JP6953126B2 - Liquid discharge head and liquid discharge device - Google Patents

Description

The present invention relates to a liquid discharge head and a liquid discharge device using the liquid discharge head.

A liquid discharge device that records by discharging a liquid to a recording medium uses a liquid discharge head having a pressure chamber communicating with a discharge port and a recording element that applies energy for discharge to the liquid in the pressure chamber. .. In an inkjet recording device, which is a typical liquid discharge device, a recording liquid containing a coloring material such as a dye or a pigment in a solvent or a processing liquid for adjusting the recording liquid is discharged from a discharge port. In such a liquid discharge device, for example, when the liquid to be discharged is a recording liquid, the volatile components in the recording liquid evaporate from the discharge port, which increases the concentration of the coloring material and causes color unevenness in the recorded image. There is. In addition, the evaporation of volatile components increases the viscosity of the liquid near the discharge port and in the pressure chamber, which reduces the discharge rate of the liquid, which makes it impossible to accurately reach the intended position on the recording medium. There is. As one of the solutions to such a problem, a method of circulating a liquid with respect to a liquid discharge head, particularly a pressure chamber thereof, is known. When the liquid is circulated in the pressure chamber, a flow path that branches from the common supply flow path and joins the common recovery flow path through the pressure chamber is provided, and the liquid is circulated in the pressure chamber through this flow path. I'm letting you. The liquid discharge head is also provided with a drive circuit for driving the recording element, but when the number of discharge ports increases and the number of recording elements also increases, the influence of heat generated by the drive circuit increases and the liquid May cause viscosity fluctuations. In this case as well, the discharge rate of the liquid fluctuates, and it becomes difficult to accurately discharge the liquid to the recording medium. In Patent Document 1, the heat generated in the drive circuit is released to the liquid that circulates in the pressure chamber and is sent to the recovery flow path, thereby suppressing the viscosity fluctuation of the liquid due to the temperature rise and the discharge rate of the liquid. It is disclosed to suppress the fluctuation of.

Japanese Patent Application Laid-Open No. 2003-51209

In the configuration as described in Patent Document 1, when the flow rate of the liquid supplied from the supply flow path to the pressure chamber is smaller than the flow rate of the liquid discharged from the discharge port, the flow rate of the liquid is discharged from the recovery flow path when the discharge is performed. The liquid flows back and flows into the pressure chamber. This means that the liquid whose viscosity has decreased due to heat transfer from the drive circuit or the like flows into the pressure chamber. Therefore, the temperature of the liquid discharge head also rises, and the liquid is discharged such as the discharge amount and the discharge speed. Changes in characteristics change. As a result, the recording quality is affected, for example, the portion recorded at the start of recording on the recording medium has a higher recording density than the portion recorded thereafter. This is an example in which the discharge characteristics change and the recording quality also changes as the driving state of the liquid discharge head changes (here, the circulation state during standby changes to the recording state). On the contrary, when the flow rate of the liquid supplied to the pressure chamber is larger than the flow rate of the discharged liquid, the liquid does not flow back from the recovery flow path side even if the liquid is discharged. However, in this case, since the pressure loss of the flow path in or near the pressure chamber becomes large, the flow path width of the flow path in or near the pressure chamber must be increased, and the pressure chambers are arranged at high density. It becomes difficult to record with high definition.

An object of the present invention is a liquid discharge head capable of suppressing the backflow of a heated liquid from the recovery flow path side even when the drive state changes, thereby suppressing the change in the drive state from affecting the discharge characteristics. And to provide a liquid discharge device.

The liquid discharge head of the present invention includes a discharge port for discharging a liquid, a recording element for generating energy for discharging the liquid, a pressure chamber having the recording element inside, and a liquid supply path for supplying the liquid to the pressure chamber. From the recording element substrate including the liquid recovery path for recovering the liquid from the pressure chamber, the supply liquid chamber for supporting the recording element substrate and supplying the liquid to the liquid supply path, and the liquid recovery path. A liquid supply unit including a recording element substrate, a supporting member, and a wiring substrate connected to the recording element substrate, further comprising, and a plurality of supporting members including a collecting liquid chamber for collecting liquid. The liquid supply unit is arranged, and has a flow path member including a common supply flow path for supplying liquid to the plurality of liquid supply units and a common recovery flow path for recovering liquid from the plurality of liquid supply units. The supply liquid chamber and the recovery liquid chamber extend in directions intersecting each other in the direction in which the discharge ports are arranged, and are alternately arranged in the direction in which the discharge ports are arranged. Includes a discharge port forming member including the discharge port and a substrate including the recording element, and the liquid supply path and the liquid recovery path are formed on the back surface of the surface of the substrate on which the recording element is provided. On the back surface of the recording element substrate, a lid member having a supply-side opening for supplying the liquid to the liquid supply path and a recovery-side opening for recovering the liquid from the liquid recovery path is provided. The volume of the supply liquid chamber and the recovery liquid chamber is the volume of the common supply flow path and the portion between the common recovery flow path and the lid member, and the volume of the recovery liquid chamber is It is characterized in that it is smaller than the volume of the supply liquid chamber.

The liquid discharge device of the present invention includes the liquid discharge head of the present invention, a storage means for storing the liquid, a first circulation system for circulating the liquid from the storage means to the common supply flow path, and a second circulation system for circulating the liquid from the storage means. It is characterized by including a second circulatory system that circulates in a common recovery flow path.

According to the present invention, the liquid discharge head can suppress the backflow of the heated liquid from the recovery flow path side even when the drive state changes, thereby suppressing the change in the drive state from affecting the discharge characteristics. Can be realized.

It is a figure which shows the schematic structure of the liquid discharge device of the 1st configuration example. It is a figure explaining the 1st circulation form. It is a figure explaining the 2nd circulation form. It is a perspective view which shows the structure of the liquid discharge head. It is an exploded perspective view which shows the liquid discharge head. It is a figure which shows the structure of the front surface and the back surface of each flow path member. It is a perspective view which shows the connection relation of each flow path. It is sectional drawing which shows the flow path component and the discharge module. It is a figure explaining the discharge module. It is a figure which shows the structure of the recording element substrate. It is a partially cutaway perspective view which shows the recording element substrate. It is a top view which shows the adjacent recording element substrate. It is a figure which shows the schematic structure of the liquid discharge device of the 2nd configuration example. It is a perspective view which shows the structure of the liquid discharge head. It is an exploded perspective view which shows the liquid discharge head. It is a figure which shows the structure of each flow path member. It is a perspective view which shows the connection relation of each flow path. It is sectional drawing which shows the flow path component and the discharge module. It is a figure explaining the discharge module. It is a figure which shows the structure of the recording element substrate. It is a perspective view which shows the liquid discharge head of one Embodiment of this invention. It is an exploded perspective view of a discharge module. It is an exploded perspective view of a recording element substrate. It is a figure explaining the pressure chamber and the discharge port in the recording element substrate. It is a figure explaining the circulation form in a liquid discharge device. It is sectional drawing which shows the supply liquid chamber and the recovery liquid chamber in Example 1 and Comparative Example 1. FIG. It is a graph which shows the time change of a pressure chamber temperature schematically. It is sectional drawing which shows the supply liquid chamber and the recovery liquid chamber in the comparative example 2. FIG. It is a graph which shows typically the pressure distribution in a liquid supply path and a liquid recovery path. It is sectional drawing explaining Example 2. FIG. It is sectional drawing which shows the supply liquid chamber and the recovery liquid chamber in Example 3. FIG. It is sectional drawing which shows the supply liquid chamber and the recovery liquid chamber in Example 4. FIG. It is a schematic cross-sectional view which shows the state of an air bubble at the time of filling a liquid. It is sectional drawing explaining the liquid filling method.

Hereinafter, each configuration example and embodiment to which the present invention can be applied will be described with reference to the drawings. However, the following description does not limit the scope of the present invention. As an example, in the following description, a heat generating element is used as a recording element that generates energy for discharging a liquid, and bubbles are generated in the liquid in the pressure chamber by heat to discharge the liquid from a discharge port, so-called thermal type liquid discharge. The head will be described as an example. However, the liquid discharge head to which the present invention is applicable is not limited to the thermal type, and the present invention is also applied to the piezo type using a piezoelectric element and the liquid discharge head adopting various other liquid discharge methods. 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 a printer, a copying machine, a facsimile having a communication system, and a word processor having a printer unit. 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.

Further, in the following description, a liquid discharge head used in a liquid discharge device that circulates a liquid such as a recording liquid (for example, ink) between a tank and a liquid discharge head will be described, but a liquid discharge head based on the present invention will be used. The liquid discharge device is not limited to this. In the form of providing tanks on the upstream side and the downstream side without circulating the liquid, and flowing the liquid from one tank to the other tank via the liquid discharge head, the liquid flows in the pressure chamber of the liquid discharge head. The present invention can also be applied to a liquid discharge device.

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

(Explanation of the liquid discharge device of the first configuration example)
First, as an example of a liquid discharge device based on the present invention, an inkjet recording device 1000 (hereinafter, also referred to as a recording device) that discharges a recording liquid as a liquid from a discharge port and records on a recording medium will be described. FIG. 1 shows a schematic configuration of a recording device 1000, which is a liquid discharge device of the first configuration example. The recording device 1000 includes a transport unit 1 for transporting the recording medium 2 and a line-type liquid discharge head 3 arranged substantially orthogonal to the transport direction of the recording medium 2, and can record a plurality of the recording media 2. It is a line-type recording device that continuously or intermittently conveys and continuously records in one pass. The recording medium 2 is, for example, cut paper, but may be continuous roll paper or the like in addition to the cut paper. The liquid discharge head 3 can record in full color by recording liquid of each color of cyan (C), magenta (M), yellow (Y) and black (K) (hereinafter, these colors are collectively referred to as CMYK). It is a thing. As will be described later, the liquid supply means, the main tank, and the buffer tank (see FIG. 2), which are supply paths for supplying the liquid to the liquid discharge head 3, are fluidly connected to the liquid discharge head 3. As shown in FIG. 2 described later, the liquid discharge head 3 is roughly classified into a liquid supply unit 220, a negative pressure control unit 230, and a liquid discharge unit 300. The liquid discharge unit 300 is provided with a plurality of recording element substrates 10, a common supply flow path 211, and a common recovery flow path 212, and each recording element substrate 10 is provided with a plurality of recording elements. In the liquid discharge head 300, the recording liquid is supplied to each recording element substrate 10 from the common supply flow path 211 as shown by the arrow in the drawing, and the recording liquid is collected through the common recovery flow path 212. ing. 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. Details of the liquid path and the electric signal path in the liquid discharge head 3 will be described later.

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

The two first circulation pumps 1001 and 1002 have a role of drawing 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 pumps 1001 and 1002, it is preferable to use a positive displacement pump having a quantitative liquid feeding capacity. Specific examples thereof include tube pumps, gear pumps, diaphragm pumps, syringe pumps, etc. For example, a general constant flow valve or relief valve is arranged at the pump outlet to secure a constant flow rate. be able to. When the liquid discharge head 300 is driven, the recording liquid flows in the common supply flow path 211 and the common recovery flow path 212 at a constant flow rate by the first circulation pump 1001 on the high pressure side and the first circulation pump 1002 on the low pressure side, respectively. The flow rate is preferably set so that the temperature difference between the recording element substrates 10 in the liquid discharge head 3 does not affect the recording quality on the recording medium 2. However, if an excessively large flow rate is set, the negative pressure difference between the recording element substrates 10 becomes too large due to the influence of the pressure loss of the flow path in the liquid discharge unit 300, resulting in density unevenness in the recorded image. 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. Of the paths through which the recording liquid circulates, the path including the first circulation pump 1001 on the high pressure side constitutes the first circulation system in this liquid discharge device, and the path including the first circulation pump 1002 on the low pressure side. The path constitutes a second circulatory system in this liquid discharge device.

A second circulation pump 1004 is provided in a path for supplying the recording liquid from the buffer tank 1003 to the liquid discharge head 3. The negative pressure control unit 230 functions as a negative pressure control means, and is provided in a path between the second circulation pump 1004 and the liquid discharge unit 300. The negative pressure control unit 230 has a constant pressure at which the pressure on the downstream side (that is, the liquid discharge unit 300 side) of the negative pressure control unit 230 is preset even when the flow rate of the circulation system fluctuates due to the difference in duty during recording. Has the function of maintaining. The negative pressure control unit 230 includes two pressure adjusting mechanisms in which different control pressures are set. As these two pressure adjusting mechanisms, any mechanism may be used as long as the pressure downstream of itself can be controlled with fluctuations within a certain range around a desired set pressure. As an example, one having a mechanism similar to that of a so-called decompression regulator can be adopted. When a pressure reducing regulator is used as the pressure adjusting mechanism, it is preferable that the upstream side of the negative pressure control unit 230 is pressurized by the second circulation pump 1004 via the liquid supply unit 220 as shown in FIG. 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 a pump having a lift pressure equal to or higher than a certain pressure within the range of the circulation flow rate of the recording liquid used when driving the liquid discharge head 3, and may be a turbo pump, a positive displacement pump, or the like. Can be used. Specifically, a diaphragm pump or the like can be used. 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 be provided.

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

In this way, in the liquid discharge unit 300, a part of the liquid passes through each recording element substrate 10 while flowing the liquid so as to pass through the common supply flow path 211 and the common recovery flow path 212, 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, when recording is performed by the liquid discharge head 3, the flow of the recording liquid can be generated even in the discharge port or the pressure chamber where the recording is not performed, so that the solvent component of the recording liquid evaporates at that site. As a result, it is possible to suppress an increase in the viscosity of the recording liquid. In addition, the thickened recording liquid and foreign matter in the recording liquid can be discharged to the common recovery flow path 212. Therefore, by using the liquid discharge head 3 described above, it is possible to perform recording at high speed and with high quality.

(Explanation of the second circulation form)
FIG. 3 shows a second circulation mode, which is a circulation mode different from the first circulation mode described above, among the circulation path configurations applied to the liquid discharge device based on the present invention. The main difference between the second circulation mode and the first circulation mode is that the two pressure adjusting mechanisms constituting the negative pressure control unit 230 both apply pressure on the upstream side of the negative pressure control unit 230. It is a mechanism that controls fluctuations within a certain range around a desired set pressure. Such a pressure adjusting mechanism can be configured as a mechanical component having the same function as a so-called back pressure regulator. Further, 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, and the first circulation pumps 1001 and 1002 on the high pressure side and the low pressure side are arranged on the upstream side of the liquid discharge head 3. ing. Along with this, the negative pressure control unit 230 is arranged on the downstream side of the liquid discharge head 3.

In the second circulation mode, the negative pressure control unit 230 presets its own upstream pressure fluctuation 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. It operates to stabilize within a certain range around the pressure. Here, the upstream side of the negative pressure control unit 230 is the liquid discharge unit 300 side. As shown in FIG. 3, it is preferable 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 may be provided.

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

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

The second advantage is that in the second circulation mode, the maximum value of the required flow rate supplied from the buffer tank 1003 to the liquid discharge head 3 is smaller than in the case of the first circulation mode. The reason is as follows. 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 the recording liquid 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 mode shown in FIG. 2 (FIG. 2), the set flow rates of the first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) 1002 become A, so that at the time of total discharge. The maximum value of the required liquid supply amount to the liquid discharge head 3 is A + F. On the other hand, in the case of the second circulation mode shown in 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 mode, the total value of the set flow rates of the first circulation pumps 1001 and 1002 on the high pressure side and the low pressure side, that is, the maximum value of the required supply flow rate is the larger value of A or F. Therefore, as long as the liquid discharge unit 300 having the same configuration is used, the maximum value (A or F) of the required supply amount in the second circulation mode is larger than the maximum value (A + F) of the required supply flow rate in the first circulation mode. Will always be smaller. Therefore, in the case of the second circulation mode, the degree of freedom of the applicable circulation pump is increased. For example, a low-cost circulation pump having a simple configuration can be used, or a load of a cooler (not shown) installed in the main body side path can be used. Can be reduced, and the cost of the recording device main body can be reduced. This advantage increases as the value of A or F becomes relatively large for the line type head, and is more beneficial for the line type head which is longer in the longitudinal direction.

However, on the other hand, there is also a point that the first circulation form is more advantageous than the second circulation form. In the second circulation mode, 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 discharge port. Therefore, especially when the flow path width of the common supply flow path 211 and the common recovery flow path 212 is reduced to reduce the head width, a high negative pressure is applied to the discharge port in a low-duty image in which unevenness is easily visible. The effect of satellite droplets may increase. Here, the flow path widths of the common supply flow path 211 and the common recovery flow path 212 are the lengths in the direction orthogonal to the liquid flow direction, and the head width is the length in the lateral direction of the liquid discharge head 3. Is. On the other hand, in the case of the first circulation mode, a high negative pressure is applied to the discharge port at the time of forming a high-duty image, so even if satellite droplets are generated, they are difficult to see in the recorded image, and the image is displayed. The advantage is that the effect of is small. In selecting these two circulation modes, a preferable one may be selected in light of the specifications of the liquid discharge head 3 and the recording device main body (discharge flow rate F, minimum circulation flow rate A, and flow path resistance in the liquid discharge head 3). ..

(Explanation of liquid discharge head configuration)
Next, the configuration of the liquid discharge head 3 will be described with reference to FIG. FIG. 4A is a perspective view seen from the side of the surface of the liquid discharge head 3 where the discharge port is formed, and FIG. 4B is a perspective view seen from the direction opposite to that of FIG. 4A. In the liquid discharge head 3, 15 recording element substrates 10 capable of discharging recording liquids of four colors of cyan (C), magenta (M), yellow (Y), and black (K) are linearly arranged (in-line). It is a line type liquid discharge head arranged in. As shown in FIG. 4A, the liquid discharge head 3 includes 15 recording element boards 10, a flexible wiring board 40, and an electrical wiring board 90. The electric wiring board 90 is provided with a signal input terminal 91 and a power supply terminal 92, and the signal input terminal 91 and the power supply terminal 92 are connected to each recording element board 10 via the electric wiring board 90 and the flexible wiring board 40. It is electrically connected. The signal input terminal 91 and the power supply terminal 92 are electrically connected to the control circuit 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. This makes it possible to reduce 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. As shown in FIG. 4B, the liquid connection portions 111 provided at both ends of the liquid discharge head 3 are connected to, for example, the liquid supply system of the recording device 1000 as shown in FIG. 2 or FIG. As a result, the recording liquid of each color of CMYK is supplied from the supply system of the recording device 1000 to the liquid discharge head 3, and the recording liquid that has passed through the liquid discharge head 3 is collected to the supply system of the recording device 1000. There is. In this way, the recording liquid of each color can be circulated through the path of the recording device 1000 and the path of the liquid discharge head 3.

FIG. 5 shows each component or unit constituting the liquid discharge head 3 divided according to its function. The liquid discharge head 3 includes a housing 80, and a liquid discharge unit 300, a liquid supply unit 220, and an electrical wiring board 90 are attached to the housing 80. The liquid supply unit 220 is provided with a liquid connection portion 111 (see FIGS. 2 to 4). Inside the liquid supply unit 220, filters 221 (see FIGS. 2 and 3) for each color that communicate with each opening of the liquid connection portion 111 are provided in order to remove foreign substances in the supplied recording liquid. In the illustrated one, two liquid supply units 220 and two negative pressure control units 230 are provided for one liquid discharge head. The two liquid supply units 220 are each provided with a filter 221 for two colors. The recording 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 has a pressure adjusting mechanism, and is generated in the supply system of the recording device 1000 (liquid discharge head) caused by fluctuations in the flow rate of the liquid due to the action of valves and spring members provided inside the pressure adjusting mechanism. The pressure loss change of the supply system on the upstream side of 3) can be significantly attenuated. As a result, the negative pressure control unit 230 can stabilize the negative pressure change on the downstream side (liquid discharge unit 300 side) of the pressure control unit within a certain range. As described above, the negative pressure control unit 230 is provided with two pressure adjusting mechanisms for each color, and the control pressures of the two pressure adjusting mechanisms for each color are set to different values. The pressure adjusting mechanism on the high pressure side communicates with the common supply flow path 211 in the liquid discharge unit 300, and the pressure adjusting mechanism on the low pressure side communicates with the common recovery flow path 212.

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

The liquid discharge unit 300 includes a plurality of discharge modules 200 and a flow path constituent member 210, and a cover member 130 is attached to the surface of the liquid discharge unit 300 on the recording medium side. As shown in FIG. 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 material 110 included in the discharge module 200 (from the opening 131). (See 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 surface of the liquid discharge head 3 on which the discharge port is formed during recording standby. Therefore, by applying an adhesive, a sealing material, a filler, or the like along the periphery of the opening 131 to fill the irregularities and gaps on the discharge port forming surface of the liquid discharge unit 300, a closed space is formed at the time of capping. It is preferable to do so.

Next, the configuration of the flow path constituent member 210 included in the liquid discharge unit 300 will be described. The flow path component 210 is for distributing the liquid such as the recording liquid supplied from the liquid supply unit 220 to each discharge module 200, and returning the liquid refluxed from the discharge module 200 to the liquid supply unit 220. be. As shown in FIG. 5, the flow path constituent 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 in this order, and is a liquid discharge unit support portion 81. It is fixed with screws. As a result, warpage and deformation of the flow path constituent member 210 are suppressed.

6 (a) to 6 (f) show the front surface and the back surface of the first to third flow path members 50, 60, 70. FIG. 6A shows the surface of the first flow path member 50 on the side on which the discharge module 200 is mounted, whereas FIG. 6F shows the liquid discharge unit of the third flow path member 70. The surface on the side that comes into contact with the support portion 81 is shown. FIG. 6 (b) shows the contact surface of the first flow path member 50 with the second flow path member 60, and FIG. 6 (c) corresponds to this, FIG. 6 (c) shows the second flow path member 60 of the second flow path member 60. 1 The contact surface with the flow path member 50 is shown. Similarly, FIG. 6 (d) shows the contact surface of the second flow path member 60 with the third flow path member 70, and FIG. 6 (e) shows the second flow path of the third flow path member 70. The contact surface with the member 60 is shown. Common flow path grooves formed in the respective flow path members 60 and 70 by joining the second flow path member 60 and the third flow path member 70 on the surfaces shown in FIGS. 6 (d) and 6 (e). The 62 and 71 form eight common flow paths extending in the longitudinal direction of the flow path members 60 and 70. As a result, a pair of the common supply flow path 211 and the common recovery flow path 212 for each color of CMYK is formed in the flow path constituent member 210 (see 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 is fluidly communicated 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 side of the first flow path member 50 in the lateral direction. In the following description, when the common supply flow path 211 is shown separately for each color of the recording liquid, the reference numerals 211a to 211d are used instead of the reference numeral 211, and when the common recovery flow path 212 is shown separately for each color. Reference numerals 212a to 212d are used instead of reference numeral 212. Similarly, when the individual supply flow paths 213 are shown separately for each color of the recording liquid, the reference numerals 213a to 213d are used instead of the reference numerals 213, and when the individual recovery flow paths 214 are shown separately for each color, the reference numerals 214 are used. Codes 214a-214d are used instead.

The first to third flow path members 50, 60, 70 constituting the flow path constituent member 210 are preferably made of a material having corrosion resistance to a liquid such as a recording liquid and having a low coefficient of linear expansion. As the material thereof, 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 preferable. Can be used. As a method for forming the flow path constituent member 210, three flow path members 50, 60, 70 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 constituent member 210 will be described with reference to FIG. 7. In FIG. 7, the discharge module 200 of the first flow path member 50 is mounted on the flow path inside the flow path component member 210 formed by joining the first to third flow path members 50, 60, 70. It is a perspective view which is a part enlarged from the surface side. The region surrounded by the alternate long and short dash line in FIG. 7 corresponds to the arrangement position of the recording element substrate 10. The flow path constituent members 210 are provided with common supply flow paths 211a to 211d and common recovery flow paths 212a to 212d extending in the longitudinal direction of the liquid discharge head 3 for each color. A plurality of individual supply channels 213a to 213d formed by the individual channel grooves 52 are connected to the common supply channels 211a to 211d of each color via communication ports 61, respectively. Further, a plurality of individual recovery channels 214a to 214d formed by the individual channel grooves 52 are connected to the common recovery channels 212a to 212d of each color via communication ports 61, respectively. With such a flow path configuration, the recording liquid is collected from each common supply flow path 211 via the individual supply flow path 213 to the recording element substrate 10 provided corresponding to the central portion of the flow path constituent member 210. can do. Further, the recording liquid 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 shows the cross-sectional configuration of the flow path constituent member 210 and the discharge module 200 on the line EE of FIG. As shown in the figure, the individual collection flow paths 214a and 214c communicate with the discharge module 200 via the communication port 51. In FIG. 8, only the individual collection flow paths 214a and 214c are shown, but in another cross section, the individual supply flow paths 213 and the discharge module 200 communicate with each other as shown in FIG. 7. In order to supply the recording liquid from the first flow path member 50 to the recording element 15 (see FIG. 10) provided on the recording element substrate 10 to the support member 30 and the recording element substrate 10 included in each discharge module 200. Flow path is formed. Further, the support member 30 and the recording element substrate 10 are also formed with a flow path for collecting (refluxing) a part or all of the liquid supplied to the recording element 15 to the first flow path member 50. The common supply flow path 211 of each color is connected to the pressure adjusting mechanism on the high pressure side of the negative pressure control unit 230 of the corresponding color via the liquid supply unit 220. Similarly, the common recovery flow path 212 is connected to the pressure adjusting mechanism on the low pressure side of the negative pressure control unit 230 of the corresponding color via the liquid supply unit 220. By these pressure adjusting mechanisms in the negative pressure control unit 230, a differential pressure (pressure difference) is generated between the common supply flow path 211 and the common recovery flow path 212. Therefore, in the liquid discharge head 3 in which each flow path is connected as shown in FIGS. 7 and 8, the common supply flow path 211 → the individual supply flow path 213 → the recording element substrate 10 → the individual recovery flow for each color. A flow is generated in order from the road 214 to the common recovery flow path 212.

(Explanation of discharge module)
Next, the discharge module 200 will be described. FIG. 9A is a perspective view of the discharge module 200, and FIG. 9B is an exploded view thereof. As a method of manufacturing the discharge module 200, first, the recording element substrate 10 and the flexible wiring substrate 40 are adhered to a support member 30 provided with a liquid communication port 31 in advance. After that, the terminal 16 on the recording element substrate 10 and the terminal 41 on the flexible wiring board 40 are electrically connected by wire bonding, and then the wire bonding portion (electrical connection portion) is covered with a sealing material 110 and sealed. Stop. The terminal 42 on 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 communication member that fluidly communicates the recording element substrate 10 and the flow path constituent member 210, the flatness is high and sufficient. It is preferable that the device can be bonded to the recording element substrate with high reliability. As the material of the support member 30, for example, alumina or a resin material is preferable.

(Explanation of the structure of the recording element substrate)
Next, the configuration of the recording element substrate 10 will be described. 10 (a) is a plan view of the surface of the recording element substrate 10 on the side where the discharge port 13 is formed, and FIG. 10 (b) is an enlarged view of the portion shown by A in FIG. 10 (a). FIG. 10 (c) is a plan view of the side corresponding to the back surface of FIG. 10 (a). As shown in FIG. 10A, the recording element substrate 10 has a discharge port forming member 12 formed by forming a plurality of discharge ports 13 in a row. The discharge port forming member 12 is formed with four rows of discharge ports corresponding to the four colors of CMYK, which are the colors of the recording liquid. 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 shown in 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), and boils the liquid in the pressure chamber 23. Then, 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 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 example shown here, the lid member 20 is provided with three openings 21 for one liquid supply path 18 and two openings 21 for one liquid recovery path 19. As shown in FIG. 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 is preferably made of a material having sufficient corrosion resistance against a liquid such as a recording liquid, and from the viewpoint of preventing color mixing, the opening shape and opening position of the opening 21 are highly accurate. Is required. Therefore, it is preferable to use a photosensitive resin material or a silicon plate as the material of the lid member 20 and to provide the opening 21 by a photolithography process. As described above, the lid member 20 changes the pitch of the flow path by the opening 21, and it is desirable that the lid member 20 is thin in consideration of the pressure loss, and it is desirable that the lid member 20 is made of a film-like member.

Next, the flow of the liquid in the recording element substrate 10 will be described. FIG. 11 shows a cross section of the recording element substrate 10 and the lid member 20 on the BB plane in FIG. 10A. In the recording element substrate 10, a substrate main body 11 formed of a silicon (Si) substrate and a discharge port forming member 12 formed of a photosensitive resin are laminated, and a lid member 20 is provided on the back surface of the substrate main body 11. It is joined. A recording element 15 is formed on one surface side of the substrate body 11 (see FIG. 10), and a liquid supply path 18 and a liquid recovery path 19 extending along the discharge port row are formed on the back surface side thereof. A groove is formed. The liquid supply path 18 and the liquid recovery path 19 formed by the substrate main body 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 component 210, respectively, and the liquid is liquid. A differential pressure is generated between the supply path 18 and the liquid recovery path 19. The first flow path member 50 is formed with an individual supply flow path 213 and an individual recovery flow path 214. The individual supply flow path 213 connects the liquid supply path 18 and the common supply flow path 211, and is an individual recovery flow path. The path 214 connects the liquid recovery path 19 and the common recovery flow path 212. In the discharge port where the discharge operation is not performed when the liquid is discharged from the plurality of discharge ports 13 of the liquid discharge head 3 and the recording is performed, the liquid in the liquid supply path 18 is supplied to the supply port 17a due to this differential pressure. → It flows to the liquid recovery path 19 via the pressure chamber 23 → the recovery port 17b. This flow is indicated by arrow C in FIG. By this flow, in the discharge port 13 and the pressure chamber 23 where recording is suspended, the thickened recording liquid, bubbles, foreign substances, etc. generated by the vaporization of the solvent from the discharge port 13 are collected in the liquid recovery path 19. Can be done. Further, it is possible to suppress thickening of the recording liquid in the discharge port 13 and the pressure chamber 23. The liquid such as the recording liquid collected in the liquid recovery path 19 passes through the opening 21 of the lid member 20 and the liquid communication port 31 of the support member 30 (see FIG. 9B), and the communication port 51 in the flow path constituent member 210. , The individual recovery flow path 214, and the common recovery flow path 212 are collected in this order. The recovered liquid is finally recovered to the supply path of the recording device 1000.

After all, the liquid such as the recording liquid supplied from the main body of the recording device 1000 to the liquid discharge head 3 flows in the following order, and is supplied and recovered. The liquid first flows into the inside of the liquid discharge head 3 from the liquid connection portion 111 of the liquid supply unit 220. The liquid is the joint rubber 100, the communication port 72 and the common flow path groove 71 provided in the third flow path member 70, the common flow path groove 62 and the communication port 61 provided in the second flow path member 60, and the first. 1 The individual flow path grooves 52 and the communication ports 51 provided in the flow path member are supplied in this order. After that, the liquid enters the pressure chamber 23 in order through the liquid communication port 31 provided in the support member 30, the opening 21 provided in the lid member 20, the liquid supply path 18 provided in the substrate main body 11, and the supply port 17a. Be supplied. Of the liquids supplied to the pressure chamber 23, the liquids not discharged from the discharge port 13 are the recovery port 17b and the liquid recovery path 19 provided in the substrate main body 11, the opening 21 provided in the lid member 20, and the support member. The liquid communication port 31 provided in 30 flows in order. After that, the liquid is applied to the communication port 51 and the individual flow path groove 52 provided in the first flow path member, the communication port 61 and the common flow path groove 62 provided in the second flow path member, and the third flow path member 70. The common flow path groove 71, the communication port 72, and the joint rubber 100 are provided in this order. Then, the liquid flows from the liquid connection portion 111 provided in the liquid supply unit 220 to the outside of the liquid discharge head 3. When the first circulation mode shown in FIG. 2 is adopted, 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. On the other hand, when the second circulation mode shown in FIG. 3 is adopted, the liquid recovered from the pressure chamber 23 passes through the joint rubber 100 and then flows from the liquid connection portion 111 via the negative pressure control unit 230. It flows to the outside of the discharge head 3.

Not all the liquid that has flowed in from one end of the common supply flow path 211 of the liquid discharge unit 300 is supplied to the pressure chamber 23 via the individual supply flow path 213a. As shown in FIGS. 2 and 3, 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. By providing the path for flowing without passing through the recording element substrate 10 in this way, even when the recording element substrate 10 having a fine flow path having a large flow resistance is provided, the backflow of the circulating flow of the liquid is suppressed. can do. In this way, the liquid discharge head 3 can suppress thickening of the liquid in the pressure chamber and the vicinity of the discharge port, so that discharge twist and non-discharge can be suppressed, and as a result, high-quality recording can be performed.

(Explanation of positional relationship between recording element substrates)
As described above, the liquid discharge head 3 includes a plurality of discharge modules 200. FIG. 12 shows a partially enlarged view of the adjacent portion of the recording element substrate 10 in the two adjacent discharge modules 200. As shown in FIG. 10, here, it is assumed that the recording element substrate 10 having a substantially parallelogram shape is used. As shown in FIG. 12, the discharge port rows 14a to 14d in which the discharge ports 13 are arranged on each recording element substrate 10 are arranged so as to be inclined at a constant angle with respect to the transport direction L of the recording medium. As a result, at least one discharge port of the discharge port row in the adjacent portion between the recording element substrates 10 overlaps in the transport direction L of the recording medium. In the one shown in FIG. 12, the two discharge ports 13 on the line D overlap each other. With such an arrangement, even if the position of the recording element substrate 10 deviates slightly from the predetermined position, black streaks and white spots in the recorded image are conspicuous due to the drive control of the discharge ports that overlap each other. Can be eliminated. Even when a plurality of recording element substrates 10 are arranged in-line instead of in a staggered arrangement, the configuration as shown in FIG. 12 suppresses an increase in the length of the liquid discharge head 3 in the transport direction of the recording medium, and the recording element substrate 10 It is possible to take measures against black streaks and white spots at the joints between each other. Although the contour shape of the recording element substrate 10 is substantially a parallelogram here, the present invention is not limited to this, and even when the recording element substrate 10 having a rectangular shape, a trapezoidal shape, or another shape is used, the configuration of the present invention is not limited to this. Can be preferably applied.

(Explanation of the liquid discharge device of the second configuration example)
The liquid discharge device to which the present invention can be applied is not limited to that of the first configuration example described above. Hereinafter, the inkjet recording device 1000 (hereinafter, also referred to as a recording device), which is a second configuration example of the liquid discharge device based on the present invention, will be described. FIG. 13 shows a schematic configuration of the recording device 1000, which is a liquid discharge device of the second configuration example. In the following description, only the parts different from the first configuration example will be mainly described, and the description of the parts similar to the first configuration example will be omitted.

The first configuration example of the recording device 1000 shown in FIG. 13 is that full-color recording is performed on the recording medium 2 by arranging four single-color liquid discharge heads 3 corresponding to each color of CMYK in parallel. It's different from the one. In the first configuration example, the number of discharge port rows that can be used per color recording liquid is one row, whereas in this second configuration example, a plurality of discharge port rows that can be used per color ( In the example shown in FIG. 20A, which will be described later, 20 columns) can be used. Therefore, by appropriately allocating the recorded data to a plurality of discharge port rows and recording the data, very high-speed recording becomes possible. Further, even if there is a discharge port that does not discharge, reliability is achieved by interpolating the discharge from the discharge port of another row located at a position corresponding to the transport direction L of the recording medium with respect to the discharge port. Is improved. Therefore, the recording device 1000 of the second configuration example is suitable for use in fields such as commercial printing. Similar to the first configuration example, the supply system of the recording device 1000, the buffer tank 1003, and the main tank 1006 are fluidly connected to each liquid discharge head 3. Further, an electric control unit that transmits electric power and a discharge control signal to the liquid discharge head 3 is electrically connected to each liquid discharge head 3. In the second configuration example, as in the first configuration example, any of the first and second circulation modes shown in FIGS. 2 and 3, respectively, can be used.

(Explanation of liquid discharge head structure)
The structure of the liquid discharge head 3 in the second configuration example will be described with reference to FIG. FIG. 14A is a perspective view seen from the side of the surface on which the discharge port is formed in the liquid discharge head 3, and FIG. 14B is a perspective view seen from the direction opposite to that of FIG. 14A. The liquid discharge head 3 includes 16 recording element substrates 10 arranged in a straight line in the longitudinal direction thereof, and is an inkjet type line type liquid discharge head capable of recording with a recording liquid of a single color. be. 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 configuration example. However, since the liquid discharge head 3 has a larger number of discharge port rows than that of the first configuration example, 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. 15 shows each component or unit constituting the liquid discharge head 3 of the second configuration example divided according to its function. The roles of each unit and member and the order of liquid flow in the liquid discharge head 3 are basically the same as those in the first configuration example, but in the second configuration example, the rigidity of the liquid discharge head 3 The function of guaranteeing is different. In the first configuration example, the rigidity of the liquid discharge head was mainly secured by the liquid discharge unit support portion 81, but in the liquid discharge head of the second configuration example, the second flow path member 60 included in the liquid discharge unit 300 is used. The rigidity of the liquid discharge head is ensured. The liquid discharge unit support portion 81 in the second configuration example 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 liquid. Position the discharge head 3. 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. In the second configuration example, the pressure is not controlled in two ways for each negative pressure control unit 230. One of the two negative pressure control units 230 is set to control the pressure at a relatively high negative pressure as a negative pressure control unit on the high pressure side, and relative to the other as a negative pressure control unit on the low pressure side. It is set to control the pressure with a low negative pressure. As shown in FIG. 15, 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 in the longitudinal direction, a common supply flow extending in the longitudinal direction of the liquid discharge head 3 is provided. The liquid flows in the path 211 and the common recovery flow path 212 face each other. By doing so, heat exchange between the common supply flow path 211 and the common recovery flow path 212 is promoted, and the temperature difference in these common flow paths is reduced. Therefore, there is an advantage that the temperature difference between the plurality of recording element substrates 10 provided along the common supply flow path 211 and the common recovery flow path 212 is less likely to occur, and recording unevenness due to the temperature difference is less likely to occur.

Next, the details of the flow path constituent member 210 of the liquid discharge unit 300 will be described. As shown in FIG. 15, the flow path constituent member 210 is a stack of a first flow path member 50 and a second flow path member 60, and each discharge module discharges a liquid such as a recording liquid supplied from the liquid supply unit 220. Distribute to 200. Further, the flow path component 210 functions as a recovery flow path member for returning the liquid refluxing from the discharge module 200 to the liquid supply unit 220. The second flow path member 60 of the flow path constituent member 210 is a member in which the common supply flow path 211 and the common recovery flow path 212 are formed therein, and has a function of mainly carrying the rigidity of the liquid discharge head 3. .. Therefore, as the material of the second flow path member 60, a material having sufficient corrosion resistance against a liquid such as a recording liquid and high mechanical strength is preferable, and specifically, stainless steel, titanium (Ti), alumina, or the like is preferably used. be able to.

Next, the details of the first flow path member 50 and the second flow path member 60 will be described with reference to FIG. FIG. 16A shows the surface of the first flow path member 50 on the side where the discharge module 200 is attached, and FIG. 16B is the back surface thereof, which is in contact with the second flow path member 60. The side surface is shown. Unlike the first configuration example, the first flow path member 50 in the second configuration example is formed by arranging a plurality of corresponding members for each discharge module 200 adjacent to each other. By adopting the structure divided in this way, by arranging a plurality of such modules, it becomes possible to correspond to the length required for the liquid discharge head 3. This configuration is particularly suitably applicable to, for example, a relatively long liquid discharge head having a length corresponding to JIS (Japanese Industrial Standards) B2 size and larger dimensions. As shown in FIG. 16A, the communication port 51 of the first flow path member 50 fluidly communicates with the discharge module 200, and as shown in FIG. 16B, 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. 16 (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. 16 (d) shows the central portion of the second flow path member 60 in the thickness direction. 16 (e) shows the 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 the recording liquid for one color in the first configuration example. 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. 17, 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 this configuration example, unlike the first configuration example, the liquid flow directions in the common supply flow path 211 and the common recovery flow path 212 are opposite to each other along the longitudinal direction of the liquid discharge head 3.

FIG. 17 shows the connection relationship of each flow path between the recording element substrate 10 and the flow path constituent 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 constituent 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. 18 shows a cross section taken along the line FF of FIG. As shown in this figure, the common supply flow path 211 is connected to the discharge module 200 via the communication port 61, the individual communication port 53, and the communication port 51. Although not shown in FIG. 18, in another cross section, it is clear with reference to FIG. 17 that the common recovery flow path 212 is connected to the discharge module 200 by a similar route. Similar to the first configuration example, each discharge module 200 and the recording element substrate 10 are formed with a flow path communicating with the pressure chamber 23, which is the formation location of each discharge port 13. A part or all of the supplied liquid can be recirculated through the pressure chamber 23 corresponding to the discharge port 13 in which the discharge operation is suspended by this flow path. Further, as in the first configuration example, the common supply flow path 211 is via the high pressure side negative pressure control unit 230, and the common recovery flow path 212 is via the low pressure side negative pressure control unit 230 and the liquid supply unit 220, respectively. It is connected. Therefore, due to the differential pressure generated by these negative pressure control units 230, a flow is generated from the common supply flow path 211, passing through the pressure chamber 23 of the recording element substrate 10, and flowing to the common recovery flow path 212.

(Explanation of discharge module)
Next, the discharge module 200 in the second configuration example will be described. FIG. 19A is a perspective view of the discharge module 200, and FIG. 19B is an exploded view thereof. The difference from the first configuration example is that 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 are electrically connected to the terminals 16. Two flexible wiring boards 40 are also arranged for each recording element board 10. This is because the number of discharge port rows provided on the recording element substrate 10 is, for example, 20 rows, which is significantly larger than the 4 rows of the first configuration example. 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 said. Further, the liquid communication port 31 of the support member 30 is opened so as to straddle all the discharge port rows provided on the recording element substrate 10. Other points are the same as those in the first configuration example.

(Explanation of the structure of the recording element substrate)
Next, the configuration of the recording element substrate 10 in the second configuration example will be described. FIG. 20A is a plan view of the surface of the recording element substrate 10 on the side where the discharge port 13 is formed, and FIG. 20B shows a portion where the liquid supply path 18 and the liquid recovery path 19 are formed. 20 (c) is a plan view of the back surface of FIG. 20 (a). Here, FIG. 20B shows a state in which the lid member 20 provided on the back surface side of the recording element substrate 10 is removed in FIG. 20C. As shown in FIG. 20B, liquid supply paths 18 and liquid recovery paths 19 are alternately provided on the back surface side of the recording element substrate 10 along the discharge port row direction. Although the number of discharge port rows is significantly increased from that of the first configuration example, the essential difference from the first configuration example is that the terminals 16 are oriented in the discharge port row direction of the recording element substrate 10 as described above. It is arranged on both sides along the line. 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 configuration example.

Hereinafter, in the liquid discharge device or the liquid discharge head as described above, even if the drive state changes, the backflow of the heated liquid from the recovery flow path side is suppressed, and the change in the drive state affects the discharge characteristics. The configuration based on the present invention, which can suppress the influence of the above, will be described. FIG. 21 shows the configuration of the liquid discharge head according to the embodiment of the present invention. In the liquid discharge head 3 shown in FIG. 21, the flow path constituent member 210 in the configuration shown in FIGS. 1 to 20 has a length corresponding to the total length of the liquid discharge head 3 (the length in the X direction in the drawing). It is configured as a modified member. Then, a plurality of recording element substrates 10 in which a plurality of recording elements that generate energy for discharging liquid are arranged at high density have a support member 30 (not shown in FIG. 21) described later on the flow path constituent member 210. They are arranged in the X direction in the drawing while being staggered in the Y direction in the drawing. This constitutes one long liquid discharge head. The liquid discharge unit is composed of the recording element substrate 10, the flow path constituent member 210, and the support member 30. Here, the recording element substrates 10 are arranged alternately, but the present invention is also applied to a liquid discharge head in which a plurality of recording element substrates 10 are arranged in a straight line as shown in FIGS. 1 to 20. Can be done.

In the liquid discharge head shown in FIG. 21, a region (L) overlapping with each other is provided between two adjacent recording element substrates 10. Due to this region L, even if some error is included in the arrangement of the individual recording element substrates 10, when recording is performed on the recording medium moving in the Y direction, a gap due to this error does not occur in the recording. It has become like. Although not shown in FIG. 21, the liquid discharge head is also provided with a liquid supply unit and a negative pressure control unit in the same manner as those shown in FIGS. 1 to 20. The electrical wiring board 90 for supplying the discharge drive signal and power to the individual recording element boards 10 is made of a composite material such as glass epoxy, and includes a connector 95 in which a signal input terminal and a power supply terminal are integrated. .. The liquid discharge unit, the electric wiring board 90, and the flexible wiring board 40 that electrically connects the individual recording element boards 10 to the electric wiring board 90 are integrally supported by the housing 80. The electrical connection portion between the recording element substrate 10 and the flexible wiring board 40 is covered and protected by a sealing material 110 having excellent sealing properties and ion blocking properties such as epoxy resin.

FIG. 22 is an exploded perspective view showing the details of the liquid discharge unit, and shows a discharge module including the support member 30 and the recording element substrate 10. The support member 30 is a member provided on the flow path constituent member 210 functioning as a base plate so as to be interposed between the recording element substrate 10 and the flow path constituent member 210 for each recording element substrate 10. In FIG. 22, for the sake of explanation, the substrate main body 11 constituting the recording element substrate 10 is divided into two in the thickness direction thereof. One of the divided portions is shown in FIG. 22 (a) in a state of being joined to the discharge port forming member 12, and the other is in a state of exposing the liquid supply path 18 and the liquid recovery path 19 in FIG. 22 (b). It is indicated by. FIG. 22 (c) shows the lid member 20, and FIG. 22 (d) shows the support member 30. Here, it is assumed that the recording element substrate 10 is formed with four rows of discharge port rows 424 for discharging recording liquids of the same color. In the discharge port row 424 of each row, a plurality of discharge ports 13 are arranged in a row. In this configuration example, the support member 30 has a function of distributing a liquid such as a recording liquid from the flow path constituent member to the recording element substrate 10. A lid member 20 is provided on the surface of the recording element substrate 10 opposite to the surface on which the discharge port 13 is formed, as described above. The lid member 20 has a fine opening that communicates with the liquid supply path 18 and the liquid recovery path 19 in the recording support substrate 10 and has a function of converting the pitch of the liquid flow path from the support member 30 to the recording element substrate 10. There are multiple. Here, among these openings, the opening communicating with the liquid supply path 18 is referred to as a supply side opening 21a, and the opening communicating with the liquid recovery path 19 is referred to as a recovery side opening 21b.

The support member 30 is formed with a slit-shaped supply liquid chamber 431 and a recovery liquid chamber 432 extending in a direction orthogonal to the extension direction of the discharge port row 424. In FIG. 22, the volume difference between the supply liquid chamber 431 and the recovery liquid chamber 432 is not reflected. The supply liquid chamber 431 and the recovery liquid chamber 432 correspond to the liquid communication port 31 in the configuration shown in FIGS. 9 and 19. The supply liquid chamber 431 is in a path for distributing and supplying the liquid from the common supply flow path 211 in the flow path component 210 to the recording element substrate 10, and communicates with the common supply flow path 211. Similarly, the recovery liquid chamber 432 is in a path for collecting the liquid from the recording element substrate 10 to the common recovery flow path 212 in the flow path component 210, and communicates with the common recovery flow path 212. The supply side opening 21a provided in the lid member 20 is provided so that the supply liquid chamber 431 and the liquid supply path 18 communicate with each other at a position where they intersect. Similarly, the recovery side opening 21b is provided so that the recovery liquid chamber 432 and the liquid recovery path 19 communicate with each other at a position where they intersect. The liquid supply path 18 and the liquid recovery path 19 are formed in the substrate main body 11 as parallel grooves extending in the extending direction of the discharge port row 424 on the surface opposite to the formation surface of the discharge port 13. Here, three liquid supply passages 18 and two liquid recovery passages 19 are provided so that the liquid supply passages 18 and the liquid recovery passages 19 are alternately arranged, and the adjacent liquid supply passages 18 and the liquid recovery passages 19 are provided. One outlet row 424 corresponds to each pair with the road 19. Further, the supply side opening 21a and the collection side opening 21b provided in the lid member 20 are arranged in a row, respectively. The row of the supply side opening 21a is called a supply row 437, and the row of the collection side opening 21a is collected. Called column 438. Both the supply row 437 and the recovery row 438 extend in the direction in which the slit-shaped openings of the supply liquid chamber 431 and the recovery liquid chamber 432 extend, that is, in the direction orthogonal to the direction in which the discharge port row 424 extends.

In the above description, the supply liquid chamber 431 and the recovery liquid chamber 432 are provided in the support member 30, but the positions where the supply liquid chamber 431 and the recovery liquid chamber 432 are provided are not limited to this. Consider a case where a common supply flow path 211 and a common recovery flow path 212 are provided in which a liquid is supplied from a storage means such as the buffer tank 1003 and the supplied liquid returns to the buffer tank 1003. At this time, the supply liquid chamber 431 communicates with both the common supply flow path 211 and the liquid supply path 18 formed in the recording element substrate 10, and the liquid formed in the common recovery flow path 212 and the recording element substrate 10. The recovery liquid chamber 432 communicates with both of the recovery paths 19. Therefore, the supply liquid chamber 431 and the recovery liquid chamber 432 may be formed so as to extend from the support member 30 into the flow path constituent member 210. Further, in the structure in which the recording element substrate 10 is directly attached to the flow path constituent member 210 without providing the support member, the supply liquid chamber 431 and the recovery liquid chamber 432 are formed from the support member 30 in the flow path constituent member 210. In any case, a plurality of supply liquid chambers 431 and recovery liquid chambers 432 are provided, and in the region sandwiched between the common supply flow path 211 and the common recovery flow path 212 and the recording element substrate 10, the discharge port rows are alternately provided. Arrange in the direction of 424.

FIG. 23 is an exploded perspective view illustrating the details of the recording element substrate 10. In FIG. 23, (a) shows a portion where the discharge port 13 is formed, (b) shows a portion where the pressure chamber 23, the supply port 17a and the discharge port 17b are formed, and (c) shows the liquid supply. The substrate main body 11 in which the passage 18 and the liquid recovery passage 19 are formed is shown. Here, for the sake of explanation, only one row of discharge port rows is drawn. FIG. 24 is a plan view showing the pressure chamber 23 and the discharge port 13, in which FIG. 24A is a plan view showing the inside of the recording element substrate 10 from the discharge port 13, and FIG. 24B is a plan view showing the inside of the recording element substrate 10. ) Is a cross-sectional view taken along the line AA. Hereinafter, the liquid discharge head in this configuration example will be described with reference to FIGS. 22 to 24. As shown in FIGS. 23 and 24, a recording element 15 which is a heat generating element is provided on the surface of the substrate main body 11 so as to face the discharge port 13, and is sandwiched between the discharge port 13 and the recording element 15. The region is the pressure chamber 23. A plurality of recording elements 15 are provided on the substrate main body 11, but a partition wall 22 is provided between the adjacent recording elements 15 to separate the pressure chambers 23. One recording element 15 and one discharge port 13 correspond to one pressure chamber 23. Therefore, as shown in FIG. 24B, the supply port 17a and the recovery port 17b are formed corresponding to both ends of the pressure chamber 23, respectively. The supply port 17a and the recovery port 17b communicate with the groove-shaped liquid supply path 18 and the liquid recovery path 19 formed on the opposite surfaces of the substrate main body 11, respectively.

In the liquid discharge head of the present configuration example, it is possible to organize the flow paths for the discharge ports 13 arranged at high density within substantially the same area as the recording element substrate 10. As a result, it is possible to suppress the enlargement of the liquid discharge head, and it is easy to supply and recover the liquid from the tank (not shown) for storing the liquid to be discharged to the liquid discharge head, and the entire system of the liquid discharge device is compact. It becomes possible to make things.

Hereinafter, the flow of a liquid such as a recording liquid in the liquid discharge head of this configuration example will be described. The circulation of the liquid to the pressure chamber 23 is set so that a pressure difference is provided between the supply side and the recovery side so that the liquid flows in the pressure chamber 23 at a flow velocity of about several mm / sec to several tens of mm / sec. .. FIG. 25 is a view seen from the common supply flow path 211 and the common recovery flow path 212 side, and shows the flow of liquid in the common supply flow path 211, the common recovery flow path 212, the supply liquid chamber 431, and the recovery liquid chamber 432 by arrows. Shown. A common supply flow path 211 and a common recovery flow path 212 are formed in the flow path constituent members 210 (FIGS. 5 and 7), and a supply liquid chamber 431 and a recovery liquid chamber 432 are formed in the support member 30 (FIG. 22). It is formed. The common supply flow path 211 and the common recovery flow path 212 are common to the common supply flow path 211 so that a backflow of liquid does not occur while generating a pressure difference required for liquid circulation between these common flow paths. The liquid is flowed at a flow rate of about 1.5 times the discharge flow rate in combination with the recovery flow path 212. In the standby state in which the liquid is not discharged from the discharge port, as shown in FIG. 25 (a), the liquid is recorded from the common supply flow path 211 through the supply liquid chamber 431 and through the supply side opening 21a of the lid member 20. It is supplied to each liquid supply path 18 of the element substrate 10. After that, it flows into the pressure chamber 23 through the supply port 17a. The liquid that has flowed into the pressure chamber 23 flows into the liquid recovery path 19 through the recovery port 17b, further flows into the recovery liquid chamber 432 of the support member 30 through the recovery side opening 21b of the lid member 20, and flows into the recovery liquid chamber 432 of the support member 30. To the common recovery flow path 212 of. This flow forms a flow that circulates in the pressure chamber 23.

By the way, in the liquid discharge head, in order to suppress a temperature change of the head due to driving and maintain good recording quality, temperature control for raising the temperature of the recording element substrate 10 to a predetermined temperature is performed. In a state where the temperature of the liquid discharge head is raised and controlled, the ink is warmed when flowing through each flow path in the recording element substrate 10, and the warmed liquid also flows into the recovery liquid chamber 432. When the liquid discharge head enters the recording operation from the standby state, the liquid flow is directed from the supply port 17a and the recovery port 17b to the discharge port 13, and the liquid that would have flowed to the recovery liquid chamber 432 during the standby state is also included. It is discharged from the discharge port 13 toward the discharge port 13. As shown in FIG. 25B, the liquid is supplied to the recovery liquid chamber 432 from the common recovery flow path 212 in order to supplement the liquid flowing from the recovery liquid chamber 432 to the discharge port 13. In the standby state, the warmed liquid flows into the recovery liquid chamber 432, and when the liquid discharge head enters the recording operation, the warmed liquid is supplied to the pressure chamber 23. The effect of cooling the recording element substrate 10 is reduced. As a result, the temperature of the liquid discharge head rises. When the heated liquid in the recovery liquid chamber 432 is gradually discharged by discharge and the unheated liquid is supplied from the common recovery flow path 212, the temperature of the liquid in the recovery liquid chamber 432 gradually rises. As the temperature drops, the temperature of the liquid discharge head also drops, reaching the steady temperature.

In the present invention, in order to suppress this phenomenon, the volume of the recovery liquid chamber 432 is made smaller than the volume of the supply liquid chamber 431 for the supply liquid chamber 431 and the recovery liquid chamber 432 formed in the support member 30. Hereinafter, the liquid discharge head based on the present invention will be described in more detail based on some examples and comparative examples.

(Example 1 and Comparative Example 1)
FIG. 26 shows a cross section of the support member 30 in the direction of the discharge port row 424 in the liquid discharge head (cross section taken along line BB in FIG. 22). FIG. 26A shows the shapes of the supply liquid chamber 431 and the recovery liquid chamber 432 in Example 1, and FIG. 26B shows the shapes of the supply liquid chamber 431 and the recovery liquid chamber 432 in Comparative Example 1. There is. In this figure, the downward direction shown is the recording element substrate 10 side.
In the first embodiment, the width of the recovery liquid chamber 432 is reduced with respect to the width of the supply liquid chamber 431 in the direction of the discharge port row, whereby the volume of the recovery liquid chamber 432 is reduced with respect to the volume of the supply liquid chamber 431. I'm making it smaller. Here, the volume of the supply liquid chamber 431 is larger than the volume of the recovery liquid chamber 432. Here, the volumes of the supply liquid chamber 431 and the recovery liquid chamber 432 are the volumes of the portions between the common supply flow path 211 and the common recovery flow path 212 and the lid member 20 of the recording element substrate 10, respectively.
In Comparative Example 1, the width of the supply liquid chamber 431 and the width of the recovery liquid chamber 432 are equal to each other in the direction of the discharge port row, and the volume of the supply liquid chamber 431 is equal to the volume of the recovery liquid chamber 432. In FIG. 26B, the distance L1 indicates the distance between the supply liquid chamber 431 and the recovery liquid chamber 432.

When each of the liquid discharge heads of Example 1 and Comparative Example 1 shifts from a state in which the liquid is circulated to the pressure chamber 23 without discharging from the discharge port (standby state) to a recording state in which the liquid is discharged at a predetermined frequency. The temperature change in the pressure chamber 23 of the above was obtained by simulation. FIG. 27 is a graph conceptually showing the temperature change when the discharge is started at the time S, the solid line shows the first embodiment, and the broken line shows the comparative example 1. As can be seen from the figure, in Example 1, the time from the start of recording to the peak temperature is shorter than that in Comparative Example 1 in which the supply liquid chamber 431 and the recovery liquid chamber 432 have the same volume. Moreover, the peak temperature is suppressed, and the time required to recover to the steady temperature is shortened. This is because, in the first embodiment in which the volume of the recovery liquid chamber 432 is relatively small, the amount of the heated liquid existing in the recovery liquid chamber 432 is also reduced, and this liquid is consumed in a shorter time by the discharge. Because.

FIG. 28 shows the support member 30 in the liquid discharge head of Comparative Example 2 as a cross section taken along line BB in FIG. In Comparative Example 2, similarly to Comparative Example 1, the width of the supply liquid chamber 431 and the width of the recovery liquid chamber 432 are equal in the direction of the discharge port row, but these supply liquid chambers 431 and the recovery liquid chamber 432 are the same. The width of is narrower than that shown in Comparative Example 1, and the arrangement is further biased. Specifically, the arrangement of each supply liquid chamber 431 and each recovery liquid chamber 432 is at the same pitch, but the distances from the supply liquid chamber 431 to the recovery liquid chambers 432 on both sides are not the same. Of the recovery liquid chambers 432 on both sides, the distance from the supply liquid chamber 431 to the recovery liquid chamber 432 that is closer to the recovery liquid chamber 432 is L1, and the distance to the recovery liquid chamber 432 that is farther from the supply liquid chamber 431 is L2. Specifically, the distances L1 and L2 are defined as the supply side opening 21a and the recovery side opening 21b measured along the discharge port row.
In Comparative Example 2, although the other dimensions of the liquid discharge head are the same, the volumes of the supply liquid chamber 431 and the recovery liquid chamber 432 are smaller than those of the liquid discharge head of Comparative Example 1. In Comparative Example 2, since the volume of the recovery liquid chamber 432 is small, the temperature rise at the start of recording can be suppressed as compared with Comparative Example 1. However, since the arrangement is biased, the distance between the supply liquid chamber 431 and the recovery liquid chamber 432 may become long, and the distance L2 through which the liquid flows through the liquid supply passage 18 and the liquid recovery passage 19 becomes long. As the distance L2 becomes longer, the pressure loss in the liquid supply path 18 and the liquid recovery path 19 increases.

FIG. 29 shows an outline of the results obtained by simulating the pressure distribution along the direction of the discharge port row in the liquid supply path 18 and the liquid recovery path 19, and the solid line shows the pressure distribution in the liquid supply path 18. Shown, the broken line shows the pressure distribution in the liquid recovery path 19. FIG. 29 (a) shows the result with the liquid discharge head described in Comparative Example 1, and FIG. 29 (b) shows the result with the liquid discharge head described with Comparative Example 2. As can be seen from the figure, when the distance between the supply side opening 21a and the recovery side opening 21b becomes long, the pressure loss in the liquid supply path 18 and the liquid recovery path 19 increases, and the pressure loss between the liquid supply path 18 and the liquid recovery path 19 increases. In the pressure difference ΔP of, a portion ΔPn having a small pressure difference is generated. In such a portion where the pressure difference is small, a desired circulating flow passing through the pressure chamber 23 cannot be obtained, and there is a possibility that discharge failure may occur due to thickening of the liquid when transitioning from the standby state to the recording state. As shown in Comparative Example 1, even when the supply liquid chamber 431 and the recovery liquid chamber 432 having the same width are arranged at equal pitches, the distance L1 becomes long and the pressure loss increases according to the distance L1. The same problem as in case 2 occurs. Therefore, the distances L1 and L2 need to be set so as to secure a predetermined circulation flow rate in the pressure chamber 23 even in the presence of pressure loss in the liquid supply passage 18 and the liquid recovery passage 19, and the supply liquid chamber 431 and The width of the recovery liquid chamber 432 is set so as to satisfy this condition.
As is clear from the results of Example 1 and Comparative Examples 1 and 2, in order to suppress the temperature rise of the pressure chamber 23 when the transition from the standby state to the recording state is performed while maintaining the desired circulating flow, the recovered liquid is used. It is effective to reduce the volume of the chamber 432 and increase the volume of the supply liquid chamber 431.

(Example 2)
In order to make the volume of the recovery liquid chamber 432 smaller than that of the supply liquid chamber 431, it is possible to make the height of the recovery liquid chamber 432 smaller than the height of the supply liquid chamber 431. In the liquid discharge head of the second embodiment shown in FIG. 30, the width in the direction of the discharge port row is the same for the supply liquid chamber 431 and the recovery liquid chamber 432, and the height of the recovery liquid chamber 432 is the same. I'm making it smaller. 30 is a diagram showing a support member 30 of the liquid discharge head of the second embodiment, FIG. 30A is a diagram corresponding to a cross section taken along the line BB of FIG. 22, and FIG. 30B is a diagram of A of FIG. 22. The cross section of the recovery liquid chamber 432 on the −A line is shown.
In the second embodiment as well as in the first embodiment, it is possible to suppress an excessive temperature rise of the pressure chamber 23 when the transition from the standby state to the recording state is performed. In the second embodiment, since the supply liquid chamber 431 and the recovery liquid chamber 432 are the same and have a sufficient width in the direction of the discharge port row, the pressure loss in the liquid supply passage 18 and the liquid recovery passage 19 becomes small, and the pressure chamber The desired circulation flow velocity at 23 can be secured.

(Example 3)
The method of making the volume of the recovery liquid chamber 432 smaller than that of the supply liquid chamber 431 is not limited to that shown in Examples 1 and 2. In the third embodiment, the width of the recovery liquid chamber 432 is narrower than that of the supply liquid chamber 431 in the direction of the discharge port row, and the height of the recovery liquid chamber 432 is lower than that of the supply liquid chamber 431. The volume of the chamber 432 is made smaller than the volume of the supply liquid chamber 431. FIG. 31 shows the support member 30 in the liquid discharge head of the third embodiment, and is a view corresponding to the cross section taken along the line BB of FIG. 22. In Example 3, since the volume of the recovery liquid chamber 432 is smaller than that of the supply liquid chamber 431, it is more effective to suppress the temperature rise after the transition from the standby state to the recording state.

(Example 4)
FIG. 32 shows the support member 30 in the liquid discharge head of the fourth embodiment, and is a view corresponding to the cross section taken along the line BB of FIG. 22. In the liquid discharge head of the fourth embodiment shown in FIG. 32, the volume of only a part of the recovery liquid chambers 432 is smaller than the volume of the supply liquid chamber 431 among the plurality of recovery liquid chambers 432. Due to the liquid circulation conditions and the thermal characteristics of each member constituting the liquid discharge head, the temperature rise at the start of the recording state becomes larger at the end of the recording element substrate 10 than at other parts of the recording element substrate 10. In some cases. In response to such a situation, in the fourth embodiment, the volume of the recovery liquid chamber 432 is reduced only in the portion where the temperature rise is likely to occur at the start of the recording state. Even if the volume of only a part of the plurality of recovery liquid chambers 432 is reduced in this way, the effect of the present invention can be achieved. In other words, the effect of the present invention is obtained by making the volume of at least one recovery liquid chamber 432 of the plurality of recovery liquid chambers 432 provided smaller than the volume of the supply liquid chamber 431 adjacent to the recovery liquid chamber 432. Will be achieved.

In each of the above-described embodiments, the width of the recovery liquid chamber 432 in the direction of the discharge port row is narrowed, and the height of the recovery liquid chamber 432 is lowered. However, by narrowing the width or lowering the height, depending on the type and physical property values of the liquid to be discharged (for example, viscosity and wettability with respect to the member), the liquid may be preliminarily placed in the support member 30 or the recording element substrate 10. Good filling can be difficult. The filling of the liquid into the support member 30 and the recording element substrate 10 is generally performed via the common supply flow path 211 and the common recovery flow path 212. If the filling is poor, large bubbles remain at the tip of the liquid chamber. For example, in the configuration shown in Example 2, as shown in FIG. 33, bubbles 450 may remain at the tip end portion (the portion where the height is low) of the recovery liquid chamber 432. Such residual bubbles grow as the temperature of the liquid discharge head rises, hindering the supply of the liquid to the pressure chamber 23, resulting in poor discharge. Such a problem is likely to occur in the recovery liquid chamber 432 having a small volume.

Therefore, a more preferable liquid filling method for the liquid chamber where air bubbles are likely to remain will be described below.
With both ends of the common recovery flow path 212 closed, the liquid is first filled through the common supply flow path 211. At this time, the supply liquid chamber 431 shall have a sufficient width and height so that the liquid can be easily filled. Further, the liquid discharge head is in a posture in which the surface on which the discharge port is formed faces downward. The ease of filling varies depending on the physical property values such as the viscosity of the liquid and the wettability of the liquid with respect to the member, but generally, the height of the supply liquid chamber 431 should be about 4 mm or more and the width should be about 2 to 3 mm or more. preferable. After filling the supply liquid chamber 431 with a liquid, both ends of the common recovery flow path 212 are opened. As a result, the liquid gradually enters the recovery liquid chamber 432 from the supply liquid chamber 431 through the pressure chamber 23, and as shown in FIG. 34, the recovered liquid is collected from the bottom surface of the recovery liquid chamber 432 (here, the recording element substrate 10 side). The chamber 432 is filled with liquid. After that, by further supplying the liquid to the common supply flow path 211, the liquid reaches the common recovery flow path 212 from the recovery liquid chamber 432 and the liquid flows through the common recovery flow path 212. In this way, the entire flow path from the common supply flow path 211 to the supply liquid chamber 431, the recording element substrate 10, the recovery liquid chamber 432, and the common recovery flow path 212 is filled with the liquid.

In the conventional filling method, the liquid is filled from both the common supply flow path 211 and the common recovery flow path 212. As described here, the supply liquid chamber 431 is filled from the common supply flow path 211 first, and then the recovery liquid chamber 432 is filled through the pressure chamber 23, which affects the recording including drawing and printing. It is possible to prevent such bubbles from remaining.

3 Liquid discharge head 10 Recording element substrate 15 Recording element 18 Liquid supply path 19 Liquid recovery path 22 Partition wall 23 Pressure chamber 211 Common supply flow path 212 Common recovery flow path 431 Supply liquid chamber 432 Recovery liquid chamber

Claims (15)

A discharge port for discharging a liquid, a recording element for generating energy for discharging the liquid, a pressure chamber having the recording element inside, a liquid supply path for supplying the liquid to the pressure chamber, and liquid from the pressure chamber. A recording element substrate comprising a liquid recovery path for recovery,
It has a support member that supports the recording element substrate and includes a supply liquid chamber for supplying liquid to the liquid supply passage and a recovery liquid chamber for recovering liquid from the liquid recovery passage.
A liquid supply unit including the recording element substrate, the support member, and a wiring substrate connected to the recording element substrate is provided.
Further, a flow path in which a plurality of the liquid supply units are arranged and includes a common supply flow path for supplying the liquid to the plurality of liquid supply units and a common recovery flow path for recovering the liquid from the plurality of liquid supply units. Has a member,
The supply liquid chamber and the recovery liquid chamber extend in directions intersecting each other in the direction in which the discharge ports are arranged, and are alternately arranged in the direction in which the discharge ports are arranged.
The recording element substrate includes a discharge port forming member including the discharge port and a substrate including the recording element.
The liquid supply path and the liquid recovery path are formed on the back surface of the surface of the substrate on which the recording element is provided.
On the back surface of the recording element substrate, a lid member including a supply-side opening for supplying the liquid to the liquid supply path and a recovery-side opening for recovering the liquid from the liquid recovery path is provided. ,
The volume of the supply liquid chamber and the recovery liquid chamber is the volume of the portion between the common supply flow path and the common recovery flow path and the lid member, and the volume of the recovery liquid chamber is the volume of the supply liquid chamber. A liquid discharge head characterized by being smaller than the volume of. The liquid discharge head according to claim 1, further comprising a negative pressure control unit for generating a pressure difference between the liquid supply path and the liquid recovery path. A page-wide liquid discharge head
The liquid discharge head according to claim 1 or 2, wherein the plurality of recording element substrates are arranged in a straight line. The liquid discharge head according to any one of claims 1 to 3, wherein the height of the recovery liquid chamber is lower than the height of the supply liquid chamber. The liquid discharge head according to any one of claims 1 to 4, wherein the width of the recovery liquid chamber is narrower than the width of the supply liquid chamber. The liquid discharge head according to any one of claims 1 to 5, wherein the liquid supply path and the liquid recovery path extend along the back surface. The liquid discharge head according to any one of claims 1 to 6, wherein the lid member forms at least a part of the liquid supply path and the liquid recovery path. The liquid discharge head according to any one of claims 1 to 7, wherein the liquid in the pressure chamber is circulated to and from the outside of the pressure chamber. A recording element substrate provided with a plurality of recording elements that generate energy for discharging a liquid on the first surface, a partition wall arranged between adjacent recording elements, and each recording element facing the recording element. A plurality of the discharge ports are arranged in a row to form a discharge port row, and a pressure chamber is formed by the partition wall for each recording element, and the discharge port is formed by the recording element. A liquid discharge head that discharges the liquid in the pressure chamber from
A liquid supply path communicating with the plurality of pressure chambers provided on the second surface of the recording element substrate, and
A liquid recovery path that communicates with the plurality of pressure chambers provided on the second surface, and
A common supply flow path for supplying the liquid to the pressure chamber,
A common recovery channel for recovering liquid from the pressure chamber,
A plurality of supply liquid chambers communicating with the common supply flow path and the liquid supply path and extending in a direction intersecting the direction of the discharge port row, and a plurality of supply liquid chambers.
A plurality of recovery liquid chambers communicating with the common recovery flow path and the liquid recovery path and extending in a direction intersecting the direction of the discharge port row, and a plurality of recovery liquid chambers.
Have,
In the region sandwiched between the common supply flow path, the common recovery flow path, and the recording element substrate, the supply liquid chamber and the recovery liquid chamber are alternately arranged in the direction of the discharge port row.
The second surface is provided with a lid member having a supply-side opening for supplying the liquid to the liquid supply path and a recovery-side opening for recovering the liquid from the liquid recovery path.
In the standby state in which the liquid is not discharged, the supply liquid chamber, the liquid supply path, and the pressure are provided from the common supply flow path according to the pressure difference between the common supply flow path and the common recovery flow path. A flow of the liquid is formed through the chamber, the liquid recovery path, and the recovery liquid chamber to the common recovery flow path.
The volume of the supply liquid chamber and the recovery liquid chamber is the volume of the portion between the common supply flow path and the common recovery flow path and the lid member, and the volume of at least one recovery liquid chamber is the said. A liquid discharge head characterized in that it is smaller than the volume of the supply liquid chamber adjacent to the recovery liquid chamber. The liquid discharge head according to claim 9, further comprising a negative pressure control means that causes the pressure difference between the common supply flow path and the common recovery flow path. 9. Liquid discharge head. The liquid in the pressure chamber is circulated to the outside of the liquid discharge head via the common supply flow path and the common recovery flow path, and the width of the recovery liquid chamber in the direction of the discharge port row is the width of the supply liquid chamber. The liquid discharge head according to any one of claims 9 to 11, which is narrower than the width of the above. The distance between the adjacent liquid supply chamber and the recovery liquid chamber is an interval that can secure a predetermined circulation flow rate in the pressure chamber even in the presence of pressure loss in the liquid supply passage and the liquid recovery passage. The liquid discharge head according to any one of 9 to 12. The liquid discharge head according to any one of claims 9 to 13, wherein the liquid in the pressure chamber is circulated to and from the outside of the pressure chamber. The liquid discharge head according to any one of claims 1 to 14.
The storage means for storing the liquid and
A first circulatory system that circulates the liquid from the storage means to the common supply flow path,
A second circulatory system that circulates the liquid from the storage means to the common recovery channel,
A liquid discharge device comprising.

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