JP6957147B2 - Liquid discharge head and liquid discharge device - Google Patents

Description

The present invention relates to a liquid ejection head and a liquid discharge equipment for discharging liquid such as ink.

In a liquid ejection head represented by an inkjet recording head that ejects a liquid such as ink for recording, volatile components in the ink contained in the head evaporate from the ejection port. As a result, the density of the coloring material in the ink near the ejection port changes, causing color unevenness in the recorded image, the viscosity near the ejection port increases, and the speed of the ejected droplets changes, resulting in improved landing accuracy. There are issues such as deterioration. As one of the countermeasures against such a problem, a method of circulating the ink supplied to the liquid ejection head through a circulation path is known.

Patent Document 1 discloses a device that prevents thickening of ink in the vicinity of a discharge port in a state where the ink is not ejected by circulating ink. Further, Patent Document 2 discloses an apparatus for cleaning the inside of a chamber by circulating ink.

Japanese Unexamined Patent Publication No. 2008-142910 Special Table 2002-533247

However, in the invention described in Patent Document 1, as described in FIG. 7 of Patent Document 1, the ink flowing into the head 11 from the first tank 12 passes through each pressure chamber in which the piezo element is arranged. It is configured to be collected from the head 11. Further, in the invention described in Patent Document 2, as described in FIGS. 4, 5, and 8 of Patent Document 2, each chamber for ejecting the ink flowing into the head 2010 from the lower container 2050. It is configured to be collected from the head 2010 via the inside.

As described above, in each of the ink circulation configurations disclosed in Cited Documents 1 and 2, the ink flowing into the head is recovered from the head via each pressure chamber (chamber). In such a configuration, for example, when the circulating flow rate is increased, the ink passes through a pressure chamber having a relatively small cross-sectional area as compared with the cross-sectional area of other flow paths, so that the flow path resistance in that portion is large. Therefore, the pressure loss in the circulating flow becomes large. By increasing the cross-sectional area of the pressure chamber, the flow path resistance in that portion can be reduced, but if the pressure chamber is increased, the ink ejection is affected and the head becomes larger.

The present invention has an object to provide a liquid discharge head and a liquid discharge equipment capable of supplying the liquid to the liquid inside the ejection head while suppressing the increase in pressure loss due to the supply of liquid.

In order to solve the above problems, the liquid discharge head of the present invention includes a plurality of recording elements including a plurality of discharge ports for discharging the liquid and a plurality of recording elements for generating energy used for discharging the liquid. With the board
A line-type liquid discharge head including a flow path member in which a plurality of recording element substrates are linearly arranged to support the plurality of recording element substrates.
The flow path member is made of an alumina or a resin material, and communicates with a plurality of supply flow paths for supplying a liquid to a plurality of recording elements and a plurality of supply flow paths, and is connected to a plurality of supply flow paths. A common supply channel for supplying a liquid, a plurality of recovery channels for recovering the liquid supplied to a plurality of recording elements from a plurality of supply channels, and a plurality of recovery channels communicating with the plurality of recovery channels. It is equipped with a common recovery channel for recovering liquid from the recovery channel.
The liquid discharge head has a first inflow port for supplying liquid from the outside to the common supply flow path and a first recovery port for recovering the liquid from the common supply flow path to the outside of the liquid discharge head. The first inflow port and the first recovery port are communicated with each other by a common supply flow path without passing through a flow path portion in which the recording element is arranged.
The liquid discharge head has a second inflow port for supplying liquid from the outside to the common recovery flow path and a second recovery port for recovering the liquid from the common recovery flow path to the outside of the liquid discharge head. The second inflow port and the second recovery port are characterized in that they communicate with each other by a common recovery flow path without passing through a flow path portion in which the recording element is arranged.

Further, the liquid discharge device of the present invention includes the above-mentioned line-type liquid discharge head, a first liquid feed pump that communicates with the first and second inlets, and a first liquid feed pump that feeds the liquid, and a first recovery port. A first recovery pump that communicates and collects the liquid and a second recovery pump that communicates with the second recovery port and collects the liquid are provided, or the line-type liquid discharge head described above is provided. A first liquid feeding pump that sends liquid to the first inflow port, a second liquid feeding pump that sends liquid to communicate with the second inflow port, and a first collection port. A first recovery pump that communicates and collects the liquid and a second recovery pump that communicates with the second recovery port and collects the liquid are provided, or the line-type liquid discharge head described above is provided. A first liquid feeding pump that feeds a liquid, which communicates with a first inlet, a second liquid feeding pump that feeds a liquid that communicates with a second inlet, and a first and second liquid feeding pump. It is equipped with a first recovery pump that collects the liquid that communicates with the collection port, or delivers the liquid that communicates with the line-type liquid discharge head described above and the first and second inflow ports. It includes a first liquid feeding pump and a first recovery pump that recovers the liquid and communicates with the first and second recovery ports.

According to the present invention, it is possible to supply the liquid in the liquid discharge head while suppressing an increase in pressure loss.

It is a perspective view which shows the outline of the inside of the recording device which is an example of the liquid discharge device of this invention. It is a figure which shows the flow path structure of the liquid discharge device in Embodiment 1 of this invention. It is external perspective view of the liquid discharge head in Embodiment 1 of this invention. It is an exploded perspective view of the liquid discharge head in Embodiment 1 of this invention. It is sectional drawing of various positions of the flow path member in Embodiment 1 of this invention. It is a perspective view of the flow path member in Embodiment 1 of this invention. It is sectional drawing of the liquid discharge head in Embodiment 1 of this invention. It is a perspective view and the exploded perspective view which shows the discharge module of the liquid discharge head of this invention. It is a figure which shows the flow path structure of the liquid discharge device of Embodiment 2 of this invention. It is a figure which shows the temperature distribution of each recording element at the time of driving a liquid discharge head of this invention. It is sectional drawing of the liquid discharge head in Embodiment 3 of this invention. It is sectional drawing of the liquid discharge head in Embodiment 4 of this invention. It is a perspective view of the recording element substrate applicable to each embodiment of this invention. It is a partially cutaway perspective view of the recording element substrate shown in FIG. It is a figure which shows the flow path structure of the liquid discharge device of Embodiment 5 of this invention. In the figure which shows the pressure distribution of each pressure chamber of the liquid discharge head of Embodiment 5 of this invention, (a) is the opposite direction of flow direction of a common flow path, (b) is the same direction of flow direction of a common flow path. be. It is a figure which shows the flow path structure of the liquid discharge device of Embodiment 6 of this invention. It is an equivalent circuit diagram of the internal flow path of the liquid discharge head in Embodiment 6 of this invention. It is a figure which shows the structure of the liquid discharge head in this invention. It is a perspective view of the liquid discharge head which concerns on Embodiment 7 of this invention. It is an exploded perspective view of the liquid discharge head shown in FIG. FIG. 20 is a plan view and a bottom view of each flow path member of the liquid discharge head shown in FIG. It is a figure which shows the connection state of the flow path of the recording element substrate of the liquid discharge head shown in FIG. 20 and the flow path member. It is a perspective view and the exploded perspective view of the discharge module of the liquid discharge head shown in FIG. FIG. 20 is a plan view, an intermediate portion, and a bottom view of the recording element substrate of the liquid discharge head shown in FIG. It is a perspective view which shows the inkjet recording apparatus according to Embodiment 7 of this invention. It is a perspective view which shows the inkjet recording apparatus according to Embodiment 8 of this invention. It is a figure which shows the liquid circulation path which concerns on Embodiment 9 of this invention. It is a figure which shows the liquid discharge head which concerns on Embodiment 9 of this invention. It is a figure which shows the liquid discharge head which concerns on Embodiment 9 of this invention.

Hereinafter, the liquid discharge head, the liquid discharge device, and the liquid discharge method according to each embodiment of the present invention will be described with reference to FIGS. 1 to 18. The liquid discharge head and liquid discharge device of the present invention are applied to devices such as printers, copiers, facsimiles having a communication system, word processors having a printer unit, and industrial recording devices combined with various processing devices. It is possible. For example, it can also be used for biochip fabrication and electronic circuit printing. Further, in the following embodiments, a thermal method in which bubbles are generated by a heat generating element to discharge a liquid is adopted, but the present invention is also applied to a liquid discharge head in which a piezo method and various other liquid discharge methods are adopted. can do.
The liquid ejection device of the present embodiment is an inkjet recording apparatus (recording apparatus) in which a liquid such as ink is circulated between the ink tank and the liquid ejection head, but other embodiments may be used. For example, two tanks are provided on the upstream side and the downstream side of the liquid ejection head without circulating the ink, and the ink flows from one ink tank to the other ink tank to flow the ink in the pressure chamber. There may be.
The liquid discharge head of the present embodiment is a so-called line type head having a length corresponding to the width of the recording medium, but is a so-called serial type liquid that records while scanning the recording medium. The present invention can also be applied to the discharge head. Examples of the serial type liquid ejection head include a configuration in which one recording element substrate for black ink and one recording element substrate for color ink are mounted. However, the present invention is not limited to this, and 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. It may be in the form of scanning the recording medium.
As described above, since the embodiments described below are appropriate specific examples of the present invention, various technically preferable limitations are given. The present invention is not limited to the embodiments and other specific methods.

[Embodiment 1]
(Explanation of inkjet recording device)
FIG. 1 shows a schematic configuration of a liquid ejection device of the present invention, particularly an inkjet recording apparatus 1000 (hereinafter, also referred to as a recording apparatus) that ejects ink for recording. The recording device 1000 includes a transport unit 1 that transports the recording medium 2, and a line-type (page-wide side) liquid discharge head 3 that is arranged substantially orthogonal to the transport direction of the recording medium. The recording device 1000 is a line-type recording device that continuously or intermittently conveys a plurality of recording media 2 and continuously records in one pass. The recording medium 2 is not limited to cut paper, and may be continuous roll paper. The liquid discharge head 3 can perform full-color printing with CMYK (cyan, magenta, yellow, black) ink. As will be described later, the liquid supply means, which is a supply path for supplying the liquid to the liquid discharge head, and two ink tanks (main tank and buffer tank) (FIG. 2) are fluidly connected. Further, an electric control unit that transmits electric power and a discharge control signal to the liquid discharge head 3 is electrically connected to the liquid discharge head 3. The liquid path and the electric signal path in the discharge head 3 will be described later.

(Explanation of the structure of the recording element substrate)
FIG. 19 describes a configuration example of a liquid ejection head that ejects a liquid such as ink of the present invention prior to the description of each embodiment of the present invention. FIG. 19A shows a plan view of the surface of the recording element substrate 10 of the liquid discharge head on the side where the discharge port 13 is formed, and FIG. 19B is a cross section taken along the line AA'of FIG. 19A. The figure is shown. As shown in FIG. 19A, the recording element substrate 10 is provided with a recording element 15 that generates energy used for discharging a liquid. Further, the recording element substrate 10 is formed with an individual supply flow path 17a for supplying ink to the pressure chamber 23 accommodating the recording element 15 and an individual recovery flow path 17b for collecting ink in the pressure chamber 23. There is. The ejection port forming member 12, which is one member forming the recording element substrate 10, is formed with an ejection port 13 for ejecting ink. In this specification, the heater, which is a heat generating element capable of generating heat energy, will be described as the recording element 15, but the present invention is not limited to this. For example, an electromechanical conversion element such as a piezoelectric element and various recording elements that generate energy for discharge can be adopted.

As shown in FIG. 19, a plurality of individual supply flow paths 17a and individual recovery flow paths 17b are formed on the recording element substrate 10, and a plurality of pressure chambers 23 are arranged between them. Each pressure chamber 23 is partitioned by a partition wall 22, a recording element 15 is arranged inside the pressure chamber 23, and a discharge port 13 is formed at a position facing the recording element 15. The recording element 15 is selectively driven according to the recorded data, and ejects a desired amount of ink from the ejection port 13. When the recording element 15 is in a dormant state, ink is supplied from the individual supply flow path 17a to the pressure chamber 23 and then collected from the recording element substrate via the individual recovery flow path 17b. In the present embodiment, such an ink flow (circulating flow) is generated when the recording element 15 is not driven, and further, a circulating flow is continuously generated when the recording element 15 is driven to eject ink. I keep letting you. That is, the recording element 15 is driven while the ink in the pressure chamber 23 is flowing to eject the ink. The recording element 15 is electrically connected to the terminal 16 of FIG. 13A by an electric wiring (not shown) provided on the recording element substrate 10. Then, the recording element generates heat based on the pulse signal input from the control circuit of the recording device 1000 via the electric wiring board 90 (FIG. 4) and the flexible wiring board 40 (FIG. 8) to boil the liquid. The liquid is discharged from the discharge port 13 by the force of foaming due to this boiling.

(Explanation of circulation configuration)
As described above, in the system in which the heat generated by driving the recording element 15 is transferred to the ink, the temperature distribution in the head becomes stable after the recording element 15 is in a dormant state or after a certain period of time has passed since the recording element 15 was driven. However, in the transient state, the appearance is different, and the heat from the recording element 15 is transmitted to the ink with a time constant. Therefore, in the transient state, the ink temperature in the pressure chamber 23 changes from moment to moment, and the ejection characteristics also change. Therefore, the temperature in the vicinity of the pressure chamber 23 is monitored, and if it is determined that the temperature is equal to or lower than a predetermined threshold value, the recording element 15 or a heat source (not shown) for warming the vicinity of the pressure chamber 23 is driven to such an extent that the ink does not boil. As a result, the ink temperature in the pressure chamber 23 can be maintained within the set range, and variations in ejection characteristics can be suppressed.

The liquid discharge head according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 8. FIG. 2 shows an example of the overall configuration of the flow path system of the recording device, which is an example of the liquid discharge device in the present embodiment. FIG. 2 is a schematic diagram showing a first circulation path, which is one form of the circulation path applied to the recording device of the present embodiment. FIG. 2 shows a state in which the liquid discharge head 3 is fluidly connected to the first circulation pump (high pressure side) 1001, the first circulation pump (low pressure side) 1002, the buffer tank 1003, and the like. Note that FIG. 2 shows only the path through which one color of ink flows for the sake of simplification of the explanation, but in reality, circulation paths for the required number of colors are provided in the liquid ejection head 3 and the recording device main body. Be done. The buffer tank 1003 as a sub tank connected to the main tank 1006 has an air communication port (not shown) that communicates the inside and the outside of the tank, and can discharge air bubbles in the ink to the outside. The buffer tank 1003 is also connected to the replenishment pump 1005. The replenishment pump 1005 discharges (discharges) ink from the discharge port of the liquid discharge head, such as recording by ink discharge and suction recovery, and when the liquid is consumed by the liquid discharge head 3, the consumed amount of ink is discharged. Transfer from the main tank 1006 to the buffer tank 1003.
The two first circulation pumps 1001 and 1002 have a role of sucking liquid from the liquid connection portion 111 of the liquid discharge head 3 and flowing it to the buffer tank 1003. As the first circulation pump, a positive displacement pump having a quantitative liquid feeding capacity is preferable. Specific examples thereof include a tube pump, a gear pump, a diaphragm pump, a syringe pump, and the like. For example, a general constant flow rate valve or relief valve may be arranged at the pump outlet to secure a constant flow rate. When the liquid discharge head 3 is driven, a certain amount of ink flows in the common supply flow path 211 and the common recovery flow path 212 by the first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) 1002, respectively.
The negative pressure control unit 230 is provided in the path between the second circulation pump 1004 and the liquid discharge unit 300. This keeps the pressure on the downstream side (that is, the liquid discharge unit 300 side) of the negative pressure control unit 230 at a preset constant pressure even when the flow rate of the circulation system fluctuates due to the difference in the duty for recording. It has a function to operate as if it were. As the two pressure adjusting mechanisms constituting the negative pressure control unit 230, any mechanism can be used as long as the pressure downstream of itself can be controlled to a fluctuation within a certain range around a desired set pressure. May be used. As an example, a mechanism similar to a so-called "decompression regulator" can be adopted. With such a configuration, the influence of the head pressure on the liquid discharge head 3 of the buffer tank 1003 can be suppressed, so that the degree of freedom in the layout of the buffer tank 1003 in the recording device 1000 can be expanded.
The second circulation pump 1004 may be a pump having a lift pressure equal to or higher than a certain pressure within the range of the ink circulation flow rate used when driving the liquid discharge head 3, and a turbo type pump, a positive displacement pump, or the like can be used. Specifically, a diaphragm pump or the like can be adopted. 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 adopted. By integrating the pumps on the side that supplies ink to the liquid discharge head 3 in this way, the number of pumps in the entire device can be reduced, and the size of the device can be reduced.

As shown in FIG. 2, the negative pressure control unit 230 includes two pressure adjusting mechanisms in which different control pressures are set for each. Of the two negative pressure adjustment mechanisms, the relative high pressure setting side (denoted as H in FIG. 2) and the relative low pressure setting side (denoted as L in FIG. 2) pass through the liquid supply unit 220, respectively. Therefore, it is connected to the common supply path 211 and the common recovery flow path 212 in the liquid discharge unit 300. The liquid discharge unit 300 is provided with a common supply flow path 211, a common recovery flow path 212, and a branch supply flow path 213a and a branch recovery flow path 213b communicating with each recording element substrate. A first inflow port 7a and a first recovery port 8a are formed in the common supply flow path 211. The first inflow port 7a is fluidly connected to the pressure adjusting mechanism H, and the first recovery port 8a is fluidly connected to the first circulation pump (first recovery pump) 1001. A second inflow port 7b and a second recovery port 8b are formed in the common recovery flow path 212. The second inflow port 7b is fluidly connected to the pressure adjusting mechanism L, and the second recovery port 8b is fluidly connected to the first circulation pump (second recovery pump) 1002. At this time, the pressure value near the first inflow port 7a in the common supply flow path is Pu_i, the pressure value near the first recovery port 8a is Pu_o, and the pressure value near the second inflow port 7b in the common recovery flow path is. Assuming that the value is Pd_i and the pressure value near the second recovery port 8b is Pd_o, the following inequality is satisfied.
Pu_i> Pd_i Inequalities 1
Pu_o> Pd_o Inequalities 2
Since the pressure adjusting mechanism H is connected to the common supply flow path 211 and the pressure adjusting mechanism L is connected to the common recovery flow path 212, a differential pressure is generated between the two common flow paths, so that inequality 1 is satisfied. Further, a certain amount of ink satisfying inequality 2 is flowed inside the common supply flow path and the common recovery flow path by the first circulation pumps 1001 and 1002.
By adopting this configuration, for each recording element substrate, the common supply flow path 211 passes through the branch supply flow path 213a, passes through a plurality of pressure chambers in the recording element substrate, and passes through the branch recovery flow path 213b, and is commonly recovered. An ink flow (white arrow in FIG. 2) to the flow path 212 is generated. Further, the ink supplied from the two inlets simultaneously flows to the collection port in each common flow path without passing through each recording element substrate. Therefore, even when a relatively large amount of ink is supplied, it is possible to suppress an increase in pressure loss in the supply path inside the liquid discharge head 3, and the ink is discharged into the pressure chamber 23 which is not ejected. A flow can be generated. Therefore, the heat generated in each recording element substrate can be discharged to the outside of the liquid discharge head 3 by the flow of the common supply flow path 211 and the common recovery flow path 212. Further, since the ink flow can be generated in the ejection port and the pressure chamber regardless of the operating state, it is possible to suppress the thickening of the ink in that portion. Further, the thickened ink and foreign substances in the ink can be discharged to the common collection flow path 212. Therefore, the liquid discharge head 3 of the present embodiment enables high-speed and high-quality recording.

(Explanation of head configuration)
The configuration of the liquid discharge head 3 according to the first embodiment will be described. 3A and 3B are perspective views of the liquid discharge head 3 according to the present embodiment. The liquid discharge head 3 is a line-type liquid discharge head in which 15 recording element substrates 10 capable of ejecting four colors of ink of C / M / Y / K are arranged in a straight line (arranged in-line). .. As shown in FIG. 3A, the liquid discharge head 3 has a recording element substrate 10, a signal input terminal 91 and a power supply terminal 92 electrically connected via the flexible wiring board 40 and the electrical wiring board 90. And have. The signal input terminal 91 and the power supply terminal 92 are electrically connected to the control unit of the recording device 1000, and supply the discharge drive signal and the power required for discharge to the recording element substrate 10, respectively. By consolidating the wiring by the electric circuit in the electric wiring board 90, the number of signal output terminals 91 and power supply terminals 92 can be reduced as compared with the number of recording element boards 10. As a result, the number of electrical connections that need to be removed when assembling the liquid discharge head 3 to the recording device 1000 or when replacing the liquid discharge head can be reduced. As shown in FIG. 3B, the liquid connection portions 111 provided at both ends of the liquid discharge head 3 are connected to the liquid supply system of the recording device 1000. As a result, CMYK four-color ink is supplied from the supply system of the recording device 1000 to the liquid ejection head 3, and the ink that has passed through the liquid ejection head 3 is collected to the supply system of the recording device 1000. In this way, the inks of each color can be circulated through the path of the recording device 1000 and the path of the liquid ejection head 3.
FIG. 4 shows an exploded perspective view of each component or unit constituting the liquid discharge head 3. The liquid discharge unit 300, the liquid supply unit 220, and the electrical wiring board 90 are attached to the housing 80. The liquid supply unit 220 is provided with a liquid connection portion 111 (FIG. 3), and inside the liquid supply unit 220, each color communicating with each opening of the liquid connection portion 111 in order to remove foreign substances in the supplied ink. Another filter 221 (FIGS. 2 and 3) is provided. The 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.

Next, the configuration of the flow path member 210 included in the liquid discharge unit 300 will be described. As shown in FIG. 4, the flow path member 210 distributes the liquid supplied from the liquid supply unit 220 to each discharge module 200, and returns the liquid recirculated from the discharge module 200 to the liquid supply unit 220. It is a flow path member of. The flow path member 210 is fixed to the liquid discharge unit support portion 81 with screws, whereby warpage and deformation of the flow path member 210 are suppressed. 5 (a) to 5 (e) are exploded views for making it easier to understand the flow path portion of the flow path member 210. FIG. 5A shows a surface on the side on which the discharge module 200 is mounted, and FIG. 5E shows a surface on the side that comes into contact with the liquid discharge unit support portion 81. The eight common flow paths extending in the longitudinal direction of the flow path member are the common supply flow path 211 and the common recovery flow path 212 for each color, respectively. Each inflow port 7 and each recovery port 8 communicate with each hole of the joint rubber 100, and are fluidly connected to the liquid supply unit 220. Further, the flow path member 210 is formed with a plurality of branch flow paths 213 in a direction intersecting the common flow path, and is fluidly connected to the plurality of discharge modules 200. The flow path member 210 is preferably made of a material having corrosion resistance against liquid and having a low coefficient of linear expansion. As the material, for example, a composite material (resin material) using alumina, LCP (liquid crystal polymer), PPS (polyphenyl sulfide) or PSF (polysulfone) as a base material and adding an inorganic filler such as silica fine particles or fibers is preferably used. be able to.

Next, the connection relationship of each flow path in the flow path member 210 will be described with reference to FIG. FIG. 6 is a perspective view of the flow path in the flow path member 210, which is partially enlarged from the surface side on which the discharge module 200 is mounted. The flow path member 210 includes a common supply flow path 211 (211a, 211b, 211c, 211d) extending in the longitudinal direction of the liquid discharge head 3 for each color, and a common recovery flow path 212 (212a, 212b, 212c, 212d). It is provided. A branch supply flow path 213a is connected to the common supply flow path 211 of each color via a communication port 61. Further, a plurality of branch recovery flow paths 213b are connected to the common recovery flow path 212 of each color via a communication port 61. With such a flow path configuration, ink can be concentrated on the recording element substrate 10 located at the center of the flow path member from each common supply flow path 211 via the branch supply flow path 213a. Ink can be recovered from the recording element substrate 10 to each common recovery flow path 212 via the branch recovery flow path 213b.

FIG. 7 is a diagram showing a cross section taken along the line EE of FIG. As shown in this figure, each branch recovery flow path 213b communicates with the discharge module 200. In FIG. 7, only the branch recovery flow path 213b is shown, but in another cross section, the branch supply flow path 213a and the discharge module 200 communicate with each other as shown in FIG. A plurality of individual supply flow paths 17a and a plurality of individual recovery flow paths 17b are formed in the recording element substrate 10 included in each discharge module 200, and the branch supply flow path 213a is a branch supply flow path 17a and a branch recovery flow path. The path 213b is fluidly connected to each individual recovery flow path 17b.

FIG. 8A shows a perspective view of one discharge module 200, and FIG. 8B shows an exploded view thereof. The terminal 42 on the side of the flexible wiring board 40 opposite to the recording element board 10 is electrically connected to the connection terminal 93 (see FIG. 4) of the electrical wiring board 90. Since the support member 30 is a support that supports the recording element substrate 10 and is a flow path member that fluidly communicates the recording element substrate 10 and the flow path member 210, the flatness is high and sufficiently high. Those that can be reliably bonded to the recording element substrate are preferable. As the material, for example, alumina or a resin material is preferable. This support member is formed by a laminated structure of a first support member on which a supply flow path and a recovery flow path are formed and a second support member on which a common supply flow path and a common recovery flow path are formed. May be good. In that case, the thermal diffusivity of at least the first support member is smaller than the thermal diffusivity of the recording element substrate.

As described above, in the present embodiment, the backflow to the common recovery flow path 212 can be suppressed regardless of the driving state of each recording element substrate 10, and the fluctuation range of the circulation (supply) flow rate can be suppressed. It is a head configuration that can maintain a circulating flow that can secure the effect of circulation. In the present embodiment, a pressure adjusting mechanism is adopted as a pressure generating source, but the present invention is not limited to this. For example, a head difference control configuration using a water level sensor may be used. This configuration is the same in the following embodiments.

[Embodiment 2]
FIG. 9 is a schematic diagram showing a second circulation path, which is a circulation mode different from the above-mentioned first circulation path, among the circulation channels applied to the recording device of the present embodiment. The main differences from the above-mentioned first circulation path are as follows. Both of the two pressure adjusting mechanisms constituting the negative pressure control unit 230 control the pressure on the upstream side of the negative pressure control unit 230 to a fluctuation within a certain range around a desired set pressure (so-called "back pressure"). It is a mechanical component that has the same function as the "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. The first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) 1002 are arranged on the upstream side of the liquid discharge head, and the negative pressure control unit 230 is arranged on the downstream side of the liquid discharge head.
The negative pressure control unit 230 of the second embodiment can preliminarily perform pressure fluctuations on the upstream side (liquid discharge unit 300 side) 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. Stabilize within a certain range around the set pressure. By doing so, the influence of the head pressure of the buffer tank 1003 on the liquid discharge head 3 can be suppressed, so that the layout selection range of the buffer tank 1003 in the recording device 1000 can be widened. Instead of the second circulation pump 1004, for example, a head tank arranged with a predetermined head difference with respect to the negative pressure control unit 230 can also be adopted. Also in this embodiment, the number of pumps in the entire device can be reduced and the size of the device can be reduced by consolidating the pumps on the side of collecting ink from the liquid ejection head 3 into one. Further, as in the first embodiment, as shown in FIG. 9, the negative pressure control unit 230 includes two pressure adjusting mechanisms in which different control pressures are set for each of the negative pressure control units 230. Of the two negative pressure adjustment mechanisms, the high pressure setting side (denoted as H in FIG. 9) and the low pressure setting side (denoted as L in FIG. 9) pass through the liquid supply unit 220 and enter the liquid discharge unit 300, respectively. It is connected to the common supply path 211 and the common recovery flow path 212. Further, a first inflow port 7a and a first recovery port 8a are formed in the common supply flow path 211, and the first inflow port 7a is a first circulation pump (first liquid feeding pump) 1001 and a first. The recovery port 8a of 1 is fluidly connected to the pressure adjusting mechanism H, respectively. A second inflow port 7b and a second recovery port 8b are formed in the common recovery flow path 212, and the second inflow port 7b is a first circulation pump (second liquid feeding pump) 1002 and a second. The recovery port 8b is fluidly connected to the pressure adjusting mechanism L, respectively.
The pressure of the common supply flow path 211 is controlled relative to the pressure of the common recovery flow path 212 by the two negative pressure adjusting mechanisms and the two first circulation pumps. As a result, an ink flow is generated from the common supply flow path 211 to the common recovery flow path 212 via the branch supply flow path 213a and the internal flow path of each recording element substrate 10, and the ink supplied from each inflow port is generated. It flows to the collection port of each common flow path without passing through each recording element substrate. As described above, in the second circulation path, the same ink flow state as in the first circulation path can be obtained in the liquid ejection unit 300, but there are two advantages different from those in the case of the first circulation path.

The first advantage is that the negative pressure control unit 230 is arranged on the downstream side of the liquid discharge head 3 in the second circulation path, so that there is a concern that dust and foreign matter generated from the negative pressure control unit 230 may flow into the head. Is less. The second advantage is that in the second circulation path, the maximum value of the required flow rate supplied from the buffer tank 1003 to the liquid discharge head 3 is smaller than in the case of the first circulation path. The reason is as follows. Let A be the total flow rate inside the common supply flow path 211 and the common recovery flow path 212 when the ink circulates during the recording standby. The value of A is defined as the minimum flow rate required to keep the temperature difference in the liquid discharge unit 300 within a desired range when the temperature of the liquid discharge head 3 is adjusted during recording standby. Further, the discharge flow rate when ink is discharged from all the discharge ports of the liquid discharge unit 300 (at the time of full discharge) is defined as F. Then, in the case of the first circulation path (FIG. 2), the set flow rates of the first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) 1002 become A, so that the liquid discharge required for all discharges is performed. The maximum value of the liquid supply amount to the head 3 is A + F.
On the other hand, in the case of the second circulation path (FIG. 9), 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 full discharge is the flow rate F. Then, in the case of the second circulation path, the total value of the set flow rates of the first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) 1002, that is, the maximum value of the required supply flow rate is the larger of A or F. Is the value of. Therefore, as long as the liquid discharge unit 300 having the same configuration is used, the maximum value (A or F) of the required supply amount in the second circulation path is larger than the maximum value (A + F) of the required supply flow rate in the first circulation path. Will always be smaller. Therefore, in the case of the second circulation path, the degree of freedom of the circulation pump that can be adopted 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. There is an advantage that the cost of the recording device itself can be reduced. This advantage increases as the value of A or F becomes relatively large, and is more beneficial for line heads having a longer length in the longitudinal direction.
However, on the other hand, there is also a point that the first circulation path is more advantageous than the second circulation path. That is, in the second circulation path, since the flow rate flowing through the liquid discharge unit 300 during the recording standby is the maximum, the lower the recording duty of the image, the higher the negative pressure is applied to the vicinity of each discharge port. .. Therefore, in particular, the flow path width (length in the direction orthogonal to the liquid flow direction) of the common supply flow path 211 and the common recovery flow path 212 is reduced to reduce the head width (length in the lateral direction of the liquid discharge head). When is reduced, a high negative pressure is applied in the vicinity of the discharge port in a low-duty image in which unevenness is easily visible. Therefore, the influence of satellite droplets may increase. On the other hand, in the case of the first circulation path, a high negative pressure is applied to the vicinity of the discharge port at the time of forming a high-duty image, so even if satellites are generated, they are difficult to see and the effect on the image is small. There are advantages. As for the selection of the two circulation paths, the preferred one can be adopted in light of the specifications of the liquid discharge head and the recording device main body (discharge flow rate F, minimum circulation flow rate A, flow path resistance in the head, etc.).

As described above, similarly to the first embodiment, the present embodiment can suppress the backflow to the common recovery flow rate 212 regardless of the driving state of each recording element substrate 10, and further, the fluctuation range of the circulation (supply) flow rate can be adjusted. It is a head configuration that can suppress and maintain the circulation flow that secures the effect of circulation.

[Thermal diffusivity of the flow path member]
FIG. 10 is a diagram showing a temperature distribution during driving on each recording element substrate suitable for explaining the characteristics of the liquid discharge head of the present invention. The horizontal axis is the extending direction of the common flow path, and the vertical axis is the vertical axis. The temperature of each recording element substrate is taken. Thermal diffusivity of the channel member 210 in the present example is smaller than the thermal diffusivity of the recording element substrate 10, a head thermal diffusivity of the flow path member 210 is 7 × 10 -7 ^{m 2} / ^s in FIG. 10 the solid line It is illustrated in. In FIG. 10, a dotted line shows a head having ^{a thermal diffusivity of 8 × 10-6} m ² / s in the flow path member 210 for comparison with the effect of this example. As is clear from the figure, when the thermal diffusivity of the flow path member 210 is higher than the thermal diffusivity of the recording element substrate 10, a temperature difference occurs from the inflow port communicating with the common flow path to the recovery port. It ends up. On the other hand, when the thermal diffusivity of the flow path member 210 is low, the temperature is kept substantially constant regardless of the position of the recording element substrate 10. In this way, in a configuration in which a plurality of recording element substrates 10 are arranged in the extension direction of the common flow path and ink flows in each common flow path, heat from each recording element substrate is difficult to transfer, so that the ink is discharged. It is possible to suppress variations in the volume of ink droplets. Although specific numerical values of the thermal diffusivity of the flow path member have been described here, it is possible to add a function of making it difficult to transfer the heat from the recording element substrate 10 to the ink of the common flow path. If so, the configuration is not limited.

[Embodiment 3]
The third embodiment will be described below with reference to FIG. Also in this embodiment, the same ink flow state as in the first embodiment or the second embodiment is obtained. Further, the same parts as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted. FIG. 11 is a view showing a cross section of the liquid discharge head of the present embodiment, in which a multi-layered flow path member is formed. Common flow paths (211a to 211d, 212a to 212d) extending in the direction in which the recording element substrates are arranged (longitudinal direction of the flow path member) in the second flow path member 60 and the third flow path member 70. Is formed. Further, the first flow path member 50 is configured with a plurality of branch flow paths 213d (individual flow paths) extending in a direction intersecting each common flow path (short direction of the flow path member). By configuring the branch flow path groove and the common flow path groove with separate members, it is possible to create a member in which a long groove and a very fine groove intersecting the long groove coexist, for example, by molding a resin. , There is a merit that the manufacturing cost can be reduced.
In this embodiment, three layers of flow path members 50, 60, and 70 are described, but if the idea of configuring each common flow path and each branch flow path with separate members is realized. , There is no particular limitation on the number of layers. Further, the flow path member forming the branch flow path may be formed for each recording element substrate, one for each of a plurality of recording element substrates, or one for all the recording element substrates. good. In any case, the configuration is not limited as long as it is achieved that the common flow path and the branch flow path are formed in separate members.

[Embodiment 4]
Also in this embodiment, the connection relationship between the common flow path, the branch flow path, and the plurality of pressure chambers is the same as that of the above-described embodiment, and the ink flow and the common supply flow path only in the common flow path not passing through the pressure chamber. An ink flow that passes through each pressure chamber and flows to a common recovery flow path is obtained. FIG. 12 is a view showing a cross section of the liquid discharge head of the present embodiment. The flow path member constituting the liquid discharge head 3 of the present embodiment has a multi-layer structure as in the third embodiment, and the elongated flow path member forming the common flow path maintains the mounting accuracy of each recording element substrate with high accuracy. Therefore, it is made of a material having a linear expansion coefficient almost the same as that of the recording element substrate 10. As the material of the second flow path member 60, specifically, an inorganic material such as silicon or alumina or a metal material having a low coefficient of linear expansion such as Invar is assumed, and the thermal diffusivity is close to that of the recording element substrate 10. It is a value. Therefore, in the present embodiment, the thermal diffusivity of the first flow path member 50 forming the plurality of branch flow paths is lower than that of the recording element substrate 10 and the second flow path member 60. By doing so, it becomes difficult to transfer heat from each recording element substrate to the ink passing through each common flow path, and it becomes possible to make the volumes of the ejected ink droplets uniform.
In the present embodiment, the two-layer flow path members 50 and 60 are described, but if the idea that each common flow path and each branch flow path are composed of separate members is realized, a special case regarding the number of layers is specified. There is no limit. Further, although the common flow path shown in the figure is only for one color, the second flow path member is not deformed by disturbance such as heat and swelling, and the recording element substrate and the second flow path member are heated by the first flow path member. A common flow path for a plurality of colors may be formed as long as the structure does not easily transfer heat.

[Construction of recording element substrate]
The configuration of the recording element substrate applicable to each embodiment will be described below with reference to FIGS. 13 and 14. As shown in FIG. 13A, the ejection port forming member 12 of the recording element substrate 10 is formed with four rows of ejection ports corresponding to each ink color. Hereinafter, the direction in which the discharge port row in which the plurality of discharge ports 13 are arranged extends is referred to as the "discharge port row direction". As shown in FIG. 13B, 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. 13 (c) and 14, a sheet-shaped cover plate 20 is laminated on the back surface of the surface of the recording element substrate 10 on which the discharge port 13 is formed. The cover plate 20 is provided with a plurality of openings 21 that communicate with the liquid supply path 18 and the liquid recovery path 19, which will be described later. In this example, the cover plate 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. 13B, each opening 21 of the cover plate 20 communicates with a plurality of communication ports. As shown in FIG. 14, which is a cross-sectional view taken along the line BB of FIG. 13, the cover plate 20 functions as a lid member for the liquid supply path 18 and the liquid recovery path 19 formed on the substrate 11 of the recording element substrate 10. Have. The cover plate 20 preferably has sufficient corrosion resistance against a liquid, and from the viewpoint of preventing color mixing, the opening shape and opening position of the opening 21 are required to have high accuracy. Therefore, it is preferable to use a photosensitive resin material or silicon as the material of the cover plate 20 and to provide the opening 21 by a photolithography process. As described above, the cover plate changes the pitch of the flow path by the opening 21, and it is desirable that the cover plate is thin in consideration of the pressure loss, and it is desirable that the cover plate is made of a film-like member.
Next, the flow of ink in the recording element substrate 10 will be described. The liquid supply path 18 and the liquid recovery path 19 formed by the substrate 11 and the cover plate 20 are the common supply flow path 211 via the branch supply flow path 213a and the common recovery flow path 212 via the branch recovery flow path 213b, respectively. Is connected to. Therefore, a differential pressure is generated between the liquid supply path 18 and the liquid recovery path 19 by the two negative pressure adjusting mechanisms, and the ink is liquid from the liquid supply path 18 via the supply port 17a, the pressure chamber 23, and the recovery port 17b. It flows to the collection path 19 (the flow indicated by the arrow C in FIG. 14).
Subsequently, the flow of ink in the liquid ejection head 3 will be described. The first inflow port 7a and the first recovery port 8a are fluidly connected to the common supply flow path, and the second inflow port 7b and the second recovery port 8b communicate with each other in the common recovery flow path. .. Since this configuration also satisfies the same two inequalities as in the first embodiment, the ink flow in the liquid ejection head 3 roughly consists of the following three paths. The first is a flow from the first inflow port through the common supply flow path to the first recovery port. The second is a flow from the second inflow port through the common recovery flow path to the second recovery port. The third is the liquid recovery path 19, the branch recovery flow path 213b, and the common recovery flow path that pass through the pressure chamber 23 from the first inflow port via the common supply flow path 211, the branch supply flow path 213a, and the liquid supply path 18. It is a flow leading to the second collection port through 212. By these flows, in the discharge port 13 and the pressure chamber 23 in which recording is suspended, thickening ink, bubbles, foreign substances, etc. generated by evaporation from the discharge port 13 can be collected in the liquid recovery path 19. Further, it is possible to suppress thickening of ink in the discharge port 13 and the pressure chamber 23. In this way, by providing the path that flows without passing through the recording element substrate 10, even when the recording element substrate 10 having a fine flow path having a large flow path resistance as in this example is provided, the liquid is provided. It is possible to suppress the backflow of the circulating flow. In this way, in the liquid discharge head of this example, the thickening of the liquid in the vicinity of the pressure chamber and the discharge port can be suppressed, so that the discharge direction deviation and non-discharge can be suppressed, and as a result, high-quality recording can be performed. can.

[Amount of ink supplied to the liquid ejection head]
In each embodiment, the total amount of ink supplied to each inflow port of the common supply flow path 211 and the common recovery flow path 212 is the total amount of ink discharged from all the recording element substrates arranged on the flow path member. is more than. As a result, the flow of each common flow path becomes a unidirectional flow from the inflow port to the entry / recovery port regardless of the ejection operation, and the ink in which the volatile components in the ink have evaporated when passing through the ejection port 13 is headed again. It will not flow back inward. Further, even if the ink heated by the heat generated by the heat insulating means for keeping the amount of ejected ink flowing through the liquid recovery path 19, the branch recovery flow path 213b, and the common recovery flow path 212, the common recovery flow flows. It is possible to suppress the temperature rise of the ink in the path.

[Explanation of ink temperature control]
The composition and effect of the temperature control of the ink applicable to each embodiment will be described with reference to specific relational expressions.
The ink temperature at the second inflow port 7b is T _ini , the ink temperature at the branch recovery flow path 213b is T _{outflow_branch} , and the ink temperature at the communication port 61 communicating with the common recovery flow path 212 is T _{outflow_out} . The ink flow rate flowing from the inflow port 7b into the common recovery flow path 212 is _defined as Q outflow, and the total ink flow rate flowing through the pressure chamber 23 into the branch recovery flow path 213b is defined as Q _branch . Here, in the case of a system in which the thermal diffusivity of the first flow path member 50 is relatively small and the heat generated in the recording element substrate 10 is difficult to be transferred to the ink in the flow path member, the respective relationships when the heat equilibrium state is reached. Satisfies the following equation.
T _{outflow_out} = (Q _outflow x T _ini + Q _branch x T _{outflow_branch} ) / (Q _outflow + Q _branch ) Equation 1
T _ini <T _{outflow_branch} formula 2
Based on the above formulas 1 and 2, if the ink flow rate supplied from the buffer tank 1003 to the second inflow port 7b of the liquid discharge head 3 is made larger than the supply amount to the first inflow port, a common recovery flow path is used. The rise in ink temperature in 212 can be suppressed.
As described above, even if the ink heated by the heat insulating means when passing through the discharge port 13 flows through the liquid recovery path 19, the branch recovery flow path 213b, and the common recovery flow path 212, the ink flows in the common recovery flow path. The temperature rise can be suppressed by the flowing ink, and as a result, high-quality recording can be performed.

さらに、吐出動作に伴うヒーターの発熱量をＳ_heaterとすると、吐出時の個別液室内のインク温度Ｔ_injeは以下の式を満たす。

An example of the liquid discharge head of the present invention will be described with reference to more specific numerical values. For example, in order to flow ink through a pressure chamber having a width of 30 μm and a height of 15 μm at a flow velocity of 30 mm / s, there are two cases where the flow resistance of the branch flow path and the common flow path is almost negligible as compared with the pressure chamber 23. The pressure difference between the pressure adjusting mechanisms may be set to about 1400 Pa.
Assuming that the discharge amount is 5 × 10 ^-15 m ³ , when the drive frequency is lower than 2.7 kHz, the discharge amount from the discharge port is smaller than the supply amount due to the pressure difference, so it is viewed on a macro time scale. Even at the time of ejection, the ink flow reaches the collection port 17b via the supply port 17a. When the ejection operation is not performed, the ink in the pressure chamber is warmed to the set temperature range, so that the ink temperature in the liquid supply path, the liquid recovery path, and the vicinity thereof is high. However, during the ejection operation, substantially the same amount of ink as the amount of ink ejected flows in, so that the ink temperature in the vicinity of the pressure chamber is lower than that in the non-driving operation. That is, even if the ink flow on the macro time scale of flowing in from the supply port 17a and flowing out through the recovery port 17b is the same, the way heat is transferred differs between non-driving and driving, and the ink temperature in the pressure chamber is transient. And induces variations in discharge characteristics. The image quality deteriorates due to the variation in the ejection characteristics, but the deterioration in the image quality is more noticeable especially when the ink does not fill the recording medium, that is, the ejection characteristics vary when the drive frequency is not very high. A large impact.
In this example, in order to suppress this phenomenon, only the flow rate of the first circulation pump (high pressure side) connected to the common supply flow path 211 is increased to increase the flow rate. The ink temperature of the branch supply flow path 213a and the liquid supply path 18 is _{a time function of T in-Ch} (t), and the ink temperature of the branch recovery flow path 213b and the liquid recovery path 19 is a time function of _{T out-Ch (t).} show. When the through flowing back side flow path during the discharge operation comes to flow into the ink supply port flow Q _in, the flow discharged to the discharge backside passage through the ink discharge port is defined as Q _out, due to the drive The total discharge amount Q _inje is expressed by the following equation.

Further, assuming that the amount of heat generated by the heater associated with the ejection operation is S _{heater , the ink temperature T inje in} the individual liquid chamber at the time of ejection satisfies the following equation.

From the above equations, proportional equations, and inequalities, the transient increase in ink temperature is suppressed by increasing the amount of ink supplied from the buffer tank 1003 and lowering the temperature of the ink flowing in from the supply port 17a. I know I can do it. However, if the amount of ink supplied is increased, the pressure loss in the pressure chamber 23 and the flow path communicating with the pressure chamber 23 increases, which causes an adverse effect. Therefore, in order to suppress the transient ink temperature, it is effective to lower the temperature of the ink flowing in from the supply port 17a. Furthermore, since only the flow rate of the first circulation pump (high pressure side) is changed, it is possible to minimize the increase in power consumption of the entire device.
As described above, in this example, the ink temperature on the inflow side where heat for temperature control is propagated and warmed is driven by increasing the flow rate of the common supply flow path 211 to suppress the increase in ink temperature. It is also possible to reduce the temperature rise of the ink due to the change in the ink.

[Embodiment 5]
The fifth embodiment will be described below with reference to FIG. As shown in FIG. 15, in the present embodiment, the flow directions of the ink flowing through the common supply flow path 211 and the common recovery flow path 212 are opposite to each other. FIG. 16A shows the distribution of the negative pressure applied to each pressure chamber 23 of the present embodiment in the extending direction of the common flow path. The solid line represents the pressure distribution in the common supply flow path 211, the alternate long and short dash line represents the pressure distribution in the common recovery flow path 212, and the dotted line represents the pressure distribution in the pressure chamber 23. The flow direction of the common supply flow path 211 is from the left side to the right side in the figure, and the flow direction of the common recovery flow path 212 is from the right side to the left side in the figure. As is clear from the figure, the pressure values in each pressure chamber are kept almost uniform. For example, when the size of the ejection port 13 is large, the amount of ink ejected from the ejection port 13 changes sensitively with respect to the static pressure value applied to the pressure chamber 23. However, by adopting the configuration of the present embodiment, it is possible to eject a uniform amount of ink from any pressure chamber in the liquid ejection head, and high-quality printing can be obtained. Further, as shown in FIG. 15, since the negative pressure control unit 230 can be divided, the dimensions can be reduced and the arrangement locations can be separated. By doing so, the degree of freedom in arranging the negative pressure control unit 230 in the liquid discharge head 3 is remarkably increased, and it is possible to make the shape easy for the user to handle. Further, also in the present embodiment, the number of pumps in the entire device can be reduced and the size of the device can be reduced by integrating the pumps communicating with the negative pressure control unit 230 into one.

On the other hand, when the flow directions of the ink flowing through the common supply flow path 211 and the common recovery flow path 212 as described in the previous embodiment are the same, the common flow is applied to the negative pressure applied to each pressure chamber 23. FIG. 16B shows the distribution in the extending direction of the road. The case where the flow direction of the common flow path is from the left side to the right side in the figure is shown. In this case, the pressure value in each pressure chamber decreases along the flow direction, but the pressure difference between the common supply flow path 211 and the common recovery flow path 212 is kept substantially the same. For example, in the case of an ink composition in which the physical properties of the ink in the pressure chamber 23 change due to the volatility of the volatile solvent in the ink from the ejection port 13, the ink is flowed from the supply port 17a to the collection port 17b via the pressure chamber 23. Therefore, it is required to suppress changes in physical properties. In that case, by making the flow directions of the common supply flow path 211 and the common recovery flow path 212 the same, it is possible to suppress the change in the physical characteristics of the ink in any pressure chamber in the liquid discharge head and obtain the desired discharge characteristics. It enables highly reliable printing. Further, when a plurality of common supply flow paths 211 and common recovery flow paths 212 are formed in one flow path member 210, the flow path breaks in the common flow paths are cut in order to suppress the pressure loss in the common flow paths to some extent. The area must be increased. However, in such a case, the length of the flow path member in the short side direction becomes long. In the liquid discharge device, in order to keep the distance between the recording medium and the liquid discharge head 3 at a predetermined value, a mechanism for mechanically pressing the recording medium is generally adopted. However, the farther away from the position where the recording medium is pressed in the transport direction, the more difficult it becomes to keep the distance between the liquid discharge head 3 and the recording medium constant. Therefore, the short side direction (length in the transport direction of the recording medium) of the liquid discharge head 3 is preferably as small as possible, and the flow direction of the common flow path may be preferably the same direction. Therefore, according to the specifications of the liquid recording head 3, the flow direction of the common flow path is set to the opposite direction when the opposite direction is suitable, and to the same direction when the same direction is preferable, so that high reliability and high image quality can be obtained. Printing is possible.

[Embodiment 6]
The common supply flow path 211 and the common recovery flow path 212 in the present embodiment are locally formed with resistance portions 217a and 217b having a flow path resistance larger than that of other flow paths. Specifically, the resistance of the resistance portion 217b is larger than the resistance of the upstream portion of the common supply flow path 211, and the resistance of the resistance portion 217a is larger than the resistance of the downstream portion of the common recovery flow path 212. The resistance portion 217a is formed between the recovery port 8 and the branch supply flow path 213a closest to the recovery port 8. Further, the resistance portion 217b is formed between the inflow port 7 and the branch recovery flow path 213b closest to the inflow port 7.

FIG. 17 shows the overall configuration of the flow path system of the liquid discharge device of the present embodiment, and FIG. 18 shows an equivalent circuit diagram of the internal flow path of the liquid discharge head. The inflow port 7 is connected to the buffer tank 1003, and the recovery port 8 is connected to the second circulation pump 1004. With this configuration, a differential pressure is generated between the common supply flow path 211 and the common recovery flow path 212 by the amount of the pressure loss in the resistance portions 217a and 217b. As a result, it is possible to form a flow that passes through the pressure chamber 23 regardless of the driving state of each recording element substrate and a flow that flows from the inflow port 7 to the recovery port 8 without passing through the pressure chamber 23. In the present embodiment, the number of joints for liquid communication between the liquid discharge head and the liquid discharge head can be reduced by combining the inflow port 7 and the recovery port 8 of the liquid discharge unit 300 into one. Further, by providing the resistance portion, the number of pumps of the entire device can be significantly reduced, and the device size can be downsized. Also in the configuration of the present embodiment, as in each of the previous embodiments, both the common supply flow path 211 and the common recovery flow path 212 have the liquid inlet and outlet, so that the increase in pressure loss is suppressed while suppressing the increase in pressure loss. It is possible to circulate and supply the liquid to the liquid discharge head.

Similar to the previous embodiment, the total flow rate of the liquid flowing through the common supply flow path 211 and the common recovery flow path 212 per unit time is discharged from all the discharge ports communicating with the common supply flow path 211 per unit time. More than the total amount of liquid produced. As a result, even if all the discharge ports communicating with the common supply flow path 211 are driven, the flow directions of the common supply flow path 211 and the common recovery flow path 212 do not change.

In the present embodiment, since the differential pressure is generated in the liquid discharge head, it is possible to generate a circulating flow passing through the discharge port without complicating the configuration of the apparatus main body. Further, although the means for adding the flow path resistance is not specified in the present embodiment, it is possible to add the flow path resistance by narrowing the cross-sectional area of the flow path or roughening the wall surface roughness. The composition is not limited.

The flow path configuration in the present embodiment includes a first circulation pump (high pressure side), a first circulation pump (low pressure side), and first and second collection ports that are fluidly connected to the first and second inflow ports. Includes a second circulation pump (high pressure side) and a second circulation pump (low pressure side) that are connected. By adopting the configuration of this embodiment as compared with the above-described embodiment, it is possible to control the pressure or the flow rate in the common supply flow path 211 and the common recovery flow path 212 with high accuracy. As a result, constant ejection characteristics can be realized regardless of the operating state, and a more accurate image can be output.

[Embodiment 7]
The configuration of the inkjet recording device 1000 and the liquid discharge head 3 according to the present embodiment will be described. In the following description, only the parts different from the first to sixth embodiments will be mainly described, and the same parts as those in the first embodiment will be omitted.
(Explanation of inkjet recording device)
The inkjet recording apparatus according to this embodiment is shown in FIG. The recording device 1000 of the present embodiment is different from the first embodiment in that full-color recording is performed on a recording medium by arranging four liquid ejection heads 3 for single colors corresponding to each ink of CMYK in parallel. In the first embodiment, the number of discharge port rows that can be used per color is two, whereas in the present embodiment, the number of discharge port rows that can be used per color is 20 (FIG. 25 (a)). Therefore, by appropriately allocating the recorded data to a plurality of discharge port rows and recording the data, very high-speed recording becomes possible. Further, even if there is a discharge port that does not discharge, reliability can be improved by interpolating the discharge from the discharge port of another row located at a position corresponding to the transport direction of the recording medium with respect to the discharge port. Improved and suitable for commercial printing and the like. Similar to the first embodiment, the supply system of the recording device 1000, the buffer tank 1003, and the main tank (ink tank) 1006 (FIG. 2) are fluidly connected to each liquid discharge head 3. Further, an electric control unit that transmits electric power and a discharge control signal to the liquid discharge head 3 is electrically connected to each liquid discharge head 3.

(Explanation of liquid discharge head structure)
The structure of the liquid discharge head 3 according to the present embodiment will be described. 20 (a) and 20 (b) are perspective views of the liquid discharge head 3 according to the present embodiment. The liquid discharge head 3 is an inkjet type line-type recording head including 16 recording element substrates 10 arranged in a straight line in the longitudinal direction of the liquid discharge head 3. The liquid discharge head 3 includes a liquid connection portion 111, a signal input terminal 91, and a power supply terminal 92, as in the first embodiment. However, since the liquid discharge head 3 of the present embodiment has more discharge port rows than the first embodiment, the signal output terminals 91 and the power supply terminals 92 are arranged on both sides of the liquid discharge head 3. This is to reduce the voltage drop and signal transmission delay that occur in the wiring portion provided on the recording element substrate 10.

FIG. 21 is an exploded perspective view of the liquid discharge head 3, and each component or unit constituting the liquid discharge head 3 is divided and displayed according to its function. The liquid discharge unit support portion 81 in the present embodiment is connected to both ends of the second flow path member 60, and the liquid discharge unit 300 is mechanically coupled to the carriage of the recording device 1000 to form a liquid discharge head 3. Perform positioning. The liquid supply unit 220 including the negative pressure control unit 230 and the electrical wiring board 90 are coupled to the liquid discharge unit support portion 81. A filter (not shown) is built in each of the two liquid supply units 220. The two negative pressure control units 230 set different pressures, and the negative pressure control unit 230 has a negative pressure but a relatively high pressure, and the negative pressure control unit 230 has a negative pressure and a relatively low pressure. The negative pressure control unit 230. When the high-pressure side and low-pressure side negative pressure control units 230 are installed at both ends of the liquid discharge head 3 as shown in this figure, the common supply flow path 211 extending in the longitudinal direction of the liquid discharge head 3 and the common recovery The flows of liquid in the flow path 212 face each other. In this way, heat exchange is promoted between the common supply flow path 211 and the common recovery flow path 212, and the temperature difference between the two common flow paths is reduced. The temperature difference between the recording element substrates 10 is less likely to occur. As a result, there is an advantage that recording unevenness due to a temperature difference is less likely to occur.

Next, the details of the flow path member 210 of the liquid discharge unit 300 will be described. As shown in FIG. 21, the flow path member 210 is a stack of a first flow path member 50 and a second flow path member 60, and distributes the liquid supplied from the liquid supply unit 220 to each discharge module 200. do. Further, the flow path member 210 functions as a flow path member for returning the liquid recirculated from the discharge module 200 to the liquid supply unit 220. The second flow path member 60 of the flow path member 210 is a flow path member in which the common supply flow path 211 and the common recovery flow path 212 are formed therein, and also has a function of mainly carrying the rigidity of the liquid discharge head 3. Have. Therefore, as the material of the second flow path member 60, a material having sufficient corrosion resistance against liquid and high mechanical strength is preferable. Specifically, stainless steel, Ti, alumina and the like can be preferably used.

FIG. 22 (a) shows the surface of the first flow path member 50 on the side where the discharge module 200 is mounted, and FIG. 22 (b) shows the back surface of the first flow path member 50, which is in contact with the second flow path member 60. It is a figure which showed the surface of. Unlike the first embodiment, the first flow path member 50 in the second embodiment is an array of a plurality of members corresponding to each discharge module 200 adjacent to each other. By adopting the divided structure in this way, a plurality of modules can be arranged to correspond to the length of the liquid discharge head, so that a relatively long scale corresponding to, for example, B2 size or longer can be used. It can be particularly preferably applied to a liquid discharge head. As shown in FIG. 22 (a), the communication port 51 of the first flow path member 50 fluidly communicates with the discharge module 200, and as shown in FIG. 22 (b), the 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. 22 (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. 22 (d) shows a cross section of the central portion of the second flow path member 60 in the thickness direction. 22 (e) is a view showing a surface of the second flow path member 60 on the side that comes into contact with the liquid supply unit 220. The functions of the flow path and the communication port of the second flow path member 60 are the same as the functions of one color of the first embodiment. One of the common flow path grooves 71 of the second flow path member 60 is the common supply flow path 211 shown in FIG. 23, and the other is the common recovery flow path 212, respectively, along the longitudinal direction of the liquid discharge head 3. The liquid is supplied from one end side to the other end side. In the present embodiment, unlike the first embodiment, the liquid flow directions of the common supply flow path 211 and the common recovery flow path 212 are opposite to each other.

FIG. 23 is a perspective view showing the connection relationship of the liquid between the recording element substrate 10 and the flow path member 210. As shown in FIG. 23, a set of a common supply flow path 211 and a common recovery flow path 212 extending in the longitudinal direction of the liquid discharge head 3 are provided in the flow path member 210. The communication port 61 of the second flow path member 60 is connected in position with the individual communication port 53 of each first flow path member 50, and is a common supply flow path from the communication port 72 of the second flow path member 60. A liquid supply path is formed that communicates with the communication port 51 of the first flow path member 50 via 211. Similarly, a liquid supply path that communicates from the communication port 72 of the second flow path member 60 to the communication port 51 of the first flow path member 50 via the common recovery flow path 212 is also formed.

Similar to the first embodiment, each discharge module 200 and the recording element substrate 10 are formed with a flow path communicating with each discharge port 13, and a part or all of the supplied liquid pauses the discharge operation. It is possible to recirculate through the discharge port 13 (pressure chamber 23). Further, as in the first embodiment, the common supply flow path 211 is via the negative pressure control unit 230 (high pressure side), and the common recovery flow path 212 is via the negative pressure control unit 230 (low pressure side) and the liquid supply unit 220, respectively. It is connected. Therefore, due to these differential pressures, a flow is generated from the common supply flow path 211, passing through the discharge port 13 (pressure chamber 23) of the recording element substrate 10, and reaching the common recovery flow path 212.

(Explanation of discharge module)
FIG. 24 (a) shows a perspective view of one discharge module 200, and FIG. 24 (b) shows an exploded view thereof. Unlike the first embodiment, a plurality of terminals 16 are arranged on both side portions (each long side portion of the recording element substrate 10) along a plurality of discharge port row directions of the recording element substrate 10, and are electrically connected to them. Two wiring boards 40 are also arranged with respect to one 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 8 rows of the first embodiment. That is, the purpose is to shorten the maximum distance from the terminal 16 to the recording element 15 provided corresponding to the discharge port row, and to reduce the voltage drop and signal transmission delay that occur in the wiring portion in the recording element substrate 10. It is said. Further, the liquid communication port 31 of the support member 30 is open across all the discharge port rows provided on the recording element substrate 10. Other points are the same as those in the first embodiment.

(Explanation of the structure of the recording element substrate)
25 (a) is a schematic view of the surface of the recording element substrate 10 on the side where the discharge port 13 is arranged, and FIG. 25 (c) is a schematic view showing the back surface of the surface of FIG. 25 (a). FIG. 25 (b) is a schematic view showing the surface of the recording element substrate 10 in the state where the cover plate 20 provided on the back surface side of the recording element substrate 10 is removed in FIG. 25 (c). As shown in FIG. 25B, liquid supply paths 18 and liquid recovery paths 19 are alternately provided on the back surface of the recording element substrate 10 along the discharge port row direction. Although the number of discharge port rows is significantly increased as compared with the first embodiment, the essential difference from the first embodiment is that the terminals 16 are located on both sides of the recording element substrate along the discharge port row direction as described above. It is arranged. A set of a liquid supply path 18 and a liquid recovery path 19 are provided for each discharge port row, and the cover plate 20 is provided with an opening 21 that communicates with the liquid communication port 31 of the support member 30. , The basic configuration is the same as that of the first embodiment.

[Embodiment 8]
The configuration of the inkjet recording device 1000 and the liquid discharge head 3 according to the present embodiment will be described. The liquid discharge head of the eighth embodiment is a page-wide type that records on a B2 size recording medium in one scan. The eighth embodiment describes the parts different from the above-described embodiment, and the description of the same parts will be omitted.
(Explanation of inkjet recording device)
FIG. 27 shows a schematic view of the inkjet recording apparatus of this embodiment. The recording device 1000 does not directly record on the recording medium from the liquid discharge head 3, but once discharges the liquid to the intermediate transfer body (intermediate transfer drum 1007) to form an image, and then transfers the image to the recording medium 2. It is a configuration to be transferred. In the recording device 1000, four liquid ejection heads 3 for single colors corresponding to each of the four types of CMYK inks are arranged in an arc shape along the intermediate transfer drum 1007. As a result, full-color recording is performed on the intermediate transfer body, and the recorded image is appropriately dried on the intermediate transfer body and then transferred to the recording medium 2 conveyed by the paper transfer roller 1009 by the transfer unit 1008. Transferred. While the paper transport system of the above-described embodiment is mainly horizontal transport intended for cut paper, this embodiment can also handle continuous paper supplied from a main body roll (not shown). In such a drum transport system, it is easy to transport the paper while applying a constant tension, so that there is little transport jam even during high-speed recording. Therefore, the reliability of the apparatus is improved, and it is suitable for commercial printing and the like. 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.

[Embodiment 9]
As the liquid circulation path between the tank of the recording device 1000 and the liquid discharge head 3, the circulation path shown in FIG. 2 or FIG. 9 can be applied, but the circulation path shown in FIG. 28 is preferable. The main difference from the above-mentioned circulation path is that a bypass valve 1010 communicating with each flow path of the first circulation pump 1001, 1002 and the second circulation pump 1004 is added. The bypass valve 1010 has a function (first function) of lowering the pressure on the upstream side of the bypass valve 1010 by opening the valve when the preset pressure is exceeded. It also has a function (second function) of opening and closing the valve at an arbitrary timing by a signal from the control board of the recording device main body.
The first function can prevent excessive or underpressure from being applied to the flow path on the downstream side of the first circulation pumps 1001 and 1002 or the upstream side of the second circulation pump 1004. For example, when the functions of the first circulation pumps 1001 and 1002 are disturbed, an excessive flow rate or pressure may be applied to the liquid discharge head 3. As a result, there is a risk that the liquid may leak from the discharge port of the liquid discharge head 3 or that each joint in the liquid discharge head 3 may break. However, when bypass valves are added to the first circulation pumps 1001 and 1002 as in the present embodiment, even if excessive pressure is generated, the bypass valve 1010 opens to allow the liquid path to the upstream side of each circulation pump. Is released, so that the above troubles can be suppressed.
Further, by the second function, when the circulation drive is stopped, after the first circulation pumps 1001, 1002 and the second circulation pump 1004 are stopped, all the bypass valves 1010 are promptly opened based on the control signal from the main body side. As a result, the high negative pressure (for example, several kPa to several tens kPa) in the downstream portion of the liquid discharge head 3 (between the negative pressure control unit 230 and the second circulation pump 1004) can be released in a short time. When a positive displacement pump such as a diaphragm pump is used as a circulation pump, a check valve is usually built in the pump. However, by opening the bypass valve, the pressure in the downstream portion of the liquid discharge head 3 can be released from the buffer tank 1003 side on the downstream side as well. Although the pressure in the downstream portion of the liquid discharge head 3 can be released only from the upstream side, there is a pressure loss in the flow path on the upstream side of the liquid discharge head and the flow path in the liquid discharge head. Therefore, it takes time to release the pressure, and the pressure in the common flow path in the liquid discharge head 3 is transiently lowered too much, which may destroy the meniscus of the discharge port. By opening the bypass valve 1010 on the downstream side of the liquid discharge head 3, the pressure release on the downstream side of the liquid discharge head is promoted, so that the risk of meniscus destruction at the discharge port is reduced.

(Explanation of liquid discharge head structure)
The structure of the liquid discharge head 3 according to the ninth embodiment of the present invention will be further described. FIG. 29 (a) is a perspective view of the liquid discharge head 3 according to the present embodiment, and FIG. 29 (b) is an exploded perspective view thereof. The liquid discharge head 3 is an inkjet page-wide type recording head provided with 36 recording element substrates 10 arranged linearly (in-line) in the longitudinal direction of the liquid discharge head 3 and recording with one color liquid. be. The liquid discharge head 3 includes a signal input terminal 91 and a power supply terminal 92, and is also provided with a shield plate 132 that protects the longitudinal side surface of the head.
FIG. 29B is a perspective exploded view of the liquid discharge head 3, and each component or unit constituting the liquid discharge head 3 is divided and displayed according to its function (shield plate 132 is not shown). The roles of each unit and each member and the order of liquid distribution in the liquid discharge head 3 are the same as those in the above-described embodiment. The main differences are the positions of the electrical wiring board 90, the negative pressure control unit 230, and the shape of the first flow path member, which are divided into a plurality of arrangements. In the case of the liquid discharge head 3 having a length corresponding to, for example, a B2 size recording medium as in the present embodiment, since the power consumption of the liquid discharge head 3 is large, eight electric wiring boards 90 are provided. Four of each of the electric wiring boards 90 are attached to both side surfaces of the long electric wiring board support portion 82 attached to the liquid discharge unit support portion 81.
30 (a) is a side view of the liquid discharge head 3 including the liquid discharge unit 300, the liquid supply unit 220 and the negative pressure control unit 230, and FIG. 30 (b) is a schematic view showing the flow of the liquid, FIG. 30 (c). ) Is a perspective view showing a cross section of the GG line portion of FIG. 30 (a). Some configurations have been simplified for ease of understanding.
A liquid connection portion 111 and a filter 221 are provided in the liquid supply unit 220, and a negative pressure control unit 230 is integrally formed below the liquid supply unit 220. As a result, the distance between the negative pressure control unit 230 and the recording element substrate 10 in the height direction is shorter than that of the above-described embodiment. This configuration has the advantage that the number of flow path connection portions in the liquid supply unit 220 is reduced, the reliability against leakage of the recorded liquid is improved, and the number of parts and the number of assembly steps can be reduced.
Further, since the head difference between the negative pressure control unit 230 and the surface on which the discharge port is formed becomes relatively small, the inclination angle of the liquid discharge head 3 as shown in FIG. 27 is different for each liquid discharge head. It can be suitably adapted to various recording devices. This is because the water arithmetic progression can be reduced, so that even if the plurality of liquid discharge heads 3 are used at different inclination angles, the negative pressure difference applied to the discharge ports of the respective recording element substrates can be reduced. Further, as the distance between the negative pressure control unit 230 and the recording element substrate 10 becomes smaller, the flow resistance between them becomes smaller, so that the pressure loss difference due to the change in the flow rate of the liquid becomes smaller, and more stable negative pressure control can be performed. But it is preferable.

FIG. 30B is a schematic view showing the flow of the recorded liquid inside the liquid discharge head 3. Although the circuit is the same as that of the circulation path shown in FIG. 28, FIG. 30B shows the actual flow of liquid in each component of the liquid discharge head 3. A set of a common supply flow path 211 and a common recovery flow path 212 extending in the longitudinal direction of the liquid discharge head 3 are provided in the long second flow path member 60. The common supply flow path 211 and the common recovery flow path 212 are configured so that liquid flows in directions facing each other, and a filter 221 is provided on the upstream side of each flow path to allow foreign matter to enter from the connection portion 111 or the like. To trap. As described above, the common supply flow path 211 and the common recovery flow path 212 are preferable in that the temperature gradient in the longitudinal direction in the liquid discharge head 3 is reduced by flowing the liquid in the directions facing each other. In FIG. 28, the flows of the common supply flow path 211 and the common recovery flow path 212 are shown in the same direction for the sake of simplification of the description.
Negative pressure control units 230 are connected to the downstream sides of the common supply flow path 211 and the common recovery flow path 212, respectively. Further, in the middle of the common supply flow path 211, there is a branch portion to a plurality of individual supply flow paths 213a, and in the middle of the common recovery flow path 212, there is a branch portion to a plurality of individual recovery flow paths 213b. The individual supply flow path 213a and the individual recovery flow path 213b are formed in a plurality of first flow path members 50, and each individual flow path is an opening 21 of a lid member 20 provided on the back surface of the recording element substrate 10. (See FIG. 19 (c)).
The negative pressure control unit 230 shown by H and L in FIG. 30B is a unit on the high pressure side (H) and a unit on the low pressure side (L). Each negative pressure control unit 230 is a back pressure type pressure adjusting mechanism set to control the pressure on the upstream side of the negative pressure control unit 230 with relatively high (H) and low (L) negative pressures. Is. The common supply flow path 211 is connected to the negative pressure control unit 230 (high pressure side), and the common recovery flow path 212 is connected to the negative pressure control unit 230 (low pressure side), thereby being common with the common supply flow path 211. A differential pressure is generated between the flow paths 212. Due to the differential pressure, the liquid passes from the common supply flow path 211 through the individual supply flow path 213a, the discharge port 13 (pressure chamber 23) in the recording element substrate 10, and the individual recovery flow path 213b in this order, and the common recovery flow path 212. Flow to.
FIG. 30 (c) is a perspective view showing a cross section taken along line GG of FIG. 30 (a). In the present embodiment, each discharge module 200 is composed of a first flow path member 50, a recording element substrate 10, and a flexible wiring board 40. In the present embodiment, there is no support member 30 (FIG. 8) described in the above-described embodiment, and the recording element substrate 10 provided with the lid member 20 is directly joined to the first flow path member 50. The common supply flow path 211 provided in the second flow path member is an individual supply flow path from the communication port 61 formed on the upper surface thereof via the individual communication port 53 formed on the lower surface of the first flow path member 50. It is supplied to 213a. After that, the liquid is recovered to the common recovery flow path 212 via the individual recovery flow path 213b, the individual communication port 53, and the communication port 61 via the pressure chamber 23 in this order.
Unlike the above-described embodiment, the individual communication port 53 on the lower surface of the first flow path member 50 (the surface on the second flow path member 60 side) is the communication port 61 formed on the upper surface of the second flow path member 50. The opening is large enough for. With this configuration, even if the position of the discharge module 200 is displaced when it is mounted on the second flow path member 60, fluid communication is ensured between the first flow path member and the second flow path member. It has become. Therefore, the yield at the time of head manufacturing is improved and the cost can be reduced.

As described above, in the present specification, two pressure adjusting mechanisms and flow path resistors are mentioned as pressure difference generation sources in the present specification, but if it conforms to the idea of the present invention, a configuration of another form is provided. But it's okay. Further, although the configuration in which the flow path resistance is higher than that in other places is disclosed as a stationary means, it is also effective in the configuration in which the flow path resistance is changed to be high at the timing when the problem is desired to be improved.
Further, the present invention can be applied to a liquid discharge head using various discharge means (for example, a piezoelectric element, a heat generating element, an electrostatic method), but a flow path portion (pressure chamber 23 and a flow communicating with the pressure chamber 23) in the liquid discharge head. It can be particularly preferably applied to a liquid discharge head having a large resistance in the road 24). For example, it can be suitably applied to a liquid discharge head having a height h of a flow path 24 communicating with a pressure chamber of 8 μm or less. Further, it is a full-line type liquid discharge head in which a plurality of recording element substrates 10 are arranged, and can be suitably applied to a liquid discharge head having a high-density discharge port having a discharge port arrangement density of 600 dpi or more.

The present invention is not limited to the above-described embodiments, and various modifications and modifications can be made without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention is defined by the appended claims.

7a, 7b Inflow port 8a, 8b Recovery port 13 Discharge port 15 Recording element 17a Individual supply flow path 17b Individual recovery flow path 18 Liquid supply path 19 Liquid recovery path 23 Pressure chamber 211 Common supply flow path 212 Common recovery flow path 213a Individual supply Flow path 213b Individual recovery flow path 3 Liquid discharge head

Claims (20)

A plurality of recording element substrates including a plurality of discharge ports for discharging a liquid and a plurality of recording elements for generating energy used for discharging the liquid.
A line-type liquid discharge head including a flow path member in which the plurality of recording element substrates are linearly arranged to support the plurality of recording element substrates.
The flow path member is made of an alumina or a resin material, and communicates with a plurality of supply flow paths for supplying a liquid to the plurality of recording elements and the plurality of supply flow paths, and the plurality of flow paths. A common supply flow path for supplying liquid to the supply flow path, a plurality of recovery flow paths for recovering the liquid supplied to the plurality of recording elements from the plurality of supply flow paths, and the plurality of recovery flows. It is provided with a common recovery channel for communicating with the road and recovering the liquid from the plurality of recovery channels.
The liquid discharge head has a first inflow port for supplying a liquid from the outside to the common supply flow path and a first recovery for recovering the liquid from the common supply flow path to the outside of the liquid discharge head. The first inflow port and the first recovery port are communicated with each other by the common supply flow path without passing through the flow path portion in which the recording element is arranged.
The liquid discharge head has a second inflow port for supplying a liquid from the outside to the common recovery flow path and a second recovery for recovering the liquid from the common recovery flow path to the outside of the liquid discharge head. It is characterized in that the second inflow port and the second recovery port are communicated with each other by the common recovery flow path without passing through the flow path portion in which the recording element is arranged. Line-type liquid discharge head. The liquid according to claim 1, wherein the liquid in the common supply flow path is supplied to the common recovery flow path through the supply flow path, the flow path portion in which the recording element is arranged, and the recovery flow path in this order. Line type liquid discharge head. The line-type liquid discharge head according to claim 1 or 2, wherein the flow path portion in which the recording element is arranged faces the discharge port and includes a pressure chamber for accommodating the recording element inside. The plurality of supply channels extend in a direction intersecting the extending direction of the common supply channel, and the plurality of recovery channels extend in a direction intersecting the extending direction of the common recovery channel. The line-type liquid discharge head according to any one of claims 1 to 3. The line-type liquid discharge head according to claim 1 or 2, wherein the common supply flow path and the common recovery flow path extend along each other. The line-type liquid discharge head according to any one of claims 1 to 5, wherein the flow direction of the liquid flowing through the common supply flow path and the liquid flowing through the common recovery flow path is the same. The line-type liquid discharge head according to any one of claims 1 to 5, wherein the flow direction of the liquid flowing through the common supply flow path and the liquid flowing through the common recovery flow path are different. The static pressure value of the liquid in the vicinity of the inflow port of the common supply flow path is larger than the static pressure value in the vicinity of the inflow port of the common recovery flow path.
The static pressure value in the vicinity of the recovery port of the common supply flow path is larger than the static pressure value in the vicinity of the recovery port of the common recovery flow path.
The line-type liquid discharge head according to any one of claims 1 to 7. The flow rate of the common supply passage and the liquid supplied to said common collecting channel, the have multi than the flow rate discharged from all the discharge ports, line type according to any one of claims 1 8 liquid discharge head. The line-type liquid discharge head according to claim 9, wherein the flow rate flowing through the common supply flow path per unit time is larger than the flow rate flowing through the common recovery flow path per unit time. The line-type liquid discharge head according to claim 9, wherein the flow rate flowing through the common recovery flow path per unit time is larger than the flow rate flowing through the common supply flow path per unit time. The line-type liquid discharge head according to any one of claims 1 to 11, wherein the thermal diffusivity of the flow path member is smaller than the thermal diffusivity of the recording element substrate. The line-type liquid discharge head according to any one of claims 1 to 12 , wherein the height of the flow path adjacent to the pressure chamber including the recording element is 8 μm or less. The line-type liquid discharge head according to any one of claims 1 to 13 , wherein the liquid in the pressure chamber including the recording element is circulated with the outside of the pressure chamber. 13. The line type liquid discharge head described. The line-type liquid discharge head according to any one of claims 1 to 15.
A first liquid feed pump that communicates with the first and second inlets and feeds a liquid.
A first recovery pump that collects liquid and communicates with the first recovery port.
A second recovery pump that collects the liquid and communicates with the second recovery port.
The provided liquid discharge device. The line-type liquid discharge head according to any one of claims 1 to 15.
A first liquid feeding pump that communicates with the first inflow port and feeds a liquid,
A second liquid feeding pump that communicates with the second inflow port and feeds a liquid, and a second liquid feeding pump.
A first recovery pump that collects liquid and communicates with the first recovery port.
A second recovery pump that collects the liquid and communicates with the second recovery port.
The provided liquid discharge device. The line-type liquid discharge head according to any one of claims 1 to 15.
A first liquid feeding pump that communicates with the first inflow port and feeds a liquid,
A second liquid feeding pump that communicates with the second inflow port and feeds a liquid, and a second liquid feeding pump.
A first recovery pump that collects liquid and communicates with the first and second recovery ports.
The provided liquid discharge device. The line-type liquid discharge head according to any one of claims 1 to 15.
A first liquid feed pump that communicates with the first and second inlets and feeds a liquid.
A first recovery pump that collects liquid and communicates with the first and second recovery ports.
The provided liquid discharge device. Billing includes a line-type liquid discharging head according to claim 15, said first negative pressure control unit and the second negative pressure control unit and an ink tank connected, the liquid material discharge device.

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