JP2011201231A - Recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for attaining the compactification of a liquid circulatory system.SOLUTION: A storage portion 62 having a supply storage portion for storing ink on the upstream side of a head 61 and a recovery storage portion for storing ink on the downstream side of the head 61 is arranged above the head 61 for discharging ink droplets from a discharge port to the base material. A flow path portion 63 on which an introduction flow path for introducing liquid from the supply storage portion to the head 61 and a deriving flow path for deriving liquid from the head 61 to the collection storage portion is arranged between the storage portion 62 and the head 61.

Description

  The present invention relates to a recording apparatus that records an image or the like on a recording material by ejecting liquid droplets toward the recording material from an ejection port.

  2. Description of the Related Art Conventionally, there is known an ink jet recording apparatus that performs printing on a recording material by scanning a recording material with a head on which a plurality of ejection openings for discharging minute ink droplets are arranged. .

  Incidentally, some ink jet recording apparatuses supply ink to the head while circulating the ink between the storage section for storing ink and the head (see Patent Document 1). Such a circulation system is useful in that a head equipped with a self-recovery function can be used or that white ink can be prevented from settling.

JP 2009-285838 A

  By the way, the total amount of ink in the entire system (hereinafter referred to as “circulation system”) including the head, the reservoir for storing ink, and the ink circulation path between the reservoir and the head may be as small as possible. preferable. When the amount of ink retained in the circulation system increases, the time for which the ink is retained in the circulation system also becomes longer. Therefore, the temperature of the circulated ink is adjusted to a predetermined temperature so that the viscosity can be easily discharged. This is because the ink quality is deteriorated by keeping the temperature-controlled ink in the circulation system for a long time in this state (preheating). This effect is particularly serious when UV ink is used.

  Further, when the circulation path is lengthened, the pressure loss generated there increases and the fluctuation of the pressure loss also increases. Therefore, there also arises a problem that a stable meniscus pressure cannot be formed on the head. The meniscus pressure refers to the pressure of ink at the ejection port when the ink meniscus is formed in the ejection port of the head. In order to suppress the fluctuation of the pressure loss, for example, a measure of suppressing the pressure loss of the ink by increasing the flow path diameter of the circulation path can be considered. The whole handling becomes difficult.

  In order to improve these problems, a technique for making the circulatory system as compact as possible has been demanded.

  The present invention has been made in view of the above problems, and an object thereof is to provide a technique capable of realizing a compact circulation system.

  According to the first aspect of the present invention, there is provided a discharge head that discharges liquid droplets from the discharge port, a first storage section that stores liquid, a second storage section that stores liquid, and the first storage section to the discharge head. A first flow path for introducing a liquid, a second flow path for deriving the liquid from the ejection head to the second reservoir, and a liquid feed for feeding the liquid from the second reservoir to the first reservoir. A head unit having a means therein, a pressure adjusting means which is provided outside the head unit and adjusts the pressure inside the second reservoir relative to the pressure inside the first reservoir, and the head unit In the middle of the circulation path formed by the first storage section, the first flow path, the discharge head, the second flow path, the second storage section, and the liquid feeding means. Replenishment means for replenishing liquid from the outside; While supporting the recording material to the head and a position opposed to and a moving means for relatively moving the recording material with respect to the discharge head.

  According to a second aspect of the present invention, in the recording apparatus according to the first aspect, in the head unit, a head layer including the ejection head, a flow path layer including the first flow path and the second flow path, The first reservoir and the reservoir including the second reservoir are stacked.

  According to a third aspect of the present invention, in the recording apparatus according to the second aspect, the flow path layer has a flow path portion that is a block body in which the first flow path and the second flow path are formed, The reservoir is formed with the first reservoir and the second reservoir, and is formed with a first through hole communicating with the first reservoir and a second through hole communicating with the second reservoir. A storage section that is a block body, the first flow path and the first storage section communicate with each other through the first through-hole, and the second flow path and the second storage section are The flow path part and the storage part are brought into contact with each other so as to communicate with each other through two through holes.

  According to a fourth aspect of the present invention, in the recording apparatus according to the third aspect, the flow path portion includes a plurality of through holes formed so as to penetrate vertically, each of the plurality of through holes being the first It functions as one flow path or the second flow path.

  According to a fifth aspect of the present invention, in the recording apparatus according to the fourth aspect, the ejection heads are arranged in a staggered manner along the first direction, and a plurality of the ejection heads are arranged along the first direction on the respective lower surfaces. A plurality of heads each having a discharge port are provided, and in the storage section, the two storage sections of the first storage section and the second storage section are juxtaposed along a second direction orthogonal to the first direction. A flow path that connects the storage portion and the head at the same position in the second direction among the two storage portions and the plurality of heads among the plurality of through holes. In which the cross-section is formed in a circular shape, and the flow connecting the storage portion and the head at the position shifted in the second direction among the two storage portions and the plurality of heads. What functions as a road has a cross section along the second direction It is formed in a Vita shape.

  According to a sixth aspect of the present invention, in the recording apparatus according to any one of the first to fourth aspects, the discharge head includes a plurality of heads each having a plurality of discharge ports formed on a lower surface thereof.

  According to a seventh aspect of the present invention, in the recording apparatus according to the sixth aspect, the plurality of heads are arranged in a staggered manner.

  According to an eighth aspect of the present invention, in the recording apparatus according to any one of the first to seventh aspects, a plurality of the head units are provided, and different types of liquid circulation paths are formed inside each of the plurality of head units. The plurality of head units are arranged in parallel along the direction in which the ejection head is moved relative to the recording material.

  According to a ninth aspect of the present invention, in the recording apparatus according to any one of the first to eighth aspects, the pressure adjusting means includes an air buffer that forms a gas reservoir therein, and an air buffer that adjusts the pressure in the air buffer. A plurality of pressure adjustment units each including a pressure adjustment means, and electrically connecting the air buffer included in the first pressure adjustment unit among the plurality of pressure adjustment units and the first storage unit; The pressure in the second reservoir is adjusted by adjusting the pressure in the reservoir and electrically connecting the air buffer provided in the second pressure regulator unit of the plurality of pressure regulator units and the second reservoir. Adjust.

  According to a tenth aspect of the present invention, in the recording apparatus according to any one of the first to eighth aspects, the pressure adjusting means includes an air buffer that forms a gas reservoir therein, and an air buffer that adjusts the pressure in the air buffer. A pressure adjusting unit including a pressure adjusting unit, and electrically connecting the air buffer and the second storage unit to adjust a pressure in the second storage unit and release the first storage unit to the atmosphere. As a result, the pressure in the first reservoir is set to atmospheric pressure.

  An eleventh aspect of the present invention is the recording apparatus according to the ninth or tenth aspect, wherein the deaeration unit is disposed in the head unit and degasses the gas dissolved in the liquid flowing in the circulation path, A deaeration negative pressure generating unit that is disposed outside the head unit and applies a negative pressure to the deaeration unit, wherein the air buffer pressure adjusting unit generates a negative pressure generated by the deaeration negative pressure generation unit. Utilizing this, the pressure in the air buffer is adjusted.

  A twelfth aspect of the present invention is the recording apparatus according to any one of the first to tenth aspects, wherein the deaeration unit is disposed in the head unit and degasses a gas dissolved in a liquid flowing in the circulation path. And a degassing negative pressure generating means that is arranged outside the head unit and applies a negative pressure to the degassing part.

  The invention of claim 13 is the recording apparatus according to claim 11 or 12, wherein the liquid feeding means includes a plurality of circulation pipes each connecting the first storage section and the second storage section, The deaeration unit is provided in any one of the plurality of circulation pipes, and degassed gas dissolved in the liquid flowing through the circulation pipes.

  A fourteenth aspect of the present invention is the recording apparatus according to any one of the first to thirteenth aspects, wherein the liquid replenished by the replenishing means and the heat of the ejection head are absorbed when circulating through the ejection head. By mixing the liquid whose temperature has increased, the liquid discharged from the discharge head is preheated.

  A fifteenth aspect of the present invention is the recording apparatus according to the fourteenth aspect, wherein at least one of the first reservoir and the second reservoir is connected to a flow path between the ejection head and the main reservoir. A storage section and a buffer storage section connected to the main storage section, guides the liquid replenished by the replenishing means to the buffer storage section, and heats the discharge head when circulating the discharge head The liquid whose temperature has been increased by absorbing the liquid is guided to the buffer reservoir, and the liquid is mixed in the buffer reservoir to preheat the liquid ejected from the ejection head.

  According to a sixteenth aspect of the present invention, in the recording apparatus according to the fourteenth aspect, the replenishing means includes a liquid in the middle of a pipe that forms a flow path for the liquid fed from the second reservoir to the first reservoir. The liquid that is replenished by the replenishing means and the liquid that has risen in temperature by absorbing the heat of the discharge head when circulating through the discharge head are mixed in the pipe, thereby discharging the discharge. Preheating of the liquid discharged from the head is performed.

  According to a seventeenth aspect of the present invention, in the recording apparatus according to the fourteenth aspect, the replenishing unit replenishes the second reservoir with liquid, and circulates between the liquid replenished by the replenishing unit and the ejection head. In addition, the liquid heated by absorbing the heat of the discharge head is mixed with the liquid in the second reservoir, thereby preheating the liquid discharged from the discharge head.

  According to the first aspect of the present invention, the discharge head, the first storage section, the second storage section, the first flow path, the second flow path, and the liquid feeding means are provided inside the head unit, and the pressure adjusting means and The replenishing means is provided outside the head unit. According to this configuration, the circulatory system can be made compact by unitizing appropriate components of the circulatory system.

  According to the third aspect of the present invention, both the flow path portion and the storage portion are constituted by the block bodies, and these are in contact with each other and arranged in a stacked manner. According to this configuration, the circulation path can be shortened.

  According to invention of Claim 4, a 1st flow path and a 2nd flow path are comprised by the through-hole formed in the flow-path part which is a block body. According to this configuration, it becomes easy to ensure a sufficient thickness of each flow path. By sufficiently securing the thickness of each flow path, the pressure loss generated in the flow path can be reduced.

  According to the fifth aspect of the present invention, each of the plurality of heads arranged in a staggered manner along the first direction and the two storage portions juxtaposed along the second direction orthogonal to the first direction are provided. The connecting flow path can be appropriately configured with a simple configuration.

  According to the eighth aspect of the present invention, different types of liquid circulation paths are formed inside each of the plurality of head units arranged in parallel. According to this configuration, the order of the liquid ejected to the recording material can be changed simply by changing the arrangement order of the head units.

  According to invention of Claim 9, each pressure in a 1st storage part and a 2nd storage part is adjusted by making it connect with the air buffer by which the internal pressure was adjusted. According to this structure, even if the capacity | capacitance of each storage part of a 1st storage part and a 2nd storage part is small, these internal pressures can be adjusted stably. That is, the capacity | capacitance of each storage part can be made small, stabilizing the internal pressure. Thereby, the unit size of the head unit can be reduced. In particular, in order to stabilize the pressure in each reservoir, it is necessary to increase the capacity of the air buffer to some extent. However, since the air buffer is provided outside the head unit, the required capacity of the air buffer is sufficient. Even if secured, the size of the head unit does not increase.

  According to the invention described in claim 10, since the pressure of the second reservoir is adjusted by connecting with the air buffer whose internal pressure is adjusted, the internal pressure of the second reservoir is small even if the capacity of the second reservoir is small. Can be adjusted stably. On the other hand, since the pressure of the first reservoir is made atmospheric by connecting it to the atmospheric space, no pressure fluctuations inside the first reservoir occur at all. Therefore, in other words, the capacity of each storage part of the first storage part and the second storage part can be reduced while the internal pressure is stabilized. Thereby, the unit size of the head unit can be reduced. In particular, in order to stabilize the pressure in the second reservoir, it is necessary to increase the capacity of the air buffer to some extent. However, since the air buffer is provided outside the head unit, the required capacity of the air buffer is sufficient. However, the size of the head unit does not increase.

  According to the eleventh aspect of the present invention, since the degassing part for degassing the gas dissolved in the liquid flowing in the circulation path is provided, the generation of bubbles in the liquid is suppressed. Further, since the air buffer pressure adjusting means adjusts the pressure in the air buffer using the negative pressure formed by the deaeration negative pressure generating means for applying a negative pressure to the deaeration part, the pressure in each air buffer is adjusted. It can always be kept stable. Further, since the deaeration negative pressure generating means is provided outside the head unit, the size of the head unit does not increase.

  According to invention of Claim 12, since the deaeration part which deaerates the gas melt | dissolved in the liquid which flows through the circulation path is provided, it is suppressed that a bubble generate | occur | produces in a liquid. Further, since the degassing negative pressure generating means for applying a negative pressure to the degassing part is provided outside the head unit, the size of the head unit is not increased.

  According to the invention described in claim 13, a plurality of circulation pipes for connecting the first storage part and the second storage part are provided, and a deaeration part is provided in any of them. According to this structure, the deaeration part does not need to deaerate the whole quantity of the circulated liquid. Therefore, it is possible to mount a small deaeration unit, and the head unit can be miniaturized.

  According to the fourteenth aspect of the invention, preheating of the liquid ejected from the ejection head is performed using the temperature rise of the liquid that has absorbed the heat of the ejection head when circulating through the ejection head. Therefore, efficient preheating can be realized.

  According to the fifteenth aspect of the present invention, since the buffer storage section for mixing the liquid is formed separately from the main storage section connected to the flow path between the discharge head, the liquid discharged from the discharge head It is possible to prevent thermal non-uniformity from occurring.

FIG. 2 is a perspective view illustrating an appearance of a recording apparatus. It is a bottom view of a discharge part. It is a bottom view of a head unit. It is a figure which shows the structure of a liquid supply apparatus typically. It is a perspective view which shows the layout in the housing | casing of a head unit. It is a figure which shows typically the positional relationship of each part in a housing | casing. It is sectional drawing in the housing | casing of a head unit. It is sectional drawing in the housing | casing of a head unit. It is sectional drawing in the housing | casing of a head unit. It is a figure which shows typically the structure of the liquid supply apparatus which concerns on 2nd Embodiment. It is a figure which shows typically the structure of the liquid supply apparatus which concerns on 3rd Embodiment. It is a figure which shows typically the structure of the liquid supply apparatus which concerns on 4th Embodiment. It is a perspective view which shows the layout in the housing | casing of the head unit which concerns on 4th Embodiment. It is a figure which shows typically the structure of the liquid supply apparatus which concerns on 5th Embodiment. It is a figure which shows the structure of the supply storage part which concerns on a modification. It is a perspective view which shows the external appearance of the recording device which concerns on a modification.

<A. First Embodiment>
<1. Recording device 1>
<1-1. Overall configuration>
The configuration of the recording apparatus 1 according to the first embodiment of the invention will be described with reference to FIG. FIG. 1 is a perspective view showing the appearance of the recording apparatus 1.

  The recording apparatus 1 is an apparatus that performs color printing by an inkjet method on a recording material (for example, a sheet-like base material 10 having liquid repellency such as a film), and controls the main body 2 and each part of the main body 2. And a control unit 3. The control unit 3 performs various processes on image data to be recorded, drive control of the transport unit 4, and the like.

  The main body 2 includes a transport unit 4 that transports the base material 10 in a predetermined direction (Y direction), and a head 61 that ejects micro droplets of ink toward the base material 10 transported by the transport unit 4 (see FIG. 3). ). Hereinafter, a direction in which the transport unit 4 transports the base material 10 is referred to as a “scanning direction”.

<Transport section 4>
The transport unit 4 includes a plurality of rollers 41 arranged along the Y direction, and base material holding units 42 provided at both ends of the plurality of rollers 41. The base material holding part 42 disposed on the + Y side of the plurality of rollers 41 holds the roll-shaped base material 10 (supply roll) and functions as a base material supply part. The base material holding part 42 disposed on the −Y side of the plurality of rollers 41 holds a roll-shaped base material (winding roll) and functions as a base material winding part. In the following, the “base material 10” refers to a part in the middle of conveyance (that is, a part of the base material 10 on the plurality of rollers 41).

  One of the plurality of rollers 41 is provided with an encoder 43 that detects the moving speed of the base material 10 in the scanning direction, and the control unit 3 is arranged on the −Y side based on the output from the encoder 43. The rotation of the motor of the base material holding part 42 is controlled. As a result, the base material 10 moves at a constant speed in the -Y direction. Further, the control unit 3 controls the rotation of the motor of the base material holding unit 42 arranged on the + Y side, and applies a load toward the + Y direction to the base material 10. Thereby, the base material 10 moves smoothly on the plurality of rollers 41 without undulating.

<Discharge unit 5>
The main body 2 includes a frame 22 that is fixed to the base 21 and arranged so as to straddle a plurality of rollers 41. The discharge unit 5 is fixed to the frame 22 so as to be arranged above the plurality of rollers 41 (+ Z side). The frame 22 is provided with a light source 23. Light from the light source 23 is introduced into the discharge unit 5 through a bundle of optical fibers 24.

  A schematic configuration of the discharge unit 5 will be described with reference to FIGS. 1 and 2. FIG. 2 is a bottom view of the discharge unit 5.

  The discharge unit 5 includes a plurality of (four in FIG. 2) head units 6 fixed to the discharge unit main body 51 and arranged along the Y direction. Each of the plurality of head units 6 ejects different colors of ink. Specifically, the most (+ Y) side head unit 6 ejects K (black) ink. The head unit 6 on the (−Y) side of the K head unit 6 ejects C (cyan) ink. The head unit 6 on the (−Y) side of the C head unit 6 ejects M (magenta) ink. The head unit 6 closest to the (−Y) side discharges Y (yellow) ink. Each color ink contains an ultraviolet curing agent and has ultraviolet curing properties. The discharge unit 5 may further be provided with head units for other colors such as light cyan, light magenta, and white.

  Further, the ejection unit 5 includes a functional unit (liquid supply device 60) for supplying ink to the plurality of heads 61 included in each head unit 6. The liquid supply device 60 will be specifically described later.

  Further, the ejection unit 5 includes a light irradiation unit 52 provided on the −Y side of the plurality of head units 6. In the light irradiation unit 52, the optical fibers 24 connected to the light source 23 are arranged along the X direction, and the region on the line extending in the X direction on the base material 10 is irradiated with ultraviolet rays.

  In the printing apparatus 1, each head unit 6 and the light irradiation unit 52 are provided over the entire printing region on the substrate 10 in the X direction (width direction) perpendicular to the printing direction.

<Head unit 6>
The schematic configuration of each head unit 6 will be described with reference to FIG. FIG. 3 is a bottom view of the head unit 6.

  The head unit 6 includes a plurality of (six in the example of FIG. 3) heads 61 arranged in a staggered manner along the X direction (width direction).

  Each head 61 discharges ink droplets from the discharge ports 611 toward the substrate 10. Specifically, each head 61 is, for example, a piezo drive type head, and a plurality of (for example, about 400 to 1000) ejection ports 611 are provided along the width direction on the lower surface (the surface on the −Z side). Is formed. Each discharge port 611 is provided with a discharge channel for guiding ink toward the discharge port 611, and a drive unit that is a piezoelectric element (piezo element) is provided near the discharge port 611 of the discharge channel. When a discharge signal is applied to the drive unit, the drive unit is deformed, and the volume of the discharge channel near the discharge port 611 (more specifically, the volume of the chamber provided near the discharge port 611 of the discharge channel). Decrease. As a result, pressure is applied to the ink in the vicinity of the ejection port 611 (that is, the ink in the chamber of the ejection channel that guides the ink to the ejection port 611), and the ink droplets are ejected from the ejection port 611. Then, when the shape of the drive unit is restored, the volume of the ejection channel returns to the original in the vicinity of the ejection port 611, and an amount of ink equal to the minute droplets of the ejected ink is supplied to the ejection channel.

<1-2. Overview of printing operations>
When printing is performed by the recording apparatus 1, the control unit 3 controls the transport unit 4 so that the substrate 10 is moved in the printing direction (that is, the Y direction in FIG. In a direction substantially perpendicular to the arrangement direction of the outlets 611. The control unit 3 controls a plurality of drive units of each head 61 of each head unit 6 based on data of an image scheduled to be printed on the substrate 10 in parallel with the movement of the substrate 10. Thus, every time the base material 10 moves by a predetermined distance in the printing direction, fine droplets of ink are ejected from the ejection port 611 and applied onto the base material 10.

  The head 61 is provided over the entire printing region (specifically, the entire width in the width direction of the substrate 10) in the width direction. That is, the discharge ports 611 formed at a constant pitch over the entire print area in the width direction are formed, and a plurality of dots arranged in a line in the width direction are formed on the substrate 10 at each position in the scanning direction. be able to. Therefore, the recording of the image on the base material 10 is completed only by the base material 10 passing under the discharge unit 5 once (so-called one-pass recording).

<2. Liquid Supply Device 50>
As described above, the ejection unit 5 includes a plurality of head units 6, and each head unit 6 includes a plurality of heads 61. The ejection unit 5 includes a functional unit (liquid supply device 60) for supplying ink to the plurality of heads 61 included in each head unit 6.

  In the following description, a configuration in which ink of the color is supplied to the plurality of heads 61 provided in the head unit 6 that ejects one color of the plurality of head units 6 provided in the ejection unit 5 will be described. However, the other head units 6 have the same mechanism. However, a “pressure adjusting mechanism 67” and a “degas pressure adjusting unit 72” to be described later are shared among the plurality of head units 6.

<2-1. Functional configuration>
The functional configuration of the liquid supply device 60 will be described with reference to FIG. FIG. 4 is a diagram illustrating a functional configuration of the liquid supply apparatus 60. In FIG. 4, only one head 61 is shown for easy understanding of the drawing, but the actual head unit 6 includes a plurality of heads 61 as shown in FIG. 3. These circumstances also apply to FIGS. 10, 11, 12, and 14.

  The liquid supply device 60 circulates and supplies ink to the plurality of heads 61. The liquid supply device 60 mainly includes a storage section 62, a flow path section 63, a liquid feeding section 64, a degas mechanism 65, an ink replenishing mechanism 66, and a pressure adjusting mechanism 67.

  Moreover, the control part 600 which controls these each part is provided. Specifically, the control unit 600 controls the pressure adjusting mechanism 67, the degas pressure adjusting unit 72, the first three-way valve 992, the second three-way valve 995, the heat radiating unit 643, and the circulation pump 642.

<Reservoir 62>
The storage unit 62 stores ink near the top of the plurality of heads 61. The storage unit 62 includes two storage units 621 and 622. The first storage section is a supply storage section 621 that stores ink on the upstream side of the plurality of heads 61 and supplies ink to the head 61 via a flow path section 63 described later. The second storage unit is a recovery storage unit 622 that stores ink on the downstream side of the plurality of heads 61 and recovers ink from the head 61 via the flow path unit 63.

  The supply storage unit 621 is provided with a level sensor 6218 that detects the position of the liquid level of the ink stored in the storage unit (that is, the ink level). Similarly, the collection storage unit 622 is also provided with a level sensor 6228 that detects the ink level stored in the storage unit. The level sensors 6218 and 6228 can be constituted by, for example, electrostatic capacitance sensors.

  In addition, the recovery storage unit 622 is provided with a heater 6229. The heater 6229 heats the ink in the collection storage unit 622 to a predetermined temperature (for example, 40 ° C.) (preliminary heating). Thus, the viscosity of the ink supplied to the supply storage unit 621 is adjusted to be lower than that at the normal temperature.

<Flow path part 63>
The flow path part 63 is provided between the storage part 62 and the plurality of heads 61, and forms a flow path of ink between the storage part 62 and the plurality of heads 61. Specifically, the flow path section 63 includes an introduction flow path for introducing ink from the supply storage section 621 to the plurality of heads 61 and a discharge flow path for deriving ink from the plurality of heads 61 to the collection storage section 622. . The configuration of the flow path portion 63 will be described more specifically later.

<Liquid feeding part 64>
The liquid sending unit 64 sends ink from the collection storage unit 622 to the supply storage unit 621. The liquid feeding unit 64 includes a circulation pipe 641 that connects the collection storage part 622 and the supply storage part 621, and a circulation pump 642 provided in the circulation pipe 641. When the circulation pump 642 is driven, the ink in the collection storage unit 622 is returned to the supply storage unit 621 through the circulation pipe 641.

  As described above, the supply storage unit 621 and the collection storage unit 622 are provided with level sensors 6218 and 6228 for detecting the ink level in the storage unit. Circulation pump 642 is controlled based on detection information from level sensors 6218 and 6228. That is, when the level sensor 6228 provided in the collection storage unit 622 detects that the ink level of the collection storage unit 622 is lower than a predetermined set level, the circulation pump 642 is operated at a low speed. On the other hand, when the level sensor 6228 provided in the collection storage unit 622 detects that the ink level of the collection storage unit 622 is higher than a predetermined set level, the circulation pump 642 is operated at a high speed.

  A heat radiating unit 643 is provided in the vicinity of the circulation pipe 641. When the ink passes through the head 61, the ink absorbs heat from a piezo or driver circuit provided in the head 61, and the temperature rises (the piezo and driver circuit are exhausted (cooled) thereby. ). The heat radiating unit 643 is a mechanism for radiating the heat of the ink flowing through the circulation pipe 641.

<Degas mechanism 65>
The degas mechanism 65 is a mechanism for degassing (degas) the dissolved gas in the ink flowing through the circulation pipe 641. The degas mechanism 65 includes a degas unit 71 that is provided in the circulation pipe 641 and degasses (degases) ink flowing in the circulation pipe 641, and a degas pressure adjustment unit 72 that supplies a negative pressure to the degas unit 71.

  The degas unit 71 is configured by a membrane, for example. A membrane is a liquid (ink) that flows inside a hollow fiber membrane with countless fine pores in a negative pressure environment, thereby discharging gas that cannot be dissolved in the liquid to the outside of the hollow fiber membrane. This reduces the amount of gas dissolved in the liquid.

  The degas unit 71 is electrically connected to the degas buffer tank 721 of the degas pressure adjustment unit 72 via the pipe 728. As will be described later, the pressure in the degas buffer tank 721 is adjusted to a pressure P4 corresponding to the negative pressure required by the degas unit 71. Therefore, the negative pressure required for the degas unit 71 is provided by being electrically connected to the degas buffer tank 721. The degas unit 71 uses the negative pressure supplied from the degas pressure adjustment unit 72 to discharge the gas dissolved in the ink flowing through the circulation pipe 641.

  The degas pressure adjustment unit 72 provides a negative pressure to the degas unit 71. The degas pressure adjustment unit 72 includes a degas buffer tank 721 that forms a gas reservoir therein. Further, as a mechanism for adjusting the pressure in the degas buffer tank 721, the degas decompression pump 722, the pipe 723 connecting the degas buffer tank 721 and the decompression pump 722, and the degas buffer tank 721 are external (atmospheric pressure). ) And a pipe 725 that is open to. The pipe 723 is provided with a pressure reducing control electromagnetic valve 724. The piping 725 is provided with a pressurizing control electromagnetic valve 726. Further, the degas buffer tank 721 is provided with a pressure sensor 727 for detecting the internal pressure.

  The degas buffer tank 721 always has a predetermined negative pressure P4 (specifically, a pressure corresponding to the negative pressure required by the degas unit 71) by appropriately controlling the two solenoid valves 724 and 726. For example, about -50 kPa (pascal)).

  That is, when the pressure sensor 727 detects that the pressure in the degas buffer tank 721 is higher than the predetermined pressure P4, the pressure reducing pump 722 is driven and the pressure reducing control electromagnetic valve 724 is opened. Then, the decompression pump 722 exhausts the gas in the degas buffer tank 721, thereby reducing the pressure in the degas buffer tank 721. When the pressure sensor 727 detects that the pressure in the degas buffer tank 721 has decreased to a predetermined pressure P4, the pressure reducing control electromagnetic valve 724 is closed. On the other hand, when the pressure sensor 727 detects that the pressure in the degas buffer tank 721 is smaller than the predetermined pressure P4, the pressurization control electromagnetic valve 726 is opened. Then, the gas flows from the outside by conducting to the outside (atmospheric pressure), and the pressure in the degas buffer tank 721 increases. When the pressure sensor 727 detects that the pressure in the degas buffer tank 721 has increased to a predetermined pressure P4, the pressurization control electromagnetic valve 726 is closed.

<Ink replenishment mechanism 66>
The ink replenishing mechanism 66 is a mechanism that replenishes ink and keeps the total amount of ink in the circulation system constant when the total ink amount in the circulation system decreases due to consumption of ink in the head unit 6. .

  The ink replenishing mechanism 66 includes a main tank 661 that stores ink. The main tank 661 is connected to the supply storage unit 621 through a replenishment line 663 provided with a pump 662. When the pump 662 is driven, the ink in the main tank 661 is supplied to the supply storage unit 621.

  When the level sensor 6218 provided in the supply storage unit 621 detects that the ink level of the supply storage unit 621 has become equal to or lower than a predetermined replenishment start level, the pump 662 is driven and ink from the main tank 661 is discharged. Replenishment (supply) is started. Further, when the level sensor 6218 detects that the ink level in the supply storage unit 621 is equal to or higher than a predetermined replenishment stop level, the pump 662 is stopped and the replenishment of ink from the main tank 661 is stopped. Thereby, the consumed ink is replenished, and the total amount of ink in the circulation system is kept constant.

  As described above, not only the pump 622 but also the circulation pump 642 is controlled based on detection information from the level sensors 6218 and 6228. As a result, the ink levels of the supply storage unit 621 and the collection storage unit 622 are controlled so as to be always at the target positions.

<Pressure adjustment mechanism 67>
The pressure adjustment mechanism 67 is a mechanism for adjusting the pressure in (the gas of) the two storage portions 621 and 622. Specifically, in the circulating state, the pressure in the supply storage unit 621 is adjusted to a pressure P1 (for example, P1 = −0.5 kPa) lower than the atmospheric pressure by a predetermined value. Further, in the circulating state, the pressure in the collection storage unit 622 is set to a pressure P2 that is smaller than the pressure in the supply storage unit 621 by a predetermined value (for example, 4.5 kPa) (in the case of P1 = −0.5 kPa, P2 = − 5 kPa). The meniscus pressure formed in the head 61 depends on both the pressure P2 in the recovery storage unit 622 and the pressure P1 of the supply storage unit 621. The pressure adjustment mechanism 67 appropriately adjusts both the pressures P1 and P2. Thus, an appropriate meniscus pressure can be formed on the head 61. Further, in the circulation stop state, the pressures in the storage units 621 and 622 are both adjusted to a pressure P3 (for example, P3 = −2 kPa) lower than the atmospheric pressure by a predetermined value.

<Pressure adjustment unit 90>
The pressure adjustment mechanism 67 includes three pressure adjustment units 90. The configuration of each pressure adjustment unit 90 and the role of each pressure adjustment unit 90 will be described.

<A. Configuration of Pressure Adjustment Unit 90>
The three pressure adjustment units 90 have the same configuration. That is, each pressure adjustment unit 90 includes a buffer tank 91 that forms a gas reservoir therein. Further, as a mechanism for adjusting the pressure in the buffer tank 91, a decompression pump 92, a pipe 93 connecting the buffer tank 91 and the decompression pump 92, and a pipe 95 for opening the buffer tank 91 to the outside (atmospheric pressure). With. The pipe 93 is provided with a pressure reducing control electromagnetic valve 94. The piping 95 is provided with a pressurizing control electromagnetic valve 96. Further, the buffer tank 91 is provided with a pressure sensor 97 for detecting the pressure inside the buffer tank 91.

  The inside of the buffer tank 91 of each pressure adjustment unit 90 is always set to a predetermined pressure value by appropriately controlling the two electromagnetic valves 94 and 96. That is, when the pressure sensor 97 detects that the pressure in the buffer tank 91 is larger than a predetermined pressure value, the pressure reducing pump 92 is driven and the pressure reducing control electromagnetic valve 94 is opened. Then, the decompression pump 92 exhausts the gas in the buffer tank 91, and thereby the pressure in the buffer tank 91 decreases. When the pressure sensor 97 detects that the pressure in the buffer tank 91 has decreased to a predetermined pressure value, the pressure reducing control electromagnetic valve 94 is closed.

  On the other hand, when the pressure sensor 97 detects that the pressure in the buffer tank 91 is smaller than a predetermined pressure value, the pressurization control electromagnetic valve 96 is opened. Then, the gas flows in from the outside by conducting to the outside (atmospheric pressure), and the pressure in the buffer tank 91 increases. When the pressure sensor 97 detects that the pressure in the buffer tank 91 has increased to a predetermined pressure value, the pressurizing control electromagnetic valve 96 is closed.

<B. Role of each pressure adjustment unit 90>
<First circulation pressure adjustment unit 901>
Of the three pressure adjustment units 90 provided in the pressure adjustment mechanism 67, the first pressure adjustment unit 90 is used to adjust the pressure in the internal space of the supply storage unit 621 in the circulation state (hereinafter referred to as “first circulation pressure adjustment”). Unit 901 ”).

  A buffer tank 91 (hereinafter referred to as “first buffer tank 911”) of the first circulation pressure adjustment unit 901 is connected to a first three-way valve 992 via a pipe 991. However, the first three-way valve 992 is connected to the supply storage unit 621 via the pipe 993.

  The pressure in the first buffer tank 911 is controlled by the two solenoid valves 94 and 96 as appropriate, so that the target pressure (pressure P1 lower than the atmospheric pressure by a predetermined value) in the supply storage unit 621 in a circulating state is obtained. Is done. Therefore, when the first three-way valve 992 connects the supply storage unit 621 and the first buffer tank 911, the inside of the supply storage unit 621 becomes the target pressure P1.

<Second circulation pressure adjustment unit 902>
The second pressure adjustment unit 90 is used to adjust the pressure in the internal space of the collection storage unit 622 in the circulation state (hereinafter referred to as “second circulation pressure adjustment unit 902”).

  The buffer tank 91 (hereinafter referred to as “second buffer tank 912”) of the second circulation pressure adjustment unit 902 is connected to the second three-way valve 995 via the pipe 994. However, the second three-way valve 995 is connected to the collection storage unit 622 via a pipe 996.

  The pressure in the second buffer tank 912 is more predetermined than the target pressure in the collection storage unit 622 in the circulation state (the target pressure P1 in the supply storage unit 621) by appropriately controlling the two electromagnetic valves 94 and 96. The pressure P2) is reduced by a value. Therefore, when the second three-way valve 995 connects the collection and storage unit 622 and the second buffer tank 912 to each other, the inside of the collection and storage unit 622 becomes the target pressure P2.

<Holding pressure adjustment unit 903>
The third pressure adjustment unit 90 is used to adjust the pressure in the internal space of the supply storage unit 621 and the recovery storage unit 622 in the circulation stop state (hereinafter referred to as “holding pressure adjustment unit 903”).

  The buffer tank 91 of the holding pressure adjusting unit 903 (hereinafter referred to as “third buffer tank 913”) is connected to the first three-way valve 992 through the bifurcated branch pipe 997, and the other is connected to the first one. 2 connected to a three-way valve 995.

  The pressure P3 in the third buffer tank 913 is controlled by appropriately controlling the two electromagnetic valves 94 and 96, so that the target pressure in the supply and storage unit 621 and the collection and storage unit 622 in the circulation stop state (predetermined from the atmospheric pressure). The pressure P3) is lower by the value. Accordingly, when the first three-way valve 992 connects the supply storage unit 621 and the third buffer tank 913, and the second three-way valve 995 connects the collection storage unit 622 and the third buffer tank 913, each storage unit 621. , 622 is the target pressure P3.

  As described above, the pressure adjusting mechanism 67 allows each of the storage units 621 and 622 to be electrically connected to the buffer tank 91 adjusted so that the internal pressure becomes a predetermined value. Adjust each pressure. According to this structure, even if each storage part 621,622 is a small thing with the small capacity | capacitance, the internal pressure can be stabilized. That is, when the capacity of the reservoirs 621 and 622 is reduced, the internal pressure is greatly affected by the fluctuation of the ink liquid level and becomes unstable. According to the above configuration, the buffer tank 91 is electrically connected. As a result, the volume of the gas space in each of the reservoirs 621 and 622 is substantially increased, so that the pressure in each of the reservoirs 621 and 621 is not easily affected even if the ink level changes. Therefore, even if the ink liquid levels of the storage portions 621 and 622 fluctuate, the internal pressure can always be stabilized. When the pressure in each reservoir 621 and 622 is stabilized, the amount of circulated ink is stabilized and the meniscus pressure formed in the head 61 is stabilized.

<2-2. Aspect of circulation supply>
A mode in which the liquid supply device 60 circulates and supplies ink to the head 61 will be described with reference to FIG.

<A. During circulation supply>
When the ink circulation supply is started, the control unit 600 switches the first three-way valve 992 to connect the supply storage unit 621 to the first buffer tank 911 and switches the second three-way valve 995 to set the collection storage unit 622. The second buffer tank 912 is electrically connected. However, the inside of the first buffer tank 911 is adjusted to the target pressure P1 in the supply storage unit 621 in the circulating state. Further, the inside of the second buffer tank 912 is adjusted to the target pressure P2 in the collection and storage unit 622 in the circulating state. Therefore, the inside of the supply storage unit 621 that is connected to the first buffer tank 911 is at the pressure P1, and the inside of the collection storage unit 622 that is connected to the second buffer tank 912 is at the pressure P2. Since the target pressure P2 is set to a value lower than the target pressure P1 by a predetermined value, the inside of the collection storage unit 622 is set to a pressure lower than the inside of the supply storage unit 621 by a predetermined value. In a state in which the flow path from the supply storage section 621 to the plurality of heads 61 through the flow path section 63 and from the head 61 to the recovery storage section 622 through the flow path section 63 is filled with ink, Ink flows from the supply reservoir 621 to the collection reservoir 622.

  On the other hand, the control unit 600 starts driving the circulation pump 642 provided in the circulation pipe 641. Then, the ink in the collection storage unit 622 is returned to the supply storage unit 621.

  That is, when the control unit 600 performs each control described above, the supply storage unit 621 passes through the head 61 to reach the recovery storage unit 622, and further from the recovery storage unit 622 to the supply storage unit 621 via the circulation pipe 641. An ink circulation state is formed in the return circulation line.

  As described above, the target pressure P1 in the supply storage unit 621 in the circulating state is set to a value lower than the atmospheric pressure by a predetermined value, but the specific value is a meniscus pressure (to be formed in the head 61 ( It is defined according to the target meniscus pressure. That is, the meniscus pressure of the head 61 in the circulation state is the pressure in the supply storage unit 621 in the circulation state, the pressure in the recovery storage unit 622, and the liquid level of the ink in each of the storage units 621 and 622 and the ejection port 611. The proper meniscus pressure in the discharge port 611 in the circulating state is determined by appropriately controlling the pressure in the supply reservoir 621, as defined by various factors such as the water head difference, the ink flow rate, and the ink viscosity. Can be formed. By forming an appropriate meniscus pressure, the ejection performance of the head 61 is improved. Further, it is possible to prevent bubbles from being mixed into the ink while preventing the ink from leaking from the ejection port 611.

<B. During circulation stop>
When stopping the circulation supply of ink, the control unit 600 switches the first three-way valve 992 to make the supply storage unit 621 and the third buffer tank 913 conductive, and switches the second three-way valve 995 to switch the recovery storage unit 622. The third buffer tank 913 is brought into conduction. However, the inside of the third buffer tank 913 is adjusted to the target pressure P3 in each of the storage units 621 and 622 in the circulation stop state. Then, the inside of the two storage parts 621 and 622 that are electrically connected to the third buffer tank 913 becomes the pressure P3.

  As described above, the target pressure P3 in each of the storage units 621 and 622 in the circulation stopped state is set to a value lower than the atmospheric pressure by a predetermined value, but the specific value should be formed in the head 61. It is defined according to the meniscus pressure (target meniscus pressure). That is, the meniscus pressure of the head 61 in the circulation stopped state is the pressure in the storage units 621 and 622 in the circulation stop state, the water head difference between the ink level in the storage units 621 and 622 and the ejection port 611. As defined by various factors such as, an appropriate meniscus pressure can be formed in the discharge port 611 in the circulation stop state by appropriately controlling the pressure in each of the storage portions 621 and 622. By forming an appropriate meniscus pressure, it is possible to prevent bubbles from entering the ink while preventing the ink from leaking from the ejection port 611.

<3. Layout of head unit 6>
As described above, the ejection unit 5 includes the plurality of head units 6 and the liquid supply device 60 that supplies ink to the plurality of heads 61 included in each head unit 6. Among the functional units included in the liquid supply device 60, the pressure adjustment mechanism 67 and the degas pressure adjustment unit 72 are shared between the plurality of head units 6, but the other functional units are provided for each head unit 6.

  By the way, each head unit 6 includes a housing 60, and a plurality of heads 61 and a liquid supply device 60 that supplies ink to the head 60 are individually provided for each head unit 6 in the housing 60. A part of the functional parts (the storage part 62, the flow path part 63, the liquid feeding part 64, and the degas part 71) is arranged in a predetermined layout. The ink replenishing mechanism 66, the pressure adjusting mechanism 67, and the degas pressure adjusting unit 72 are provided outside the casing 60 of the head unit 6, and are connected to each part disposed inside the casing 60 via a pipe. (See FIG. 1).

  The layout in the housing 60 will be described with reference to FIGS. In the following description, attention is paid to the head unit 6 of one of a plurality of colors, but the other colors have the same configuration.

  FIG. 5 is a perspective view showing a layout in the housing 60 of the head unit 6. FIG. 6 is a diagram for explaining the arrangement of the two storage units 621 and 622. The two storage units 621 and 622 arranged in the housing 60, the flow path unit 63, and a plurality of A positional relationship with the head 61 is schematically shown. 6A is a front view of the inside of the housing 60 viewed from the Y direction, and FIG. 6B is a side view of the inside of the housing 60 viewed from the X direction. FIG. 6B also schematically shows the piping lines connected to the storage portions 621 and 622. FIG. 7 is a cross-sectional view of the inside of the housing 60 of the head unit 6 as viewed from the arrow Ka-Ka in FIG. 6A, and is a cross-sectional view of the storage layer 603. 8 is a cross-sectional view of the inside of the housing 60 of the head unit 6 as viewed from the arrow Kb-Kb of FIG. FIG. 9 is a cross-sectional view of the inside of the housing 60 of the head unit 6 as viewed from the arrow Kc-Kc in FIG.

  Inside the housing 60, a head layer 601, a flow path layer 602, and a reservoir layer 603 are formed in order from the bottom along the vertical direction (Z direction).

<Head layer 601>
A plurality of heads 61 are arranged on the head layer 601. As described above, the plurality of heads 61 are arranged in a staggered manner along the X direction (see FIG. 3). In addition, it is preferable that the bottom surface size of the housing 60 is a minimum size in which a plurality of heads 61 arranged in a staggered manner can be arranged from the viewpoint of miniaturization of the head unit 6. That is, the length (depth) along the Y direction of the housing 60 is set to a length obtained by doubling the length (depth) along the Y direction of the head 61 with a necessary minimum margin. Is preferred (see FIG. 3). The length (width) along the X direction of the housing 60 is the same as the −X side end face of the head 61 arranged at the −X side end portion among the plurality of heads 61 arranged along the X direction. It is preferable that the length is obtained by adding a minimum margin to the distance (arrangement width) from the + X side end surface of the head 61 disposed at the + X side end (see FIG. 3).

<Storage part layer 603>
A reservoir 62 is disposed in the reservoir 603. The storage part 62 includes a main body part 620 configured by a block body. A supply storage unit 621 and a collection storage unit 622 are formed inside the main body 620.

  The formation positions of the two storage portions 621 and 622 in the main body portion 620 will be described with reference to FIGS.

  The two storage parts 621 and 622 are formed so as to be juxtaposed along the Y direction inside the main body part 620. For example, the supply storage part 621 is formed on the −Y direction side, and the collection storage part 622 is formed on the + Y direction side. Moreover, the two storage parts 621 and 622 are configured to have substantially the same size and shape, and are formed at the same position in the X direction and the Z direction.

  In addition, it is preferable that the bottom surface size in each storage part 621,622 is prescribed | regulated according to the bottom surface size of the housing | casing 60. FIG. For example, the length (depth) along the Y direction of each storage unit 62 is the length obtained by subtracting the necessary minimum margin from the half of the depth of the housing 60, and the length along the X direction. Let (width) be a length obtained by subtracting a necessary minimum margin from the width of the housing 60. According to this configuration, it is possible to increase the internal capacity of each of the storage units 621 and 622 while utilizing the limited space in the casing 60 as much as possible.

  The main body 620 is provided with a plurality of through holes (opening holes 6211) that communicate with the bottom surface of the supply storage unit 621. The same number of openings 6211 as the heads 61 included in the head unit 6 are provided, and each opening 6211 is provided at a position corresponding to each head 61. The main body portion 620 is further provided with a plurality of through holes (opening holes 6221) communicating with the bottom surface of the collection storage portion 622. The same number of openings 6221 as the heads 61 included in the head unit 6 are provided, and each opening 6221 is provided at a position corresponding to each head 61.

  Note that a liquid feeding unit 64 (specifically, a circulation pipe 641 and a circulation pump 642), a degas unit 71, and a control panel 610 are arranged on the upper part of the storage unit layer 603. In addition, pipes 993 and 996 that connect the storage units 621 and 622 to the pressure adjusting mechanism 67 and a replenishment line 663 that connects the supply storage unit 621 to the main tank 661 are arranged (FIGS. 5 and 6B). )reference). However, the control panel 610 is a substrate that controls the ejection of ink from each head 61. The control panel 610 also detects the temperature of the head 61.

<Flow path layer 602>
A flow path portion 63 is disposed in the flow path layer 602. The flow path portion 63 includes a main body portion 630 that is a block body. As shown in FIGS. 5 and 6, the body portion 630 of the flow path portion 63 and the body portion 620 of the storage portion 62 are in contact with each other. More specifically, the main body portion 630 of the flow path portion 63 and the main body portion 620 of the storage portion 62 are configured such that an introduction flow path 6301 (described later) formed in the flow path portion 63 and a supply storage portion 621 are opened. In addition to communicating with each other through the holes 6211, the outlet flow path 6302 (described later) and the collection storage unit 622 are in contact with each other so as to communicate with each other through the respective openings 6221. As a result, a laminated structure of the flow path layer 602 and the reservoir layer 603 is formed.

  The configuration of the flow path portion 63 will be specifically described with reference to FIG. A plurality of through-holes 631 are formed in the main body portion 630 along the X direction. The through holes 631 are formed so as to penetrate the main body portion 630 in the vertical direction and extend straight below. The plurality of through holes 631 function as channels for guiding ink.

  As described above, the two reservoirs 621 and 622 provided in the main body 620 of the reservoir 62 are arranged along the Y direction (see FIG. 7). On the other hand, the plurality of heads 61 are arranged in a staggered manner along the X direction (see FIG. 9). According to such circumstances, there are two types of through holes 631 formed in the flow path portion 63 having different shapes. The first is a through-hole 631 having a substantially circular cross section (hereinafter referred to as “circular through-hole 6311”). Second, a groove (hereinafter, referred to as a “long groove 63121”) having a cross-sectional shape extending along the Y direction (specifically, a rectangular shape having a long direction along the Y direction), and a long groove A through hole 631 formed from a circular through hole 63122 formed at the bottom of 6312 (hereinafter referred to as “deformed through hole 6312”).

  Two circular through-holes 6311 and two modified through-holes 6312 are alternately formed along the X direction (however, one deformed through-hole 6312 is formed at both ends), and the adjacent circular through-hole 6311 is deformed. A pair of through-holes 6312 forms a flow path for ink related to one head 61.

  Of the pair of circular through holes 6311 and deformed through holes 6312 associated with each head 61, the circular through hole 6311 constitutes a flow path connecting the storage unit 62 and the head 61 at the same position as the head 61 in the Y direction. To do. On the other hand, the deformed through hole 6312 constitutes a flow path that connects the head 61 and the reservoir 62 located at a position shifted in the Y direction with respect to the head 61.

  For example, in FIG. 9, attention is paid to the head 61 arranged first from the end on the −X direction side. In FIG. 8, the first through hole 631 (deformed through hole 6312) arranged from the end on the −X direction side is paired with the second through hole 631 (circular through hole 6311). The ink flow path related to the head 61 is formed.

  The head 61 currently focused on is arranged on the + Y direction side. In the case of the head 61 arranged on the + Y direction side, of the two through holes 6311 and 6312 related to the head 61, the modified through hole 6312 is a supply storage unit 621 that is a storage unit arranged on the −Y direction side. Functions as a flow path (introduction flow path 6301) for guiding ink from the head to the head 61. Specifically, the deformed through hole 6312 is electrically connected to an opening 6211 formed in the bottom surface of the supply storage unit 621 on the upper end side of the elongated groove 63121, and the ink introduction port of the head 61 on the lower end side of the through hole 63122. By conducting with 611, an introduction flow path 6301 that guides ink from the supply reservoir 621 to the ink introduction port 611 is formed. In addition, the upper end surface of the long groove 63121 is configured to prevent ink from leaking out by contacting with the bottom surface of the main body portion 620 formed of a block body, except for a portion where the upper end surface is electrically connected to the opening 6211.

  On the other hand, of the two through-holes 6311 and 6312 related to the head 61, the circular through-hole 6311 is a flow path (leading out) from the head 61 to the collection storage section 622 which is a storage section arranged in the + Y direction. It functions as a flow path 6302). Specifically, the circular through hole 6311 is electrically connected to the ink outlet port 612 of the head 61 on the lower end side, and is connected to the opening 6221 formed in the bottom surface of the collection storage unit 622 on the upper end side. It functions as a lead-out flow path 6302 that guides ink from 612 to the collection storage section 622.

  For example, in FIG. 9, attention is paid to the head 61 arranged second from the end on the −X direction side. In FIG. 8, the third through hole 631 (circular through hole 6311) arranged third from the end on the −X direction side and the fourth through hole 631 (deformed through hole 6312) are paired, and attention is paid to them. The ink flow path related to the head 61 is formed.

  The head 61 currently focused on is arranged on the −Y direction side. In the case of the head 61 arranged on the −Y direction side, of the two through holes 6311 and 6312 related to the head 61, the circular through hole 6311 is a supply storage unit that is a storage unit arranged on the −Y direction side. It functions as a flow path (introduction flow path 6301) for guiding ink from 621 to the head 61. Specifically, the circular through-hole 6311 is electrically connected to an opening 6211 formed on the bottom surface of the supply reservoir 621 on the upper end side, and is electrically connected to the ink introduction port 611 of the head 61 on the lower end side, thereby supplying the supply reservoir. An introduction flow path 6301 for guiding ink from 621 to the ink introduction port 611 is formed.

  On the other hand, of the two through holes 6311 and 6312 related to the head 61, the modified through hole 6312 is a flow path (leading out) from the head 61 to the collection storage unit 622 that is a storage unit arranged in the + Y direction. It functions as a flow path 6302). Specifically, the deformed through hole 6312 is electrically connected to the ink outlet 612 of the head 61 on the lower end side of the through hole 63122, and the opening 6221 formed on the bottom surface of the collection storage unit 622 on the upper end side of the long groove 63121. , And functions as a lead-out flow path 6302 that guides ink from the lead-out port 612 to the collection storage unit 622. In addition, the upper end surface of the long groove 63121 is configured to prevent ink from leaking out by coming into contact with the bottom surface of the main body portion 620 formed of a block body except for a portion where it is electrically connected to the opening 6221.

  As described above, the introduction flow path 6301 and the discharge flow path 6302 are formed by the through-holes 631 that vertically penetrate the main body portion 630 and extend straight below, thereby reducing pressure loss in the flow paths 6301 and 6302. Can be small. In particular, since each of the flow paths 6301 and 6302 is constituted by the through-hole 631, it is easy to increase the thickness of each flow path. By sufficiently ensuring the thickness of each flow path, the pressure loss can be further reduced. When the pressure loss in each of the flow paths 6301 and 6302 is reduced, the fluctuation of the pressure loss in each of the flow paths 6301 and 6302 is also reduced, and a stable meniscus pressure can be formed in the head 61.

<4. Effect>
According to this embodiment, among the plurality of heads 61 and the liquid supply device 60 that supplies ink thereto, some of the functional units provided individually for each head unit 6 (reservoir 62, flow path 63). , The liquid feeding section 64 and the degas section 71) are arranged in the same head unit 6. On the other hand, the ink replenishing mechanism 66, the pressure adjusting mechanism 67, and the like are disposed outside the head unit 6. According to this configuration, the circulatory system can be made compact by unitizing appropriate components of the circulatory system. By making the circulation system compact, it is possible to avoid a situation in which the ink is deteriorated due to the ink being held in the circulation system for a long time. Also, since the total amount of ink held in the circulation system is reduced, the time required for preheating the ink can be shortened. Further, the manufacturing cost can be reduced by making the circulation system compact.

  In the head unit 6, a head layer 601, a flow path layer 602, and a reservoir layer 603 are stacked. In particular, the flow path portion 63 and the storage portion 62 are both constituted by block bodies, and these are in contact with each other and arranged in a stacked manner. According to this configuration, each flow path length of the introduction flow path 6301 and the discharge flow path 6302 included in the flow path section 63 can be shortened, and the length of the circulation path can be shortened. Note that by reducing the lengths of the introduction flow path 6301 and the discharge flow path 6302, the pressure loss in each flow path is reduced, and the fluctuation of the pressure loss is also reduced. Therefore, a stable meniscus pressure can be formed on the head 61.

  In addition, the two storage portions 621 and 622 are disposed adjacent to each other. According to this configuration, the length of the circulation pipe 641 can be shortened, and the length of the circulation path can also be shortened from this point.

  Also, different types (different colors) of ink circulation paths are formed inside each of the plurality of head units 6 arranged in parallel. According to this configuration, it is possible to change the order of the ink ejected to the base material 10 simply by changing the arrangement order of the head units 6.

  Further, since the pressure adjusting mechanism 67 is provided outside the head unit 6, the size of the head unit 6 does not increase even if the capacity of the buffer tank 91 is sufficiently secured. By sufficiently securing the capacity of the buffer tank 91, the capacity of the supply storage unit 621 and the recovery storage unit 622 can be reduced while the internal pressure is stabilized.

  Further, since the degas pressure adjusting unit 72 is provided outside the head unit 6, the size of the head unit 6 does not increase even if the capacity of the degas buffer tank 721 is sufficiently secured.

<B. Second Embodiment>
The configuration of the recording apparatus 1a according to the second embodiment of the invention will be described. In the following, only differences from the first embodiment will be described. In addition, components that are not different from the first embodiment are denoted by the same reference numerals.

  In the liquid supply device 60a provided in the recording apparatus 1a according to this embodiment, the plurality of pressure adjustment units 90a provided in the pressure adjustment mechanism 67a do not have a pressure reduction pump, and the degas pressure reduction pump 722 provided in the degas pressure adjustment unit 72. The inside of the buffer tank 91 is decompressed using the negative pressure formed by

<1. Pressure adjusting mechanism 67a>
The configuration of the pressure adjusting mechanism 67a will be described with reference to FIG. FIG. 10 is a diagram showing a functional configuration of the liquid supply device 60a.

  The pressure adjustment mechanism 67a is a mechanism that adjusts the pressure in (the gas in) the two storage portions 621 and 622, as in the first embodiment. The pressure adjustment mechanism 67a includes three pressure adjustment units 90a. The roles of the pressure adjustment units 901a, 902a, and 903a are the same as those of the pressure adjustment units 901, 902, and 903 according to the first embodiment.

  The three pressure adjustment units 90a have the same configuration. That is, each pressure adjustment unit 90a includes a buffer tank 91 that forms a gas reservoir therein. As a mechanism for adjusting the pressure in the buffer tank 91, a pipe 93a that connects the buffer tank 91 and the degas buffer tank 721 and a pipe 95 that opens the buffer tank 91 to the outside (atmospheric pressure) are provided. . The piping 93a is provided with a pressure reducing control electromagnetic valve 94a. The piping 95 is provided with a pressurizing control electromagnetic valve 96. Further, the buffer tank 91 is provided with a pressure sensor 97 for detecting the pressure inside the buffer tank 91.

  The inside of the buffer tank 91 of each pressure adjusting unit 90a is always set to a predetermined pressure value by appropriately controlling the two electromagnetic valves 94a and 96. That is, when the pressure sensor 97 detects that the pressure in the buffer tank 91 is larger than a predetermined pressure value, the pressure reducing control electromagnetic valve 96a is opened. Then, the buffer tank 91 is electrically connected to the degas buffer tank 721. The degas buffer tank 721 has a negative pressure (for example, −50 kPa) required by the degas unit 71 (however, the negative pressure required by the degas unit 71 is reduced by the buffer tank 91 of each pressure adjustment unit 90a. Significantly lower than the target pressure value). Therefore, the pressure in the buffer tank 91a is lowered by conducting with the degas buffer tank 721. When the pressure sensor 97 detects that the pressure in the buffer tank 91 has decreased to a predetermined pressure value, the pressure reducing control electromagnetic valve 94a is closed.

  On the other hand, when the pressure sensor 97 detects that the pressure in the buffer tank 91 is smaller than a predetermined pressure value, the pressurization control electromagnetic valve 96 is opened. Then, the pressure in the buffer tank 91 increases due to electrical connection with the outside (atmospheric pressure). When the pressure sensor 97 detects that the pressure in the buffer tank 91 has increased to a predetermined pressure value, the pressurizing control electromagnetic valve 96 is closed.

  Note that the negative pressure required by the degas unit 71 does not have to be strictly adjusted. Therefore, even if the pressure in the degas buffer tank 721 is slightly changed by being connected to the buffer tank 91a of the pressure adjustment unit 90a, the operation of the degas unit 71 is not affected.

<2. Effect>
According to this embodiment, the plurality of pressure adjustment units 90 a provided in the pressure adjustment mechanism 67 a reduce the pressure in the buffer tank 91 using the negative pressure formed by the degas pressure reduction pump 722 provided in the degas pressure adjustment unit 72. According to this configuration, when the pressure in the buffer tank 91 is reduced, it is only necessary to open the pressure reducing control electromagnetic valve 94a, so that the response of the pressure drop in the buffer tank 91 can be improved. As a result, the pressure in the two reservoirs 621 and 622 can always be stably maintained at the target pressure value. Further, according to this embodiment, the number of pumps required is reduced, so that the manufacturing cost can be reduced.

<C. Third Embodiment>
A configuration of a recording apparatus 1b according to the third embodiment of the present invention will be described. In the following, only differences from the above embodiments will be described. In addition, components that are not different from the above embodiments are denoted by the same reference numerals.

  In the liquid supply apparatus 60b included in the recording apparatus 1b according to this embodiment, the pressure adjustment mechanism 67b includes two pressure adjustment units 90b.

<1. Pressure adjusting mechanism 67b>
The configuration of the pressure adjustment mechanism 67b will be described with reference to FIG. FIG. 11 is a diagram showing a functional configuration of the liquid supply apparatus 60b.

  The pressure adjustment mechanism 67b is a mechanism that adjusts the pressure in (the gas in) the two reservoirs 621 and 622, as in the first embodiment. The pressure adjustment mechanism 67b includes two pressure adjustment units 90b.

  The configuration of each pressure adjustment unit 90b is the same as that of the pressure adjustment unit 90 according to the first embodiment or the pressure adjustment unit 90a according to the second embodiment (FIG. 11 shows the second embodiment). The case where it is set as the structure similar to the pressure adjustment unit 90a which concerns on a form is illustrated).

  The role of each pressure adjustment unit 90b is the same as that of the second circulation pressure adjustment unit 902 and the holding pressure adjustment unit 903 in the first embodiment.

  That is, one pressure adjustment unit 90b is used to adjust the pressure in the internal space of the collection storage unit 622 in the circulation state (hereinafter referred to as “second circulation pressure adjustment unit 902b”). The pressure in the buffer tank 91b (hereinafter referred to as “second buffer tank 912b”) of the second circulation pressure adjustment unit 902b is a predetermined value higher than the atmospheric pressure P0 by appropriately controlling the two electromagnetic valves 94a and 96. Only a low pressure P2 ′ is set. Therefore, when the second three-way valve 995 connects the collection and storage unit 622 and the second buffer tank 912, the inside of the collection and storage unit 622 becomes the target pressure P2 '.

  The other pressure adjustment unit 90b is used to adjust the pressure in the internal space of the supply storage unit 621 and the collection storage unit 622 in the circulation stop state (hereinafter referred to as “holding pressure adjustment unit 903b”). The pressure in the buffer tank 91b (hereinafter referred to as “third buffer tank 913b”) of the third circulation pressure adjusting unit 903b is controlled by appropriately controlling the two electromagnetic valves 94a and 96, whereby the supply storage section in the circulation stop state. 621, the target pressure in the collection storage unit 622 (pressure P3 lower than the atmospheric pressure by a predetermined value). Accordingly, when the first three-way valve 992 connects the supply storage unit 621 and the third buffer tank 913, and the second three-way valve 995 connects the collection storage unit 622 and the third buffer tank 913, each storage unit 621. , 622 is the target pressure P3.

  In this embodiment, the pressure adjustment unit 90 corresponding to the first circulation pressure adjustment unit 901 according to the first embodiment is not provided. The first three-way valve 992b connected to the supply storage unit 621 via the pipe 993 has one connection port connected to the third buffer tank 913b, and the other connection port has a pipe 998b with one end open to the atmosphere. It is connected to the. Therefore, when the second three-way valve 995 connects the collection and storage unit 622 and the pipe 998b, the inside of the collection and storage unit 622 becomes the atmospheric pressure P0.

<2. Aspect of circulation supply>
An aspect in which the liquid supply device 60b circulates and supplies ink to the head 61 will be described with reference to FIG. Note that the case where the circulating supply of ink is stopped is not different from the first embodiment, and thus the description thereof is omitted.

  When starting to circulate and supply ink, the controller 600b switches the first three-way valve 992b to release the supply storage unit 621 to the atmosphere, and switches the second three-way valve 995 to switch the collection storage unit 622 to the second buffer tank 912b. And conduct. However, the inside of the second buffer tank 912b is adjusted to the target pressure P2 'in the collection storage unit 622 in the circulating state. Therefore, the inside of the supply storage unit 621 is at the atmospheric pressure P0, and the inside of the collection storage unit 622 that is electrically connected to the second buffer tank 912 is at the pressure P2 '. Since the target pressure P2 ′ is set to a value lower than the atmospheric pressure P0 by a predetermined value, the inside of the collection storage unit 622 is set to a pressure lower than the inside of the supply storage unit 621 by this, thereby The flow path reaches the plurality of heads 61 from the supply storage section 621 through the flow path section 63, and again reaches the collection storage section 622 from the head 61 through the flow path section 63 with the ink filled. Ink flows from the supply reservoir 621 to the recovery reservoir 622 via

  On the other hand, the controller 600b starts driving the circulation pump 642 provided in the circulation pipe 641. Then, the ink in the collection storage unit 622 is returned to the supply storage unit 621. The controller 600b performs these controls to form an ink circulation state.

  In the first embodiment, an appropriate meniscus pressure is formed in the discharge port 611 by adjusting the pressure in the supply reservoir 621 in the circulating state to a pressure P1 that is lower than the atmospheric pressure by a predetermined value. It was. On the other hand, in this embodiment, the pressure in the supply reservoir 621 in the circulating state is the atmospheric pressure P0. Therefore, the adjustment for forming an appropriate meniscus pressure in the discharge port 611 needs to be performed in another manner. For example, the water head difference between the ink level in the supply storage section 621 and the ejection port 611 in the circulation state, the flow rate of the ink to be circulated, the viscosity of the ink, the ink flow path (for example, the flow path shape), etc. By adjusting the pressure, an appropriate meniscus pressure can be formed in the discharge port 611 while setting the pressure in the supply storage unit 621 to atmospheric pressure.

<3. Effect>
According to this embodiment, the supply storage section 621 in the circulating state is opened to the atmosphere, so that the internal pressure is set to the atmospheric pressure P0. Therefore, since the pressure in the supply storage part 621 does not fluctuate at all, a stable ink flow rate can be formed. Further, the meniscus pressure formed on the head 61 can be stabilized.

  In addition, according to this embodiment, the number of pressure adjustment units 90b can be reduced, so that the manufacturing cost is reduced. In addition, power consumption can be reduced.

<D. Fourth Embodiment>
A configuration of a recording apparatus 1c according to the fourth embodiment of the present invention will be described. In the following, only differences from the first embodiment will be described. In addition, components that are not different from the first embodiment are denoted by the same reference numerals.

  In the liquid supply device 60c included in the recording apparatus 1c according to this embodiment, the liquid feeding unit 64c includes two circulation pipes 641c and 6411c that connect the supply storage unit 621 and the recovery storage unit 622, A degas unit 71c is provided only in the circulation pipe 641c.

<1. Liquid feeding part 64c>
The configuration of the liquid feeding unit 64c will be described with reference to FIGS. FIG. 12 is a diagram showing a functional configuration of the liquid supply apparatus 60c. FIG. 13 is a perspective view showing a layout in the housing 60 of the head unit 6c provided in the recording apparatus 1c according to this embodiment.

  The liquid feeding unit 64 c sends ink from the collection storage unit 622 to the supply storage unit 621. The liquid feeding unit 64c includes two circulation pipes (a first circulation pipe 641c and a second circulation pipe 6411c) as circulation pipes connecting the collection storage part 622 and the supply storage part 621. Furthermore, a first circulation pump 642c provided in the first circulation pipe 641c and a second circulation pump 6422c provided in the second circulation pipe 6411c are provided.

  Note that the degas unit 71 provided in the degas mechanism 65 is provided only in one of the first circulation pipe 641c and the second circulation pipe 6411c, and degassed dissolved gas in the ink flowing through the provided circulation pipe. To do. In FIG. 12, the degas unit 71 is provided in the first circulation pipe 641c.

  When the circulation supply is performed, the control unit 600c drives both the first circulation pump 642c and the second circulation pump 6422c. Then, the ink in the collection storage unit 622 is returned to the supply storage unit 621 via the two circulation pipes 641c and 6411c. However, the ink flowing through the first circulation pipe 641 c is deaerated by the degas unit 71 and then flows into the collection storage unit 622.

  Here, the ratio of the amount of ink circulated through the first circulation pipe 641 c and the amount of ink circulated through the second circulation pipe 6411 c is defined according to the performance of the degas mechanism 65. That is, an ink having a flow rate that can be degassed by the degas mechanism 65 is caused to flow through the first circulation pipe 641c. The remaining ink (the amount of ink obtained by subtracting the amount of ink circulated through the first circulation pipe 641c from the total amount of ink to be returned from the collection storage section 622 to the supply storage section 621) is the second circulation pipe. 6411c.

  For example, when it is necessary to return “360 ml (milliliter)” of ink from the collection storage unit 622 to the supply storage unit 621 per minute, and the degas mechanism 65 has a capability of degassing “100 ml” of ink per minute, The amount of ink circulated through the first circulation pipe 641c is defined as “100 ml”. The amount of ink circulated through the second circulation pipe 6411c is defined as “260 ml”.

  According to the above configuration, only a part of the ink returned from the collection storage unit 622 to the supply storage unit 621 is degassed by the degas unit 71, but the ink in the head unit 6 is always circulated. Therefore, as a result, the degassing effect of the degas unit 71 is exerted on the entire ink in the head unit 6. In order to further enhance the deaeration effect, for example, a degas unit is also provided in the replenishment line 663 provided in the ink replenishment mechanism 66, and the ink supplied from the main tank 661 to the supply storage unit 621 via the replenishment line 663. May also be degassed.

<2. Effect>
In order to reduce the size of the head unit 6, it is desirable to mount the degas unit 71 as small as possible. However, the total amount of ink to be returned from the collection storage unit 622 to the supply storage unit 621 (that is, the total amount of ink to be circulated) increases accordingly as the number of heads 61 increases. Further, in order to exhaust (cool) the piezo, driver circuit, etc., a circulation flow rate greater than the discharge amount from each head 61 is required. Therefore, if all of the ink to be returned from the collection storage unit 622 to the supply storage unit 621 is to be deaerated, the required degas unit size increases. According to this embodiment, the degas unit 71 does not have to deaerate the entire amount of the circulated ink, and thus the above problem does not occur. That is, a small degas unit 71 can be mounted, and the head unit 6 can be miniaturized (see FIG. 13). Further, since the performance required for the degas mechanism 65 is low, the degas unit 71 and the degas decompression pump 722 can be made small and inexpensive. Therefore, the manufacturing cost can be reduced.

<E. Fifth embodiment>
A configuration of a recording apparatus 1d according to the fifth embodiment of the present invention will be described. In the following, only differences from the first embodiment will be described. In addition, components that are not different from the first embodiment are denoted by the same reference numerals.

<1. Configuration of Liquid Supply Device 60d>
The configuration of the liquid supply device 60d will be described with reference to FIG. FIG. 14 is a diagram showing a functional configuration of the liquid supply apparatus 60d.

<Storage part 62d>
The reservoir 62d stores ink in the vicinity of the tops of the plurality of heads 61, as in the reservoir 62 according to the first embodiment. The storage unit 62d includes two storage units 621d and 622d. The first storage section is a supply storage section 621 d that stores ink on the upstream side of the plurality of heads 61 and supplies ink to the head 61 via the flow path section 63. The second storage unit is a recovery storage unit 622 d that stores ink on the downstream side of the plurality of heads 61 and recovers ink from the head 61 via the flow path unit 63.

  The supply storage unit 621d includes a supply main storage unit 6211d and a supply buffer storage unit 6212d. The supply main storage unit 6211d and the supply buffer storage unit 6212d are connected to each other through a flow path 6213d. One end of the flow path 6213d is electrically connected to the vicinity of the bottom of the main supply reservoir 6211d (specifically, a position sufficiently lower than the ink level of the main supply reservoir 6211d). Also, the opening at the other end is electrically connected to the vicinity of the bottom of the supply buffer reservoir 6212d (that is, a position sufficiently lower than the ink level of the supply main reservoir 6211d). As a result, the supply main storage portion 6211d and the supply buffer storage portion 6212d are in a state of being conducted in the liquid layer while being separated in the gas layer.

  Similarly, the collection storage unit 622d includes a collection main storage unit 6221d and a collection buffer storage unit 6222d. The collection main storage unit 6221d and the recovery buffer storage unit 6222d are connected to each other through a flow path 6223d. One end of the flow path 6223d is electrically connected to the vicinity of the bottom of the recovery main reservoir 6221d (specifically, a position sufficiently lower than the ink level of the recovery main reservoir 6221d). Further, the opening at the other end is electrically connected to the vicinity of the bottom of the recovery buffer storage unit 6222d (specifically, a position sufficiently lower than the ink level of the recovery main storage unit 6221d). As a result, the recovery main storage portion 6221d and the recovery buffer storage portion 6222d are brought into a conductive state in the liquid layer while being separated in the gas layer.

<Liquid feeding part 64d>
The liquid feeding unit 64d sends ink from the collection storage unit 622 (specifically, the recovery buffer storage unit 6222d) to the supply storage unit 621 (specifically, the supply buffer storage unit 6212d). The liquid feeding unit 64d includes a circulation pipe 641d that connects the recovery buffer storage unit 6222d and the supply buffer storage unit 6212d, and a circulation pump 642d provided in the circulation pipe 641d. When the circulation pump 642d is driven, the ink in the recovery buffer reservoir 6222d is returned to the supply buffer reservoir 6212d through the circulation pipe 641d.

  A heat radiating unit 643d, which is a mechanism for radiating the heat of the ink flowing through the circulation pipe 641d, is provided in the vicinity of the circulation pipe 641d.

<Flow path part 63d>
The flow path portion 63 d is provided between the storage portion 62 d and the plurality of heads 61, similarly to the flow path portion 63 according to the first embodiment, and the ink between the storage portion 62 d and the plurality of heads 61. A flow path is formed. The flow path part 63 includes an introduction flow path for introducing ink from the supply main storage part 6211d to the plurality of heads 61, and a discharge flow path for deriving ink from the plurality of heads 61 to the recovery main storage part 6221d.

<Ink replenishment mechanism 66d>
The ink replenishing mechanism 66d replenishes the ink consumed in the head unit 6d, similarly to the ink replenishing mechanism 66 according to the first embodiment. The ink replenishing mechanism 66 includes a main tank 661 that stores ink. The main tank 661 is connected to the supply buffer storage unit 6212d through a replenishment line 663d provided with a pump 662. When the pump 662 is driven, the ink in the main tank 661 is supplied to the supply buffer storage unit 6212d.

  In the first embodiment, the ink in the circulation system is preheated by the heater 6229. In this embodiment, as described below, when the circulation state is started, Preheating in such a manner is not performed.

<2. Aspect of circulation supply>
A mode in which the liquid supply device 60b circulates and supplies ink to the head 61 will be described with reference to FIG. Note that the case where the circulating supply of ink is stopped is not different from the first embodiment, and thus the description thereof is omitted.

  When the ink circulation supply is started, the control unit 600d switches the first three-way valve 992 so that the supply storage unit 621d (specifically, the supply main storage unit 6211d and the supply buffer storage unit 6212d) is the first buffer. The tank 911 is electrically connected, and the second three-way valve 995 is switched to electrically connect the recovery and storage unit 622 (specifically, the recovery main storage unit 6221d and the recovery buffer storage unit 6222d) to the second buffer tank 912. Then, the inside of the supply main reservoir 6211d connected to the first buffer tank 911 is at a pressure P1, and the inside of the recovery main reservoir 6221d connected to the second buffer tank 912 is a pressure P2 that is lower than the pressure P1 by a predetermined value. As a result, the supply main reservoir 6211d reaches the plurality of heads 61 via the channel 63, and the flow from the head 61 to the recovery main reservoir 6221d again via the channel 63 is filled with ink. The ink flows from the supply main storage portion 6211d to the recovery main storage portion 6221d through the flow path.

  As a result, the ink level in the recovery main reservoir 6221d becomes higher than the ink level in the recovery buffer reservoir 6222d. Ink flows from the recovery main storage portion 6221d to the recovery buffer storage portion 6222d through the flow path 6223d with a pressure corresponding to the water head difference.

  In addition, the ink level in the supply main reservoir 6211d is lower than the ink level in the supply buffer reservoir 6212d. Ink flows from the supply buffer reservoir 6212d to the supply main reservoir 6211d through the flow path 6213d with a pressure corresponding to the water head difference.

  On the other hand, the controller 600d starts driving the circulation pump 642d provided in the circulation pipe 641d. Then, the ink in the collection buffer storage unit 6222d is returned to the supply buffer storage unit 6212d.

  That is, when the control unit 600 performs each control described above, the supply main storage unit 6211d passes through the head 61d to the recovery main storage unit 6221d, and further, from the recovery main storage unit 6221d to the recovery buffer 6223d. Circulation reaches the storage section 6222d, further reaches the supply buffer storage section 6212d from the recovery buffer storage section 6222d through the circulation pipe 641d, and further returns from the supply buffer storage section 6212d to the supply main storage section 6211d through the flow path 6213d. An ink circulation state is formed in the line.

<3. Preheating mode>
As described above, the ink supplied to the head 61d needs to be preheated so that its viscosity is lower than normal temperature. In the first embodiment, the ink replenished to the supply storage unit 621 is preheated by the heater 6229 provided in the collection storage unit 622. In this embodiment, when the circulation state is started and heat is generated by the ejection of the head 61d, the ink in the main tank 661 is supplied to the supply buffer storage unit 6212d via the replenishment line 663d while being kept at room temperature without being preheated. Supply. Note that the recovery buffer storage unit 6222d is replenished by the heater 6229 as in the first embodiment, except for a case where a predetermined time elapses after the circulation state is started and when heat is generated by the ejection of the head 61d. Preheat the ink to be produced.

  By the way, as described above, in the circulating state, when the ink passes through the head 61, the ink absorbs heat from the piezo or driver circuit provided in the head 61 and the temperature rises (piezo or driver circuit or the like). Is exhausted (cooled) by this). The ink whose temperature has risen flows into the supply buffer storage unit 6212d through the recovery main storage unit 6221d, the recovery buffer storage unit 6222d, and the circulation pipe 641d.

  Then, the ink whose temperature has risen flowing through the circulation pipe 641d and the non-preheated normal temperature ink supplied from the main tank 661 are mixed in the supply buffer reservoir 6212d. As a result, the temperature of the entire ink stored in the supply buffer storage unit 6212d is raised to a temperature higher than the normal temperature. That is, the ink is preheated using the temperature rise of the ink flowing in through the circulation pipe 641d.

  The controller 600d detects the amount of heat generated by the head 61 from a heat sensor (not shown) provided in the head 61, and controls the driving of the heat radiation unit 643d according to the amount of heat generated. Thereby, the temperature of the preheating in the supply buffer storage part 6212d is appropriately controlled. That is, when the amount of heat generated by the head 61 increases, if all of the heat is used for preheating, the temperature of the ink in the supply buffer storage unit 6212d will increase too much. Therefore, in this case, the controller 600d drives the heat radiating unit 643d to radiate the heat of the ink flowing through the circulation pipe 641d to some extent. Thereby, the temperature rise of the ink flowing into the supply buffer storage part 6212d is appropriately controlled, and appropriate preheating is performed.

<4. Effect>
According to this embodiment, since the ink is preheated by utilizing the temperature rise of the ink by absorbing heat from a piezo or driver circuit, the heater 6229 is turned on at least after the circulation state is started. There is no need to perform the preheating used. Further, since the burden on the heat dissipation mechanism is reduced, the mounted heat dissipation mechanism can be downsized. As described above, efficient preheating is performed, whereby the head unit 6 can be reduced in size and the manufacturing cost can be reduced.

  In the above-described embodiment, the supply buffer storage unit 6212d is provided in the storage unit 62d, and the normal temperature ink and the ink whose temperature has increased are mixed in the supply buffer storage unit 6212d. On the other hand, the supply of ink to the head 61 is not performed directly from the supply buffer storage unit 6212d, but is performed from the supply main storage unit 6211d connected to the supply buffer storage unit 6212d via the flow path 6213d. That is, the storage unit that mixes the ink and the storage unit that supplies the ink to the head 61 are configured separately.

  When the storage unit that mixes the ink and the storage unit that supplies the ink are integrally configured, the ink is supplied to the head 61 in a state where the temperature of the ink is not sufficiently uniform. Therefore, thermal nonuniformity occurs in the ink supplied to the head 61. On the other hand, when the storage unit that mixes the ink and the storage unit that supplies the ink are configured separately as in this embodiment, the ink from the supply main storage unit 6222d to the head 61 is used. Before the ink is supplied, the temperature of the ink is sufficiently uniformed in the supply buffer storage unit 6212d, so that thermal nonuniformity is unlikely to occur in the ink supplied to the head 61.

  In addition, the buffer storage part 6212d and 6222d are provided in each storage part 621d and 622d, and the advantage that the pressure fluctuation of the main storage parts 6211d and 6221d in a circulation state can be made small is also acquired.

  That is, when the circulation state is started, in the supply buffer reservoir 6212d into which the ink flows through the circulation pipe 641d and the replenishment line 663, the ink liquid level fluctuates relatively greatly, and the internal pressure changes. Relatively unstable. On the other hand, the main supply reservoir 6211d receives inflow of ink through the supply buffer reservoir 6212d, so that the fluctuation of the ink liquid level is more gradual than the supply buffer reservoir 6212d, and the internal pressure is relatively stable. . That is, the pressure in the supply main storage part 6211d can be stabilized by absorbing the pressure fluctuation in the supply buffer storage part 6212d.

  Similarly, when the circulation state is started, in the recovery buffer storage unit 6222d from which ink flows out through the circulation pipe 641d, the ink liquid level fluctuates relatively greatly, and the internal pressure becomes relatively unstable. Become. On the other hand, since the ink flows out of the recovery main storage part 6221d through the recovery buffer storage part 6222d, the fluctuation of the ink liquid level becomes gentler than that of the recovery buffer storage part 6222d, and the internal pressure is relatively stable. That is, the pressure in the recovery main storage part 6221d can be stabilized by absorbing the pressure fluctuation in the recovery buffer storage part 6222d.

  Thus, according to this embodiment, a stable meniscus pressure can be formed by stabilizing the pressure in the supply main reservoir 6211d and the recovery main reservoir 6221d.

<F. Modification>
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made.

  For example, in the above-described embodiment, in the flow path portion 63, the introduction flow path 6301 and the outlet flow path 6302 are configured by the through holes 631 formed in the main body portion 630. In the part 63, the introduction flow path 6301 and the outlet flow path 6302 may be configured by an assembly of hollow pipes. In this case, the piping forming the introduction flow path 6301 and the discharge flow path 6302 can be configured using an inexpensive hard tube such as PTFE (Polytetrafluoroethylene).

  In the above embodiment, the deformed through hole 6312 is formed of the long groove 63121 and the circular through hole 63122 formed in the bottom thereof. May be formed by a through hole having a shape extending along the Y direction (specifically, a rectangular shape having the long direction along the Y direction). In this case, for example, a bottom plate (however, a bottom plate in which an opening for connecting the deformed through hole 6312 to the introduction port 611 or the outlet port 612) is provided at the lower end of the deformed through hole 6312, and ink is transferred from the deformed through hole 6312. It is only necessary to prevent leakage.

  In the above-described embodiment, the degas unit 71 is provided in the circulation pipe 641. However, the degas unit 71 may be provided in a replenishment line 663 provided in the ink replenishment mechanism 66.

  In the above embodiment, in the head unit 6, the two storage portions 621 and 622 are arranged along the Y direction, the supply storage portion 621 is on the −Y direction side, and the recovery storage is on the + Y direction side. Although the units 622 are arranged, the supply storage unit 621 may be arranged on the + Y direction side, and the collection storage unit 622 may be arranged on the −Y direction side.

  In addition, the two storage units 621 and 622 are configured to have substantially the same size and shape, and are arranged at the same position in the X direction and the Z direction. 622 may be different from each other in at least one of size and shape. Moreover, you may arrange | position in the position which shifted | deviated about the X direction and the Z direction.

  In the fifth embodiment, the supply storage unit 621d includes two storage units (a main supply storage unit 6211d and a supply buffer storage unit 6212d), and the two storage units flow. It is assumed that they are connected to each other via a path 6213d. Here, a mesh structure barrier 6214d as shown in FIG. 15 may be provided between the supply buffer reservoir 6212d and the flow path 6213d. By providing the barrier 6214d having a mesh structure, the change in the ink flow rate in the flow path 6213d becomes gradual, and the liquid level fluctuation in the supply main reservoir 6211d also becomes gradual. As a result, the pressure fluctuation of the supply main storage portion 6211d can be further suppressed.

  Similarly, a barrier having a mesh structure may be provided between the recovery buffer storage unit 6222d and the flow path 6223d. Also in this case, the pressure fluctuation of the recovery main storage portion 6221d can be further reduced.

  In the fifth embodiment, the room temperature ink supplied from the main tank 661 flows into the supply buffer storage unit 6212d, and the room temperature ink supplied from the main tank 661 in the supply buffer storage unit 6212d. And the ink whose temperature has risen flowing in via the circulation pipe 641d is mixed. However, the ink at normal temperature supplied from the main tank 661 is allowed to flow into the recovery buffer storage unit 6222d, and the recovery buffer storage unit 6222d Alternatively, the normal temperature ink supplied from the main tank 661 may be mixed with the ink whose temperature has increased via the circulation pipe 641d. In addition, normal temperature ink supplied from the main tank 661 flows into the circulation pipe 641d, and the normal temperature ink supplied from the main tank 661 and the circulation pipe 641d in the circulation pipe 641d (and the supply buffer storage unit 6212d). It is also possible to mix the heated ink that flows in through the ink.

  Further, in the configuration in which the buffer storage portion is not provided as in the first embodiment (see FIG. 4), the room temperature ink supplied from the main tank 661 is caused to flow into the circulation pipe 641, and the circulation pipe 641 (and The supply storage unit 621) may be configured to mix the normal temperature ink supplied from the main tank 661 and the ink whose temperature has increased flowing from the recovery storage unit 622.

  Further, in the configuration in which the buffer storage section is not provided as in the first embodiment (see FIG. 4), the room temperature ink supplied from the main tank 661 is caused to flow into the recovery storage section 622, and the recovery storage section 622 is configured. The normal temperature ink supplied from the main tank 661 and the ink whose temperature has been recovered collected from the head 61 may be mixed.

  Further, unlike the first embodiment, the buffer storage section is not provided, and the room temperature ink supplied from the main tank 661 is allowed to flow into the supply storage section 621 (see FIG. 4). In the supply storage section 621, A configuration may be adopted in which normal temperature ink supplied from the main tank 661 and ink whose temperature has increased via the circulation pipe 641 are mixed.

  Further, in each of the above-described embodiments, the recording apparatuses 1 and 1a to 1d are configured so that the base material 10 is in the scanning direction intersecting the arrangement direction of the plurality of discharge ports by the transport unit 47 that moves the base material 10 in the scanning direction. However, the scanning mechanism for moving the base material 10 in the scanning direction relative to the ejection unit 5 can be realized in various configurations. For example, a mechanism for moving the ejection unit in the scanning direction may be provided. Further, as in the recording apparatus 1e (sheet-fed printing apparatus) illustrated in FIG. 16, the stage 201 that holds the rectangular base material 10 and the stage 201 are moved in the scanning direction (Y direction in FIG. 16). A stage moving mechanism 202 may be provided. In the recording apparatus 1e shown in FIG. 16, the position of the stage 201 relative to the base 200 can be detected by the position detection module 203 provided on the base 200.

  Further, in each of the above embodiments, the recording apparatuses 1 and 1a to 1d are configured to move the base material 10 relative to the discharge part 5 by the transport unit 47 moving the base material 10. The substrate 10 may be moved relatively with respect to the discharge unit 5 by moving the discharge unit 5 instead of the substrate 10.

  Further, the recording material in the recording apparatuses 1 to 1 e may be a plate-like member or printing paper formed of plastic in addition to the sheet-like base material 10.

  The liquid ejected from the head is a color filter material (ink), an organic EL (Electro-Luminescence) material (ink), in addition to various inks used for image recording, such as pigment-based ink and dye-based ink. It may be a wiring material (ink). Moreover, the liquid etc. which contain the spacer particle | grains for liquid crystal display devices may be sufficient.

1, 1a to 1e Recording device 5 Discharge unit 6 Head unit 7 Degas mechanism 8 Ink replenishment mechanism 9 Pressure adjustment mechanism 60, 60a to 60d Liquid supply device 62 Storage unit 63 Channel unit 64 Liquid supply unit 65 Degas mechanism 66 Ink replenishment mechanism 67 Pressure adjustment mechanism 621 Supply storage unit 622 Recovery storage unit

Claims (17)

An ejection head for ejecting droplets from the ejection port;
A first reservoir for storing liquid;
A second reservoir for storing liquid;
A first flow path for introducing liquid from the first reservoir to the ejection head;
A second flow path for leading the liquid from the ejection head to the second reservoir,
Liquid feeding means for feeding a liquid from the second reservoir to the first reservoir;
A head unit having
Pressure adjusting means provided outside the head unit, for adjusting the pressure inside the second reservoir with respect to the pressure inside the first reservoir;
In the middle of a circulation path formed by the first storage section, the first flow path, the discharge head, the second flow path, the second storage section, and the liquid feeding means in the head unit, the head Replenishment means for replenishing liquid from outside the unit;
A moving means for supporting the recording material at a position facing the ejection head and moving the recording material relative to the ejection head;
A recording apparatus comprising: The recording apparatus according to claim 1,
In the head unit, a head layer including the ejection head, a flow path layer including the first flow path and the second flow path, and a storage layer including the first storage section and the second storage section. A recording apparatus characterized by being arranged in a stacked manner. The recording apparatus according to claim 2,
The flow path layer has a flow path portion that is a block body in which the first flow path and the second flow path are formed,
The reservoir is formed with the first reservoir and the second reservoir, and is formed with a first through hole communicating with the first reservoir and a second through hole communicating with the second reservoir. A storage part that is a block body,
The first flow path and the first storage section communicate with each other through the first through hole, and the second flow path and the second storage section communicate with each other through the second through hole. A recording apparatus, wherein the flow path section and the storage section are arranged in contact with each other. The recording apparatus according to claim 3,
The flow path section is
A plurality of through holes formed so as to penetrate vertically;
With
Each of the plurality of through holes functions as the first flow path or the second flow path. The recording apparatus according to claim 4,
The ejection head is
A plurality of heads arranged in a zigzag pattern along the first direction, each having a plurality of discharge ports arranged along the first direction on the lower surface thereof;
In the reservoir,
Two reservoirs of the first reservoir and the second reservoir are formed so as to be juxtaposed along a second direction orthogonal to the first direction,
Among the plurality of through holes,
Among the two reservoirs and the plurality of heads, the one that functions as a flow path connecting the reservoir and the head at the same position in the second direction has a circular cross section.
Among the two reservoirs and the plurality of heads, the one that functions as a flow path connecting the reservoir and the head at a position shifted in the second direction has a cross section along the second direction. A recording apparatus characterized by being formed in an elongated shape. The recording apparatus according to any one of claims 1 to 4,
The ejection head is
A plurality of heads each having a plurality of discharge ports formed on the lower surface;
A recording apparatus comprising: The recording apparatus according to claim 6, wherein
The recording apparatus, wherein the plurality of heads are arranged in a staggered manner. The recording apparatus according to any one of claims 1 to 7,
A plurality of the head units are provided,
A circulation path for different types of liquids is formed inside each of the plurality of head units,
The recording apparatus, wherein the plurality of head units are arranged in parallel along a direction in which the ejection head is moved relative to a recording material. The recording apparatus according to any one of claims 1 to 8,
The pressure adjusting means is
A plurality of pressure adjustment units each including an air buffer that forms a gas reservoir therein, and an air buffer pressure adjusting unit that adjusts the pressure in the air buffer,
By adjusting the air buffer provided in the first pressure adjustment unit of the plurality of pressure adjustment units and the first storage unit, the pressure in the first storage unit is adjusted,
Recording in which the pressure in the second reservoir is adjusted by connecting the air buffer included in the second pressure regulator of the plurality of pressure adjustment units and the second reservoir. apparatus. The recording apparatus according to any one of claims 1 to 8,
The pressure adjusting means is
An air buffer that forms a gas reservoir therein, and an air buffer pressure adjusting means that adjusts the pressure in the air buffer;
By connecting the air buffer and the second reservoir, the pressure in the second reservoir is adjusted,
The recording apparatus according to claim 1, wherein the pressure in the first reservoir is set to atmospheric pressure by opening the first reservoir to the atmosphere. The recording apparatus according to claim 9 or 10,
A deaeration unit disposed in the head unit and degassing a gas dissolved in the liquid flowing in the circulation path;
A deaeration negative pressure generating means disposed outside the head unit and applying a negative pressure to the deaeration part;
With
The air buffer pressure adjusting means is
A recording apparatus, wherein the pressure in the air buffer is adjusted using a negative pressure formed by the deaeration negative pressure generating means. The recording apparatus according to any one of claims 1 to 10,
A deaeration unit disposed in the head unit and degassing a gas dissolved in the liquid flowing in the circulation path;
A degassing negative pressure generating means that is disposed outside the head unit and applies a negative pressure to the degassing section;
A recording apparatus comprising: The recording apparatus according to claim 11 or 12,
The liquid feeding means is
A plurality of circulation pipes each connecting the first reservoir and the second reservoir;
With
The recording apparatus according to claim 1, wherein the deaeration unit is provided in any one of the plurality of circulation pipes to degas the gas dissolved in the liquid flowing through the circulation pipes. The recording apparatus according to any one of claims 1 to 13,
By preliminarily heating the liquid to be discharged from the discharge head by mixing the liquid to be replenished by the replenishing means and the liquid whose temperature has increased by absorbing the heat of the discharge head when circulating through the discharge head A recording apparatus. The recording apparatus according to claim 14, wherein
At least one of the first reservoir and the second reservoir is
A main reservoir to which a flow path between the discharge heads is connected;
A buffer reservoir connected to the main reservoir;
With
The liquid to be replenished by the replenishing means is guided to the buffer storage section, and the liquid whose temperature has been increased by absorbing the heat of the discharge head when circulating through the discharge head is guided to the buffer storage section. A recording apparatus, wherein the liquid ejected from the ejection head is preheated by mixing the liquid in the unit. The recording apparatus according to claim 14, wherein
The replenishing means replenishes liquid in the middle of a pipe that forms a flow path for liquid fed from the second reservoir to the first reservoir,
The liquid that is replenished by the replenishing means and the liquid that has risen in temperature by absorbing the heat of the ejection head when circulating through the ejection head are discharged from the ejection head by mixing in the pipe. The recording apparatus is characterized by preheating the liquid. The recording apparatus according to claim 14, wherein
The replenishing means replenishes the second reservoir with liquid;
By mixing the liquid to be replenished by the replenishing means and the liquid whose temperature has been increased by absorbing the heat of the ejection head when circulating through the ejection head in the second reservoir, A recording apparatus for preheating a liquid to be discharged.

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