JP2017144719A - Liquid discharge head and liquid discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to suppress generation of a temperature distribution of a liquid in a direction of a discharge port arrangement in a recording element substrate in a liquid discharge head.SOLUTION: A liquid discharge head, which is provided with a discharge port arrangement in which plural discharge ports for discharging a liquid are arranged, comprises: a pressure chamber which is communicated with the discharge port, and which includes a pressure generating element; a flow channel which is provided with an opening, which supplies the liquid flown therein via the opening to the pressure chamber, and which extends along the discharge port arrangement; a heater provided near the opening; and a temperature sensor provided on an area along the discharge port arrangement.SELECTED DRAWING: Figure 22

Description

  The present invention relates to a liquid discharge head and a liquid discharge apparatus, and more particularly to a configuration for controlling the temperature of the liquid discharge head.

  In a liquid discharge head provided with a plurality of liquid discharge ports, the temperature of the ink is made uniform for each discharge port by controlling the temperature thereof. Thereby, for example, variation in the amount of ink ejected from each ejection port is suppressed.

  On the other hand, as described in Patent Document 1, one recording element substrate constituting a liquid ejection head is formed with ejection openings for different types of ink and individual flow paths along the ejection openings. There is. In this configuration, liquid is supplied from each flow path to each discharge port of the corresponding discharge port array. This makes it possible to reduce the size of the recording element substrate when configuring a plurality of types of ink discharge heads, and as a result, it is possible to reduce the size and cost of the liquid discharge head.

US Pat. No. 6,955,424

  In the liquid discharge head, the temperature of the liquid in the recording element substrate and the flow path provided on the substrate tends to increase due to the driving of the heat generating element accompanying the discharge of the liquid. On the other hand, the liquid newly flowing into the flow path of the recording element substrate is at a relatively lower temperature than the recording element substrate, and functions to lower the temperature of the recording element substrate.

  Here, in the recording element substrate as described in Patent Document 1, a plurality of openings for guiding the liquid to the flow path along the ejection port array are arranged in the direction in which the flow path extends. For this reason, a temperature difference occurs between the liquid discharged from the discharge port near the opening and the liquid discharged from the discharge port in a region away from the opening due to the relatively low temperature liquid flowing into the opening. . As a result, temperature distribution occurs in the liquid ejected by the plurality of ejection ports in the ejection port array, and the amount of the ejected liquid may vary.

  An object of the present invention is to provide a liquid discharge head and a liquid discharge apparatus capable of suppressing the occurrence of a liquid temperature distribution in the direction of the discharge port array in a recording element substrate.

  To achieve the above object, the present invention is a liquid discharge head provided with a discharge port array in which a plurality of discharge ports for discharging a liquid are arranged, and is a pressure chamber communicating with the discharge port, A pressure chamber having a pressure generating element for discharging liquid therein, an opening for supplying liquid to the pressure chamber, and the discharge for supplying liquid flowing in from the opening to the pressure chamber. It is characterized by comprising a flow path extending along the outlet row, a heater provided in the vicinity of the opening, and a temperature sensor provided in a region along the discharge port row.

  According to the above configuration, it is possible to suppress the occurrence of the temperature distribution of the liquid in the direction of the ejection port array in the recording element substrate.

1 is a perspective view illustrating a schematic configuration of an ink jet recording apparatus according to an embodiment of a liquid discharge apparatus that discharges a liquid according to the present invention. It is a schematic diagram which shows the 1st circulation form of the circulation path applied to the recording device of one Embodiment. It is a schematic diagram which shows the 2nd circulation form of the circulation path applied to the recording device of one Embodiment. (A)-(f) is a figure explaining the difference in the inflow amount of the ink to the liquid discharge head 3 in a 1st circulation form and a 2nd circulation form. (A) And (b) is a perspective view which shows the liquid discharge head which concerns on one Embodiment. FIG. 6 is an exploded perspective view showing each component or unit constituting the liquid discharge head. (A)-(f) is the figure which showed the surface and the back surface of each 1st, 2nd and 3rd flow-path member. FIG. 8 is a perspective view showing a part of FIG. 7A and enlarging a flow path in a flow path member formed by joining first to third flow path members. It is the figure which showed the cross section in IX-IX of FIG. (A) And (b) is the perspective view and exploded perspective view which showed one discharge module. (A), (b), and (c) are the top view of the surface by which the discharge port of a recording element board | substrate is formed, the partial enlarged view, and the top view of the back side of the said surface. It is a perspective view which shows the cross section of the XII-XII line | wire in Fig.11 (a). FIG. 6 is a plan view showing a partially enlarged adjacent portion of a recording element substrate in two adjacent ejection modules. (A) And (b) is the perspective view which showed the liquid discharge head which concerns on the other example of one Embodiment. FIG. 5 is a perspective exploded view showing a liquid ejection head according to another example of an embodiment. (A)-(e) is the figure which showed each flow path member which comprises the liquid discharge head which concerns on the other example of one Embodiment. FIG. 10 is a perspective view illustrating a liquid connection relationship between a recording element substrate and a flow path member in a liquid ejection head according to another example of an embodiment. It is the figure which showed the cross section in the XVIII-XVIII line | wire of FIG. (A) And (b) is the perspective view and exploded view which showed the discharge module in the liquid discharge head which concerns on the other example of one Embodiment. (A) is the surface of the recording element substrate on which the discharge port is arranged, (b) is the surface of the recording element substrate when the cover plate provided on the back side of the recording element substrate is removed, and (c) is FIG. 5 is a schematic diagram showing the back surface of the surface on which the discharge ports are arranged. It is the figure which showed the 2nd form of the inkjet recording device which concerns on one Embodiment. (A) And (b) is a figure which shows typically the positional relationship of an opening, a heater, and a temperature sensor in the recording element board | substrate of 1st Embodiment of this invention. (A) And (b) is a figure which shows the positional relationship of the opening for simulation which concerns on 1st Embodiment, a heater, and a temperature sensor. (A) And (b) is a figure which shows the temperature part distribution along the discharge outlet arrangement | sequence as a result of the said simulation. (A)-(c) is a figure which shows typically the positional relationship of an opening, a heater, and a temperature sensor in the recording element board | substrate of 2nd Embodiment of this invention. It is a figure which shows typically the positional relationship of an opening, a heater, and a temperature sensor in the recording element board | substrate of 3rd Embodiment of this invention. FIG. 3 is a diagram schematically showing the positional relationship between the arrangement of the recording element substrate and the distribution channel according to the embodiment of the present invention. FIG. 10 is a diagram illustrating a temperature part distribution along an ejection port array as a result of simulation by a configuration of a recording element substrate according to a third embodiment. (A) And (b) is a figure which shows typically the positional relationship of an opening, a heater, and a temperature sensor in the recording element board | substrate of 4th Embodiment of this invention. (A) And (b) is a figure which shows typically the modification of the positional relationship of an opening, a heater, and a temperature sensor in the recording element board | substrate of 4th Embodiment. It is a figure which shows typically the positional relationship of an opening, a heater, and a temperature sensor in the recording element board | substrate of 5th Embodiment of this invention. (A) And (b) is a figure which shows the example of a shape and arrangement | positioning of the recording element board | substrate which concerns on one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The liquid discharge head of the present invention that discharges liquid such as ink and the liquid discharge device equipped with the liquid discharge head are printers, copiers, facsimiles having a communication system, word processors having a printer unit, and various types. The present invention can be applied to an industrial recording apparatus combined with a processing apparatus. For example, it can be used for applications such as biochip fabrication, electronic circuit printing, and semiconductor substrate fabrication.

(Inkjet recording apparatus of first form)
FIG. 1 is a diagram showing a schematic configuration of a liquid ejection apparatus for ejecting a liquid according to the present invention, in particular, an ink jet recording apparatus (hereinafter also referred to as a recording apparatus) 1000 that performs recording by ejecting ink. The recording apparatus 1000 includes a transport unit 1 that transports the recording medium 2 and a line-type liquid ejection head 3 that is disposed substantially orthogonal to the transport direction of the recording medium 2, and continuously or intermittently records a plurality of recording media 2. This is a line type recording apparatus that performs continuous recording in a single pass while being conveyed. The recording medium 2 is not limited to cut paper, and may be a continuous roll medium. The liquid discharge head 3 includes a negative pressure control unit 230 that controls the pressure (negative pressure) in the circulation path, a liquid supply unit 220 that is in fluid communication with the negative pressure control unit 230, and supply and discharge of ink to the liquid supply unit 220. The liquid connection part 111 used as an exit and the housing 80 are provided. The liquid discharge head 3 according to this embodiment includes discharge port arrays that discharge cyan C, magenta M, yellow Y, and black K inks, respectively, thereby enabling full color recording. As will be described later with reference to FIG. 2, the liquid discharge head 3 is fluidly connected to a liquid supply mechanism, a main tank, and a buffer tank (see FIG. 2 described later) that are supply paths for supplying liquid to the liquid discharge head 3. Is done. Four negative pressure control units 230 and liquid supply units 220 are provided corresponding to the four colors of ink. The liquid discharge head 3 is electrically connected to an electric control unit that transmits power and a discharge control signal to the liquid discharge head 3. The liquid path and the electric signal path in the liquid discharge head 3 will be described later.

  The recording apparatus 1000 is an ink jet recording apparatus configured to circulate a liquid such as ink between a tank described later and the liquid ejection head 3. The ink jet recording apparatus according to the present embodiment includes a first circulation form that circulates by operating two circulation pumps (for high pressure and low pressure) on the downstream side of the liquid discharge head 3 as a circulation form (configuration), and a liquid. Either one of the two forms of the second circulation form that circulates by operating two circulation pumps (for high pressure and low pressure) on the upstream side of the discharge head 3 is adopted. Hereinafter, the first circulation mode and the second circulation mode of the circulation will be described.

<Description of first circulation mode>
FIG. 2 is a schematic diagram showing a first circulation form of a circulation path applied to the recording apparatus 1000 of the present embodiment. The liquid discharge head 3 is fluidly connected to a first circulation pump (high pressure side) 1001, a first circulation pump (low pressure side) 1002, a buffer tank 1003, and the like. In FIG. 2, for the sake of simplicity, only the path through which one of the inks of cyan C, magenta M, yellow Y, and black K flows is shown. A circulation path is provided in the liquid discharge head 3 and the recording apparatus main body.

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

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

  The two first circulation pumps 1001 and 1002 draw liquid from the liquid connection portion 111 of the liquid discharge head 3 and flow it to the buffer tank 1003. As the first circulation pump, a positive displacement pump having a quantitative liquid feeding capacity is preferable. Specific examples include a tube pump, a gear pump, a diaphragm pump, and a syringe pump. For example, a general constant flow valve or a relief valve may be arranged at the pump outlet to ensure a constant flow rate. When the liquid discharge head 3 is driven, the first circulation pump (high-pressure side) 1001 and the first circulation pump (low-pressure side) 1002 are operated, so that the ink in the common supply path 211 and the common recovery path 212 has a predetermined flow rate, respectively. Flows. By flowing ink in this way, the temperature of the liquid discharge head 3 during recording is maintained at an optimum temperature. The predetermined flow rate at the time of driving the liquid discharge head 3 is preferably set to be equal to or higher than a flow rate that can be maintained so that the temperature difference between the recording element substrates 10 in the liquid discharge head 3 does not affect the recording image quality. However, if the flow rate is set too high, the negative pressure difference is increased in each recording element substrate 10 due to the pressure loss of the flow path in the liquid discharge unit 300, resulting in uneven density of the image. Therefore, it is preferable to set the flow rate in consideration of the temperature difference and the negative pressure difference between the recording element substrates 10.

  The negative pressure control unit 230 is provided in a path between the second circulation pump 1004 and the liquid discharge unit 300. The negative pressure control unit 230 controls the pressure downstream of the negative pressure control unit 230 (that is, the liquid discharge unit 300 side) even when the ink flow rate in the circulation system fluctuates due to a difference in the discharge amount per unit area. It operates to maintain a preset constant pressure. As the two pressure adjustment mechanisms of the high pressure side (H) and the low pressure side (L) that constitute the negative pressure control unit 230, the pressure downstream of the negative pressure control unit 230 is constant around a desired set pressure. Any mechanism may be used as long as it can be controlled with fluctuations below the range. As an example, a mechanism similar to a so-called “pressure reduction regulator” can be employed. In the circulation channel in the present embodiment, the second circulation pump 1004 pressurizes the upstream side of the negative pressure control unit 230 through the liquid supply unit 220. By doing so, the influence of the water head pressure on the liquid discharge head 3 of the buffer tank 1003 can be suppressed, so the degree of freedom of the layout of the buffer tank 1003 in the recording apparatus 1000 can be expanded.

  The second circulation pump 1004 may be any pump that has a head pressure higher than a certain pressure within the range of the ink circulation flow rate used when the liquid discharge head 3 is driven, and a turbo pump or a positive displacement pump can be used. . Specifically, a diaphragm pump or the like is applicable. Further, instead of the second circulation pump 1004, for example, a water head tank arranged with a certain water head difference with respect to the negative pressure control unit 230 can be applied.

  As shown in FIG. 2, the negative pressure control unit 230 includes two pressure adjustment mechanisms H and L each set with a different control pressure. Of the two negative pressure adjustment mechanisms, the relatively high pressure setting side (denoted as H in FIG. 2) and the relatively low pressure side (denoted as L in FIG. 2) pass through the liquid supply unit 220, They are connected to a common supply path 211 and a common recovery channel 212 in the liquid discharge unit 300, respectively. The liquid discharge unit 300 is provided with a common supply path 211, a common recovery path 212, and individual paths 215 (individual supply paths 213, individual recovery paths 214) communicating with the respective recording element substrates. A pressure adjustment mechanism H is connected to the common supply flow path 211, and a pressure adjustment mechanism L is connected to the common recovery flow path 212, thereby generating a differential pressure between the two common flow paths. Since the individual flow path 215 communicates with the common supply path 211 and the common recovery flow path 212, a part of the liquid passes through the internal flow path of the recording element substrate 10 from the common supply flow path 211. A flow (arrow in FIG. 2) flowing to the common recovery flow path 212 is generated. Note that the two negative pressure adjusting mechanisms H and L are connected to the path from the liquid connecting portion 111 via the filter 221, respectively.

  In this way, in the liquid ejection unit 300, a part of the liquid passes through each recording element substrate 10 while flowing the liquid so as to pass through the common supply flow path 211 and the common recovery flow path 212. Flow occurs. Therefore, the heat generated in each recording element substrate 10 can be discharged to the outside of the recording element substrate 10 by the ink flowing through the common supply channel 211 and the common recovery channel 212. Further, with such a configuration, when recording is performed by the liquid ejection head 3, it is possible to cause ink to flow even in ejection ports and pressure chambers where ejection is not performed. As a result, the viscosity of the ink that has increased in viscosity within the ejection port is reduced, thereby suppressing the increase in the viscosity of the ink. Further, the thickened ink and the foreign matter in the ink can be discharged to the common recovery channel 212. For this reason, the liquid discharge head 3 of the present embodiment can perform high-speed and high-quality recording.

<Description of second circulation mode>
FIG. 3 is a schematic diagram showing a second circulation form that is a circulation form different from the first circulation form described above, among the circulation paths applied to the recording apparatus of the present embodiment. The main difference from the first circulation mode described above is that both of the two pressure adjustment mechanisms constituting the negative pressure control unit 230 are configured so that the pressure upstream of the negative pressure control unit 230 is centered on a desired set pressure. It is a point to control by fluctuation within a certain range. Further, the difference from the first circulation mode is that the second circulation pump 1004 acts as a negative pressure source for reducing the pressure downstream of the negative pressure control unit 230. Further, a first circulation pump (high pressure side) 1001 and a first circulation pump (low pressure side) 1002 are arranged on the upstream side of the liquid discharge head 3, and a negative pressure control unit 230 is arranged on the downstream side of the liquid discharge head 3. This is also different.

  In the second circulation mode, as shown in FIG. 3, the ink in the main tank 1006 is supplied to the buffer tank 1003 by the replenishment pump 1005. Thereafter, the ink is divided into two flow paths, and circulates through the two flow paths on the high pressure side and the low pressure side by the action of the negative pressure control unit 230 provided in the liquid discharge head 3. The ink divided into the two flow paths on the high pressure side and the low pressure side passes through the liquid connecting portion 111 of the liquid discharge head 3 by the action of the first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) 1002. To the liquid discharge head 3. Thereafter, the ink circulated in the liquid discharge unit 300 by the action of the first circulation pump (high-pressure side) 1001 and the first circulation pump (low-pressure side) 1002 passes through the negative pressure control unit 230 and the liquid connection portion 111. The liquid is ejected from the liquid ejection head 3. The discharged ink is returned to the buffer tank 1003 by the second circulation pump 1004.

  The negative pressure control unit 230 in the second circulation mode can change the pressure on the upstream side of the negative pressure control unit 230 (that is, the liquid discharge unit 300 side) even if the flow rate varies due to the change in the discharge amount per unit area. It acts to stabilize the pressure within a certain range around a preset pressure. In the circulation channel of this embodiment, the second circulation pump 1004 pressurizes the downstream side of the negative pressure control unit 230 via the liquid supply unit 220. In this way, since the influence of the water head pressure of the buffer tank 1003 on the liquid discharge head 3 can be suppressed, the selection range of the layout of the buffer tank 1003 in the recording apparatus 1000 can be widened. Instead of the second circulation pump 1004, for example, a water head tank arranged with a predetermined water head difference with respect to the negative pressure control unit 230 can be applied. In the second circulation mode, similarly to the first circulation mode described above, the negative pressure control unit 230 includes two pressure adjustment mechanisms H and L each set with a different control pressure. Of the two negative pressure adjusting mechanisms H and L, the high pressure setting side (denoted as H in FIG. 3) and the low pressure setting side (denoted as L in FIG. 3) each discharge liquid via the liquid supply unit 220. The unit 300 is connected to a common supply path 211 and a common recovery channel 212 in the unit 300. By making the pressure of the common supply flow path 211 relatively higher than the pressure of the common recovery flow path 212 by two negative pressure adjusting mechanisms, the individual flow paths 211 to the individual flow paths 213 and the inside of each recording element substrate 10 An ink flow that flows to the common recovery flow path 212 via the flow path is generated.

  In such a second circulation mode, an ink flow state similar to that in the first circulation mode can be obtained in the liquid ejection unit 300, but there are two advantages different from those in the first circulation mode. First, in the second circulation mode, since the negative pressure control unit 230 is disposed on the downstream side of the liquid discharge head 3, dust and foreign matters generated from the negative pressure control unit 230 flow into the liquid discharge head 3. There are few concerns. Second, in the second circulation mode, the maximum value of the required flow rate supplied from the buffer tank 1003 to the liquid ejection head 3 is smaller than in the first circulation mode. The reason is as follows.

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

  FIG. 4 is a diagram illustrating the difference in the amount of ink flowing into the liquid ejection head 3 between the first circulation mode and the second circulation mode. 4A shows the standby time in the first circulation mode, and FIG. 4B shows the full discharge time in the first circulation mode. FIGS. 4C to 4F show the flow rates in the case of the second circulation flow path, and FIGS. 4C and 4D show the case where the flow rate F <the flow rate A. FIG. ) And (f) are the cases where the flow rate F> the flow rate A, and show the flow rates during standby and full discharge, respectively.

  In the case of the first circulation mode in which the first circulation pump (high pressure side) 1001 and the first circulation pump (low pressure side) 1002 having a quantitative liquid feeding capacity are arranged on the downstream side of the liquid discharge head 3 (FIG. 4 ( a), (b)), the total set flow rate of the first circulation pump 1001 and the first circulation pump 1002 is the flow rate A (FIG. 4A). With this flow rate A, the temperature in the liquid discharge unit 300 during standby can be managed. When total discharge is performed by the liquid discharge head 3, the total set flow rate of the first circulation pump 1001 and the first circulation pump 1002 remains the flow rate A, but the negative pressure generated by the discharge by the liquid discharge head 3. As a result, the maximum flow rate supplied to the liquid discharge head 3 is obtained by adding the consumption amount (flow rate F) for the total discharge to the flow rate A of the total set flow rate. Therefore, since the flow rate F is added to the flow rate A, the maximum value of the supply amount to the liquid ejection head 3 becomes the flow rate A + the flow rate F (FIG. 4B).

  On the other hand, in the case of the second circulation mode in which the first circulation pump 1001 and the first circulation pump 1002 are arranged on the upstream side of the liquid discharge head 3 (FIGS. 4C to 4F), it is necessary at the time of recording standby. The supply amount to the liquid discharge head 3 is the flow rate A as in the first circulation mode. Therefore, in the second circulation mode in which the first circulation pump 1001 and the first circulation pump 1002 are arranged on the upstream side of the liquid discharge head 3, the flow rate A is higher than the flow rate F (FIG. 4C, (d )), The flow rate A is sufficient for the supply amount to the liquid discharge head 3 even during full discharge. At that time, the discharge flow rate from the liquid discharge head 3 is flow rate A−flow rate F (FIG. 4D). However, when the flow rate F is higher than the flow rate A (FIGS. 4E and 4F), the flow rate becomes insufficient if the supply flow rate to the liquid ejection head 3 is the flow rate A at the time of full ejection. Therefore, when the flow rate F is higher than the flow rate A, the supply amount to the liquid ejection head 3 needs to be the flow rate F. At this time, if the full discharge is performed, the flow rate F is consumed in the liquid discharge head 3, and therefore, the discharge flow rate from the liquid discharge head 3 is hardly discharged (FIG. 4F). When the flow rate F is higher than the flow rate A and discharge is performed but not all discharges, an amount obtained by subtracting the amount consumed by the discharge from the flow rate F is discharged from the liquid discharge head 3.

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

  Therefore, in the case of the second circulation mode, the degree of freedom of the applicable circulation pump is increased. For example, a low-cost circulation pump with a simple configuration is used, or a load of a cooler (not shown) installed in the main body side path is reduced. There is an advantage that the cost of the recording apparatus can be reduced. This advantage increases as the line head has a relatively large value of the flow rate A or the flow rate F. Among line heads, a line head having a long length in the longitudinal direction is more beneficial.

  On the other hand, however, the first circulation mode is advantageous over the second circulation mode. That is, in the second circulation mode, the flow rate that flows through the liquid ejection unit 300 during recording standby is maximum, so that the smaller the amount of ejection per unit area (hereinafter also referred to as a low-duty image), A high negative pressure is applied. For this reason, when the flow path width is narrow and the negative pressure is high, a high negative pressure is applied to the discharge port in a low-duty image in which unevenness is easily visible, so that many so-called satellite droplets are discharged along with the main ink droplets. It may occur and the recording quality may deteriorate. On the other hand, in the case of the first circulation mode, since a high negative pressure is applied to the discharge port when an image with a large discharge amount per unit area (hereinafter also referred to as a high duty image) is formed, satellite droplets are temporarily generated. Even if it is difficult to see, there is an advantage that the influence on the image is small. These two circulation modes can be selected in light of the specifications of the liquid discharge head and the recording apparatus main body (discharge flow rate F, minimum circulation flow rate A, and in-head flow path resistance).

<Description of liquid discharge head configuration>
The configuration of the liquid ejection head 3 according to the first embodiment will be described. 5A and 5B are perspective views showing the liquid discharge head 3 according to the present embodiment. The liquid discharge head 3 has 15 recording element substrates 10 arranged in a straight line (arranged in-line) that can eject inks of four colors of cyan C / magenta M / yellow Y / black K with one recording element substrate 10. This is a line type liquid discharge head. As shown in FIG. 5A, the liquid ejection head 3 includes a signal input terminal 91 and a power supply terminal 92 electrically connected to each recording element substrate 10 via the flexible wiring board 40 and the electric wiring board 90. Is provided. The signal input terminal 91 and the power supply terminal 92 are electrically connected to the control unit of the recording apparatus 1000, and supply an ejection drive signal and electric power necessary for ejection to the recording element substrate 10, respectively. By consolidating the wiring by the electric circuit in the electric wiring board 90, the number of the signal output terminals 91 and the power supply terminals 92 can be reduced as compared with the number of the recording element boards 10. Thus, the number of electrical connection portions that need to be removed when the liquid discharge head 3 is assembled to the recording apparatus 1000 or when the liquid discharge head is replaced can be reduced. As shown in FIG. 5B, the liquid connection portions 111 provided at both ends of the liquid ejection head 3 are connected to the liquid supply system of the recording apparatus 1000 described above with reference to FIGS. Thus, cyan C / magenta M / yellow Y / black K four color inks are supplied from the supply system of the recording apparatus 1000 to the liquid discharge head 3, and ink that has passed through the liquid discharge head 3 is supplied to the supply system of the recording apparatus 1000. It has come to be collected. As described above, the ink of each color can be circulated through the path of the recording apparatus 1000 and the path of the liquid discharge head 3.

  FIG. 6 is an exploded perspective view showing each component or unit constituting the liquid ejection head 3. The liquid discharge unit 300, the liquid supply unit 220, and the electric wiring substrate 90 are attached to the housing 80. The liquid supply unit 220 is provided with a liquid connection portion 111 (see FIG. 3), and the liquid supply unit 220 communicates with each opening of the liquid connection portion 111 in order to remove foreign matter in the supplied ink. A filter 221 (see FIGS. 2 and 3) for each color is provided. The two liquid supply units 220 are each provided with filters 221 for two colors. The liquid that has passed through the filter 221 is supplied to the negative pressure control unit 230 disposed on the liquid supply unit 220 corresponding to each color. The negative pressure control unit 230 is a unit composed of a pressure regulating valve for each color, and the inside of the supply system of the recording apparatus 1000 (which is caused by the fluctuation of the liquid flow rate by the action of a valve or a spring member provided in each of the negative pressure control units 230 The pressure loss change of the supply system upstream of the liquid discharge head 3) is greatly attenuated. Accordingly, the negative pressure control unit 230 can stabilize the negative pressure change on the downstream side (liquid ejection unit 300 side) from the pressure control unit within a certain range. In the negative pressure control unit 230 for each color, two pressure regulating valves for each color are incorporated as described in FIG. The two pressure regulating valves are set to different control pressures, the high pressure side is the common supply channel 211 (see FIG. 2) in the liquid discharge unit 300, and the low pressure side is the common recovery channel 212 (see FIG. 2) and the liquid supply unit. Communicate via 220.

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

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

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

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

  It is preferable that the first to third flow path members are made of a material having corrosion resistance against a liquid and a low linear expansion coefficient. As a material, for example, a composite material (resin material) in which inorganic fillers such as silica fine particles and fibers are added using alumina, LCP (liquid crystal polymer), PPS (polyphenyl sulfide), and PSF (polysulfone) as a base material is preferably used. be able to. As a method of forming the flow path member 210, three flow path members may be laminated and bonded to each other. When a resin composite resin material is selected as the material, a joining method by welding may be used.

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

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

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

  Here, the common supply flow path 211 of each color is connected to the corresponding negative pressure control unit 230 (high pressure side) via the liquid supply unit 220, and the common recovery flow path 212 is connected to the negative pressure control unit 230. (Low pressure side) and the liquid supply unit 220 are connected. By this negative pressure control unit 230, a differential pressure (pressure difference) is generated between the common supply channel 211 and the common recovery channel 212. For this reason, as shown in FIGS. 8 and 9, in the liquid discharge head of the present embodiment in which the respective channels are connected, the common supply channel 211 to the individual supply channel 213 a to the recording element substrate 10 for each ink color. Ink flows that flow in order from the individual recovery channel 213b to the common recovery channel 212 are generated.

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

<Description of structure of recording element substrate>
FIG. 11A shows a plan view of the surface of the recording element substrate 10 on which the ejection port 13 is formed, and FIG. 11B shows an enlarged view of the portion indicated by A in FIG. FIG.11 (c) shows the top view of the back surface of Fig.11 (a). Here, the configuration of the recording element substrate 10 in the present embodiment will be described. As shown in FIG. 11A, the four ejection port arrays corresponding to the respective ink colors are formed on the ejection port forming member 12 of the recording element substrate 10. Hereinafter, the direction in which the discharge port array in which the plurality of discharge ports 13 are arranged is referred to as “discharge port array direction”. As shown in FIG. 11B, a recording element 15 that is a heating element (pressure generating element) for foaming the liquid by utilizing the heat energy generated by the liquid is disposed at a position corresponding to each discharge port 13. ing. A partition 22 defines a pressure chamber 23 having the recording element 15 therein. The recording element 15 is electrically connected to the terminal 16 by electrical wiring (not shown) provided on the recording element substrate 10. The recording element 15 generates heat and generates liquid based on pulse signals input from the control circuit of the recording apparatus 1000 via the electric wiring board 90 (see FIG. 6) and the flexible wiring board 40 (see FIG. 10). Bring to a boil. The liquid is discharged from the discharge port 13 by the foaming force due to the boiling. As shown in FIG. 11B, along each discharge port array, a liquid supply path 18 extends on one side, and a liquid recovery path 19 extends on the other side. The liquid supply path 18 and the liquid recovery path 19 are channels extending in the direction of the discharge port array provided in the recording element substrate 10 and communicate with the discharge port 13 via the supply port 17a and the recovery port 17b, respectively.

  As shown in FIG. 11C, a sheet-like cover plate 20 is laminated on the back surface of the recording element substrate 10 on which the discharge ports 13 are formed. A plurality of openings 21 (opening rows) communicating with the passage 18 and the liquid recovery passage 19 are provided. In the present embodiment, three openings 21 are provided in the cover plate 20 for one of the liquid supply paths 18 and two openings 21 for one of the liquid recovery paths 19. As shown in FIG. 11B, each opening 21 of the cover plate 20 communicates with a plurality of communication ports 51 shown in FIG. The cover plate 20 preferably has sufficient corrosion resistance to the liquid, and high accuracy is required for the opening shape and the opening position of the opening 21 from the viewpoint of preventing color mixing. For this reason, it is preferable to use a photosensitive resin material or a silicon plate as the material of the cover plate 20 and provide the opening 21 by a photolithography process. As described above, the cover plate 20 converts the pitch of the flow path by the openings 21, and considering the pressure loss, the cover plate 20 is preferably thin and is preferably formed of a film-like member.

  FIG. 12 is a perspective view showing a cross section of the recording element substrate 10 and the cover plate 20 along XII-XII in FIG. Here, the flow of the liquid in the recording element substrate 10 will be described. The cover plate 20 has a function as a lid that forms part of the walls of the liquid supply path 18 and the liquid recovery path 19 formed on the substrate 11 of the recording element substrate 10. The recording element substrate 10 includes a substrate 11 formed of Si and a discharge port forming member 12 formed of a photosensitive resin, and a cover plate 20 is bonded to the back surface of the substrate 11. A recording element 15 is formed on one surface side of the substrate 11 (see FIG. 11), and a liquid supply path 18 and a liquid recovery path 19 extending along the ejection port array are formed on the back surface side thereof. Grooves are formed. The liquid supply path 18 and the liquid recovery path 19 formed by the substrate 11 and the cover plate 20 are connected to the common supply path 211 and the common recovery path 212 in the flow path member 210, respectively. And a liquid recovery path 19 has a differential pressure. When recording is performed by discharging liquid from the discharge port 13, the liquid in the liquid supply path 18 provided in the substrate 11 is supplied to the supply ports 17 a and 17 a by the differential pressure. It flows to the liquid recovery path 19 via the pressure chamber 23 and the recovery port 17b (arrow C in FIG. 12). By this flow, in the ejection port 13 and the pressure chamber 23 that are not performing the ejection operation, it is possible to collect the thickened ink, bubbles, foreign matters, and the like generated by evaporation from the ejection port 13 in the liquid recovery path 19. Further, it is possible to prevent the ink in the ejection port 13 and the pressure chamber 23 from being thickened or the color material density from increasing. The liquid recovered into the liquid recovery path 19 passes through the opening 21 of the cover plate 20 and the liquid communication port 31 of the support member 30 (see FIG. 10b). They are collected in the order of the collection channel 212 and collected to the supply path of the recording apparatus 1000. That is, the liquid supplied from the recording apparatus main body to the liquid discharge head 3 flows in the following order, and is supplied and recovered.

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

  In the first circulation mode shown in FIG. 2, the liquid flowing in from the liquid connecting portion 111 is supplied to the joint rubber 100 after passing through the negative pressure control unit 230. In the second circulation mode shown in FIG. 3, the liquid recovered from the pressure chamber 23 passes through the joint rubber 100 and then passes from the liquid connection portion 111 to the outside of the liquid discharge head via the negative pressure control unit 230. To flow. In addition, not all liquids that have flowed from one end of the common supply channel 211 of the liquid discharge unit 300 are supplied to the pressure chamber 23 via the individual supply channel 213a. That is, there is a liquid that flows from one end of the common supply channel 211 and flows from the other end of the common supply channel 211 to the liquid supply unit 220 without flowing into the individual supply channel 213a. As described above, even if the recording element substrate 10 having a flow path having a fine flow resistance and a relatively large flow resistance as in the present embodiment is provided by providing a flow path without passing through the recording element substrate 10. In addition, the backflow of the liquid circulation flow can be suppressed. As described above, in the liquid discharge head 3 of the present embodiment, it is possible to suppress the increase in the viscosity of the liquid in the pressure chamber 23 and the vicinity of the discharge port. As a result, high-quality recording can be performed.

<Description of positional relationship between recording element substrates>
FIG. 13 is a plan view that partially enlarges the adjacent portion of the recording element substrate in two adjacent ejection modules 200. In this embodiment, a substantially parallelogram recording element substrate is used. The respective ejection port arrays (14a to 14d) in which the ejection ports 13 in each recording element substrate 10 are arranged are arranged so as to be inclined at a certain angle with respect to the conveyance direction of the recording medium. The ejection port arrays in the adjacent portions of the recording element substrates 10 are configured such that at least one ejection port overlaps in the conveyance direction of the recording medium. In FIG. 13, the two discharge ports on the line D are in a relationship of overlapping each other. With such an arrangement, even if the position of the recording element substrate 10 is slightly deviated from the predetermined position, black stripes and white spots in the recorded image can be made inconspicuous by driving control of the overlapping discharge ports. Even when the plurality of recording element substrates 10 are arranged in a straight line (inline) instead of the so-called staggered arrangement, the configuration as shown in FIG. 13 suppresses an increase in the length of the liquid ejection head 10 in the conveyance direction of the recording medium. It is possible to take measures against black streaks and white spots at the connecting portion between the recording element substrates 10. In this embodiment, the main plane of the recording element substrate is a parallelogram, but the present invention is not limited to this. For example, even when a recording element substrate having a rectangular, trapezoidal or other shape is used, the configuration of the present invention is used. It can be preferably applied.

(Inkjet recording apparatus of second form)
Next, the configurations of the ink jet recording apparatus 2000 and the liquid ejection head 2003 according to the second embodiment, which are different from the ink jet recording apparatus according to the first embodiment, will be described. In the following description, only the parts different from the recording apparatus of the first embodiment will be mainly described, and the description of the same parts as those of the apparatus of the first embodiment will be omitted.

<Description of inkjet recording apparatus>
FIG. 21 is a diagram showing an ink jet recording apparatus 2000 according to the second embodiment. The recording apparatus 2000 of the present embodiment performs full-color recording on a recording medium by arranging four monochromatic liquid ejection heads 2003 corresponding to each of cyan C, magenta M, yellow Y, and black K in parallel. Is different from the first embodiment. In the first embodiment, the number of ejection port rows that can be used per color is one, whereas in this embodiment, the number of ejection port rows that can be used per color is 20. For this reason, it is possible to perform very high-speed recording by appropriately recording the recording data to a plurality of ejection port arrays. Furthermore, even if there is a discharge port that does not discharge, reliability is improved by interpolating discharge from the discharge ports in other rows that are at positions corresponding to the discharge direction of the recording medium. And suitable for commercial records. As in the first embodiment, the supply system of the recording apparatus 2000, the buffer tank 1003 (see FIGS. 2 and 3), and the main tank 1006 (see FIGS. 2 and 3) are fluids for each liquid discharge head 2003. Connected. Each liquid discharge head 2003 is electrically connected to an electric control unit that transmits power and a discharge control signal to the liquid discharge head 2003.

<Description of circulation route>
As in the first embodiment, as the liquid circulation path between the recording apparatus 2000 and the liquid discharge head 2003, the first and second circulation forms shown in FIG. 2 or FIG. 3 are used as in the first embodiment. Can do.

<Description of liquid discharge head structure>
FIGS. 14A and 14B are perspective views showing a liquid discharge head 2003 according to the present embodiment. The liquid ejection head 2003 is a line type recording head that includes 16 recording element substrates 2010 arranged linearly in the longitudinal direction of the liquid ejection head 2003 and ejects one color ink. The liquid discharge head 2003 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 2003 of this embodiment has more discharge port arrays than the head of the first embodiment, the signal output terminal 91 and the power supply terminal 92 are arranged on both sides of the liquid discharge head 2003. Thereby, voltage drop and signal transmission delay occurring in the wiring portion provided on the recording element substrate 2010 can be reduced.

  FIG. 15 is an exploded perspective view showing the liquid discharge head 2003, and shows each component or unit constituting the liquid discharge head 2003 divided for each function. The role of each unit and member and the order of liquid circulation in the liquid discharge head are basically the same as those in the first embodiment, but the functions for ensuring the rigidity of the liquid discharge head are different. In the first embodiment, the liquid discharge head support portion 81 mainly secures the liquid discharge head rigidity. However, in the liquid discharge head 2003 of the second embodiment, the second flow path member 2060 included in the liquid discharge unit 2300 is used. This ensures the rigidity of the liquid discharge head. In the present embodiment, the liquid discharge unit support portion 81 is connected to both ends of the second flow path member 2060, and the liquid discharge unit 2300 is mechanically coupled to the carriage of the recording apparatus 2000 to provide a liquid discharge head 2003. Perform positioning. The liquid supply unit 2220 including the negative pressure control unit 2230 and the electrical wiring board 90 are coupled to the liquid discharge unit support portion 81. Each of the two liquid supply units 2220 includes a filter (not shown).

  The two negative pressure control units 2230 are set so as to control the pressure with different relatively high and low negative pressures. Further, as shown in FIG. 14, when the negative pressure control units 2230 on the high pressure side and the low pressure side are installed at both ends of the liquid discharge head 2003, a common supply channel extending in the longitudinal direction of the liquid discharge head 2003. And the flow of liquid in the common recovery channel face each other. In such a configuration, heat exchange is promoted between the common supply channel and the common recovery channel, and a temperature difference between the two common channels is reduced. Accordingly, there is an advantage that a temperature difference in each of the recording element substrates 2010 provided along the common flow path is reduced, and recording unevenness due to the temperature difference is less likely to occur.

  Next, details of the flow path member 2210 of the liquid discharge unit 2300 will be described. As shown in FIG. 15, the flow path member 2210 is a laminate of a first flow path member 2050 and a second flow path member 2060, and the liquid supplied from the liquid supply unit 2220 is supplied to each discharge module 2200. Distribute. The flow path member 2210 functions as a flow path member for returning the liquid circulating from the discharge module 2200 to the liquid supply unit 2220. The second flow path member 2060 of the flow path member 2210 is a flow path member in which a common supply flow path and a common recovery flow path are formed, and has a function of mainly responsible for the rigidity of the liquid discharge head 2003. For this reason, as a material of the 2nd flow path member 2060, what has sufficient corrosion resistance with respect to a liquid and high mechanical strength is preferable. Specifically, SUS, Ti, alumina or the like can be used.

  FIG. 16A is a view showing a surface of the first flow path member 2050 on which the discharge module 2200 is mounted, and FIG. 16B shows the back surface thereof, and the second flow path member 2060 is shown. It is the figure which showed the surface contact | abutted with. Unlike the first embodiment, the first flow path member 2050 in the present embodiment is formed by arranging a plurality of members corresponding to each discharge module 2200 adjacent to each other. By adopting such a divided structure, a plurality of modules can be arranged to correspond to the length of the liquid discharge head 2003. For example, a relatively long scale corresponding to the B2 size or longer The present invention can be particularly preferably applied to the liquid discharge head. As shown in FIG. 16A, the communication port 51 of the first flow path member 2050 is in fluid communication with the discharge module 2200, and as shown in FIG. The communication port 53 is in fluid communication with the communication port 61 of the second flow path member 2060. FIG. 16C shows a surface of the second flow path member 60 that comes into contact with the first flow path member 2050, and FIG. 16D shows a cross section of the central portion in the thickness direction of the second flow path member 60. FIG. 16E is a diagram showing a surface of the second flow path member 2060 that comes into contact with the liquid supply unit 2220. The functions of the flow path and the communication port of the second flow path member 2060 are the same as for one color of the first form. One of the common flow channel grooves 71 of the second flow channel member 2060 is a common supply flow channel 2211 shown in FIG. 17 to be described later, and the other is a common recovery flow channel 2212. The longitudinal direction of the liquid discharge head 2003, respectively. The liquid is supplied from one end side to the other end side. In the present embodiment, unlike the first embodiment, the liquid flows in the common supply flow path 2211 and the common recovery flow path 2212 are in opposite directions.

  FIG. 17 is a perspective view showing a liquid connection relationship between the recording element substrate 2010 and the flow path member 2210. In the flow path member 2210, a set of a common supply flow path 2211 and a common recovery flow path 2212 extending in the longitudinal direction of the liquid discharge head 2003 are provided. The communication port 61 of the second flow channel member 2060 is connected to the individual communication port 53 of each first flow channel member 50 in alignment, and is connected to the common supply flow channel from the communication port 72 of the second flow channel member 2060. A liquid supply path that communicates with the communication port 51 of the first flow path member 2050 via 2211 is formed. Similarly, a liquid supply path that communicates from the communication port 72 of the second flow channel member 2060 to the communication port 51 of the first flow channel member 2050 via the common recovery flow channel 2212 is also formed.

  18 is a diagram showing a cross section taken along line XVIII-XVIII in FIG. The common supply channel 2211 is connected to the discharge module 2200 via the communication port 61, the individual communication port 53, and the communication port 51. Although not shown in FIG. 18, it is apparent with reference to FIG. 17 that in another cross section, the common recovery flow path 2212 is connected to the discharge module 2200 through a similar path. Similarly to the first embodiment, each ejection module 2200 and the recording element substrate 2010 are formed with a flow path communicating with each ejection port, and part or all of the supplied liquid pauses the ejection operation. It can be recirculated through the outlet. Similarly to the first embodiment, the common supply flow path 2211 is connected to the negative pressure control unit 2230 (high pressure side), and the common recovery flow path 2212 is connected to the negative pressure control unit 2230 (low pressure side). Connected through. Therefore, the differential pressure causes a flow that flows from the common supply channel 2211 to the common recovery channel 2212 through the discharge port of the recording element substrate 2010.

<Description of discharge module>
FIG. 19A is a perspective view showing one discharge module 2200, and FIG. 19B is an exploded view thereof. The difference from the first embodiment is that a plurality of terminals 16 are arranged on both sides (long side portions of the printing element substrate 2010) along the plurality of ejection port array directions of the printing element substrate 2010, respectively. Accordingly, two flexible wiring boards 40 that are electrically connected to the recording element substrate 2010 are also arranged on one recording element substrate 2010. This is because the number of ejection port arrays provided on the recording element substrate 2010 is 20, which is significantly larger than the eight arrays in the first embodiment, and the maximum distance from the terminal 16 to the recording element is shortened. This is to reduce a voltage drop and a signal delay that occur in the wiring portion in the recording element substrate 2010. Further, the liquid communication port 31 of the support member 2030 is provided in the recording element substrate 2010 and is opened so as to straddle all the ejection port arrays. Other points are the same as in the first embodiment.

<Description of structure of recording element substrate>
FIG. 20A is a schematic diagram of the surface on which the ejection port 13 of the recording element substrate 2010 is arranged, and FIG. 20C is a schematic diagram showing the back surface of the surface of FIG. FIG. 20B is a schematic diagram showing the surface of the recording element substrate 2010 when the cover plate 2020 provided on the back side of the recording element substrate 2010 is removed in FIG. As shown in FIG. 20B, the liquid supply path 18 and the liquid recovery path 19 are alternately provided on the back surface of the recording element substrate 2010 along the discharge port array direction. Although the number of ejection port arrays is greatly increased as compared with the first embodiment, the essential difference from the first embodiment is that the terminals 16 are arranged in the ejection port array direction of the recording element substrate as described above. It is arranged on both sides along. A set of liquid supply path 18 and liquid recovery path 19 is provided for each discharge port array, and an opening 21 communicating with the liquid communication port 31 of the support member 2030 is provided on the cover plate 2020. The basic configuration is the same as that of the first embodiment.

  In addition, the description of the said embodiment does not limit the scope of the present invention. As an example, in the present embodiment, a thermal method in which bubbles are generated by a heating element to discharge a liquid has been described. However, the present invention is also applied to a liquid discharge head employing a piezo method and other various liquid discharge methods. be able to.

  In the present embodiment, an ink jet recording apparatus (recording apparatus) in which liquid such as ink is circulated between a tank and a liquid discharge head has been described. However, other forms may be used. As another mode, for example, two tanks are provided on the upstream side and the downstream side of the liquid discharge head without circulating ink, and the ink in the pressure chamber is caused to flow by flowing ink from one tank to the other tank. Form may be sufficient.

  In this embodiment, an example of using a so-called line type head having a length corresponding to the width of the recording medium has been described. However, a so-called serial type liquid ejection that performs recording while scanning the recording medium. The present invention can also be applied to the head. As the serial type liquid discharge head, for example, a configuration in which a recording element substrate for discharging black ink and a recording element substrate for discharging color ink are mounted one by one, but the present invention is not limited to this. That is, a mode in which a plurality of recording element substrates are arranged so that the discharge ports overlap in the discharge port array direction, and a short liquid discharge head shorter than the width of the recording medium is created, and the recording medium is scanned with respect to the recording medium It may be.

(First embodiment)
1st Embodiment of this invention is related with the structure for performing temperature control of the liquid discharge head which circulates ink with respect to each discharge port mentioned above with reference to FIGS.

  As described above, in the liquid discharge head, heat is generated by the discharge operation of driving the heat generating element to discharge the liquid, thereby increasing the temperature of the recording element substrate. Further, the temperature of the liquid discharge head may rise due to the temperature control of the liquid discharge head itself. In such an environment in which the temperature is rising, liquid (ink) having a relatively low temperature is supplied to the liquid supply path 18 shown in FIGS. As described above, in the present embodiment, three openings 21 are provided in one liquid supply path 18. For this reason, among the plurality of discharge ports 13 arranged along the liquid supply path 18, there are discharge ports arranged near the opening 21 and discharge ports arranged away from the opening 21. In this case, a liquid having a relatively low temperature is supplied to the discharge port (the pressure chamber 23) disposed in the vicinity of the opening 21, and the discharge port disposed away from the opening 21 is connected to the discharge port from the opening 21. The liquid heated by the heat transfer from the recording element substrate is supplied up to the ejection port. As a result, the temperature of the liquid varies along the ejection port array, and the amount of liquid ejected for each ejection port may vary. This appears as uneven density in an image in an apparatus that records an image with ink. In the present embodiment, the liquid temperature variation along the discharge port array as described above is suppressed by the arrangement of the heaters on the recording element substrate.

  FIGS. 22A and 22B are diagrams schematically showing the positional relationship between the opening 21, the heater, and the temperature sensor in the recording element substrate according to the first embodiment of the present invention. FIG. 22A shows the arrangement of the openings 21 along the ejection port array in which the ejection ports 13 are arranged in the recording element substrate 10. 11 and 12, the openings 21 are respectively arranged in the liquid supply path 18 and the liquid recovery path 19 extending on both sides along the discharge port array. In FIGS. 22 (a) and (b), the openings are shown in a straight line for simplification of illustration and description. In this respect, 21 a is an opening disposed in the liquid supply path 18, and 21 b is an opening disposed in the liquid recovery path 19. Further, the size of each opening is schematically shown unlike the one shown in FIG. 11 and the like, and the number of openings is three for one of the liquid supply paths 18 described above, and a liquid recovery path. It is shown without being limited to two for one of the nineteen. FIG. 22B shows the positional relationship between the heater 102 (and the heater array) and the temperature sensor 103 (and the temperature sensor array) with respect to the positions of the openings 21a and 21b along the discharge port array. The number of the openings 21 a and 21 b is an example, and two openings 21 a for one liquid supply path 18 and one opening 21 b for one liquid recovery path 19 may be used. The number of openings 21a and the number of openings 21b may be the same.

  In the present embodiment, as shown in FIG. 22A, a region near the opening 21 a or the opening 21 b is set as a temperature control adjustment area 101. In each of these areas, as shown in FIG. 22B, a temperature sensor 103 and a temperature adjusting heater 102 are arranged. Specifically, in FIG. 11B, the temperature control heater 102 and the temperature sensor 103 are provided around the recording element 15 which is a heat generating element for discharge at a distance that does not affect the operation of each other. A diode sensor etc. can be mentioned as a specific example of a temperature sensor. In addition, the shape of the temperature sensor 103 is long in the direction of the discharge port array in the figure, but the shape may be a circle, a square, or the like.

  When the temperature sensor 103 corresponding to each area 101 detects a temperature equal to or lower than a certain threshold temperature, the heater 102 in that area is driven to perform heating, and when a temperature higher than the above threshold is detected, the heater Heating by 102 is stopped. Accordingly, since the ink having a relatively low temperature flows in the vicinity of the opening 21a through which the ink flows into the recording element substrate, the corresponding temperature sensor 103 detects the relatively low temperature. As a result, by the temperature control, the heating by the corresponding heater 102 has a high frequency of heating or a long heating time. On the other hand, since the temperature of the ink in the vicinity of the opening 21b through which the ink flows out is relatively high, the corresponding temperature sensor 103 detects a relatively high temperature. As a result, by the temperature control, the heating by the corresponding heater 102 is performed less frequently, the heating time is shortened, or no heating is performed. As a result, it is possible to suppress ink temperature fluctuations along the ejection port array that may occur due to ink circulation. In the present embodiment, the number of openings and the number of temperature control areas can be made the same, and the number of temperature sensors and heaters for temperature adjustment can be reduced.

  Here, the improvement effect of the heat distribution of this embodiment by simulation is demonstrated. 23A and 23B are diagrams showing the positional relationship between the openings 21a and 21b, the temperature adjustment heater 102, and the temperature sensor 103 for simulation. FIGS. 24A and 24B are diagrams showing the temperature distribution along the discharge port array as a result of the simulation. FIG. 23A shows a case where heaters and temperature sensors are arranged at regular intervals without matching the position of the opening, and FIG. 24A shows a temperature distribution in that case. On the other hand, FIG. 23B shows the case where the heater 102 and the temperature sensor 103 are arranged corresponding to the position of the opening as in this embodiment, and FIG. 24B shows the temperature distribution in that case. ing.

  In the arrangement shown in FIG. 23A, as shown in FIG. 24A, the temperature difference ΔT in the temperature distribution is 5.7 ° C. On the other hand, when the heater 102 and the temperature sensor 103 are arranged corresponding to the position of the opening, as shown in FIG. 24B, the temperature difference ΔT in the temperature distribution is 4.4 ° C. Thus, by arranging the heater and the sensor in correspondence with the position of the opening, it is possible to effectively suppress the temperature difference in the temperature distribution that can occur in the recording element substrate.

(Second Embodiment)
FIGS. 25A to 25C are diagrams schematically showing the positional relationship between the opening 21, the heater, and the temperature sensor in the recording element substrate according to the second embodiment of the present invention. FIG. 25A shows a state where the recording element substrate 10 and the cover plate 20 are separated. In this embodiment, only the liquid supply path is provided, that is, the ink is not circulated to the ejection port 13. An opening 21 is provided corresponding to the liquid supply path, and ink is supplied to the pressure chamber 23 and the ejection port 13 through the opening 21. As shown in FIG. 25 (b), the temperature control area 101 includes an area corresponding to each opening 21 and an area where the opening 21 does not exist, and these areas serve as the discharge port arrays of the plurality of discharge ports 13. Are arranged along. Further, as shown in FIG. 25C, a temperature control heater 102 and a temperature sensor 103 are arranged in each temperature control area 101. In the example shown in FIG. 25C, one heater 102 is provided for each temperature control area 101, but a plurality of heaters may be arranged. There may be a plurality of temperature sensors in one temperature control area 101.

  In the above configuration, when the temperature sensor 103 detects a temperature equal to or lower than a predetermined threshold temperature, it is heated by the heater 102 in that area. Further, when the temperature sensor 103 detects a temperature higher than the threshold temperature, heating by the heater is stopped. As a result, in the area 101 where the openings 21 are arranged, ink having a relatively low temperature flows. Therefore, the heating by the corresponding heater 102 is frequently performed or the heating time is increased by temperature control. Further, temperature control is not performed in the area 101 where the temperature adjusting heater 102 and the temperature sensor 103 are not arranged. As a result of the above, heating is performed particularly at a location where the ink temperature is relatively low, and temperature fluctuations along the ejection port array can be mitigated.

(Third embodiment)
FIG. 26 is a diagram schematically illustrating the positional relationship between the openings 21a and 21b, the heater 102, and the temperature sensor 103 in the recording element substrate according to the third embodiment of the invention. This embodiment has substantially the same configuration as the first embodiment, but differs in the following points. In the first embodiment, the heater 102 and the temperature sensor 103 are arranged corresponding to the opening 21a for the ink to flow into the recording element substrate and the opening 21b for the ink to flow out of the recording element substrate. In the present embodiment, in addition to this, as shown in FIG. 26, the heater 102a and the temperature sensor 103a are arranged in a region (region A) where the openings 21a and 21b are not present at the end of the discharge port array.

  The openings 21 for inflow of ink are desirably at both ends of the recording element substrate. Then, as shown in FIG. 27, in order to supply a plurality of colors of ink to one recording element substrate, the openings shown in FIG. As indicated by the arrows, the distance from the end of the recording element substrate of the opening 21 on one end side becomes longer. For example, in the case of black ink (K), the distance between the opening 21 at the right end of the drawing and the right end of the printing element substrate (the portion indicated by the arrow) is the distance between the opening 21 at the left end of the drawing and the printing element substrate. Greater than the distance to the left edge. As a result, the temperature of the ink supplied to the ejection port at the right end of the graph shown in FIG. In FIG. 24, the temperatures of a plurality of nozzle rows of the same color are averaged and plotted. The temperature rise is observed at the left end because there is a nozzle row that overlaps the right end of the adjacent recording element substrate, and the temperature rise at the right end of the adjacent recording element substrate is averaged. I'm not doing it. In the present embodiment, in order to suppress the temperature rise at the end portion, as shown in FIG. 26, the opening 21 is the end portion on the side where the distance between the recording element substrate end portion and the end side opening 21 is large. A heater 102a and a temperature sensor 103 (A region) a are arranged in a region where the temperature sensor is not provided, and temperature control is performed. As a result, as shown in FIG. 28, the temperature rise of the ink supplied to the ejection port at the end is suppressed (4.4 ° C. to 2.6 ° C.), and the temperature variation in the ejection port array direction is further alleviated. be able to.

  If the circulation flow rate is small or the circulation flow rate is small, the temperature rise at the end becomes noticeable at both ends, so that not only one end of the recording element substrate comes out, but also the heater and temperature corresponding to both side edges. It is desirable to control the temperature by adding a sensor.

(Fourth embodiment)
FIGS. 29A and 29B are diagrams schematically showing a positional relationship between the opening, the heater, and the temperature sensor in the recording element substrate according to the fourth embodiment of the present invention. This embodiment is basically the same configuration as the first embodiment, but differs in the following points.

  In the present embodiment, as shown in FIG. 29, a temperature sensor 103 is disposed between adjacent heaters 102, that is, between adjacent temperature control areas. In temperature control, the reference temperature when driving one heater is the value calculated from the two temperature sensors on both sides of the heater, and the reference temperature of the outermost heater is the temperature calculated from the nearest temperature sensor. And Here, the calculated temperature may be a value that is simply averaged or may be an average value that is weighted in consideration of the distance between the heater and the temperature sensor. Specifically, in FIG. 29B, the value of the temperature sensor 103A is referred to when the heater 102A is driven, and the temperature calculated from the values of the temperature sensor 103A and the temperature sensor 103B is referred to when the heater 102B is driven.

  FIGS. 30A and 30B are diagrams schematically illustrating a modification of the positional relationship between the opening 21, the heater 102, and the temperature sensor 103 in the recording element substrate of the fourth embodiment. The temperature control in this example refers to the value of the temperature sensor 103A for driving the heater 102A in FIG. The driving of the heater 102B refers to the value of the temperature sensor 103B, the driving of the heater 102C refers to the value calculated from the values of the temperature sensor 103A and the temperature sensor 103C, and the driving of the heater 102D refers to the value of the temperature sensor 103B and the temperature sensor 103D. Refer to the value calculated from. Such control makes it possible to perform appropriate temperature control with a small number of temperature sensors.

(Fifth embodiment)
5th Embodiment of this invention is related with the form provided with the row | line | column of one heater and a temperature sensor in one ink color. That is, when the number of ejection port arrays differs for each ink color, one heater 102 array and temperature sensor 103 array are arranged for each ink color. For example, as shown in FIG. 31, the discharge port rows for K (black) ink are four rows, and the discharge port rows for Y (yellow), M (magenta), and C (cyan) ink are respectively from two discharge port rows. In this embodiment, the heater 102 and the temperature sensor 103 are arranged in one row regardless of the number of discharge port rows. In this embodiment, it is desirable that the heater 102 and the temperature sensor 103 be arranged near the center of the plurality of ejection port arrays. This is because when there are a plurality of ejection port arrays for the same color ink, they are generally used evenly, and therefore it may not be necessary to individually control the temperature of the ejection port arrays for the same color ink. As a result, the number of heaters and temperature sensors can be reduced, and the recording element substrate can be further miniaturized. In FIG. 31, any of the openings shown in the above-described embodiments can be provided, but the illustration thereof is omitted.

(Other embodiments)
FIGS. 32A and 32B are views showing a shape example and an arrangement example of a recording element substrate according to an embodiment of the present invention. FIG. 32A shows the shape and arrangement of the recording element substrates according to the first to fifth embodiments described above with reference to FIG. . On the other hand, FIG. 32B shows a staggered configuration in which the recording element substrates are alternately arranged, and such a staggered configuration can also be used. The in-line configuration is advantageous in terms of cost because the liquid discharge head can be made smaller and the total area of the recording element substrate can be made smaller than the staggered configuration. On the other hand, in the staggered configuration, a large number of redundant ejection openings can be provided at the connecting portion of the recording element substrate, and the reliability of the image quality can be ensured. In the above-described embodiment, an example in which the present invention is applied to a recording element substrate that discharges multicolor inks has been described. However, it is needless to say that the present invention can be applied to a monochrome recording element substrate.

DESCRIPTION OF SYMBOLS 10 Recording element board | substrate 13 Ejection port 18 Liquid supply path 19 Liquid recovery path 21, 21a, 21b Opening 101 Temperature control area 102, 102A Temperature control heater 103, 103A Temperature sensor

Claims (17)

A liquid discharge head provided with a discharge port array in which a plurality of discharge ports for discharging liquid are arranged,
A pressure chamber communicating with the discharge port, and a pressure chamber provided with a pressure generating element for discharging a liquid therein;
An opening for supplying liquid to the pressure chamber;
A flow path extending along the discharge port array for supplying the liquid flowing in from the opening to the pressure chamber;
A heater provided in the vicinity of the opening;
A temperature sensor provided in a region along the discharge port array;
A liquid discharge head characterized by comprising: The opening includes a first opening and a second opening communicating with the flow path,
The liquid discharge head according to claim 1, wherein the heater and the temperature sensor are provided in the vicinity of the first opening and between the first opening and the second opening.   2. The liquid discharge head according to claim 1, wherein a plurality of the openings are provided, and the heater and the temperature sensor are provided in the vicinity of each of the plurality of openings and between the plurality of openings. A second opening for discharging the liquid in the flow path is further provided;
The liquid discharge head according to claim 2, wherein the heater and the temperature sensor are provided in the vicinity of the first opening and between the first opening and the second opening.   The liquid discharge head according to claim 4, wherein a plurality of the openings are provided, and the heater and the temperature sensor are provided in the vicinity of each of the plurality of openings and between the plurality of openings.   The liquid discharge head according to claim 1, wherein a heater and a temperature sensor are provided in regions adjacent to both ends of the discharge port array.   The liquid discharge head according to claim 1, wherein a heater and a temperature sensor are provided in a region adjacent to one end of the discharge port array.   The liquid discharge head according to claim 1, wherein the liquid in the pressure chamber is circulated between the outside of the pressure chamber. A liquid ejection apparatus that ejects liquid using a liquid ejection head provided with an ejection port array in which a plurality of ejection ports for ejecting liquid are arranged,
The liquid discharge head is a pressure chamber communicating with the discharge port, the pressure chamber having a pressure generating element therein, an opening, and the liquid for flowing in from the opening is supplied to the pressure chamber. A flow path extending along the discharge port array, a heater provided in the vicinity of the opening, and a temperature sensor provided in a region along the discharge port array,
The liquid ejection apparatus includes a control unit that controls a temperature of the liquid ejection head,
The liquid ejecting apparatus according to claim 1, wherein the control unit controls driving of the heater based on a temperature detected by the temperature sensor.   The liquid ejecting apparatus according to claim 9, wherein the control unit drives the heater to heat the liquid when the temperature detected by the temperature sensor is equal to or lower than a predetermined threshold temperature. The liquid discharge head has a plurality of the temperature sensors around the heater,
The said control means drives the heater to heat the liquid when the temperature calculated from the plurality of temperature sensors around the heater is equal to or lower than the threshold temperature. The liquid discharge apparatus according to 1. The liquid ejection head includes the ejection port array for each of a plurality of ink colors,
12. The liquid according to claim 9, wherein the control unit controls the driving of the heater based on a temperature detected by the temperature sensor for each of the plurality of ink colors. Discharge device.   The liquid ejecting apparatus according to claim 9, further comprising a circulation unit that circulates the liquid in the pressure chamber between the pressure chamber and the outside of the pressure chamber. A discharge port array in which a plurality of discharge ports for discharging liquid are arranged;
A plurality of elements that generate energy used for discharging liquid, each provided at a position facing the plurality of discharge ports;
A plurality of pressure chambers having the plurality of elements therein;
A plurality of openings communicating with the plurality of pressure chambers, the opening row being arranged along the discharge port row; and
A heater row in which a plurality of heaters are arranged along the opening row;
A temperature sensor row in which a plurality of temperature sensors are arranged along the opening row.
A liquid ejection head comprising: A discharge port forming member provided with the discharge port array;
A substrate bonded to the discharge port forming member,
The plurality of elements, the heater array, and the temperature sensor array are provided on one surface side of the substrate, and the opening array is provided on a back surface side of the one surface. 14. A liquid discharge head according to item 14.   The liquid ejection head according to claim 15, wherein a cover plate on which the opening row is formed is disposed on a back surface side of the substrate.   The liquid discharge head according to claim 14, wherein the liquid in the pressure chamber is circulated between the pressure chamber and the outside.