JP2013071247A - Image recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image recording device capable of stably supplying liquid by suppressing pressure fluctuation.SOLUTION: Ink is fed to a supply pump 26 and supplied from an ink tank 20 via a damper device 100 to an inkjet head 16. Ink pressure is detected by a pressure sensor 30, and the supply pump 26 is controlled to make the pressure constant. The damper device 100 is formed to be able to switch the damping capacity by expanding/contracting a volume of an air chamber. While discharging ink from the inkjet head 16, the damping capacity of the damper device 100 is decreased for suppressing the pressure fluctuation caused by ink discharge. On the other hand, while not discharging ink, the damping capacity is increased for suppressing pulsation caused by liquid feeding of the supply pump 26.

Description

  The present invention relates to an image recording apparatus, and more particularly to a technique for suppressing pressure fluctuation of a liquid supplied to a head in an image recording apparatus that records an image by an ink jet method.

  In order to record a high-quality image in an image recording apparatus that records an image by an inkjet method, it is necessary to correctly control the ejection of ink from each nozzle.

  On the other hand, in order to correctly control the ejection of ink from each nozzle, it is necessary to stably supply ink to the head. Here, “stable supply” means that the pressure fluctuation is suppressed as much as possible.

  As a method of suppressing this pressure fluctuation, Patent Document 1 proposes a method of keeping the pressure constant by controlling the pump while monitoring the pressure.

  Patent Document 2 proposes a method in which a damper device is provided in the middle of the ink supply path to the head, and the elastic modulus of the damper film of the damper device is variably controlled in accordance with the ink discharge amount.

Japanese Patent Laid-Open No. 2003-341028 JP 2009-241426 A

  However, when the flow rate greatly fluctuates (pulsates) at the time of liquid feeding as in the case of liquid feeding using a tube pump, the method described in Patent Document 1 has a drawback that the pressure cannot be controlled efficiently. .

  Further, the method of Patent Document 2 has a drawback that when the elastic modulus of the damper film is greatly changed, the pressure is greatly changed at that moment.

  SUMMARY An advantage of some aspects of the invention is that it provides an image recording apparatus capable of stably supplying a liquid while suppressing pressure fluctuation.

  Means for solving the above problems are as follows.

  According to a first aspect, there is provided a liquid discharge head that discharges liquid toward a recording medium and records an image on the recording medium, a liquid tank that stores the liquid, and the liquid from the liquid tank to the liquid discharge head. A liquid supply path for supplying liquid, a liquid chamber provided in the middle of the liquid supply path, in which the liquid flowing in the liquid supply path is temporarily stored, and the liquid chamber and the damper film are partitioned. A main air chamber; a sub air chamber connected to the main air chamber; and an opening / closing means provided at a connection portion between the main air chamber and the sub air chamber, for opening and closing the connection portion. A damper device whose damper capacity is variable by opening and closing, a supply pump that is provided in the middle of the liquid supply path, and that feeds the liquid from the liquid tank toward the damper device, and a pressure of the liquid is To provide a constant A liquid supply control means for controlling the pump, so as to suppress the pressure fluctuation of the liquid by the discharge of the liquid, an image recording apparatus and a damper control means for controlling the damper capacity of the damper device.

  According to this aspect, the damper device capable of changing the damper capacity (elastic modulus) is installed in the liquid supply path. In the damper device, the damper capacity is controlled so as to suppress pressure fluctuation due to discharge. For example, when non-ejection (or when the ejection volume is small), the damper capacity is set large (set so that the elastic modulus is small), and when ejection (or when the ejection volume is large), the damper capacity is small. Is set (the elastic modulus is set to be large). In the damper device, as the damper capacity is increased (the elastic modulus is decreased), the pressure response is delayed with respect to the amount of change in the liquid fed by the pump. Conversely, the smaller the damper capacity (the greater the elastic modulus), the faster the pressure response with respect to the amount of change in pumping liquid. Therefore, pulsation due to the supply pump can be suppressed by setting the damper capacity large (by setting the elastic modulus small) during non-ejection (or when the ejection amount is small). On the other hand, at the time of discharge (or when the discharge amount is large), by setting the damper capacity small (by setting the elastic modulus large), the responsiveness of the liquid feed control by the supply pump can be improved. Pressure fluctuation can be effectively suppressed. Moreover, pressure control can be performed with a small flow rate change by setting the damper capacity small. In addition, since the damper device of this aspect is configured to vary the damper capacity by the communication / non-communication between the main air chamber and the sub air chamber, the damper capacity can be varied without giving a sudden pressure fluctuation ( The effect on back pressure control is almost negligible.) Thereby, the liquid can be stably supplied to the liquid discharge head.

  A second aspect is an image recording apparatus according to the first aspect, wherein a plurality of the auxiliary air chambers are connected in series or in parallel to the main air chamber, and the opening / closing means is provided at each connection portion.

  According to this aspect, a plurality of sub air chambers are connected in series or in parallel to the main air chamber, and opening / closing means are provided at each connection portion. As a result, the volume of the air chamber can be switched in multiple stages, and the damper capacity can be switched in multiple stages. Moreover, the control can be easily performed.

  A third aspect is an image recording apparatus according to the first or second aspect, wherein the opening / closing means is a valve.

  According to this aspect, the opening / closing means is constituted by a valve. Thereby, the volume of the air chamber can be easily switched by opening / closing control of the valve.

  A fourth aspect is an image recording apparatus according to any one of the first to third aspects, wherein the main air chamber is formed in a dome shape.

  According to this aspect, the main air chamber is formed in a dome shape. Thereby, when a damper film | membrane contacts the inner surface of a main air chamber, it can prevent that a damper film | membrane is damaged.

  A fifth aspect according to any one of the first to fourth aspects further comprises pressure detection means for detecting the pressure of the liquid, wherein the liquid supply control means is based on the pressure detected by the pressure detection means. The image recording apparatus controls the supply pump so that the pressure of the liquid becomes constant.

  According to this aspect, the pressure detection means for detecting the pressure of the liquid is further provided, and the supply pump is controlled based on the pressure detected by the pressure detection means so that the pressure of the liquid becomes constant. That is, so-called feedback control is performed. Thereby, the pressure of the liquid supplied to the liquid ejection head can be controlled based on the actual pressure value.

  A sixth aspect further includes pressure fluctuation prediction means for predicting pressure fluctuation of the liquid from an image recorded on the recording medium in any one of the first to fourth aspects, and the liquid supply control means includes the liquid supply control means, The image recording apparatus controls the supply pump so that the pressure of the liquid becomes constant based on the pressure fluctuation of the liquid predicted by a pressure fluctuation prediction unit.

  According to this aspect, the pressure fluctuation prediction means for predicting the pressure fluctuation of the liquid from the image recorded on the recording medium is further provided, and the pressure of the liquid is determined based on the pressure fluctuation of the liquid predicted by the pressure fluctuation prediction means. The feed pump is controlled to be constant. That is, so-called feedforward control is performed. Thereby, the pressure of the liquid supplied to the liquid ejection head can be controlled with a simple configuration.

  According to a seventh aspect, in any one of the first to sixth aspects, the damper control unit is configured to control the damper capacity of the damper device according to a discharge operation and / or a discharge amount of the liquid by the liquid discharge head. Is an image recording apparatus for controlling the image.

  According to this aspect, the damper capacity of the damper device is controlled according to the liquid discharge operation and / or the discharge amount by the liquid discharge head. For example, during non-ejection, the damper capacity is set large (set so that the elastic modulus is small), and during ejection, the damper capacity is set small (set so that the elastic modulus is large). . In addition, for example, when the discharge amount is small or when the discharge amount is small, the damper capacity is set large (set so that the elastic modulus is small), and when the discharge amount is large, the damper capacity is set small (elasticity). The rate is set to be large.) Thereby, it is possible to stably supply the liquid while suppressing the pressure fluctuation.

  According to an eighth aspect, in the seventh aspect, the damper control unit reduces the damper capacity of the damper device in accordance with the timing of the liquid discharge start, and adjusts the liquid discharge in accordance with the timing of the liquid discharge end. This is an image recording apparatus that controls the damper capacity of the damper apparatus to be increased.

  According to this aspect, in the damper device, the damper capacity is reduced in accordance with the liquid discharge start timing, and the damper capacity is increased in accordance with the liquid discharge end timing. Thereby, the pressure fluctuation accompanying discharge can be effectively suppressed, and the pulsation of the liquid due to the liquid feeding of the supply pump can be effectively suppressed.

  According to a ninth aspect, in the seventh aspect, the damper control means reduces the damper capacity of the damper device in accordance with the timing of the liquid discharge start, and after the liquid discharge ends, the liquid pressure In the image recording apparatus, the damper capacity of the damper apparatus is controlled to be increased in accordance with a timing at which the fluctuation falls below a predetermined threshold.

  According to this aspect, the damper device reduces the damper capacity in accordance with the liquid discharge start timing, and the damper capacity in accordance with the timing when the pressure fluctuation of the liquid falls below the predetermined threshold after the liquid discharge ends. Is increased. Thereby, the pressure fluctuation accompanying discharge can be effectively suppressed, and the pulsation of the liquid due to the liquid feeding of the supply pump can be effectively suppressed.

  According to a tenth aspect, in any one of the first to ninth aspects, a head damper device having a damper capacity that is smaller than a damper capacity that can be set by the damper apparatus is provided in the middle of the liquid supply path. An image recording apparatus further provided in the vicinity of the liquid ejection head.

  According to this aspect, the head damper having a small damper capacity is provided in the vicinity of the liquid discharge head. Thereby, the pressure fluctuation accompanying discharge can be suppressed more effectively. Since this head damper device only requires a small damper capacity, a small damper device can be used.

  In an eleventh aspect, a liquid discharge head that discharges liquid toward a recording medium and records an image on the recording medium, a liquid tank that stores the liquid, and the liquid from the liquid tank to the liquid discharge head A liquid supply path for supplying the liquid, a liquid recovery path for recovering the liquid from the liquid discharge head to the liquid tank, and the liquid flowing in the liquid supply path are temporarily stored. A liquid chamber, a main air chamber formed by partitioning the liquid chamber and a damper film, a sub air chamber connected to the main air chamber, and a connection portion between the main air chamber and the sub air chamber An opening / closing means that opens and closes the connecting portion, and opens and closes the opening / closing means to change a damper capacity, and is provided in the middle of the liquid recovery path. The liquid flowing through A liquid chamber that is stored in a reservoir, a main air chamber formed by partitioning the liquid chamber and a damper film, a sub air chamber connected to the main air chamber, the main air chamber, and the sub air chamber, An opening / closing means for opening and closing the connecting portion, and opening and closing the opening / closing means to change the damper capacity, and provided in the middle of the liquid supply path, A supply pump that sends the liquid from the liquid tank toward the supply-side damper device, and a recovery that is provided in the middle of the liquid recovery path and that sends the liquid from the recovery-side damper device toward the liquid tank A pump, a liquid supply control means for controlling the supply pump and the recovery pump so that the pressure of the liquid is constant, and the supply-side damper device so as to suppress pressure fluctuations of the liquid due to the discharge of the liquid The damper capacity of A damper control means for controlling the damper volume of fine the recovery side damper device, an image recording apparatus comprising a.

  According to this aspect, in the image recording apparatus in which liquid is circulated and supplied to the liquid ejection head, the damper device (supply side damper device, recovery side damper device) that can change the damper capacity (elastic modulus) Installed in each of the supply channel and the liquid recovery channel. The damper capacity of each damper device is controlled so as to suppress pressure fluctuation due to discharge. For example, when non-ejection (or when the ejection volume is small), the damper capacity is set large (set so that the elastic modulus is small), and when ejection (or when the ejection volume is large), the damper capacity is small. Is set (the elastic modulus is set to be large). In each damper device, the pressure response becomes slower with respect to the amount of change in liquid delivered by the pump, as the damper capacity increases (the elastic modulus decreases). Conversely, the smaller the damper capacity (the greater the elastic modulus), the faster the pressure response with respect to the amount of change in pumping liquid. Therefore, pulsation caused by each pump (supply pump, recovery pump) can be suppressed by setting the damper capacity large (by setting the elastic modulus small) during non-discharge (or when the discharge amount is small). . On the other hand, at the time of discharge (or when the discharge amount is large), by setting the damper capacity to a small value (by setting the elastic modulus to a large value), the responsiveness of the liquid feed control by each pump can be improved. Pressure fluctuation can be effectively suppressed. Moreover, pressure control can be performed with a small flow rate change by setting the damper capacity small. In addition, the supply-side damper device and the recovery-side damper device of the present aspect are configured to vary the damper capacity by connecting / disconnecting the main air chamber and the sub air chamber, so that the damper does not give a sudden pressure fluctuation. Capacitance can be varied (the effect on back pressure control is almost negligible). Thereby, the liquid can be stably supplied to the liquid discharge head.

  A twelfth aspect is an image recording apparatus according to the eleventh aspect, wherein a plurality of the auxiliary air chambers are connected in series or in parallel to the main air chamber, and the opening / closing means is provided at each connection portion.

  According to this aspect, a plurality of sub air chambers are connected in series or in parallel to the main air chamber, and opening / closing means are provided at each connection portion. As a result, the volume of the air chamber can be switched in multiple stages, and the damper capacity can be switched in multiple stages. Moreover, the control can be easily performed.

  A thirteenth aspect is an image recording apparatus according to the eleventh or twelfth aspect, wherein the opening / closing means is a valve.

  According to this aspect, the opening / closing means is constituted by a valve. Thereby, the volume of the air chamber can be easily switched by opening / closing control of the valve.

  A fourteenth aspect is an image recording apparatus according to any one of the eleventh to thirteenth aspects, wherein the main air chamber is formed in a dome shape.

  According to this aspect, the main air chamber is formed in a dome shape. Thereby, when a damper film | membrane contacts the inner surface of a main air chamber, it can prevent that a damper film | membrane is damaged.

  A fifteenth aspect according to any one of the eleventh to fourteenth aspects, further comprises pressure detection means for detecting the pressure of the liquid, wherein the liquid supply control means is based on the pressure detected by the pressure detection means. The image recording apparatus controls the supply pump and the recovery pump so that the pressure of the liquid becomes constant.

  According to this aspect, the pressure detection means for detecting the pressure of the liquid is further provided, and each pump is controlled based on the pressure detected by the pressure detection means so that the pressure of the liquid becomes constant. That is, so-called feedback control is performed. Thereby, the pressure of the liquid supplied to the liquid ejection head can be controlled based on the actual pressure value.

  A sixteenth aspect according to any one of the eleventh to fourteenth aspects, further comprises pressure fluctuation predicting means for predicting pressure fluctuation of the liquid from an image recorded on the recording medium, wherein the liquid supply control means comprises The image recording apparatus controls the supply pump and the recovery pump so that the pressure of the liquid becomes constant based on the pressure fluctuation of the liquid predicted by the pressure fluctuation prediction unit.

  According to this aspect, the pressure fluctuation prediction means for predicting the pressure fluctuation of the liquid from the image recorded on the recording medium is further provided, and the pressure of the liquid is determined based on the pressure fluctuation of the liquid predicted by the pressure fluctuation prediction means. Each pump is controlled to be constant. That is, so-called feedforward control is performed. Thereby, the pressure of the liquid supplied to the liquid ejection head can be controlled with a simple configuration.

  According to a seventeenth aspect, in any one of the eleventh to sixteenth aspects, the damper control unit is configured to perform the liquid discharge operation and / or the discharge amount of the liquid by the liquid discharge head. It is an image recording apparatus for controlling the damper capacity and the damper capacity of the collection-side damper device.

  According to this aspect, the damper capacity of the damper device is controlled according to the liquid discharge operation and / or the discharge amount by the liquid discharge head. For example, during non-ejection, the damper capacity is set large (set so that the elastic modulus is small), and during ejection, the damper capacity is set small (set so that the elastic modulus is large). . In addition, for example, when the discharge amount is small or when the discharge amount is small, the damper capacity is set large (set so that the elastic modulus is small), and when the discharge amount is large, the damper capacity is set small (elasticity). The rate is set to be large.) Thereby, it is possible to stably supply the liquid while suppressing the pressure fluctuation.

  According to an eighteenth aspect, in the seventeenth aspect, the damper control unit reduces the damper capacity of the supply-side damper device and the damper capacity of the recovery-side damper device in accordance with the timing of the liquid discharge start. The image recording apparatus controls to increase the damper capacity of the supply-side damper apparatus and the damper capacity of the recovery-side damper apparatus in accordance with the timing of completion of the liquid discharge.

  According to this aspect, in the damper device, the damper capacity is reduced in accordance with the liquid discharge start timing, and the damper capacity is increased in accordance with the liquid discharge end timing. Thereby, while being able to suppress the pressure fluctuation accompanying discharge effectively, the pulsation of the liquid by the liquid feeding of a supply pump and a recovery pump can be controlled effectively.

  According to a nineteenth aspect, in the seventeenth aspect, the damper control unit reduces the damper capacity of the supply-side damper device and the damper capacity of the recovery-side damper device in accordance with the timing of the liquid discharge start. After completion of the liquid discharge, control is performed to increase the damper capacity of the supply-side damper device and the damper capacity of the recovery-side damper device in accordance with the timing when the pressure fluctuation of the liquid falls below a predetermined threshold value. An image recording apparatus.

  According to this aspect, each damper device reduces the damper capacity in accordance with the liquid discharge start timing, and after the liquid discharge ends, the damper device matches the timing when the pressure fluctuation of the liquid falls below a predetermined threshold value. Capacity is increased. Thereby, while being able to suppress the pressure fluctuation accompanying discharge effectively, the pulsation of the liquid by the liquid feeding of a supply pump and a recovery pump can be controlled effectively.

  A twentieth aspect is the head supply side according to any one of the eleventh to nineteenth aspects, wherein the head has a damper capacity smaller than a damper capacity that can be set by the supply side damper device in the middle of the liquid supply path. A damper device is further provided in the vicinity of the liquid ejection head, and has a damper capacity that is smaller than the damper capacity that can be set by the recovery side damper device in the middle of the liquid recovery path. Is an image recording apparatus further provided in the vicinity of the liquid discharge head.

  According to this aspect, each of the liquid supply path and the liquid recovery path is provided with a head damper (head supply side damper device, head recovery side damper device) having a small damper capacity. Thereby, the pressure fluctuation accompanying discharge can be suppressed more effectively. This head damper device (head supply side damper device, head recovery side damper device) can be small in size because it requires only a small damper capacity.

  According to the present invention, it is possible to stably supply a liquid while suppressing pressure fluctuation.

Schematic configuration diagram of drawing unit of image recording apparatus Schematic configuration diagram of the first embodiment of the ink supply device Sectional view showing the configuration of the damper device Schematic configuration diagram of ink supply apparatus according to second embodiment Schematic configuration diagram of a third embodiment of an ink supply device Schematic configuration diagram of a modification of the third embodiment of the ink supply device Schematic configuration diagram of a fourth embodiment of an ink supply device Schematic configuration diagram of a modification of the fourth embodiment of the ink supply device Schematic configuration diagram of a modification of the fourth embodiment of the ink supply device Sectional drawing which shows the structure of other embodiment of a damper apparatus Sectional drawing which shows the structure of other embodiment of a damper apparatus

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[Configuration of image recording apparatus]
First, the configuration of the image recording apparatus will be outlined. Here, only the configuration of the drawing unit, which is the main part of the image recording apparatus, will be described.

  FIG. 1 is a schematic configuration diagram of a drawing unit of the image recording apparatus. The image recording apparatus 10 of this example is an ink jet recording apparatus that records color images by discharging color ink onto a single-sheet recording medium 12, and the drawing unit includes a conveyance drum 14 that conveys the recording medium 12, and a conveyance An inkjet head that records a color image by ejecting ink droplets of each color of cyan (C), magenta (M), yellow (Y), and black (K) onto the surface of the recording medium 12 conveyed by the drum 14. (Liquid discharge heads) 16C, 16M, 16Y, and 16K, and ink supply devices 18C, 18M, 18Y, and 18K that supply ink to the inkjet heads 16C, 16M, 16Y, and 16K, respectively.

  The conveyance drum 14 conveys the recording medium 12 by winding the recording medium 12 around the circumferential surface and rotating the recording medium 12. The conveying drum 14 is provided with grippers 14A (installed at two positions on the outer peripheral surface in this example), and the recording medium 12 is conveyed with its leading end held by the grippers 14A. A number of suction holes (not shown) are formed on the peripheral surface of the transport drum 14, and the recording medium 12 is sucked from the suction holes and sucked and held on the outer peripheral surface of the transport drum 14.

  The conveying drum 14 receives the recording medium 12 from a preceding recording medium conveying mechanism (not shown) at a predetermined receiving position. Then, the recording medium 12 is conveyed along a predetermined conveyance path, and the recording medium is delivered to a subsequent recording medium conveyance mechanism (not shown) at a predetermined delivery position.

  The inkjet heads 16C, 16M, 16Y, and 16K are so-called line heads, and are formed corresponding to the width of the recording medium 12 (the length in the direction orthogonal to the transport direction). The inkjet heads 16C, 16M, 16Y, and 16K are arranged at regular intervals along the conveyance path of the recording medium 12, and are arranged orthogonal to the conveyance direction of the recording medium 12. Further, each of the inkjet heads 16C, 16M, 16Y, and 16K has a nozzle surface (a surface on which the nozzle is formed) opposed to the outer peripheral surface of the transport drum 14, and is transported by the transport drum 14. The nozzle surface is disposed at a predetermined height from the surface of the medium 12.

  The ink supply devices 18C, 18M, 18Y, and 18K are provided for each of the inkjet heads 16C, 16M, 16Y, and 16K. Each ink supply device 18C, 18M, 18Y, 18K supplies the corresponding color ink to the inkjet heads 16C, 16M, 16Y, 16K. The configuration of the ink supply devices 18C, 18M, 18Y, and 18K will be described in detail later.

  The drawing unit is configured as described above. The recording medium 12 is subjected to a predetermined pretreatment (for example, application of a predetermined processing liquid (such as a processing liquid having a function of aggregating the coloring material in ink), drying, etc.) as necessary, and then a conveyance drum 14 is passed. The recording medium 12 delivered to the transport drum 14 rotates while being sucked and held on the peripheral surface of the transport drum 14 and is transported along a predetermined transport path. In this transport process, ink droplets are ejected from the inkjet heads 16C, 16M, 16Y, and 16K toward the surface of the recording medium 12, and a color image is recorded on the surface of the recording medium 12. Thereafter, the recording medium 12 on which the image is recorded is transferred from the conveying drum 14 to a recording medium conveying mechanism at a subsequent stage, and subjected to predetermined post-processing (for example, drying, fixing processing, etc.) as necessary.

[Ink supply device]
Next, the ink supply device will be described.

  As described above, the ink supply devices 18C, 18M, 18Y, and 18K supply ink to the inkjet heads 16C, 16M, 16Y, and 16K. Since the configurations of the ink supply devices 18C, 18M, 18Y, and 18K are the same, the configuration of the ink supply device 18 will be described here (the inkjet heads 16C, 16M, 16Y, and 16K are also referred to as the inkjet heads 16). explain.).

[First Embodiment]
<Constitution>
First, the configuration of the ink supply device 18 will be described.

  FIG. 2 is a schematic configuration diagram of the ink supply device according to the first embodiment. As shown in the figure, the ink supply device 18 of the present embodiment mainly includes an ink tank 20 that stores ink, an ink supply pipe 22 that connects the ink tank 20 and the inkjet head 16, and an ink supply pipe 22. A damper device 100 provided in the middle of the ink supply, a supply pump 26 for feeding ink from the ink tank 20 to the inkjet head 16, a supply valve 28 for opening and closing the ink supply pipe 22, and the pressure of the ink flowing through the ink supply pipe 22. The pressure sensor 30 to detect and the control apparatus 32 which controls the whole operation | movement of the ink supply apparatus 18 are comprised.

  The ink tank 20 stores ink to be supplied to the inkjet head 16.

  The ink supply pipe 22 connects the ink tank 20 and the inkjet head 16 and supplies ink from the ink tank 20 to the inkjet head 16.

  The damper device 100 is provided in the middle of the ink supply pipe 22 and suppresses ink pressure fluctuation and adjusts the back pressure. The configuration of the damper device 100 will be described in detail later.

  The supply pump 26 is provided in the middle of the ink supply pipe 22 (between the damper device 100 and the ink tank 20 in this example), and sends ink from the ink tank 20 to the inkjet head 16 via the ink supply pipe 22. To do. The supply pump 26 is constituted by a tube pump, for example. The tube pump controls the amount of liquid delivery by controlling the number of rotations.

  The supply valve 28 is an electromagnetic valve, and is provided in the middle of the ink supply pipe 22 (in this example, between the damper device 100 and the inkjet head 16).

  The pressure sensor 30 is installed between the damper device 100 and the supply valve 28 and detects the pressure of the ink flowing through the ink supply pipe 22. Information on the detected pressure is output to the control device 32.

  The control device 32 is constituted by a microcomputer and executes a predetermined control program to control the overall operation of the ink supply device 18. By opening the supply valve 28 and driving the supply pump 26, the ink stored in the ink tank 20 is sent toward the inkjet head 16. The ink sent from the ink tank 20 is supplied to the inkjet head 16 via the damper device 100. The control device 32 controls the drive of the supply pump 26 so that the pressure value output from the pressure sensor 30 becomes constant (so as to be a preset target pressure).

  FIG. 3 is a cross-sectional view showing the configuration of the damper device.

  As shown in the figure, the damper device 100 includes a damper device body 110, an air tank 130, a main valve 140, and an air release valve 150.

  The damper device main body 110 is formed as a sealed container and is formed of a rigid body. A damper film 112 is disposed inside the damper device main body 110. The internal space of the damper device main body 110 is divided into a liquid chamber 114 and an air chamber (main air chamber) 116 by the damper film 112.

  The liquid chamber 114 temporarily stores the ink flowing through the ink supply pipe 22. In the damper device main body 110, an ink introduction port 118 and an ink discharge port 120 communicating with the liquid chamber 114 are formed. The ink supply pipe 22 is connected to the ink introduction port 118 and the ink discharge port 120 in the middle of the pipeline.

  In this example, the liquid chamber 114 is formed as a rectangular parallelepiped space, and a circular opening 114A is formed on one surface thereof (a surface adjacent to the main air chamber 116).

  The main air chamber 116 is formed as a dome-shaped space having a circular opening 116A. The main air chamber 116 stores gas (air). An air tank communication port 122 communicating with the main air chamber 116 is formed in the damper device main body 110. The air tank communication port 122 communicates with the top portion (central portion) of the main air chamber 116 formed in a dome shape.

  The opening 116A of the main air chamber 116 and the opening 114A of the liquid chamber 114 are formed with the same diameter. The main air chamber 116 and the liquid chamber 114 are arranged adjacent to each other so that the openings 116A and 114A are located on the same axis.

  The damper film 112 is attached so as to block the opening 116A of the main air chamber 116 and the opening 114A of the liquid chamber 114. The damper film 112 is composed of a flexible film body (for example, a film made of an elastic body such as a rubber film). As described above, since the opening 116A of the main air chamber 116 and the opening 114A of the liquid chamber 114 are formed in a circular shape, the damper film 112 is also formed in a circular shape.

  The air tank 130 is formed as a tank that stores gas (air), and is formed of a rigid body. Inside the air tank 130, an air chamber (sub-air chamber) 132 for storing gas (air) is formed. The air tank 130 is formed with an air release port 134 and a damper device main body communication port 136 that communicate with the auxiliary air chamber 132.

  Connected to the atmosphere opening 134 is an atmosphere opening pipe 160 having one end opened to the atmosphere. On the other hand, one end of the connecting pipe 162 is connected to the damper device main body communication port 136. The connection pipe 162 is formed of a rigid body, and the other end is connected to an air tank communication port 122 formed in the damper device main body 110. That is, the connection pipe 162 connects the main air chamber 116 of the damper device main body 110 and the sub air chamber 132 of the air tank 130.

  The main valve 140 is provided in the connection pipe 162 and opens and closes the pipe line of the connection pipe 162. The main air chamber 116 of the damper device main body 110 communicates with the sub air chamber 132 of the air tank 130 when the main valve 140 is opened, and communication with the sub air chamber 132 of the air tank 130 is blocked when the main valve 140 is closed. .

  The atmosphere release valve 150 is provided in the atmosphere release pipe 160 and opens and closes the conduit of the atmosphere release pipe 160. The auxiliary air chamber 132 of the air tank 130 is opened to the atmosphere when the atmosphere release valve 150 is opened, and is sealed when the atmosphere is closed.

  The damper device 100 is configured as described above. As described above, in the damper device 100, the main air chamber 116 and the sub air chamber 132 are communicated / not communicated by opening / closing the main valve 140. The main air chamber 116 and the sub air chamber 132 constitute an air chamber of the damper device 100, and the volume of the air chamber is enlarged / reduced by opening and closing the main valve 140. That is, when the main valve 140 is closed, an air chamber is formed only by the main air chamber 116, and when the main valve 140 is opened, an air chamber is formed by the main air chamber 116 and the sub air chamber 132. In the damper device 100, when the volume of the air chamber is reduced, the damper capacity is reduced (the elastic modulus is increased), and when the volume of the air chamber is increased, the damper capacity is increased (the elastic modulus is reduced). Therefore, when the damper capacity is reduced (when the elastic modulus is increased), the main valve 140 is closed, and when the damper capacity is increased (when the elastic modulus is decreased), the main valve 140 is opened to arbitrarily set the damper capacity. The damper capacity can be switched. The damper device 100 can increase the responsiveness of the liquid feeding control by the supply pump 26 by reducing the damper capacity (increasing the elastic modulus). On the other hand, by increasing the damper capacity (decreasing the elastic modulus), it is possible to absorb the pulsation of the ink accompanying the liquid feeding of the supply pump 26. Therefore, stable ink supply can be achieved by controlling the switching of the damper capacity according to the purpose.

<Action>
Next, the ink supply operation by the ink supply device 18 will be described.

  By opening the supply valve 28 and driving the supply pump 26, the ink stored in the ink tank 20 is fed toward the inkjet head 16, and the ink is supplied to the inkjet head 16 via the damper device 100.

  The control device 32 acquires the pressure of the ink flowing through the ink supply pipe 22 from the pressure sensor 30, and drives the supply pump 26 so that the pressure value becomes constant (so that it becomes a preset target pressure). Control. For example, the rotational speed of the supply pump 26 is determined from the difference between the target pressure value and the current pressure value, and the pressure of the ink flowing through the ink supply pipe 22 is controlled to be constant (so-called PID control).

  By the way, as described above, the damper device 100 can switch the damper capacity (elastic modulus) between large and small by opening and closing the main valve 140. The switching of the damper capacity is performed in conjunction with the ink ejection operation (image recording operation) from the inkjet head 16. That is, during ejection (during image recording), the main valve 140 is closed, the air chamber is reduced, and the damper capacity is reduced (elastic modulus is increased). On the other hand, when not discharging (during non-recording), the main valve 140 is opened, the air chamber is expanded, and the damper capacity is increased (elastic modulus is decreased).

  The reason for opening the main valve 140 when not discharging and increasing the damper capacity (decreasing the elastic modulus) is to reduce the ink pulsation caused by the liquid feeding of the supply pump 26 as much as possible.

  On the other hand, when the damper capacity is increased, the pressure response is delayed with respect to the amount of change in liquid supply by the supply pump 26. If pressure fluctuations occur during discharge in this state, even if the amount (rotation speed) of the supply pump 26 is changed in order to suppress the fluctuations, the response cannot catch up and the pressure fluctuations can be effectively suppressed. Can not. That is, since the pressure fluctuation time due to the discharge is sufficiently shorter than the response time when the damper capacity is increased, even if the liquid feed amount of the supply pump 26 is adjusted by feedback control, the response cannot catch up, and the effect Fluctuations cannot be suppressed.

  Therefore, during ejection (during image recording), the main valve 140 is closed, the damper capacity is reduced (increase the elastic modulus), the response time is shortened, and the rotation of the supply pump 26 is controlled against pressure fluctuations. Increase responsiveness.

  Thus, in the image recording apparatus 10 of the present embodiment, stable ink supply can be performed by switching the damper capacity of the damper device 100 in conjunction with the ink ejection operation from the inkjet head 16.

  Further, when the damper capacity (elastic modulus) of the damper device 100 is switched, the elastic capacity of the damper film 112 is not switched, but the volume of the air chamber (main air chamber 116 + sub air chamber 132) is switched to switch the damper capacity. Since the configuration is adopted, the damper capacity can be switched without significant pressure fluctuation at the time of switching. Thereby, more stable ink supply can be performed.

  In addition, by reducing the damper capacity at the time of discharge (increasing the elastic modulus), the pressure control can be performed with a small flow rate change when adjusting the pressure fluctuation caused by the discharge with the liquid feed amount of the supply pump 26.

<Adjustment of initial position of damper film>
In the damper device 100, the position of the damper film 112 changes with time. When the position of the damper film 112 changes, the ink pressure control varies. Therefore, the position adjustment of the damper film 112 is performed as appropriate.

  Examples of the timing at which the position adjustment of the damper film 112 is executed include when the pressure in the ink supply pipe 22 is greatly changed due to an abnormality of the supply pump 26 or the like after the start-up of the apparatus or after execution of the pressure purge. .

  Hereinafter, a method for adjusting the position of the damper film will be described.

  When the position adjustment process of the damper film 112 is started, first, the supply valve 28 is closed. As a result, the ink supply pipe 22 and the ink jet head 16 are not in communication.

  Next, the main valve 140 and the air release valve 150 are opened. As a result, the main air chamber 116 and the sub air chamber 132 communicate with each other, and the main air chamber 116 and the sub air chamber 132 are opened to the atmosphere.

  Next, the supply pump 26 is driven forward (pressure drive). Thereby, ink is sent from the ink tank 20. Here, since the supply valve 28 is closed as described above, the inside of the liquid chamber 114 is pressurized by feeding ink from the ink tank 20. When the inside of the liquid chamber 114 is pressurized, the damper film 112 is displaced in the direction of the main air chamber 116.

  The control device 32 monitors the pressure detected by the pressure sensor 30 and stops driving the supply pump 26 when a predetermined pressure set in advance is reached.

  After stopping the drive of the supply pump 26, the control device 32 drives the supply pump 26 in the reverse direction (reduced pressure drive). Then, the elapsed time from the start of decompression is monitored, and when the predetermined time set in advance is reached, the atmosphere release valve 150 is closed. As a result, the damper film 112 is positioned at a predetermined position.

  In this way, by appropriately performing the position adjustment of the damper film 112, it is possible to avoid variations in pressure control over time and to perform more stable ink supply.

<Pressure purge>
Next, operations of the supply valve 28, the main valve 140, the air release valve 150, and the supply pump 26 when performing a pressure purge will be described.

  The pressure purge is a process for forcibly discharging the ink in the head from the nozzles with the internal pressure of the inkjet head 16 as a positive pressure.

  The pressure purge includes a step of fixing the film position, a step of storing pressure, and a step of discharging ink.

  First, a step of fixing the film position is performed. This step is a step in which the damper film 112 is deformed and attached to the inner wall surface of the main air chamber 116.

  First, the supply valve 28 is closed.

  Next, the main valve 140 and the air release valve 150 are opened, the main air chamber 116 is communicated with the sub air chamber 132 and the air is released to the atmosphere.

  Next, the supply pump 26 is rotated forward (pressurized). Thereby, ink is sent from the ink tank 20. Here, since the supply valve 28 is closed as described above, the inside of the liquid chamber 114 is pressurized by feeding ink from the ink tank 20. When the inside of the liquid chamber 114 is pressurized, the damper film 112 is displaced in the direction of the main air chamber 116.

  When the displaced damper film 112 is attached to the inner wall surface of the main air chamber 116, the main valve 140 and the air release valve 150 are closed.

  Thus, the process of fixing the film position is completed. By this process, the damper film 112 is fixed in a state of being attached to the inner wall surface of the main air chamber 116. Since the damper film 112 is fixed in a state where it is adhered to the inner wall surface of the main air chamber 116, the liquid chamber 114 is in a state in which the volume is maximum.

  When the step of fixing the membrane position is completed, the step of storing pressure is subsequently performed. This step is a step of filling the liquid chamber 114 having the maximum volume with ink and accumulating the pressure required for purging in the liquid chamber 114.

  The supply pump 26 continues to perform forward rotation (pressurization drive). Thereby, the inside of the liquid chamber 114 is pressurized.

  The control device 32 monitors the detected pressure of the pressure sensor 30. When the detected pressure of the pressure sensor 30 reaches a preset specified pressure, this process ends.

  When the step of storing pressure (pressure storage step) is completed, the step of discharging ink is subsequently executed. This step is a step of discharging (purging) ink from the nozzles of the inkjet head 16 using the pressure stored in the pressure storage step.

  First, the supply valve 28 is opened. As a result, the ink stored in the pressure storage process flows into the inkjet head 16. As the ink flows into the inkjet head 16, the internal pressure of the inkjet head 16 becomes positive and the ink is discharged from the inkjet head 16. At this time, the supply pump 26 is positively operated (pressurized) so that the internal pressure of the inkjet head 16 does not drop.

  The control device 32 monitors the elapsed time since the supply valve 28 was opened. When the predetermined time has elapsed, the control device 32 closes the supply valve 28 and stops driving the supply pump 26.

  The pressure purge process is completed in a series of steps as described above.

  According to the above method, the damper film 112 is brought into close contact with the inner wall surface of the main air chamber 116, and the pressure is increased with the liquid chamber 114 being maximized, so that the pressure wave of the pressure purge can be sharpened, and bubbles and foreign matters can be removed. It can be efficiently removed from the nozzle.

  At this time, since the inner air wall 116 is formed in an arc shape, the main air chamber 116 can be brought into close contact without damaging the damper film 112.

[Second Embodiment]
FIG. 4 is a schematic configuration diagram of a second embodiment of the ink supply device.

  As shown in the figure, the ink supply device 18 of the present embodiment is different from the ink supply device 18 of the first embodiment described above in that it further includes a head damper device 170.

  The head damper device 170 is installed mainly for the purpose of suppressing pressure fluctuations accompanying ink ejection, and is disposed in the vicinity of the inkjet head 16. Unlike the damper device 100, the head damper device 170 is formed with a constant damper capacity (elastic modulus), and the damper capacity is reduced by closing the damper capacity of the damper apparatus 100 (the main valve 140 is closed). It is set smaller than the damper capacity at the time.

  By providing such a head damper device 170, it is possible to more efficiently suppress ink pressure fluctuations. In other words, when a pressure fluctuation accompanying ink ejection occurs, the head damper device 170 can suppress the pressure fluctuation up to a certain range, so that the ink pressure fluctuation can be suppressed more efficiently. Further, even when pressure fluctuations occur beyond a certain range, as described above, the damper capacity of the damper device 100 is reduced, and the responsiveness by the rotation control of the supply pump 26 is improved, so that the efficiency is improved. Pressure fluctuations can be absorbed.

  As described above, since the damper capacity for the head 170 is set smaller than that of the damper apparatus 100, a small-sized one can be used. Therefore, even if it is the case where it installs in the vicinity of the inkjet head 16, the circumference | surroundings of the inkjet head 16 can be installed without enlarging. That is, it can be installed even in a space-saving manner.

  In addition, unlike the damper device 100, the head damper device 170 may have a constant damper capacity, and the specific configuration thereof is not particularly limited. The liquid chamber and the air chamber may be separated from each other by a damper film, or the air chamber side may be open to the atmosphere. Moreover, the structure which hold | maintains a damper film | membrane with a biasing member (a spring etc.) and ensures fixed damper capacity | capacitance may be sufficient.

[Third Embodiment]
FIG. 5 is a schematic configuration diagram of a third embodiment of the ink supply device.

  As shown in the figure, the ink supply device 18 of the present embodiment supplies ink to a so-called multi-type inkjet head 16.

  The inkjet head 16 is configured by connecting n head modules 180. An ink supply pipe 22 that supplies ink to the inkjet head 16 is connected to the manifold 182. The manifold 182 is connected to each head module 180 via the branch pipe 184. Each branch pipe 184 is provided with a supply valve 28 individually.

  In this way, even when ink is supplied to the so-called multi-type inkjet head 16, a head damper device can be installed. In this case, as shown in FIG. 6, each branch pipe 184 is provided with a head damper device 170.

[Fourth Embodiment]
FIG. 7 is a schematic configuration diagram of the fourth embodiment of the ink supply apparatus.

  As shown in the figure, the ink supply device 18 of the present embodiment supplies ink circulated to the inkjet head 16.

  The ink supply device 18 of this embodiment mainly includes an ink tank 20 that stores ink, and an ink supply pipe 22S that connects the ink tank 20 and the inkjet head 16 to supply ink from the ink tank 20 to the inkjet head 16. A supply-side damper device 100S provided in the middle of the ink supply pipe 22S, a supply pump 26S for feeding ink from the ink tank 20 to the inkjet head 16, a supply valve 28S for opening and closing the ink supply pipe 22S, and an ink supply A supply-side pressure sensor 30S that detects the pressure of the ink flowing through the tube 22S, an ink recovery tube 22R that connects the ink tank 20 and the inkjet head 16 and recovers ink from the inkjet head 16 to the ink tank 20, and an ink recovery tube Collection provided in the middle of 22R A damper device 100R, a recovery pump 26R for feeding ink from the inkjet head 16 to the ink tank 20, a recovery valve 28R for opening and closing the ink recovery tube 22R, and a recovery-side pressure for detecting the pressure of the ink flowing through the ink recovery tube 22R The sensor 30 </ b> R and a control device (not shown) that controls the overall operation of the ink supply device 18 are configured.

  The ink tank 20 stores ink for circulating supply to the inkjet head 16.

  The ink supply pipe 22 </ b> S connects the ink tank 20 and the inkjet head 16 and supplies ink from the ink tank 20 to the inkjet head 16.

  The supply-side damper device 100S is provided in the middle of the ink supply tube 22S, and suppresses ink pressure fluctuations and adjusts back pressure. The configuration of the supply-side damper device 100S is the same as that of the damper device 100 of the first embodiment described above.

  The supply pump 26S is provided in the middle of the ink supply pipe 22S (between the supply-side damper device 100S and the ink tank 20 in this example), and supplies ink from the ink tank 20 to the inkjet head 16 via the ink supply pipe 22S. Deliver liquid.

  The supply valve 28S is an electromagnetic valve, and is provided in the middle of the ink supply pipe 22S (in this example, between the supply-side damper device 100S and the inkjet head 16).

  The supply-side pressure sensor 30S is installed between the supply-side damper device 100S and the supply valve 28S, and detects the pressure of ink flowing through the ink supply pipe 22S. Information on the detected pressure is output to the control device.

  The ink recovery tube 22R connects the ink tank 20 and the inkjet head 16 and recovers ink from the inkjet head 16 to the ink tank 20.

  The recovery-side damper device 100R is provided in the middle of the ink recovery tube 22R and suppresses ink pressure fluctuation and adjusts the back pressure. The configuration of the recovery-side damper device 100R is the same as that of the damper device 100 of the first embodiment described above.

  The recovery pump 26R is provided in the middle of the ink recovery tube 22R (between the recovery-side damper device 100R and the ink tank 20 in this example), and supplies ink from the inkjet head 16 to the ink tank 20 via the ink recovery tube 22R. Deliver liquid.

  The recovery valve 28R is configured by an electromagnetic valve, and is provided in the middle of the ink recovery pipe 22R (in this example, between the recovery-side damper device 100R and the inkjet head 16).

  The recovery side pressure sensor 30R is installed between the recovery side damper device 100R and the recovery valve 28R, and detects the pressure of the ink flowing through the ink recovery pipe 22R. Information on the detected pressure is output to the control device.

  The control device (not shown) is composed of a microcomputer and executes a predetermined control program to control the overall operation of the ink supply device 18. By opening the supply valve 28S and the recovery valve 28R and driving the supply pump 26S and the recovery pump 26R, the ink stored in the ink tank 20 is circulated and supplied to the inkjet head 16. The ink is supplied to the inkjet head 16 via the supply-side damper device 100S and is recovered to the ink tank 20 via the recovery-side damper device 100R. The control device drives the supply pump 26S and the recovery pump 26R so that the pressure values output from the supply-side pressure sensor 30S and the recovery-side pressure sensor 30R are constant (so that the target pressure is set in advance). Control.

  The ink supply device 18 of the present embodiment is configured as described above. Ink supply by the ink supply device 18 of the present embodiment is performed as follows.

  Next, the ink supply operation by the ink supply device 18 will be described.

  First, the supply valve 28S and the recovery valve 28R are opened. Next, the supply pump 26S and the recovery pump 26R are driven. Thereby, the ink stored in the ink tank 20 is circulated and supplied to the inkjet head 16. At this time, the ink is supplied to the ink-jet head 16 via the supply-side damper device 100S and is recovered to the ink tank 20 via the recovery-side damper device 100R.

  The control device acquires the pressure of the ink flowing through the ink supply pipe 22S and the ink recovery pipe 22R from the supply side pressure sensor 30S and the recovery side pressure sensor 30R, and makes the pressure value constant (a preset target pressure). The driving of the supply pump 26S and the recovery pump 26R is controlled.

  On the other hand, the control device controls driving of the supply-side damper device 100S and the recovery-side damper device 100R in accordance with the ejection of ink from the inkjet head 16. That is, during ejection (during image recording), the volume of the air chamber is reduced to reduce the damper capacity (increase the elastic modulus), and when not ejected (during image non-recording), the volume of the air chamber is reduced. Enlarge to increase damper capacity (decrease elastic modulus). As described above, by switching the damper capacities of the supply-side damper device 100S and the recovery-side damper device 100R in accordance with the ink ejection operation, stable ink supply can be performed as in the first embodiment. it can.

  In addition, in the ink supply device 18 of the present embodiment, by circulating the ink, it is possible to prevent ink stagnation and the like and to realize more stable ink discharge.

  In addition, as shown in FIG. 8, also when supplying ink to what is called a multi-type inkjet head 16, it can circulate and supply. In this case, the ink supply pipe 22S that supplies ink to the inkjet head 16 is connected to the supply side manifold 182S, and the supply side manifold 182S is connected to each head module 180 via the supply side branch pipe 184S. The ink recovery pipe 22R that recovers ink from the inkjet head 16 is connected to the recovery side manifold 182R, and the recovery side manifold 182R is connected to each head module 180 via the recovery side branch pipe 184R. Each supply-side branch pipe 184S is individually provided with a supply valve 28S, and each recovery-side branch pipe 184R is individually provided with a recovery valve 28R.

  In addition, even when ink is circulated and supplied to the multi-type inkjet head 16, a head damper device can be installed. In this case, as shown in FIG. 9, each supply-side branch pipe 184S is provided with a head supply-side damper device 170S, and each recovery-side branch pipe 184R is provided with a head recovery-side damper device 170R.

[Other forms of damper device]
The damper device 100 of the first embodiment is configured such that one air tank 130 is connected to the damper device main body 110 so that the damper capacity (elastic modulus) can be switched in two stages, large and small. An air tank may be connected so that the damper capacity can be switched in multiple stages.

  For example, as shown in FIG. 10, two air tanks, a first air tank 130A and a second air tank 130B, can be connected in series to the damper device main body 110 so that the damper capacity can be switched in three stages. In this case, the damper device main body 110 and the first air tank 130A are connected by the first connection pipe 162A, and the first air tank 130A and the second air tank 130B are connected by the second connection pipe 162B. Then, the first valve 140A is installed in the first connection pipe 162A, and the second valve 140B is installed in the second connection pipe 162B. The second air tank 130 </ b> B is connected to the atmosphere release pipe 160, and the atmosphere release valve 150 is installed in the atmosphere release pipe 160.

  According to the above configuration, when the first valve 140A is opened, the air chamber (main air chamber) 116 of the damper device main body 110 and the air chamber (first sub air chamber) 132A of the first air tank 130A communicate with each other. When the second valve 140B is opened, the air chamber (first sub air chamber) 132A of the first air tank 130A communicates with the air chamber (second sub air chamber) of the second air tank 130B.

  Therefore, when both the first valve 140A and the second valve 140B are closed, the total volume of the air chamber becomes only the volume of the main air chamber 116. When the first valve 140A is opened and the second valve 140B is closed, the total volume of the air chamber becomes the sum of the volumes of the main air chamber 116 and the first sub air chamber 132A. When both the first valve 140A and the second valve 140B are opened, the total volume of the air chamber is equal to the volume of the main air chamber 116, the first sub air chamber 132A, and the second sub air chamber 132B. Become sum.

  Therefore, when both the first valve 140A and the second valve 140B are closed, the volume of the air chamber is small, and when the first valve 140A is opened and the second valve 140B is closed, the volume of the air chamber is medium. When both the valve 140A and the second valve 140B are opened, the total volume of the air chamber becomes large, and the damper capacity can be switched between three levels: small, medium, and large.

  Similarly, as shown in FIG. 11, two air tanks, a first air tank 130A and a second air tank 130B, can be connected in parallel to the damper device main body 110 so that the damper capacity can be switched in three stages. In this case, the damper device main body 110 and the first air tank 130A are connected by the first connection pipe 162A, and the damper device main body 110 and the second air tank 130B are connected by the second connection pipe 162B. Then, the first valve 140A is installed in the first connection pipe 162A, and the second valve 140B is installed in the second connection pipe 162B. In addition, atmospheric release pipes 160A and 160B are connected to the first air tank 130A and the second air tank 130B, respectively, and atmospheric release valves 150A and 150B are installed in the atmospheric release pipes 160A and 160B.

  According to the above configuration, when the first valve 140A is opened, the air chamber (main air chamber) 116 of the damper device main body 110 and the air chamber (first sub air chamber) 132A of the first air tank 130A communicate with each other. When the second valve 140B is opened, the air chamber (main air chamber) 116 of the damper device main body 110 and the air chamber (second sub air chamber) of the second air tank 130B are communicated.

  Therefore, when both the first valve 140A and the second valve 140B are closed, the total volume of the air chamber becomes only the volume of the main air chamber 116. When the first valve 140A is opened and the second valve 140B is closed, the total volume of the air chamber becomes the sum of the volumes of the main air chamber 116 and the first sub air chamber 132A, and the first valve 140A is closed. When the second valve 140B is opened, the total volume of the air chamber becomes the sum of the volumes of the main air chamber 116 and the second sub air chamber 132B. When both the first valve 140A and the second valve 140B are opened, the total volume of the air chamber is equal to the volume of the main air chamber 116, the first sub air chamber 132A, and the second sub air chamber 132B. Become sum.

  Therefore, when both the first valve 140A and the second valve 140B are closed, the volume of the air chamber is small, and when the first valve 140A is opened and the second valve 140B is closed, or the first valve 140A is closed. When the second valve 140B is opened, the volume of the air chamber is medium, and when both the first valve 140A and the second valve 140B are opened, the total volume of the air chamber is large, and the damper capacity is small, medium, and large. It is possible to switch to three stages.

  In this way, the damper capacity can be switched in multiple stages by increasing or decreasing the number of installed air tanks as necessary.

  For this reason, for example, when printing with non-ejection or a pattern with a small ejection volume, the damper capacity is set to a large value (the elastic modulus is small). When the capacity is set to medium (elastic modulus is medium), the discharge amount is large, and the pressure fluctuation is large, it is possible to perform control such that the damper capacity is set to small (elastic modulus is large).

[Other forms of pump control]
In the above embodiment, the feedback method is adopted as the control method of the pump (supply pump, recovery pump) for keeping the pressure constant, but the pump control method is not limited to this. For example, you may make it control by a feedforward system. In the case of the feed-forward method, for example, the discharge droplet amount is calculated in advance from the image data information, and the pressure fluctuation range predicted from the discharge droplet amount is tabulated and acquired in advance (test printing). Time). Then, based on the information, the amount of pumped liquid (rotation speed) that cancels the fluctuating pressure is calculated, and pressure control is performed.

[Other Embodiments]
In the above embodiment, the damper capacity is switched according to the ejection of ink from the inkjet head 16, but the damper capacity may be switched according to the ejection amount. For example, when the discharge is not performed and when the discharge amount is small, the main valve 140 is opened, the air chamber is expanded to increase the damper capacity (decrease the elastic modulus), and when the discharge amount is large, the main valve 140 is closed. The air chamber may be reduced to reduce the damper capacity (increase the elastic modulus).

  Further, in the above embodiment, the damper capacity is reduced in accordance with the timing of the start of liquid discharge, and the damper capacity is increased in accordance with the timing of the end of liquid discharge. However, the timing of increasing the damper capacity again. That is, the timing at which the main valve 140 is opened again can be the timing at which the ink pressure fluctuation falls below a certain level (timing at which the ink pressure falls below a predetermined threshold) after the end of ejection.

  In the above embodiment, the main air chamber and the sub air chamber are connected / disconnected by opening / closing the valve (main valve). However, the main air chamber and the sub air chamber are connected / disconnected. The configuration to be made is not limited to this. In addition, for example, a shutter may be provided between the main air chamber and the sub air chamber, and the main air chamber and the sub air chamber may be connected / disconnected by opening / closing the shutter.

  DESCRIPTION OF SYMBOLS 10 ... Image recording device, 12 ... Recording medium, 14 ... Conveying drum, 14A ... Gripper, 16 (16C, 16M, 16Y, 16K) ... Inkjet head, 18 (18C, 18M, 18Y, 18K) ... Ink supply device, 20 Ink tank, 22 ... Ink supply tube, 22R ... Ink recovery tube, 22S ... Ink supply tube, 26 ... Supply pump, 26R ... Recovery pump, 26S ... Supply pump, 28 ... Supply valve, 28R ... Recovery valve, 28S ... Supply Valve, 30 ... Pressure sensor, 30R ... Recovery side pressure sensor, 30S ... Supply side pressure sensor, 32 ... Control device, 100 ... Damper device, 100R ... Recovery side damper device, 100S ... Supply side damper device, 110 ... Damper device body 112 ... Damper film, 114 ... Liquid chamber, 114A ... Opening, 116 ... Main air chamber, 116A ... Opening, 118 Ink introduction port, 120 ... Ink discharge port, 122 ... Air tank communication port, 130 ... Air tank, 130A ... First air tank, 130B ... Second air tank, 132 ... Sub air chamber, 132A ... First sub air chamber, 132B ... First 2 sub-air chambers, 134 ... atmosphere release port, 136 ... damper device main body communication port, 140 ... main valve, 140A ... first valve, 140B ... second valve, 150 ... atmosphere release valve, 150A ... atmosphere release valve, 150B ... Air release valve, 160 ... Air release pipe, 160A ... Air release pipe, 160B ... Air release pipe, 162 ... Connection pipe, 162A ... First connection pipe, 162B ... Second connection pipe, 170 ... Head damper device, 170R ... head recovery side damper device, 170S ... head supply side damper device, 180 ... head module, 182 ... manifold, 1 2R ... recovery side manifold, 182S ... supply-side manifold, 184 ... branch pipe, 184R ... recovery side branch pipes, 184s ... supply branch pipe

Claims (20)

A liquid discharge head that discharges liquid toward a recording medium and records an image on the recording medium;
A liquid tank for storing the liquid;
A liquid supply path for supplying the liquid from the liquid tank to the liquid discharge head;
A liquid chamber provided in the middle of the liquid supply path and temporarily storing the liquid flowing through the liquid supply path; a main air chamber formed by partitioning the liquid chamber and a damper film; and the main air An auxiliary air chamber connected to the chamber; and an opening / closing means provided at a connection portion between the main air chamber and the auxiliary air chamber for opening and closing the connection portion, and opening and closing the opening / closing means to A damper device that is variable,
A supply pump that is provided in the middle of the liquid supply path and feeds the liquid from the liquid tank toward the damper device;
Liquid supply control means for controlling the supply pump so that the pressure of the liquid is constant;
Damper control means for controlling the damper capacity of the damper device so as to suppress pressure fluctuations of the liquid due to the discharge of the liquid;
An image recording apparatus comprising:   The image recording apparatus according to claim 1, wherein a plurality of the auxiliary air chambers are connected in series or in parallel to the main air chamber, and the opening / closing means is provided at each connection portion.   The image recording apparatus according to claim 1, wherein the opening / closing means is a valve.   The image recording apparatus according to claim 1, wherein the main air chamber is formed in a dome shape.   The apparatus further comprises pressure detection means for detecting the pressure of the liquid, and the liquid supply control means controls the supply pump based on the pressure detected by the pressure detection means so that the pressure of the liquid becomes constant. The image recording apparatus according to claim 1, wherein the image recording apparatus is an image recording apparatus.   Pressure fluctuation predicting means for predicting the pressure fluctuation of the liquid from the image recorded on the recording medium, the liquid supply control means based on the pressure fluctuation of the liquid predicted by the pressure fluctuation predicting means, The image recording apparatus according to claim 1, wherein the supply pump is controlled so that the pressure of the liquid becomes constant.   7. The damper control unit according to claim 1, wherein the damper control unit controls the damper capacity of the damper device according to a discharge operation and / or a discharge amount of the liquid by the liquid discharge head. The image recording apparatus described in 1.   The damper control means controls to reduce the damper capacity of the damper device in accordance with the timing of the liquid discharge start and to increase the damper capacity of the damper device in accordance with the timing of the liquid discharge end. The image recording apparatus according to claim 7, wherein:   The damper control means reduces the damper capacity of the damper device in accordance with the timing of starting the discharge of the liquid, and in accordance with the timing when the pressure fluctuation of the liquid falls below a predetermined threshold after the end of the discharge of the liquid. The image recording apparatus according to claim 7, wherein the damper device is controlled to increase the damper capacity.   The head damper device having a damper capacity smaller than a damper capacity that can be set by the damper device is further provided in the vicinity of the liquid discharge head in the middle of the liquid supply path. The image recording apparatus according to any one of 1 to 9. A liquid discharge head that discharges liquid toward a recording medium and records an image on the recording medium;
A liquid tank for storing the liquid;
A liquid supply path for supplying the liquid from the liquid tank to the liquid discharge head;
A liquid recovery path for recovering the liquid from the liquid discharge head to the liquid tank;
A liquid chamber provided in the middle of the liquid supply path and temporarily storing the liquid flowing through the liquid supply path; a main air chamber formed by partitioning the liquid chamber and a damper film; and the main air An auxiliary air chamber connected to the chamber; and an opening / closing means provided at a connection portion between the main air chamber and the auxiliary air chamber for opening and closing the connection portion, and opening and closing the opening / closing means to A supply-side damper device that is variable,
A liquid chamber provided in the middle of the liquid recovery path and temporarily storing the liquid flowing through the liquid recovery path; a main air chamber formed by partitioning the liquid chamber and a damper film; and the main air An auxiliary air chamber connected to the chamber; and an opening / closing means provided at a connection portion between the main air chamber and the auxiliary air chamber for opening and closing the connection portion, and opening and closing the opening / closing means to A recovery-side damper device that is variable,
A supply pump that is provided in the middle of the liquid supply path and feeds the liquid from the liquid tank toward the supply-side damper device;
A recovery pump which is provided in the middle of the liquid recovery path and sends the liquid from the recovery side damper device toward the liquid tank;
Liquid supply control means for controlling the supply pump and the recovery pump so that the pressure of the liquid becomes constant;
Damper control means for controlling the damper capacity of the supply-side damper device and the damper capacity of the recovery-side damper device so as to suppress pressure fluctuations of the liquid due to the discharge of the liquid;
An image recording apparatus comprising:   12. The image recording apparatus according to claim 11, wherein a plurality of the auxiliary air chambers are connected in series or in parallel to the main air chamber, and the opening / closing means is provided at each connection portion.   13. The image recording apparatus according to claim 11, wherein the opening / closing means is a valve.   The image recording apparatus according to claim 11, wherein the main air chamber is formed in a dome shape.   Pressure detection means for detecting the pressure of the liquid; and the liquid supply control means is configured to make the pressure of the liquid constant based on the pressure detected by the pressure detection means. The image recording apparatus according to claim 11, wherein the recovery pump is controlled.   Pressure fluctuation predicting means for predicting the pressure fluctuation of the liquid from the image recorded on the recording medium, the liquid supply control means based on the pressure fluctuation of the liquid predicted by the pressure fluctuation predicting means, The image recording apparatus according to claim 11, wherein the supply pump and the recovery pump are controlled so that a pressure of the liquid becomes constant.   The damper control means controls the damper capacity of the supply-side damper device and the damper capacity of the recovery-side damper device in accordance with the liquid discharge operation and / or discharge amount by the liquid discharge head. The image recording apparatus according to any one of claims 11 to 16.   The damper control means reduces the damper capacity of the supply-side damper device and the damper capacity of the recovery-side damper device in accordance with the liquid discharge start timing, and matches the liquid discharge end timing with the liquid discharge end timing. 18. The image recording apparatus according to claim 17, wherein control is performed to increase the damper capacity of the supply-side damper apparatus and the damper capacity of the recovery-side damper apparatus.   The damper control means reduces the damper capacity of the supply-side damper device and the damper capacity of the recovery-side damper device in accordance with the timing of starting the discharge of the liquid, and after the discharge of the liquid, the pressure of the liquid 18. The image according to claim 17, wherein control is performed so that the damper capacity of the supply-side damper device and the damper capacity of the recovery-side damper device are increased in accordance with a timing at which the fluctuation falls below a predetermined threshold value. Recording device.   In the middle of the liquid supply path, a head supply-side damper device having a damper capacity smaller than a damper capacity that can be set by the supply-side damper device is further provided near the liquid discharge head, and the liquid In the middle of the recovery path, a head recovery side damper device having a damper capacity smaller than a damper capacity that can be set by the recovery side damper device is further provided in the vicinity of the liquid ejection head. The image recording apparatus according to claim 11.

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