid supply unit 220. The second flow path member 60 of the flow path member 210 is a flow path member in which the common supply flow path 211 and the common recovery flow path 212 are formed therein, and also has a function of mainly carrying the rigidity of the liquid discharge head 3. Have. Therefore, as the material of the second flow path member 60, a material having sufficient corrosion resistance against liquid and high mechanical strength is preferable. Specifically, SUS, Ti, alumina and the like can be preferably used.

FIG. 15A shows the surface of the first flow path member 50 on the side on which the discharge module 200 is mounted, and FIG. 15B shows the back surface of the first flow path member 50, which is in contact with the second flow path member 60. It is a figure which showed the surface of. Unlike the first embodiment, the first flow path member 50 in the second embodiment is formed by arranging a plurality of members corresponding to each discharge module 200 adjacent to each other. By adopting the structure divided in this way, it is possible to correspond to the length of the liquid discharge head by arranging a plurality of modules, so that it is a relatively long scale corresponding to, for example, B2 size and longer. It can be particularly preferably applied to the liquid discharge head of. As shown in FIG. 15A, the communication port 51 of the first flow path member 50 fluidly communicates with the discharge module 200, and as shown in FIG. 15B, individual communication of the first flow path member 50. The port 53 fluidly communicates with the communication port 61 of the second flow path member 60. FIG. 15 (c) shows the surface of the second flow path member 60 on the side where it comes into contact with the first flow path member 50, and FIG. 15 (d) shows a cross section of the central portion of the second flow path member 60 in the thickness direction. 15 (e) is a view showing a surface of the second flow path member 60 on the side that comes into contact with the liquid supply unit 220. The functions of the flow path and the communication port of the second flow path member 60 are the same as those for one color of the first embodiment. One of the common flow path grooves 71 of the second flow path member 60 is the common supply flow path 211 shown in FIG. 16, and the other is the common recovery flow path 212, respectively, along the longitudinal direction of the liquid discharge head 3. , The liquid is supplied from one end side to the other end side. In the present embodiment, unlike the first embodiment, the longitudinal directions of the liquids in the common supply flow path 211 and the common recovery flow path 212 are opposite to each other.

FIG. 16 is a perspective view showing the connection relationship of the liquid between the recording element substrate 10 and the flow path member 210. As shown in FIG. 16, 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 flow path member 210. The communication port 61 of the second flow path member 60 is connected in position with the individual communication port 53 of each first flow path member 50, and is a common supply flow path from the communication port 72 of the second flow path member 60. A liquid supply path is formed that communicates with the communication port 51 of the first flow path member 50 via 211. Similarly, a liquid supply path that communicates from the communication port 72 of the second flow path member 60 to the communication port 51 of the first flow path member 50 via the common recovery flow path 212 is also formed.
FIG. 17 is a diagram showing a cross section taken along the line FF of FIG. As shown in this figure, the common supply flow path is connected to the discharge module 200 via the communication port 61, the individual communication port 53, and the communication port 51. Although not shown in FIG. 8, in another cross section, it is clear with reference to FIG. 16 that the individual recovery channels are connected to the discharge module 200 by a similar path. Similar to the first embodiment, each discharge module 200 and the recording element substrate 10 are formed with a flow path communicating with each discharge port 13, and a part or all of the supplied liquid suspends the discharge operation. It is possible to recirculate through the discharge port 13 (pressure chamber 23). Further, as in the first embodiment, the common supply flow path 211 is via the negative pressure control unit 230 (high pressure side), and the common recovery flow path 212 is via the negative pressure control unit 230 (low pressure side) and the liquid supply unit 220. It is connected. Therefore, due to the differential pressure, a flow is generated from the common supply flow path 211, passing through the discharge port 13 (pressure chamber 23) of the recording element substrate 10, and flowing to the common recovery flow path 212.

(Explanation of discharge module)
FIG. 18A shows a perspective view of one discharge module 200, and FIG. 18B shows an exploded view thereof. The differences from the first embodiment are as follows. That is, the flexible wiring board 40 in which a plurality of terminals 16 are arranged on both side portions (each long side portion of the recording element substrate 10) along the plurality of discharge port row directions of the recording element substrate 10 and electrically connected to the terminals 16 is also formed. The point is that two sheets are arranged with respect to one recording element substrate 10. This is because the number of discharge port rows provided on the recording element substrate 10 is 20, which is significantly larger than that of the 8 rows of the first embodiment. That is, the purpose is to shorten the maximum distance from the terminal 16 to the recording element 15 provided corresponding to the discharge port row, and to reduce the voltage drop and signal transmission delay that occur in the wiring portion in the recording element substrate 10. It is supposed to be. Further, the liquid communication port 31 of the support member 30 is provided on the recording element substrate 10 and opens so as to straddle all the discharge port rows. Other points are the same as those in the first embodiment.

(Explanation of the structure of the recording element substrate)
FIG. 19A is a schematic view of the surface of the recording element substrate 10 on the side where the discharge port 13 is arranged, and FIG. 19C is a schematic view showing the back surface of the surface of FIG. 19A. FIG. 19B is a schematic view showing the surface of the recording element substrate 10 when the lid member 20 provided on the back surface side of the recording element substrate 10 is removed in FIG. 19C. As shown in FIG. 19B, liquid supply paths 18 and liquid recovery paths 19 are alternately provided on the back surface of the recording element substrate 10 along the discharge port row direction. Although the number of discharge port rows is significantly increased as compared with the first embodiment, the essential difference from the first embodiment is that the terminals 16 are on both sides of the recording element substrate along the discharge port row direction as described above. It is arranged in the department. A set of a liquid supply path 18 and a liquid recovery path 19 are provided for each discharge port row, and the lid member 20 is provided with an opening 21 that communicates with the liquid communication port 31 of the support member 30. , The basic configuration is the same as that of the first embodiment.

[Explanation of features common to each embodiment]
Next, a characteristic configuration common to each of the above-described embodiments will be described. Hereinafter, the case of the liquid discharge head according to the first embodiment shown in FIGS. 1 to 12 will be described, but the same applies to the case of the liquid discharge head according to the second embodiment.

(Explanation of liquid flow in the discharge port)
FIG. 21 is a schematic view for explaining in detail the vicinity of the discharge port of the recording element substrate. 21 (a) is a plan view seen from the discharge direction in which the liquid is discharged, FIG. 21 (b) is a cross-sectional view taken along the line GG of FIG. 21 (a), and FIG. 21 (c) is FIG. 21. It is a perspective view which shows the cross section in the line GG of (a).
In the discharge port 13 that does not perform the discharge operation in the recording element substrate 10, as described above, the liquid in the liquid supply path 18 provided in the substrate 11 passes through the supply port 17a, the pressure chamber 23, and the recovery port 17b. A circulating flow C flowing to the liquid recovery path 19 is formed. The velocity of the circulating flow C in the pressure chamber is, for example, about 0.1 to 100 mm / s, and even if the discharge operation is performed while the liquid is flowing, the velocity is less affected by the impact accuracy and the like. At this time, the discharge port 13 is formed with a liquid meniscus, that is, a discharge port interface 24, which is an interface between the liquid and the atmosphere. As shown in FIG. 21B, the discharge port 13 is an opening located at the end of the tubular discharge port portion 25 formed in the discharge port forming member 12, and is a discharge port portion 25. Communicates the discharge port 13 and the pressure chamber 23. The direction in which the liquid is discharged from the discharge port 13 (vertical direction in FIG. 21 (b)) is referred to as the "discharge direction", and the flow direction of the liquid in the pressure chamber 23 (horizontal direction in FIG. 21 (b)) is simply ". It is called "flow direction".
Here, the dimensions of the pressure chamber 23 and the discharge port 25 are defined as follows. That is, as shown in FIG. 21B, the height of the pressure chamber 23 on the upstream side in the flow direction with respect to the communication portion with the discharge port portion 25 is defined as H, and the discharge direction of the discharge port portion 25. Is defined as P, and the length in the flow direction is defined as W. As an example, these dimensions are 3 to 30 μm for H, 3 to 30 μm for P, and 6 to 30 μm for W. Further, in the following description, an example is used in which an ink having a non-volatile solvent concentration of 30%, a coloring material concentration of 3%, and a viscosity adjusted to 0.002 to 0.003 Pa · s is used as the discharged liquid. Listed in.

FIG. 22 is an enlarged cross-sectional view of the vicinity of the discharge port 13, showing the state of the circulation flow C in the discharge port 13, the discharge port 25, and the pressure chamber 23 when the circulation flow C is in a steady state. .. Specifically, for the recording element substrate 10 having H of 14 μm, P of 5 μm, and W of 12.4 μm, ^{ink having a flow rate of 1.26 × 10 -4} ml / min is supplied from the supply port 17a to the pressure chamber 23. The state of the flow when it flows into is shown by an arrow. In this figure, the length of the arrow does not represent the magnitude of the velocity.
Although the colorant density of the ink changes due to the evaporation of the ink from the ejection port 13, the recording element substrate 10 having the above-mentioned dimensions prevents such ink from staying in the ejection port 13 and the ejection port 25. It is designed to be suppressed. That is, as shown in FIG. 22, after a part of the circulating flow C in the pressure chamber 23 flows into the discharge port portion 25 and reaches the meniscus position (near the meniscus interface) formed in the discharge port 13. It returns from the discharge port 25 to the pressure chamber 23 again. As a result, not only the discharge port 25, which is easily affected by evaporation, but also the ink near the discharge port interface 24, which is particularly affected by evaporation, flows out to the pressure chamber 23 without staying inside the discharge port 25. It becomes possible. Here, the circulating flow C has a velocity component (hereinafter, "positive velocity" in the flow direction (from left to right in FIG. 21B) at least in the vicinity of the central portion (central portion of the discharge port) of the discharge port interface 24. It is characteristic that it has (called "ingredients"). In the following, a flow mode in which the circulating flow C has a positive velocity component at least in the vicinity of the central portion of the discharge port interface 24 as shown in FIG. 22 is referred to as “flow mode A”. Further, as will be described later, a flow mode having a negative velocity component (from right to left in FIG. 21B) opposite to the positive velocity component near the center of the discharge port interface 24 is referred to as “flow mode”. I will call it "B".

Whether the circulation flow C in the liquid discharge head is in the flow mode A (or in the flow mode B) is determined according to the dimensions H, P, and W of the pressure chamber 23 and the discharge port 25 described above. , Found by the present inventors. That is, in the liquid discharge head of the flow mode A, the height H of the pressure chamber 23 on the upstream side in the flow direction, the length P of the discharge port portion 25 in the discharge direction, and the length W in the flow direction (FIG. 21B). See), but satisfies the following relationship.
H ^−0.34 × P ^−0.66 × W> 1.7 (1)
Therefore, the flow mode A as shown in FIG. 22 is realized in the liquid discharge head satisfying the relation of the formula (1), and the flow mode B is realized in the liquid discharge head not satisfying the relation of the formula (1). The left side of the equation (1) is called a determination value J.

図２３において、ＨとＰとＷの関係がしきい線Ｔの上部（斜線を付した領域）となる液体吐出ヘッドでは流れモードＡが実現され、しきい線Ｔの下部となる液体吐出ヘッドでは流れモードＢが実現される。すなわち、以下の関係を満たす液体吐出ヘッドでは流れモードＡが実現される。

式（３）を整理すると式（１）が得られることから、ＨとＰとＷの関係が式（１）を満たす液体吐出ヘッド（判定値Ｊが１．７以上の液体吐出ヘッド）では流れモードＡが実現される。
一方、ＨとＰとＷが以下の関係を満す液体吐出ヘッドでは流れモードＢが実現される。
Ｈ^{−０．３４}×Ｐ^{−０．６６}×Ｗ≦１．７ （４）
なお、流れモードＢの液体吐出ヘッドは、吐出口部２５の吐出方向における長さＰ、すなわち吐出口形成部材１２の厚さを厚くすることができるため、吐出口形成部材１２の割れを抑制することができる点で有利である。また、圧力室２３の高さＨを高くすることができるため、循環流Ｃを生じさせるために必要な圧力差を小さくすることができる点でも有利である。 FIG. 23 is a graph for explaining the relationship between each dimension of the liquid discharge head and the flow mode. The horizontal axis shows the ratio of P to H (P / H), and the vertical axis shows the ratio of W to P (W / P). The thick line T in the figure is a threshold line, which satisfies the following relationship.

In FIG. 23, the flow mode A is realized in the liquid discharge head in which the relationship between H, P, and W is the upper part of the threshold line T (the shaded area), and in the liquid discharge head in the lower part of the threshold line T. Flow mode B is realized. That is, the flow mode A is realized in the liquid discharge head that satisfies the following relationship.

Since the formula (1) is obtained by rearranging the formula (3), the flow flows in the liquid discharge head (the liquid discharge head having the determination value J of 1.7 or more) in which the relationship between H, P, and W satisfies the formula (1). Mode A is realized.
On the other hand, the flow mode B is realized in the liquid discharge head in which H, P and W satisfy the following relationship.
H ^−0.34 × P ^−0.66 × W ≦ 1.7 (4)
Since the liquid discharge head in the flow mode B can increase the length P of the discharge port portion 25 in the discharge direction, that is, the thickness of the discharge port forming member 12, cracking of the discharge port forming member 12 is suppressed. It is advantageous in that it can be done. Further, since the height H of the pressure chamber 23 can be increased, it is also advantageous in that the pressure difference required to generate the circulating flow C can be reduced.

Here, the above relational expression and the flow in the discharge port portion will be described in detail with reference to FIGS. 24 and 25. FIG. 24 is a graph showing the results of confirming the state of the flow in the discharge port portion for the liquid discharge heads having various shapes. In FIG. 24, ● indicates the liquid discharge head determined to be in the flow mode A, and × indicates the liquid discharge head determined to be in the flow mode B. 25 (a) to 25 (d) are diagrams showing an example of the state of the circulating flow in the discharge port portion in the liquid discharge heads shown at points A to D in FIG. 24, respectively.
The liquid discharge head shown at point A in FIG. 24 has H of 3 μm, P of 9 μm, and W of 12 μm, and the determination value J on the left side of the equation (1) is 1.93, which is larger than 1.7. In this case, as shown in FIG. 25A, the actual flow in the discharge port portion 25 is the flow mode A having a positive velocity component in the vicinity of the central portion of the discharge port interface 24. The liquid discharge head shown at point B in FIG. 24 has H of 8 μm, P of 9 μm, and W of 12 μm, and the determination value J is 1.39, which is smaller than 1.7. In this case, the actual flow in the discharge port portion 25 is in the flow mode B having a negative velocity component in the vicinity of the central portion of the discharge port interface 24, as shown in FIG. 25 (b). The liquid discharge head corresponding to the point C in FIG. 24 has H of 6 μm, P of 6 μm, and W of 12 μm, and the determination value J is 2.0, which is larger than 1.7. In this case, as shown in FIG. 25 (c), the actual flow in the discharge port portion 25 is the flow mode A having a positive velocity component in the vicinity of the central portion of the discharge port interface 24. The liquid discharge head corresponding to the point D in FIG. 24 has H of 6 μm, P of 6 μm, and W of 6 μm, and the determination value J is 1.0, which is smaller than 1.7. In this case, the actual flow in the discharge port portion 25 is in the flow mode B having a negative velocity component in the vicinity of the central portion of the discharge port interface 24, as shown in FIG. 25 (d).

In this way, the liquid discharge head in the flow mode A and the liquid discharge head in the flow mode B can be distinguished from each other with the threshold line T in FIG. 23 as a boundary. That is, in the liquid discharge head in which the determination value J of the equation (1) is larger than 1.7, the flow mode A is realized, and the circulating flow C has a positive velocity component at least in the vicinity of the central portion of the discharge port interface 24.
The above conditions of H, P, and W have a dominant influence on whether the circulating flow C in the discharge port 25 is in the flow mode A or the flow mode B. Conditions other than these, such as the flow velocity of the circulating flow C, the viscosity of the ink, and the width of the ejection port 13 (the length in the direction orthogonal to the flow direction), are more affected than the conditions of H, P, and W. Is very small. Therefore, the circulation flow velocity and the viscosity of the ink can be appropriately set according to the required specifications of the liquid ejection head (inkjet recording device) and the environmental conditions used. For example, an ink having a flow velocity of 0.1 to 100 mm / s and a viscosity of 0.01 Pa · s or less of the circulating flow C in the pressure chamber 23 can be used. Further, in the liquid ejection head of the flow mode A, when the amount of ink evaporated from the ejection port increases due to an environmental change during use or the like, the flow mode A is maintained by appropriately increasing the flow rate of the circulating flow C. can do. On the other hand, in the liquid discharge head whose dimensions are set so as to be in the flow mode B, the flow mode A is not set even if the flow rate of the circulating flow C is increased. Among the liquid discharge heads in the flow mode A, a liquid discharge head having H of 20 μm or less, P of 20 μm or less, and W of 30 μm or less is particularly preferable, and this enables higher-definition image formation.

The liquid discharge head in the flow mode A and the liquid discharge head in the flow mode B have different velocity components of the circulating flow C near the center of the discharge port interface 24, so that the ink color material concentration in the discharge port 25 is different. The state of is also different. 26 (a) and 26 (b) are diagrams showing the state of the ink color material density in the discharge port 25 in the liquid discharge heads of the flow mode A and the flow mode B, respectively. ^{Specifically, in FIGS. 26 (a) and 26 (b), ink having a flow rate of 1.26 × 10 -4} ml / min is applied to the pressure chamber 23 in the liquid discharge heads of the flow mode A and the flow mode B, respectively. The color material density of the ink when it flows in is represented by contour lines. FIG. 26 (a) corresponds to a liquid discharge head having H of 14 μm, P of 5 μm, and W of 12.4 μm, and FIG. 26 (b) shows a liquid having H of 14 μm, P of 11 μm, and W of 12.4 μm. Compatible with discharge heads.
In the liquid discharge head of the flow mode A shown in FIG. 26 (a), the concentration of the color material of the ink in the discharge port 25 is relatively lower than that of the liquid discharge head of the flow mode B shown in FIG. 26 (b). It has become. This is because in the liquid discharge head of the flow mode A shown in FIG. 26 (a), the circulation flow C having a positive velocity component reaches the vicinity of the discharge port interface 24, so that the ink in the discharge port portion 25 is pressure chambered. It means that it is moved (outflowed) to 23. As a result, in the liquid ejection head of the flow mode A, it is possible to suppress the retention of ink inside the ejection port portion 25, and it is possible to reduce the increase in the color material concentration.

27 shows a coloring material of ink ejected from the liquid ejection head (head A) of the flow mode A shown in FIG. 26 (a) and the liquid ejection head (head B) of the flow mode B shown in FIG. 26 (b), respectively. It is a graph which shows the experimental result which compared the concentration. Specifically, in FIG. 27, in each head, ink is applied to the recording medium in a state where the circulation flow C is generated in the pressure chamber 23 and in a state where there is no ink flow without generating the circulation flow C. The results of the experiment are shown in which the ink is ejected and the color material density of the ink at that time is compared. The horizontal axis shows the leaving time after the droplets are ejected from the ejection port, and the vertical axis represents the color material density ratio of the dots formed on the recording medium by the ejected ink, specifically, the ejection frequency is 100 Hz. The ratio when the density of the dots formed by the ink ejected in 1 is 1.
As shown in FIG. 27, when the circulating flow C is not generated, both the head A and the head B have a concentration ratio of 1.3 or more when the leaving time is 1 second or more, and the ink coloring material is left in an early time. The concentration is high. On the other hand, when the circulating flow C is generated, the concentration ratio of the head B is about 1.3, and the increase in the colorant concentration can be reduced as compared with the case where the circulating flow C is not generated. However, the reduction effect is not sufficient because the ink having a high colorant concentration is retained in the ejection port 25 due to the evaporation of the ink from the ejection port 13. Further, the present inventors have found that it is difficult to visually recognize the color unevenness when the color material density change is about 1.2 or less, but the head B is not sufficient in this respect as well. On the other hand, in the head A, the color material density ratio can be suppressed to 1.1 or less even if the leaving time is about 1.5 seconds, and the occurrence of color unevenness in the image can be reduced. Note that FIG. 27 shows the experimental results when the color material concentration increases with evaporation, but the same applies when the color material concentration decreases with evaporation.

As described above, in the liquid discharge head of the flow mode A, the circulating flow C having a positive velocity component reaches the discharge port interface 24, thereby pressing the ink in the discharge port portion 25, particularly the ink in the vicinity of the discharge port interface 24. It can be moved to room 23. As a result, it is possible to suppress the retention of ink in the ejection port 25, and it is possible to reduce the increase in the color material concentration of the ink in the ejection port 25 even when the ink is evaporated from the ejection port 13. It will be possible. Further, in the liquid discharge head of the flow mode A, the circulating flow C having a positive velocity component reaches the discharge port interface 24 even when the discharge operation is stopped, so that the ink coloring material in the discharge port portion 25 is always used. The increase in concentration is reduced. Therefore, it is possible to satisfactorily discharge the first shot after the pause, and it is possible to reduce the occurrence of color unevenness in the image.

(Explanation of deviation in the discharge direction of the first shot after pause)
By the way, in the liquid discharge head of the flow mode A, the concentration of the coloring material in the discharge port 25 is high on the downstream side of the circulating flow C as shown in FIG. 26A, and the liquid viscosity is also high on the downstream side. .. On the other hand, in the liquid discharge head in the flow mode B, the concentration of the coloring material in the discharge port 25 is high on the upstream side of the circulating flow C as shown in FIG. 26 (b), and the liquid viscosity is also high on the upstream side. .. In this way, in the liquid discharge head in each flow mode, the color material concentration and the liquid viscosity in the discharge port 25 are biased, and due to this bias, the target direction is in the liquid discharge direction as shown below. There may be a deviation from. Since it takes a certain period of time for the concentration distribution and the viscosity distribution in the discharge port 25 to be formed, this deviation in the discharge direction does not occur in the case of continuous discharge, and is the first shot after a certain period of pause. This is a phenomenon that occurs in the case of discharge.
FIG. 28A is a diagram showing a state of deviation in the discharge direction in the liquid discharge head in the flow mode A. FIG. 28 (b) is a graph plotting the average value of deviations from the target landing position when the flow velocity of the circulating flow C is changed in the liquid discharge head of the flow mode A shown in FIG. 26 (a). In the liquid discharge head of the flow mode A, since the portion having a relatively high viscosity is located on the downstream side of the circulation flow C in the discharge port portion 25, the liquid discharge direction is as compared with the case where the liquid is continuously discharged. As shown in 28 (a), it may shift to the upstream side with respect to the direction of the circulating flow C. This deviation is, for example, about 5 μm, as shown in FIG. 28 (b).
FIG. 29A is a diagram showing a state of deviation in the discharge direction in the liquid discharge head in the flow mode B. FIG. 29 (b) is a graph plotting the average value of deviations from the target landing position when the flow velocity of the circulating flow C is changed in the liquid discharge head of the flow mode B shown in FIG. 26 (b). In the liquid discharge head of the flow mode B, since the portion having a relatively high viscosity is located on the upstream side of the circulation flow C in the discharge port portion 25, the liquid discharge direction is as compared with the case where the liquid is continuously discharged. As shown in 29 (a), it may shift to the downstream side with respect to the direction of the circulating flow C. This deviation is, for example, about 5 μm, as shown in FIG. 29 (b).

(Explanation of liquid discharge head configuration considering deviation in liquid discharge direction)
FIG. 30A is a plan view showing a configuration example of a liquid discharge head configured in consideration of the deviation in the liquid discharge direction described above, and FIG. 30B is a plan view showing another configuration example. Is. In FIGS. 30A and 30B, the direction of the circulation flow C in the pressure chamber 23 corresponding to each discharge port 13 is indicated by an arrow. In this way, by making the directions of the circulating flows C the same in all the discharge ports 13 of the liquid discharge head 3, the deviation of the discharge direction of the first shot after the pause can be made uniform. As a result, even if the discharge direction of the first shot after the pause is deviated, the deviation direction at each discharge port 13 is the same direction, so that a higher quality ruled line is formed even when printing a ruled line, for example. It is possible to form a higher-definition and high-quality image.
The configuration of the liquid discharge head 3 is not limited to the example of the in-line arrangement shown in FIGS. 30A and 30B, and various configurations are possible. FIG. 31 (a) shows a diagram corresponding to FIG. 30 (b). FIG. 31 (b) shows a configuration example in which a plurality of recording element substrates 10 are linearly arranged. As shown, it is also possible to arrange a plurality of recording element substrates 10 in a staggered pattern. Further, with respect to a configuration example in which a plurality of recording element substrates 10 are provided on one support member 30 as shown in FIGS. 31 (a) and 31 (b), FIGS. 31 (c) and 31 (d) are shown. As shown in the above, the recording element substrate 10 may be individually provided on the plurality of support members 30. Further, as described above, the shape of the main plane of the recording element substrate 10 may also be the parallelogram shown in FIGS. 31 (a) and 31 (c), and FIGS. 31 (b) and 31 (d). ) May be a rectangle. In any of the configuration examples shown in FIGS. 31 (a) to 31 (d), the direction of the corresponding circulating flow C is the same in all the discharge ports 13 of the liquid discharge head 3.

(Explanation of decrease in discharge speed of the first shot after pause)
FIG. 32 is a graph in which the pause time of the discharge operation is variously changed in the liquid discharge head of the flow mode A shown in FIG. 26A, and the discharge rate with respect to the number of discharges after the pause at that time is plotted. Specifically, it is a graph in which the ratio when the average value of the discharge rates from the 10th to 30th shots after the pause is set to 1 is plotted on the vertical axis. As is clear from FIG. 32, from the second and subsequent discharges after the pause, the discharge speed is almost the same as the discharge speed in the case of continuous discharge, but in the first discharge after the pause, the discharge speed is almost the same. The discharge rate is slightly slower. This is because, as described above, by suspending the discharge operation, the viscosity of the liquid in the discharge port 25 becomes slightly higher than that in the pressure chamber 23. That is, since it takes a certain period of time for the color material concentration (liquid viscosity) in the discharge port 25 to increase in the decrease in the discharge rate, the case of continuous discharge is the same as the above-mentioned deviation in the discharge direction. This is a phenomenon that does not occur and occurs in the case of the first discharge after a certain period of pause. Such a decrease in the discharge speed also occurs in the liquid discharge head in the flow mode B.

(Explanation of liquid discharge head configuration considering the relative movement direction with the recording medium)
The decrease in the ejection speed of the first shot after pausing as compared with the case of continuous ejection means that the actual landing position on the recording medium deviates from the target landing position. The direction of this deviation is always the upstream side of the moving direction of the recording medium relative to the liquid discharge head (hereinafter, also simply referred to as “moving direction”). On the other hand, the deviation of the landing position also occurs due to the deviation of the liquid discharge direction, but the direction of the deviation of the landing position differs depending on the relationship between the discharge deviation direction and the moving direction of the recording medium. Further, as described above, the direction in which the discharge deviates differs depending on the type of the flow mode. The liquid discharge head in the flow mode A is on the upstream side in the direction of the circulation flow C, and the liquid discharge head in the flow mode B circulates. It is on the downstream side in the direction of flow C. Therefore, as shown below, by appropriately setting the moving direction of the recording medium according to the type of flow mode, the deviation of the landing position due to the decrease in the ejection speed and the deviation of the landing position due to the deviation of the ejection direction are substantially offset. Will be possible.

FIG. 33 is a diagram showing the relationship between the direction of the circulating flow C in the pressure chamber 23 and the relative moving direction between the liquid discharge head and the recording medium in the liquid discharge head in the flow mode A. As shown in FIG. 33, in the liquid discharge head in the flow mode A, the direction of the circulating flow C in the pressure chamber 23 and the transport direction S of the recording medium 2 are set in opposite directions. Here, the opposite direction does not necessarily mean only the completely opposite direction shown in FIG. 33 (a), and as shown in FIG. 33 (b), the circulating flow C is vectored in the moving direction S of the recording medium 2. It means that it has a component in the direction opposite to the component in the moving direction S when decomposed.
In the liquid discharge head of the flow mode A shown in FIG. 33, the deviation of the discharge direction of the first shot after the pause is on the upstream side of the circulation flow C as described above, and therefore, the deviation of the landing position due to this deviation moves. It is on the downstream side of the direction S. On the other hand, the deviation of the landing position due to the decrease in the discharge speed of the first shot after the pause is on the upstream side of the moving direction S as described above. Therefore, the deviation of the landing position due to the deviation of the ejection direction and the deviation of the landing position due to the decrease of the ejection speed cancel each other out, so that the ink is landed in the vicinity of the target landing position in the first ejection after the pause. Will be possible.

FIG. 34 is a diagram showing the relationship between the direction of the circulating flow C in the pressure chamber 23 and the relative moving direction between the liquid discharge head and the recording medium in the liquid discharge head in the flow mode B. As shown in FIG. 34, in the liquid discharge head in the flow mode B, the direction of the circulating flow C in the pressure chamber 23 and the transport direction S of the recording medium 2 are set to be the same direction. Here, the same direction does not necessarily mean only the completely same direction shown in FIG. 34 (a), but as shown in FIG. 34 (b), the circulating flow C is vectored in the moving direction S of the recording medium 2. It means that it has a component in the same direction as the component in the moving direction S when decomposed.
In the liquid discharge head of the flow mode B shown in FIG. 34, the deviation of the discharge direction of the first shot after the pause is on the downstream side of the circulation flow C as described above, and therefore, the deviation of the landing position due to this deviation moves. It is on the upstream side of the direction S. On the other hand, the deviation of the landing position due to the decrease in the discharge speed of the first shot after the pause is on the upstream side of the moving direction S as described above. Therefore, the deviation of the landing position due to the deviation of the ejection direction and the deviation of the landing position due to the decrease of the ejection speed cancel each other out, so that the ink is landed in the vicinity of the target landing position in the first ejection after the pause. Will be possible.

As described above, by appropriately setting the moving direction of the recording medium according to the type of flow mode, the landing position is disturbed due to the change in the ejection speed that occurs at the time of the first ejection after the pause and the disturbance in the ejection direction. It becomes possible to form a higher-definition and higher-quality image by reducing the number of images.
It should be noted that such a method is particularly effective for a liquid discharge head configured to control the temperature of the substrate 11. That is, by adjusting the temperature of the substrate 11, the change in the discharge speed and the change in the discharge amount caused by the temperature change of the substrate 11 can be suppressed, but when the temperature of the liquid rises, the liquid from the discharge port 13 is charged. The amount of evaporation increases, and the concentration distribution in the discharge port 25 increases. As a result, both the deviation of the ejection direction of the first shot after the pause and the decrease of the ejection speed may become large, but the moving direction of the recording medium is appropriately set according to the type of the flow mode. It is possible to cancel each other out the disorder of the landing position caused by. In order to adjust the temperature of the substrate 11, the recording element 15 used for discharging the liquid can be used as the temperature adjusting means, and another heater for controlling the temperature can be provided.
Further, such a method can also be applied to a serial type liquid discharge head, and in that case, the direction of the circulating flow C may be reversed according to the scanning direction of the liquid discharge head. Examples of the method of reversing the direction of the circulating flow C include a method of reversing the pressure difference between the two tanks and a method of reversing the rotation of the pump.

3 Liquid discharge head 10 Recording element substrate 18 Liquid supply path 19 Liquid recovery path 23 Pressure chamber

Claims (14)

The first and second discharge port rows in which the discharge ports for discharging the liquid are arranged and parallel to each other,
The first and second pressure chamber rows provided corresponding to the first and second discharge port rows are internally provided with a recording element for generating energy used for discharging the liquid, and the above-mentioned A first and second pressure chamber row in which pressure chambers communicating through the discharge port and the discharge port are arranged, respectively.
A first liquid supply path for supplying liquid to the first pressure chamber row, a first liquid recovery path for recovering liquid from the first pressure chamber row, and the like.
A second liquid supply path for supplying liquid to the second pressure chamber row, a second liquid recovery path for recovering liquid from the second pressure chamber row, and the like.
A page-wide type liquid discharge head provided with a plurality of recording element substrates provided with a plurality of recording element substrates over a length corresponding to the width of the recording medium .
The first liquid supply path, the first liquid recovery path, the second liquid supply path, and the second liquid recovery path are provided in this order in parallel.
At the time of recording, in each of the plurality of pressure chambers included in the first and second pressure chamber rows, the liquid in the pressure chamber flowing from the liquid supply passage to the liquid recovery passage through the pressure chamber. The flow direction is the same,
The height H of the pressure chamber on the upstream side in the liquid flow direction with respect to the communication portion with the discharge port portion, the length P of the discharge port portion in the liquid discharge direction, and the discharge port portion. The length W in the flow direction of the liquid (H, P, W have the same unit of length) is
^{H -0.34 × P -0.66 × W>} 1.7
If you meet the relationship
Said first and second plurality of flow direction of the liquid flowing within each of said pressure chamber included in the pressure chamber row in the relative moving direction of the recording medium with respect to the liquid discharge head definitive when the liquid discharge Liquid discharge head in the opposite direction. The first and second discharge port rows in which the discharge ports for discharging the liquid are arranged and parallel to each other,
The first and second pressure chamber rows provided corresponding to the first and second discharge port rows are internally provided with a recording element for generating energy used for discharging the liquid, and the above-mentioned A first and second pressure chamber row in which pressure chambers communicating through the discharge port and the discharge port are arranged, respectively.
A first liquid supply path for supplying liquid to the first pressure chamber row, a first liquid recovery path for recovering liquid from the first pressure chamber row, and the like.
A second liquid supply path for supplying liquid to the second pressure chamber row, a second liquid recovery path for recovering liquid from the second pressure chamber row, and the like.
A page-wide type liquid discharge head provided with a plurality of recording element substrates provided with a plurality of recording element substrates over a length corresponding to the width of the recording medium .
The first liquid supply path, the first liquid recovery path, the second liquid supply path, and the second liquid recovery path are provided in this order in parallel.
At the time of recording, in each of the plurality of pressure chambers included in the first and second pressure chamber rows, the liquid in the pressure chamber flowing from the liquid supply passage to the liquid recovery passage through the pressure chamber. The flow direction is the same,
The height H of the pressure chamber on the upstream side in the liquid flow direction with respect to the communication portion with the discharge port portion, the length P of the discharge port portion in the liquid discharge direction, and the discharge port portion. The length W in the flow direction of the liquid (H, P, W have the same unit of length) is
H ^−0.34 × P ^−0.66 × W ≦ 1.7
If you meet the relationship
Said first and second plurality of flow direction of the liquid flowing within each of said pressure chamber included in the pressure chamber row in the relative moving direction of the recording medium with respect to the liquid discharge head definitive when the liquid discharge Liquid discharge head in the same direction as. The liquid discharge head according to claim 1 or 2, wherein the recording element substrate includes a discharge port forming member including the discharge port and a substrate including the recording element. The recording element substrate includes a first supply port row in which a plurality of first supply ports for supplying liquid from the first liquid supply path to the first pressure chamber row are arranged, and the first supply port row. A first collection port row in which a plurality of first collection ports for collecting liquid from the pressure chamber row 1 are arranged in the first liquid recovery path, and the second collection port row from the second liquid supply path. A second supply port row in which a plurality of second supply ports for supplying liquid to the pressure chamber row of the liquid are arranged, and a liquid is collected from the second pressure chamber row to the second liquid recovery path. A second collection port row, in which a plurality of second collection ports are arranged for the purpose, is provided.
From claim 1, the first and second liquid supply paths and the first and second liquid recovery paths each extend along the extending direction of the first discharge port row. The liquid discharge head according to any one of 3. Said first and second supply ports, the first and second recovery ports each, the recording element of the substrate extends in a direction intersecting the plane provided, according to claim 4 Liquid discharge head. The liquid discharge head according to any one of claims 1 to 5, wherein the recording element is a heat generating element that generates heat energy used for discharging a liquid. The one according to any one of claims 1 to 6, wherein the flow velocity of the liquid flowing through the pressure chamber flowing from the liquid supply passage to the liquid recovery passage through the pressure chamber is 0.1 to 100 mm / s. Liquid discharge head. The liquid discharge head according to any one of claims 1 to 7, wherein different types of liquids are discharged from the first and second discharge port rows. The liquid discharge head according to any one of claims 1 to 7, wherein the same type of liquid is discharged from the first and second discharge port rows. A page-wide liquid discharge head
With the plurality of recording element substrates,
A flow path member that supports the plurality of recording element substrates and includes a common supply flow path for supplying liquid to the plurality of recording element substrates and a common recovery flow path for recovering liquid from the plurality of recording element substrates. When,
The liquid discharge head according to any one of claims 1 to 9. The liquid discharge head according to claim 10, wherein the plurality of recording element substrates are arranged in a straight line. The liquid discharge head according to claim 10 or 11, wherein the outer shape of each of the plurality of recording element substrates is a parallelogram. The liquid discharge head according to claim 3, wherein the substrate has a temperature adjusting means for adjusting the temperature of the substrate. The liquid discharge head according to any one of claims 1 to 13, wherein the liquids in the plurality of pressure chambers included in the first and second pressure chamber rows are circulated to and from the outside.

Images