JP2013014111A - Liquid ejection head and liquid ejection recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid ejection head and a liquid supply apparatus that hardly cause air to be accumulated in a filter portion on an ink supply port side.SOLUTION: A second liquid supply chamber 35 has a second liquid ejection supply chamber opening 36 communicating with a liquid supply path 37. A supply filter 18 is arranged between a plurality of ejection ports and the second liquid ejection supply chamber opening 36. This can realize a liquid ejection head and a liquid supply apparatus that hardly cause air to be accumulated in a supply filter 18.

Description

  The present invention relates to a liquid discharge head that discharges liquid for recording and a liquid discharge recording apparatus using the liquid discharge head.

  2. Description of the Related Art In a liquid discharge recording apparatus that performs recording by discharging liquid from a liquid discharge head onto a recording medium (hereinafter, also simply referred to as a recording apparatus), a plurality of nozzles that discharge liquid are generally formed with high density. High-definition recording is performed using this liquid discharge head. By arranging a plurality of liquid discharge heads and supplying inks of different colors to the respective heads, color recording can be performed on a recording medium with a relatively inexpensive and small configuration. For this reason, liquid discharge recording apparatuses are used in various recording apparatuses such as printers, facsimiles, and copying machines regardless of whether they are for business use or home use.

  In the liquid discharge recording apparatus as described above, in order to stabilize the liquid discharge operation from the liquid discharge head, the liquid in the liquid discharge head is maintained at a predetermined negative pressure (pressure acting on the liquid in the liquid discharge head). Is maintained at a predetermined negative pressure).

  As an appropriate form of a liquid discharge head mounted in such a liquid discharge recording apparatus, in Patent Document 1, a liquid layer and an air layer coexist in one space in a head liquid chamber, and bubbles generated and generated in the head are detected. Proposals have been made to eliminate the gas and efficiently perform gas-liquid separation. In this proposal, air bubbles connected to the outside from the air chamber are guided to the air chamber side by the guide surface that rises toward the air chamber side from the supply port side provided at the upper portion of the liquid chamber. The structure leads to the roadway. Therefore, stable recording quality can be maintained for a long time.

  In general, in order to remove foreign matters mixed in the liquid supplied to the nozzle, it is necessary to provide a filter in the liquid discharge head. However, the pressure loss of the liquid flow in the filter portion is the recording speed. There is a risk of speeding up.

JP 2010-201925 A

  In the liquid ejection head disclosed in Patent Document 1, air may accumulate in the filter portion provided on the ink supply port side. When air accumulates in the filter portion in this way, the filter is covered with air, so that the portion of the filter through which ink can pass decreases and the pressure loss of the filter portion increases.

  Accordingly, an object of the present invention is to provide a liquid discharge head and a liquid supply apparatus in which air is not easily accumulated in the filter portion on the ink supply port side.

Therefore, the liquid discharge head according to the present invention includes a nozzle row composed of a plurality of nozzles each communicating with a plurality of discharge ports for discharging liquid, a main liquid supply chamber for supplying liquid to the nozzles, and the main A liquid supply path that communicates with the liquid supply chamber and supplies the liquid to the main liquid supply chamber, and a sub that communicates with the liquid supply path and supplies the liquid to the main liquid supply chamber via the liquid supply path A liquid supply chamber, a supply filter disposed so as to separate the sub liquid supply chamber into a first liquid supply chamber and a second liquid supply chamber from the upstream side in the liquid flow direction;
A gas-liquid separation unit provided in the main liquid supply chamber, as a space for separating the liquid flowing into the main liquid supply chamber and air, and an air chamber communicating with the gas-liquid separation unit; The liquid supply chamber has an inclined surface that forms an inclination with portions farthest from the plurality of discharge ports as the gas-liquid separation unit, and the second liquid supply chamber communicates with the liquid supply path. A supply chamber opening is provided, and the supply filter is disposed between the plurality of discharge ports and the second liquid supply chamber opening.

  According to the present invention, the liquid discharge head includes a second liquid supply chamber opening that communicates with the liquid supply path in the second liquid supply chamber, and the supply filter includes the plurality of discharge ports and the second liquid supply chamber opening. Arranged between. As a result, it is possible to realize a liquid discharge head and a liquid supply apparatus in which air does not easily accumulate in the supply filter.

FIG. 2 is a front view schematically showing a liquid discharge recording apparatus. (A) is a diagram showing a liquid ejection head to which the present embodiment can be applied, and (b) is a diagram showing a four-unit liquid ejection head. It is the figure which showed typically the liquid supply system and recovery system from a liquid tank to a liquid discharge head. (A) is a front view for demonstrating the structural example of the liquid discharge head of this embodiment, (b) is sectional drawing which follows front view AA, (c) is a front view. It is sectional drawing which follows a BB line.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a front view schematically showing a liquid discharge recording apparatus (hereinafter also simply referred to as a recording apparatus) to which this embodiment can be applied. The recording apparatus 100 is connected to the host PC 110. Then, the recording apparatus 100 transfers the four liquid ejection heads (hereinafter also simply referred to as heads) 22K, 22C, 22M, and 22Y to the recording medium (hereinafter also referred to as roll paper) P based on the recording information transmitted from the host PC 110. Recording is performed by discharging liquid. The four liquid discharge heads 22K, 22C, 22M, and 22Y are arranged along the conveyance direction (arrow A direction) of the recording medium P. The liquid ejection heads are arranged in parallel with each other in the order of the black ink liquid ejection head 22K, the cyan ink liquid ejection head 22C, the magenta ink liquid ejection head 22M, and the yellow ink liquid ejection head 22Y in the transport direction. . The liquid discharge heads 22K, 22C, 22M, and 22Y are so-called line heads, and nozzles are arranged at a predetermined density along a direction (width direction) that intersects the recording medium conveyance direction. The arrangement width of the nozzles (arrangement range in the direction (width direction) intersecting with the conveyance direction of the recording medium) is larger than the maximum recording width of the recording medium to be used. When recording is performed by the recording apparatus, recording is performed by ejecting liquid from the nozzles by driving a heater provided in the liquid ejection head without moving each head.

  In the liquid discharge head, foreign matters such as dust and ink droplets adhere to the surfaces (hereinafter also referred to as discharge port surfaces) 22Ks, 22Cs, 22Ms, and 22Ys on which the discharge ports, which are nozzle openings, are formed during recording. In this case, the discharge state changes, which may affect recording. Therefore, the recovery unit 40 is incorporated in the recording apparatus 100 so that liquid can be stably discharged from the heads 22K, 22C, 22M, and 22Y. By regularly cleaning the discharge port surface by the recovery unit 40, the liquid discharge state from the nozzles of the liquid discharge heads 22K, 22C, 22M, and 22Y can be recovered to a good discharge state. The recovery unit 40 is used to remove liquid and fine bubbles from the discharge port surfaces 22Ks, 22Cs, 22Ms, and 22Ys of the four liquid discharge heads 22K, 22C, 22M, and 22Y during the cleaning operation. A cap 50 is provided. The cap 50 is provided independently for each liquid ejection head 22K, 22C, 22M, 22Y.

  The recording medium P is supplied from the roll paper supply unit 24 and is conveyed in the direction of arrow A by the conveying mechanism 26 incorporated in the recording apparatus 100. The transport mechanism 26 includes a transport belt 26a for loading and transporting the roll paper P, a transport motor 26b for rotating the transport belt 26a, and a roller 26c for applying tension to the transport belt 26a. When recording, when the roll paper P being conveyed reaches under the black liquid ejection head 22K, black ink is ejected from the liquid ejection head 22K based on the recording information sent from the host PC 110. Similarly, ink of each color is ejected in the order of the liquid ejection head 22C, the liquid ejection head 22M, and the liquid ejection head 22Y, and color recording on the roll paper P is completed.

  The liquid discharge recording apparatus of the present embodiment is an application example as a recording apparatus using a long liquid discharge head 22 that extends over the entire width direction of the recording area of the recording paper P. However, the present invention is also applicable to a serial scan type recording apparatus that repeats recording scanning in the main scanning direction of the liquid ejection head and conveyance of a predetermined amount of recording paper in the sub-scanning direction that intersects the main scanning direction. Can do.

  Next, the form of the liquid discharge head incorporated in the recording apparatus will be described with reference to FIG. FIG. 2A is a diagram illustrating a liquid ejection head to which the present embodiment is applicable, and FIG. 2B is a diagram illustrating a four-unit liquid ejection head. The recording apparatus to which this embodiment can be applied has four liquid discharge heads corresponding to the inks of the respective colors, and these liquid discharge heads are integrated with each nozzle row positioned precisely. (Hereinafter, the four-head configuration in this state is referred to as a combined head). In other words, the pitches between the nozzle rows, the nozzle row direction deviation, the nozzle row height deviation, and the parallelism between the nozzle rows of each liquid ejection head are combined so as to form a combined head within a specified accuracy. In the present embodiment, the four liquid discharge heads 22K, 22C, 22M, and 22Y are connected. The through holes formed at both ends of the base plates 22Kb, 22Cb, 22Mb, and 22Yb to which the discharge chips (not shown) on which the nozzle rows are formed are bonded are arranged on the same axis, and the two shafts 50 are penetrated. The assembly head is configured by fixing with the stopper 52. The nozzle rows 22Kn, 22Cn, 22Mn, and 22Yn of the respective liquid discharge heads are positioned with high accuracy with respect to each other by a separately prepared assembled head forming jig.

  Nowadays, there is an increasing demand for ultra-miniaturization of the recording apparatus, that is, space saving of the installation area. Therefore, in the case where the above-described assembled head is mounted on the recording apparatus, it is important to reduce the size of the liquid discharge head alone, particularly to reduce the thickness of the liquid discharge head to reduce the pitch between the liquid discharge heads. It becomes. In this embodiment, the thickness of the single unit of the liquid discharge head formed into a plate shape while satisfying the liquid supply performance and the bubble removing function by adopting the above-described assembled head form and further having the configuration of the head described later (FIG. 2). (Dimension in the left-right direction in (b)) can be 10.5 mm. The plurality of discharge ports of each liquid discharge head are provided at the end of the plate-shaped liquid discharge head.

  FIG. 3 is a diagram schematically illustrating a liquid supply system and a recovery system from the liquid tank 28 to the liquid ejection head 22 in the recording apparatus of the present embodiment. Since each liquid discharge head has the same structure, only the liquid discharge head 22K for black ink will be described below as an example.

  The recording apparatus 100 includes a liquid discharge head 22, a liquid tank 28 that is detachable from the main body, a liquid flow path 40 that connects the liquid tank 28 and the liquid discharge head 22, and air that communicates with the liquid flow path 40 through the liquid discharge head. A flow path 41 and a pump 42 provided in the air flow path 41 are provided. When the pump 42 is driven to depressurize the air flow path 41 and the liquid discharge head 22, the liquid is supplied into the liquid discharge head 22 from the liquid tank 28 via the liquid flow path 40. The liquid discharge head 22 is provided with a supply filter 18, and the liquid supplied to the liquid discharge head 22 flows into the main liquid supply chamber 26 through the supply filter 18. The liquid in the main liquid supply chamber 26 is eventually supplied and discharged into the nozzle. Details of the liquid supply system in the liquid discharge head will be described later.

  A liquid level detection sensor 21 is attached to a part of the main liquid supply chamber 26, and liquid supply is controlled based on the measurement result. That is, when it is determined that the liquid level in the main liquid supply chamber 26 is below a certain level, the pump 42 is driven to suck the liquid from the liquid tank 28. Then, when the sucked liquid is detected by the liquid level detection sensor 21 to be above a certain level, the pump 42 is stopped and the supply of the liquid is stopped.

  On the other hand, the pump 44 is used for a cleaning operation for each liquid discharge head to stably discharge liquid. The cleaning operation is an operation of removing fine bubbles and dust remaining in the nozzle and filling the nozzle with a liquid. A recovery cap 43 (hereinafter also referred to as a cap) is provided opposite to the liquid discharge head discharge port surface, and there is a recovery flow path 49 that connects the cap 43 and the pump 44. A waste liquid tank 46 for storing waste liquid generated by the cleaning operation is connected to the side of the recovery flow path 49 opposite to the side where the cap 43 is connected.

  At the time of cleaning, the cap 43 is abutted so as to seal the discharge port surface of the liquid discharge head. Thereafter, by driving the pump 44, the inside of the cap 43 and the recovery flow path 49 are depressurized, and residual bubbles and dust are sucked from the nozzle surface of the liquid discharge head 22 together with a small amount of liquid. The sucked liquid or bubbles are guided to the waste liquid tank 46.

  4A is a front view for explaining a structural example of the liquid ejection head of the present embodiment, FIG. 4B is a cross-sectional view taken along a front view AA, and FIG. It is sectional drawing which follows the front view BB line. For convenience of explanation, the liquid supply case cover is omitted from the front view. 4A is the same as the vertical positional relationship when the liquid discharge head 22 is incorporated in the recording apparatus 100. In FIG.

  In these drawings, a ceramic base plate 10 supports a heater substrate 11 formed of silicon. The heater substrate 11 has a plurality of electrothermal transducers (heaters or energy generators) as liquid discharge energy generating elements and a plurality of flow path walls for constituting nozzles corresponding to these electrothermal transducers. Is formed. A plurality of nozzles are arranged in the longitudinal direction of the liquid discharge head 22 formed into a plate shape (the left-right direction in FIG. 4A), and the plurality of nozzles are referred to as nozzle rows. The heater substrate 11 is also formed with a liquid chamber frame surrounding the common liquid chamber 12 communicating with each nozzle. A top plate 13 forming the common liquid chamber 12 is joined on the side wall of the nozzle and the liquid chamber frame formed in this manner. Therefore, the heater substrate 11 and the top plate 13 are laminated and bonded to the base plate 10 in an integrated state. Such lamination adhesion is performed with an adhesive having good thermal conductivity such as silver paste. A mounted PCB (electric wiring board) 14 is supported on the base plate 10 by a double-sided tape (not shown) behind the heater substrate 11 in the base plate 10. Each discharge energy generating element on the heater substrate 11 and the PCB 14 are electrically connected by wire bonding corresponding to each wiring.

  A liquid supply member 15 is joined to the top surface of the top plate 13. The liquid supply member 15 includes a liquid supply case 16 (first case) and a liquid supply case cover 17 (second case). The liquid supply case cover 17 closes the upper surface of the liquid supply case 16 and will be described later. A liquid chamber and a liquid supply path are formed, and the liquid discharge head 22 is formed into a plate shape. In the present embodiment, the liquid supply case 16 and the liquid supply case cover 17 are joined by a thermosetting adhesive. The liquid supply case 16 is provided with a supply filter 18 and a discharge filter 19. The supply filter 18 aims to remove foreign substances in the liquid supplied to the liquid supply member 15, and the discharge filter 19 aims to prevent foreign substances from entering from the outside of the liquid discharge head. Each filter is fixed to the liquid supply case 16 by heat welding. Further, a part of the liquid supply case 16 is formed with a gas-liquid separator 20 as a space for separating the liquid flowing into the main liquid supply chamber 26 and the air, and protrudes from the outside in a form protruding to the gas-liquid separator 20. A liquid level detection sensor 21 is mounted, and controls the amount of liquid in the liquid chamber as described above.

  Here, the configuration of the liquid chamber, the liquid supply path, and the like formed by fitting the two parts of the liquid supply case and the 16 liquid supply case cover 17 will be described. A rectangular opening (hereinafter referred to as a liquid supply port 27) is formed on the joint surface of the liquid supply case 16 with the top plate 13 and substantially parallel to the nozzle arrangement direction and across the width of the nozzle row. A storage chamber-like main liquid supply chamber 26 is formed on the extension of the liquid supply port 27. That is, the main liquid supply chamber 26 is formed substantially parallel to the nozzle row and across the width of the nozzle row. Further, the liquid supply port 27 and the upper top surface form an inclination (hereinafter referred to as a main liquid supply chamber inclination 29) with the gas-liquid separation unit 20 as the uppermost portion over almost the entire area. Two openings are formed in the main liquid supply chamber slope 29, one being a liquid communication portion 31 that is an ink supply path to the main liquid supply chamber 26, and the other being a gas-liquid separation portion 20.

  The gas-liquid separator 20 forms a part of the main liquid supply chamber 26 and has a depth larger than the other parts of the main liquid supply chamber 26. This is to enhance the effect of breaking bubbles that are mixed in the liquid in the liquid chamber, as will be described later. In the present embodiment, three stainless steel electrodes are mounted inside the gas-liquid separator 20, and are the upper limit detection electrode 23, the ground electrode 24, and the lower limit electrode 25 from the left side in the figure. The liquid level in the main liquid supply chamber 26 is maintained between the upper limit and the lower limit by energization between the ground electrode 24 and the upper limit detection electrode 23 and energization between the ground electrode 24 and the lower limit detection electrode 25. In the liquid discharge head of this embodiment, the detection reliability can be improved by detecting the liquid level of the liquid that has undergone gas-liquid separation.

  On the extension of the gas-liquid separation unit 20, there is an air communication unit 30, and the tip is an air flow path (air chamber) 41. Further, the above-described discharge filter 19 is disposed and communicates with the discharge joint 33. The discharge filter 19 is made of a material having water repellency. Even if a liquid flows into the air flow path 41 and ink adheres to the discharge filter 19, even if an ink meniscus is formed inside the filter, The capillary force of the filter part can be reduced by water repellency, and the ink meniscus can be easily removed.

  On the other hand, a liquid supply path 37 is provided via a liquid communication portion 31 provided in the main liquid supply chamber inclined portion 29. The liquid supply path 37 has a tubular shape from the liquid communication portion 31 to the vicinity of the supply filter 18 and is formed on substantially the same plane as the main liquid supply chamber 26. The supply filter 18 is also disposed on substantially the same plane as the main liquid supply chamber 26. The supply filter 18 is disposed so as to separate the sub liquid supply chamber into two chambers, and the chamber on the side communicating with the supply joint 32, that is, the upstream chamber in the liquid supply flow in the liquid discharge head is the first liquid supply. The chamber 34 and the downstream side are the second liquid supply chamber 35.

  The second liquid supply chamber 35 has an opening above the supply filter 18 (hereinafter referred to as a second liquid supply chamber opening 36), and communicates with the liquid supply path 37 through this. In addition, the top surface of the second liquid supply chamber 35 is formed with a slope (hereinafter referred to as a second liquid supply chamber slope 38) with this opening as the uppermost portion (the portion farthest from the supply filter). In other words, the supply filter 18 is disposed between the discharge port of each nozzle row and the second liquid supply chamber opening 36. Similarly, the supply filter 18 is disposed between the discharge port of each nozzle row and the second liquid supply chamber inclination 38.

  As described above, the main liquid supply chamber 26, the gas-liquid separation unit 20, the liquid supply path 37, and the supply filter 18 are each set on a plane that intersects with the nozzle arrangement surface 39 (this plane is referred to as plane A). The On the other hand, as shown in the AA cross section, the main liquid supply chamber 26, the liquid supply path 27, the supply filter 18, and the gas-liquid separator 20 overlap each other in the direction intersecting the plane A (the thickness direction of the liquid discharge head 22). It is important to arrange so that it does not become. The reason will be described below.

  In a liquid discharge head capable of high-speed recording, it is important that the liquid flows without stagnation in the liquid discharge head, and it is necessary to design the liquid chamber and the supply path so that the flow resistance does not become excessive. In addition, it is necessary to avoid bubbles remaining in the liquid chamber and the supply path. Therefore, it is necessary to reduce the pressure loss in the liquid discharge head and facilitate the movement of the bubbles by increasing the cross-sectional area of the main liquid supply chamber and the supply path with respect to the liquid flow. Furthermore, in order to enable high-speed recording, it is effective to increase the area of a filter that causes an increase in flow path resistance in the liquid discharge head. From the above viewpoint, in this embodiment, the liquid chamber thickness is 2.2 mm or more and the filter area is equivalent to φ14 by calculating the flow path resistance in the liquid discharge head and confirming the behavior of bubbles.

  In the development of a liquid discharge head capable of such high-speed recording, in recent years, there has been a demand for further downsizing of the liquid discharge head in response to a demand for ultra-miniaturization of the recording apparatus. In particular, when a plurality of liquid discharge heads are arranged in parallel and incorporated in a recording apparatus, it is an important issue to make each liquid discharge head thin. Therefore, in order to achieve both high-speed recording and thinning, in the liquid ejection head of this embodiment, the main liquid supply chamber 26, the gas-liquid separation unit 20, the liquid supply path 37, the supply filter 18, the first liquid supply chamber 34, the first The two liquid supply chambers 35 are each set on a plane (plane A) intersecting with the nozzle arrangement surface 39. The main liquid supply chamber 26, the liquid supply path 37, the supply filter 18, and the gas-liquid separator 20 are arranged so as not to overlap each other in the direction intersecting the plane A (thickness direction of the liquid discharge head 22).

  Further, in the liquid discharge head of this embodiment, the PCB 14 is disposed adjacent to the liquid supply member 15 in which the liquid chamber and the supply path are formed in the thickness direction of the liquid discharge head 22. As shown in the A-A cross section, the PCB 14 is formed so as to overlap and adjoin the main liquid supply chamber 26 with respect to the direction intersecting the plane A, while the PCB 14 is the first liquid supply chamber. 34 and the gas-liquid separator 20 are arranged so as not to overlap each other in the direction intersecting the plane A, and are stored in a non-adjacent region. As described above, the gas-liquid separation unit 20 is set to be thicker than the main liquid supply chamber 26 in order to break bubbles, and the first liquid supply chamber 34 and the second liquid supply chamber 35 in which the supply filter 18 is interposed. The direction that intersects the plane A also increases (thickness increases). Therefore, in order to suppress the thickness of the entire liquid discharge head, the PCB 14 is not overlapped with the first liquid supply chamber 34 and the gas-liquid separator 20 in the direction intersecting the plane A, and the main liquid supply chamber 26 is not overlapped. It is effective to form a laminate so that at least a part of the layers overlap each other in the direction intersecting the plane A.

  Next, the function of the liquid ejection head in the present embodiment will be described along the flow of the liquid with reference to FIG. By the suction operation by the pump described in FIG. 3, the inside of the liquid discharge head 22 reaches a negative pressure via the discharge joint 33. Then, the liquid is supplied from the liquid tank to the first liquid supply chamber 34 through the supply joint 32 of the liquid discharge head. The liquid in the first liquid supply chamber 34 passes through the supply filter 18 and fills the second liquid supply chamber 35. At this time, the air in the second liquid supply chamber 35 moves upward as the liquid flows in. When the upper end of the liquid and air supply filter 18 is exceeded, the liquid and air supply filter 18 is guided toward the liquid supply path 37 along the second liquid supply chamber slope 38. That is, when the liquid is supplied to the liquid supply path 37, the second liquid supply chamber 35 is filled with the liquid. The liquid and air supplied to the liquid supply path 37 eventually flow out to the main liquid supply chamber 26. Thus, since the second liquid supply chamber inclination 38 is configured, even if air flows into the second liquid supply chamber 35, the air is pushed by the inflowing liquid, and the air is reliably transferred to the main liquid. It is possible to flow into the supply chamber 26. The air flowing into the main liquid supply chamber 26 moves upward as the liquid is supplied, and is eventually guided to the gas-liquid separation unit 20 along the main liquid supply chamber slope 29. When a bubble in which liquid and air are mixed reaches the gas-liquid separation unit 20, the bubble disappears because the thickness of the liquid chamber is deep. When the supply of liquid further proceeds, the liquid level detection sensor 21 installed in the gas-liquid separation unit 20 determines that the amount of liquid in the main liquid supply chamber 26 has reached the upper limit. At that time, the suction operation of the pump is stopped and the supply of liquid is stopped.

  Next, the flow of liquid in the liquid discharge head and the behavior of bubbles during the recording operation and the function of the liquid discharge head will be described. During recording, liquid droplets are ejected from the ejection surface using the liquid in the nozzle, but the internal pressure in the liquid ejection head decreases due to the ejection, and the liquid is replenished from the liquid tank by capillary action in the nozzle (hereinafter referred to as the following). Called refill). At this time, the refill performance is determined by the flow path resistance until the liquid reaches the nozzle from the liquid tank to the liquid flow path, the supply chamber, the supply filter, the liquid chamber, the common liquid chamber, and the like. In particular, the pressure loss of the supply filter 18 is dominant, but in the present embodiment, the supply filter 18 is arranged so as to be set to a large area, so that high-speed recording is possible. Further, as can be seen from the BB cross section, the liquid is supplied substantially linearly from the main liquid supply chamber 26 to the liquid supply port 27, the common liquid chamber 12, and the nozzle over the entire nozzle row. The liquid is smoothly supplied toward the nozzle.

  By the way, the liquid discharge head according to the present embodiment requires heat generation energy for liquid discharge. That is, the liquid is foamed by the thermal energy generated by the electrothermal transducer on the heater substrate, and the liquid is discharged from the nozzle using the foaming energy. For this reason, when the recording operation is continued for a long time, thermal energy is accumulated in the liquid, and the temperature of the liquid rises, and there is a possibility that the gas dissolved in the liquid accumulates in the liquid ejection head. Unless the bubbles in the liquid discharge head are removed, the liquid cannot be discharged properly. Therefore, with the configuration of the liquid discharge head of the present embodiment, bubbles generated in the liquid discharge head can be efficiently removed. Note that the discharge energy generating means for discharging the liquid is not limited to the configuration using the electrothermal transducer, and is arbitrary. For example, the configuration may be such that the liquid is discharged using a piezo element or the like.

  The liquid discharge head in the present embodiment is configured to communicate substantially linearly from the nozzles to the common liquid chamber 12 and the main liquid supply chamber 26 over the entire nozzle row. Therefore, even if air bubbles remain in the nozzle, the air bubbles are removed from the nozzle by the buoyancy of the air bubbles themselves and guided to the main liquid supply chamber 26. Further, the air bubbles guided to the main liquid supply chamber 26 move along the main liquid supply chamber inclination 29 and disappear when they reach the gas-liquid separator 20. Therefore, bubbles do not hinder the smooth supply of liquid. That is, a stable recording operation for a long time is possible.

  Thus, in the liquid discharge head, the main liquid supply chamber 26, the gas-liquid separation unit 20, the liquid supply path 37, the supply filter 18, the first liquid supply chamber 34, and the second liquid supply chamber 35 are respectively connected to the nozzle array surface 39. It is set on a substantially parallel plane (plane A). The main liquid supply chamber 26, the liquid supply path 37, the supply filter 18, and the gas-liquid separator 20 are arranged so as not to overlap each other in the direction intersecting the plane A. By having the configuration of the liquid discharge head in this way, the liquid supply speed to the nozzles in the liquid discharge head can be increased, bubbles in the liquid discharge head can be efficiently removed, and the liquid discharge head can be downsized. In particular, it is possible to improve the thinning.

12 Common liquid chamber 14 PCB
DESCRIPTION OF SYMBOLS 18 Supply filter 20 Gas-liquid separation part 22 Liquid discharge head 26 Main liquid supply chamber 27 Liquid supply port 34 First liquid supply chamber 35 Second liquid supply chamber 37 Liquid supply path 39 Nozzle arrangement surface

Claims (7)

A nozzle array composed of a plurality of nozzles each communicating with a plurality of ejection openings for ejecting liquid;
A main liquid supply chamber for supplying liquid to the nozzle;
A liquid supply path that communicates with the main liquid supply chamber and supplies liquid to the main liquid supply chamber;
A sub liquid supply chamber that communicates with the liquid supply path and supplies a liquid to the main liquid supply chamber via the liquid supply path;
A supply filter arranged to separate the sub liquid supply chamber into a first liquid supply chamber and a second liquid supply chamber from the upstream side in the liquid flow direction;
A gas-liquid separation unit provided in the main liquid supply chamber, as a space for separating the liquid flowing into the main liquid supply chamber and air;
An air chamber communicating with the gas-liquid separator,
The main liquid supply chamber has an inclined surface that forms an inclination in which the gas-liquid separation unit is a portion farthest from the plurality of discharge ports,
The second liquid supply chamber has a second liquid supply chamber opening communicating with the liquid supply path, and the supply filter is disposed between the plurality of discharge ports and the second liquid supply chamber opening. A liquid discharge head characterized by the above.   2. The liquid discharge head according to claim 1, wherein the second liquid supply chamber has an inclined surface that forms an inclination in which a portion farthest from the supply filter is an opening of the second liquid supply chamber.   3. The liquid discharge head according to claim 1, wherein the inclination of the main liquid supply chamber is formed over an entire area on an extension of an opening communicating with the plurality of nozzles. The main liquid supply chamber, the liquid supply path, the sub liquid supply chamber, the gas-liquid separator, and the air chamber are configured by a plate-shaped case, and the plurality of discharge ports are formed in the plate shape. Configured at the end of the case
An energy generation unit disposed to correspond to each of the nozzles and generating energy for discharging the liquid; and an electrical wiring board electrically connected, the electrical wiring board comprising: The liquid discharge according to any one of claims 1 to 3, wherein the supply filter, the gas-liquid separator, and the plate-like case are arranged so as not to overlap each other in the thickness direction. head.   The liquid discharge head according to claim 4, wherein the case includes two parts, a first case and a second case that closes the first case.   6. The liquid discharge head according to claim 1, further comprising an electrothermal converter that generates thermal energy for discharging the liquid from the nozzle. 7.   A liquid discharge recording apparatus comprising the liquid discharge head according to any one of claims 1 to 6.

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