JP5219566B2 - Ink supply device for inkjet printer - Google Patents

Description

  The present invention relates to an ink supply device for an ink jet printer that supplies ink to a printer head that discharges ink.

  Inkjet printers discharge ink particles from the nozzles and apply them to the print medium while moving the printer head with a large number of nozzles relative to the print medium. It is a device that draws the information. Ink jet printers consume ink as ink is ejected, so an ink tank (ink cartridge) with a capacity corresponding to the application is provided in the carriage of the printer head or the printer body. In a large inkjet printer that prints commercial large format advertisements and banners, a large amount of ink is consumed in a relatively short time. For this reason, in such a commercial inkjet printer, a large-capacity ink tank is generally provided in the printer body, and the ink tank and the printer head are connected by a tube or the like, and ink is ejected in accordance with ink ejection. The tank is configured to be supplied from the tank to the printer head.

Here, when the internal pressure of the ink chamber of the printer head becomes higher than the atmospheric pressure, the ink is pushed out from the nozzle and dripped onto the print medium, which causes a so-called “dropping” problem. Therefore, in the ink jet printer, the ink supply device is configured so that the internal pressure of the ink chamber is a slightly negative pressure slightly lower than the atmospheric pressure. As a conventional ink supply device, an ink tank is disposed at a height where the liquid level of the ink stored in the ink tank is lower than the nozzle surface of the printer head, and due to a water head difference between the ink liquid surface and the nozzle surface. A “water head type” ink supply device that makes an ink chamber in a slightly negative pressure state is widely used. Further, a small-capacity subtank is provided between the ink tank (main tank) provided in the printer body and the printer head provided in the carriage, and the subchamber is decompressed to bring the ink chamber of the printer head into a slightly negative pressure state. 2. Description of the Related Art “Negative pressure generation type” ink supply devices are known (see, for example, Patent Document 1 and Patent Document 2).
JP 2004-284207 A JP 2006-622330 A

  However, the conventional ink supply apparatus as described above has the following problems. First, in the water head type ink supply device, the arrangement position of the ink tank with respect to the printer head is limited to a very narrow height range, and it is not easy to ensure the workability of ink replacement without increasing the size of the printer body. There was a problem. In addition, in an ink jet printer in which the printer head scans the print medium, the ink chamber pressure fluctuates due to acceleration acting on the ink in the piping connecting the ink chamber of the printer head and the ink tank during carriage acceleration / deceleration. To do. As a result, if the carriage scanning speed is increased, it becomes difficult to obtain stable ink ejection, which is a factor that hinders improvement in throughput. Furthermore, since the nozzle surface is positioned above the liquid surface of the ink tank, it is impossible to fill the ink chamber with ink or to degas bubbles in the ink chamber only with the ink supply circuit. For this reason, this type of ink supply device is provided with a suction circuit for capping the bottom surface of the printer head and vacuuming it to draw ink from the ink tank. As a result, the circuit configuration becomes complicated and the rubber cap A problem has also been pointed out that it is difficult to obtain stable ink ejection after ink filling because the suction force is reduced due to damage, deterioration, dust adhesion, and the like.

  In addition, even in a negative pressure generating ink supply apparatus, only a negative pressure circuit that reduces the subtank to a slight negative pressure by a negative pressure pump fills the ink chamber from which ink has been removed or removes bubbles in the ink chamber. I can't care. Therefore, it is necessary to provide a dedicated suction circuit in the same manner as the water head method, or to use a vacuum pump with a high ultimate vacuum as a negative pressure generation source to control the pressure of the negative pressure circuit and the suction circuit. It is difficult to solve the problem of making it difficult and stable ink ejection. On the other hand, a configuration in which a positive pressure circuit that pressurizes the sub tank by a positive pressure pump is provided to push out the ink stored in the sub tank can be considered. However, with such a configuration, there is a problem that the system configuration of the ink supply device becomes complicated and large, and an increase in control burden is inevitable.

  The present invention has been made in view of the above problems, and an object thereof is to provide an ink supply device for an inkjet printer that can realize stable ink ejection with a simple device configuration.

To achieve the above object, an ink supply device for an inkjet printer according to the present invention is connected to a printer head for ejecting ink, and the sub tank for storing ink to be supplied to the printer head, the sub tank is connected to said sub tank a main tank for storing ink to be supplied to a sub tank depressurizing means for depressurizing the internal pressure of the sub tank in a negative pressure state (e.g., the sub tank vacuum unit 140 in the embodiment), pressurizing the internal pressure of the sub tank in a positive pressure state sub tank pressurizing unit (e.g., the sub tank pressurizing unit 150 in the embodiment) and a said sub-tank pressure reducing means and the sub tank pressurizing means, suction and one air pump (e.g., feed gas in the embodiment the pump 160) The internal pressure of the sub tank is reduced or increased using the discharge action. Configured to. The sub-tank decompression means opens and closes the negative pressure circuit, and closes the negative pressure circuit to connect the suction port of the air pump and the sub tank. And a negative pressure circuit opening / closing means (for example, a negative pressure control valve 145 in the embodiment) that opens the circuit on the suction port side of the air pump to the atmosphere when shut off. A positive pressure circuit connecting the discharge port of the air pump and the sub-tank, and a side of the discharge port of the air pump when the positive pressure circuit is opened and closed and the connection of the discharge port of the air pump and the sub tank is shut off And a positive pressure circuit opening / closing means (for example, a positive pressure control valve 155 in the embodiment) that opens the circuit to the atmosphere. Is rotated by opening and closing switching of the negative pressure route and the positive pressure route by the negative pressure route switching means and the positive pressure route switching means, it constituted the internal pressure of the sub tank to press vacuum or pressure.

In the ink supply apparatus having the above configuration, when the internal pressure of the sub tank is reduced to a negative pressure state, the negative pressure circuit opening means opens the negative pressure circuit to connect the suction port of the air pump and the sub tank, and When the positive pressure circuit opening / closing means is used to cut off the connection between the discharge port of the air pump and the sub tank, the circuit on the discharge port side of the air pump is opened to the atmosphere, and when the internal pressure of the sub tank is pressurized to a positive pressure state, In the positive pressure circuit opening / closing means, the positive pressure circuit is opened to connect the discharge port of the air pump and the sub tank, and the negative pressure circuit opening / closing means is used to cut off the connection between the suction port of the air pump and the sub tank. It is preferable that the circuit on the suction port side of the air pump is open to the atmosphere .

  Further, it is preferable to form a merging circuit where the positive pressure circuit and the negative pressure circuit merge and connect to the sub tank, and to provide a merging circuit opening / closing valve for opening and closing the merging circuit in the merging circuit, and a plurality of printer heads and sub tanks are provided. When provided, it is preferable that the merging circuit on-off valve is configured to be able to open and close each merging circuit branched in correspondence with the plurality of sub tanks.

  The inkjet printer includes a main body member (for example, the apparatus main body 1 in the embodiment) including a medium support portion (for example, the platen 20 in the embodiment) that supports the print medium, and a print medium supported by the medium support portion. And a carriage movably provided on the main body member, the main tank is provided on the main body member, and the printer head and the sub tank are provided on the carriage.

  In the ink supply device for an ink jet printer according to the present invention, a main tank for storing ink and a subtank connected to the printer head for supplying ink are provided, and a subtank decompression unit and a positive pressure for reducing the internal pressure of the subtank to a negative pressure state. A sub-tank pressurizing unit that pressurizes the sub-tank, and the sub-tank depressurizing unit and the sub-tank pressurizing unit are configured by a single pump. For this reason, the disposition position of the main tank can be freely set regardless of the relative height relationship with the printer head. In addition, since the subtank can be placed close to the printer head, even if the printer head is moved by the carriage, it is less susceptible to changes in acceleration due to the acceleration / deceleration of the carriage, and is stable even at high scan speeds. Ink ejection can be realized and throughput can be improved. Further, the subtank pressurizing means can pressurize the subtank to fill the ink chamber from which ink has been removed, or to degas bubbles in the ink chamber. For this reason, it is not necessary to provide a suction circuit for capping the lower surface of the printer head to perform vacuum suction, and it is stable immediately after ink filling by eliminating defective ink filling due to deterioration of the rubber cap or adhesion of dust. Ink discharge can be performed. Further, since the sub-tank pressure reducing means and the sub-tank pressurizing means are constituted by a single pump, the mechanism configuration of the entire ink supply device can be simplified and miniaturized, and the pump start / stop control is performed for each means. There is no need, and the control burden can be reduced.

  In the present invention, the sub tank pressure reducing means is formed by a negative pressure circuit connecting the sub tank and the pump inlet, and the sub tank pressurizing means is formed by a positive pressure circuit connecting the sub tank and the pump outlet. Accordingly, it is possible to provide an ink supply apparatus having the above-described effects with a rational and simple configuration using the suction and discharge actions of a single pump.

  In addition, according to the configuration in which the positive pressure circuit is provided with a positive pressure circuit opening means that opens the circuit on the discharge port side of the pump to the atmosphere by cutting off the connection between the sub tank and the discharge port of the pump, the sub tank is not pressurized. In the state, the connection between the pump discharge port and the sub tank can be cut off, and the circuit on the pump discharge port side of the blocked positive pressure circuit (the anti-sub tank side circuit) can be opened to the atmosphere. For this reason, for example, in an operating state in which the internal pressure of the sub tank is maintained at a slight negative pressure, the pressure (back pressure) of the positive pressure circuit does not increase and the intake efficiency does not decrease. A stable slight negative pressure state can be set, thereby realizing stable ink ejection. The same applies to the configuration in which the negative pressure circuit opening means is provided in the negative pressure circuit. For example, in an operation state in which the sub tank is pressurized and ink is filled in the ink chamber of the printer head, the pressure (intake pressure) of the negative pressure circuit is increased. There is no reduction in discharge efficiency, and ink can be reliably filled with a simple circuit configuration and pressure control, and stable ink discharge can be realized immediately after ink filling. Furthermore, according to the configuration in which both of these are provided, the sub tank can be pressurized with a simple control configuration in which the positive pressure release means and the negative pressure circuit release means are switched while one pump is rotated in a certain direction. And depressurization can be switched and controlled.

  Further, according to the configuration in which a confluence circuit in which the positive pressure circuit and the negative pressure circuit merge is formed and connected to the sub tank, and the confluence circuit opening / closing valve for opening and closing the merge circuit is provided in the confluence circuit, the sub tank that is easily complicated The surrounding piping can be simplified and the sub tank can be shut off from the positive / negative pressure circuit. In addition, if a plurality of printer heads and sub tanks are provided, and the merge circuit open / close valve is configured to be able to individually open and close each merge circuit branched corresponding to the plurality of sub tanks, an arbitrary sub tank (printer head) can be singularly or A plurality of inks can be selected and ink filling or cleaning can be performed.

  The ink jet printer is configured to include a main body member having a medium support portion, and a carriage that is movably provided on the main body member so as to face the print medium supported by the medium support portion. According to the configuration in which the main body member is provided and the printer head and the sub tank are provided in the carriage, a large ink tank can be disposed at an arbitrary position of the main body member. It is possible to achieve both the ease of work. Further, since the subtank can be arranged close to the printer head, it is not easily affected by the acceleration change accompanying the acceleration / deceleration of the carriage, thereby increasing the carriage scanning speed and improving the throughput.

  Therefore, according to the present invention, it is possible to provide an ink supply device for an ink jet printer capable of realizing stable ink ejection with a simple device configuration.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. As an example of an inkjet printer to which the present invention is applied, out of two orthogonal axes along the surface to be printed, a type in which one axis moves the print medium and the other axis moves the printer head is taken and cured by irradiation with ultraviolet light. A configuration example applied to a UV curable ink jet printer (hereinafter referred to as a printer device) using an ultraviolet curable ink (so-called UV ink) is described. FIG. 2 shows a perspective view of the printer device P of the present embodiment as viewed obliquely from the front, and FIG. 3 shows a perspective view of the printer device P as viewed from the oblique rear. FIG. First, the overall configuration of the printer apparatus P will be outlined with reference to these drawings. In the following description, directions indicated by arrows F, R, and U added in FIG. 2 will be referred to as “front”, “right”, and “upward”, respectively.

  The printer device P is broadly divided into a device main body 1 that performs a drawing function, a support mechanism 2 that is provided in front of and behind a support portion 2 that supports the device main body 1, and sends out an unprocessed print medium M wound in a roll shape. 3 and a winding mechanism 4 that winds up the print medium M that has been drawn.

  The apparatus main body 1 is formed with a horizontally long window-shaped media insertion portion 15 through which the print medium M is inserted in the front and rear intermediate portions of the frame 10 forming the casing, and a lower frame 10L positioned below the media insertion portion 15. Are provided with a platen 20 that supports the print medium M, and a medium moving mechanism 30 that moves the print medium M supported by the platen 20 back and forth. The upper frame 10U positioned above the medium insertion portion 15 is provided with a printer head. A carriage 40 that holds 60 and a carriage movement mechanism 50 that moves the carriage 40 to the left and right are provided. The apparatus main body 1 includes a printer, such as a forward / backward movement of the print medium M by the medium moving mechanism 30, a left / right movement of the carriage 40 by the carriage moving mechanism 50, an ink discharge by the printer head 60, and an ink supply by the ink supply device 100 described later. A control unit 80 for controlling the operation of each part of the apparatus P is provided, and an operation panel 88 is disposed on the front surface of the apparatus body 1.

  The platen 20 is provided on the lower frame 10 </ b> L so as to extend back and forth below the media insertion portion 15, and a media support portion 21 that horizontally supports the print medium M is formed in the left and right belt-like drawing areas by the printer head 60. Has been. A large number of small-diameter suction holes are formed in the media support portion 21 and connected to a decompression chamber (not shown) provided therebelow, and the decompression chamber is set to a negative pressure by operating a vacuum generator or the like. Sometimes, the print medium M is attracted and held by the medium support portion 21 so that the position of the print medium M is not shifted during processing such as printing or cutting.

  The media moving mechanism 30 includes a cylindrical feed roller 31 that is disposed with its upper peripheral surface exposed to the platen and extends to the left and right, and a roller drive motor 33 that rotationally drives the feed roller 31 via a timing belt 32. Above the feed roller 31, a plurality of roller assemblies 35 each having a pinch roller 36 that is pivotable back and forth are provided side by side. The roller assembly 35 is configured to be settable to a clamp position where the pinch roller 36 is pressed against the feed roller 31 and an unclamp position separated from the feed roller 31. When the roller drive motor 33 is rotationally driven in a state where M is sandwiched between the pinch roller 36 and the feed roller 31, the rotation angle of the print medium M (drive control value output from the control unit 80). It is transported back and forth with a feed amount according to. In FIG. 4, both the state where the roller assembly 35 is set at the clamp position and the state where the roller assembly 35 is set at the unclamp position are shown.

  The carriage 40 is supported by a guide rail 45 extending in parallel with the feed roller 31 and attached to the upper frame 10U so as to be movable left and right via a slide block (not shown). Driven. The carriage 40 is provided with a printer head 60 that discharges UV ink, and the nozzle surface at the lower end of the head is disposed to face the media support portion 21 of the platen 20 with a predetermined gap therebetween.

  In general, the printer head 60 includes a number of printer heads arranged side by side according to the quantity of ink used in the printer apparatus P. For example, cyan (C), magenta (M), and yellow (Y). In the case of a printer apparatus using one ink cartridge for each of the four basic colors of black (K) UV ink, as shown in a perspective view around the carriage in FIG. Two printer heads 60 (first printer head 60C, second printer head 60M, third printer head 60Y, fourth printer head 60K) are provided. In the carriage 40, sub tanks 120 (first sub tank 120C, second sub tank 120M, third sub tank 120Y, and fourth sub tank 120K) of the ink supply device 100, which will be described in detail later, correspond to the printer heads 60C, 60M, 60Y, and 60K. Is provided. The printer head 60 may be driven by a thermal method or a piezo method (ink fine particle ejection method).

  On the left and right sides of the carriage 40, UV light sources are provided for irradiating the UV ink deposited on the print medium M from the printer head with ultraviolet light and curing it. The UV light source includes a left UV light source 70L provided on the left side of the carriage 40 and a right UV light source 70R provided on the right side of the carriage 40. These left and right UV light sources 70L and 70R are provided on the carriage 40. The first to fourth printer heads 60C, 60M, 60Y, and 60K are disposed so as to be sandwiched from the left and right outer sides. The left UV light source 70L and the right UV light source 70R are configured by using a light source that emits ultraviolet light having a wavelength λ = 100 to 380 nm, for example, a UV lamp, a UV-LED, or the like. The blinking operation of the left and right UV light sources 70 </ b> L and 70 </ b> R is controlled by the control unit 80 in accordance with the movement of the carriage 40 by the carriage drive mechanism 50 and the ejection of ink from the printer head 60.

  The carriage moving mechanism 50 includes a driving pulley 51 and a driven pulley 52 provided on the left and right side portions of the frame 10 with the guide rail 45 interposed therebetween, a carriage driving motor 53 that rotates the driving pulley 51, and a driving pulley 51 and a driven pulley 52. And an endless belt-like timing belt 55 wound around the belt. The carriage 40 is connected and fixed to the timing belt 55, and the carriage 40 supported by the guide rail is rotated by the rotation of the carriage drive motor 53, so that the rotation angle of the carriage drive motor 53 (the drive output from the control unit 80). The platen 20 is moved left and right by a movement amount corresponding to the control value.

  The control unit 80 includes a ROM 81 in which a control program for controlling the operation of each unit of the printer device is written, a RAM 82 for temporarily storing a print program for drawing on the print medium M, a print program read from the RAM 82, and an operation panel 88. An arithmetic processing unit 83 that performs arithmetic processing on the input operation signal and the like and controls the operation of each unit in accordance with a control program, an operation panel 88 provided with various operation switches, a display panel that displays the operating state of the printer device P, and the like The print medium M is moved back and forth by the medium moving mechanism 30, the carriage 40 is moved left and right by the carriage moving mechanism 50, the ink is supplied by the ink supply device 100, the ink is discharged from each nozzle of the printer head 60, and the ink supply device 100. Control ink supply etc. That.

  For example, when drawing on the print medium M based on the print program read into the control unit 80, the forward / backward movement M of the print medium by the medium movement mechanism 30 and the left / right movement of the carriage 40 by the carriage movement mechanism 50 are combined. The print medium M and the printer head 60 are moved relative to each other to eject ink from the printer heads 60 to the print medium M, and the UV light source located behind the carriage 40 in the movement direction (for example, the left UV light source when the carriage moves to the right). 70L) is turned on to draw information according to the printing program.

  In this way, in the printer apparatus P that is schematically configured, UV ink is supplied from the ink supply apparatus 100 to the printer head 60 provided in the carriage 40. FIG. 1 is a system diagram of the ink supply apparatus 100, FIG. 6 is an external perspective view of the sub tank 120, and FIG. 7 is a schematic block diagram of the ink supply apparatus 100.

  The ink supply device 100 includes a sub tank 120 connected to the printer head 60, a main tank 110 connected to the sub tank 120 and storing UV ink supplied to the sub tank, and a sub tank pressure reducing unit that reduces the internal pressure of the sub tank 120 to a negative pressure state. 140, a sub tank pressurizing unit 150 that pressurizes the internal pressure of the sub tank 120 to a positive pressure state, an ink transfer unit 115 that transfers UV ink stored in the main tank 110 to the sub tank 120, and the like. The unit 150 includes a single air pump 160.

  The main tank 110 is set so as to store UV ink having a capacity corresponding to the ink consumption per unit time in the printer device P. In the present embodiment, for the four colors C, M, Y, and K described above, the cartridge-type main tank 110 (first main tank 110C, second main tank 110M, third main tank 110Y, capacity of about 500 ml for each color). A configuration example is shown in which a fourth main tank 110K) is used and these main tanks 110 are detachably disposed on the back of the apparatus main body 1 (see FIG. 3). The main tank 110 may have another form such as a cylindrical container or a flexible bag. The ink tank may be disposed at the front side or upper part of the apparatus main body 1 or the apparatus main body 1. It can be arranged appropriately, such as separately.

  As shown in FIG. 6, the sub tank 120 is opened to one side (right side), and is closed so as to cover a thin rectangular box-shaped container member 121 that is vertically long in a side view and the opening surface of the container member 121. An ink storage chamber 123 for storing UV ink is formed inside a tank formed by closing the cover member 122, and a groove-like float storage that extends vertically at the rear of the ink storage chamber 123 is formed. A portion 124 is formed. In the float accommodating part 124, a disk-shaped float 134 having a magnet fixed to the center and floating on the UV ink is accommodated so as to be movable up and down.

  The sub tank 120 is joined integrally by applying a sealant or an adhesive to the opening edge surface of the container member 121 and closing the lid member 122, and is firmly joined by a fastening means such as a screw (not shown). The storage chamber 123 is kept sealed. At least one of the lid member 122 and the container member 121 is formed using a transparent or semi-transparent material, and the storage state of the UV ink in the ink storage chamber 123, the floating state of the float 134 in the UV ink, etc. It is configured to be visually confirmed.

  On the lower surface side of the sub tank 120, a short columnar connector portion 125 that protrudes downward from the bottom wall 121b of the container member 121 and is detachably connected to the printer head 60 is formed. A block-shaped duct portion 126 extending upward in the ink storage chamber 123 is formed. Then, a first lead-out path 127a that penetrates the bottom wall 121b up and down and connects the bottom surface of the ink storage chamber 123 and the connector part 125 is formed, and penetrates the duct part 126 and the bottom wall 121b up and down to form the duct part 126. A second lead-out path 126b that connects the upper surface 126a and the connector portion 125 is formed. Therefore, when the connector portion 125 on the lower surface of the sub tank is fitted and connected to the printer head 60, the ink storage chamber 123 of the sub tank 120 and the ink chamber of the printer head 60 are connected via the first outlet path 126a and the second outlet path 126b. Is done. Note that a bat-shaped ink tray 180 that receives UV ink is located below the printer head 60 (60C, 60M, 60Y, 60K) in a state where the carriage 40 is positioned at a reference position (so-called home position) during non-printing. Is provided.

  On the rear side of the sub tank 120, a sub tank storage detection unit 130 that detects the storage state of the UV ink in the ink storage chamber 123 is provided. The sub-tank storage detection unit 130 is accommodated in the float storage unit 124 so as to be movable up and down, and moves up and down together with the liquid level of the UV ink in the ink storage chamber, and the liquid level of the UV ink is detected by detecting the float 134. And a liquid level detection substrate 135 for detecting the thickness.

  A dovetail-shaped substrate mounting portion 131 that extends vertically is formed on the rear wall 121r of the container member 121, and a liquid level detection substrate on which a magnetic sensor 136 (136H, 136L) is mounted on the substrate mounting portion 131. 135 is mounted and fixed. That is, the liquid level detection substrate 135 is disposed to face the float 124 with the rear wall 121r interposed therebetween, and the magnetic sensor 136 detects the magnet fixed to the float 134 in the ink storage chamber 123, thereby allowing the float 134 to move. The height position, that is, the liquid level of the UV ink stored in the ink storage chamber 123 can be detected.

  In the present embodiment, as the magnetic sensor 136, the Hi detection sensor 136H that detects that the ink storage chamber 123 is filled with UV ink and the liquid level of the UV ink is the reference filling height, and the UV in the ink storage chamber 123 are used. An example of a configuration in which two Lo detection sensors 136L that detect that ink is consumed and less than a predetermined amount is provided on the liquid level detection substrate 135 is shown. The number of magnetic sensors 136 may be three or more, and a change in the liquid level in the ink storage chamber may be continuously detected based on a change in magnetic force. An output signal of the liquid level detection substrate 135 is input to the control unit 80.

  An ink introduction path that penetrates the front wall 121f of the container member 121 back and forth is formed at a predetermined height position between the upper and lower sides on the front side of the sub tank 120, and a tube connector 128 that connects to the ink introduction path is provided. Yes. Further, on the upper surface side of the sub tank 120, a gas introduction path that penetrates the ceiling wall 121t of the container member 121 in the vertical direction is formed, and a tube connector 129 connected to the gas introduction path is provided.

  The ink transfer unit 115 is formed by a main supply circuit 116 that connects between the main tank 110 and the sub tank 120. The main supply circuit 116 has one end connected to the main tank 110 and the other end connected to the suction port of the liquid feed pump 118, one end connected to the discharge port of the liquid feed pump 118, and the other end connected to the sub tank 120. The ink delivery line 117b connected to the tube connector 128 and the main body 110 is located between the main tank 110 and the sub tank 120, and the UV ink stored in the main tank 110 is passed through the ink suction line 117a. A liquid feed pump 118 that inhales and supplies the sub tank 120 via the ink delivery line 117b.

  The liquid feed pump 118 can suck up the UV ink from the main tank 110 and pump it to the sub tank 120 even when the ink suction line 117a is not filled with UV ink and air is mixed, and the ink suction line 117a side or A pump that can shut off the pressure acting from the ink delivery line 117b side is used. For example, a tube pump or a diaphragm pump is preferably used.

  The sub tank decompression unit 140 is formed by a negative pressure circuit 141 that connects between the sub tank 120 and the suction port 161 of the air pump 160. The negative pressure circuit 141 includes an air chamber 142 constituted by an airtight container, a pressure sensor 144 for detecting the pressure of the negative pressure circuit 141, and a negative pressure circuit, as shown in FIG. A negative pressure control valve 145 for opening and closing 141, and a line 147 (147a, 147b, 147c, 147d) formed by a tube connecting these devices and connecting the suction port 161 of the pneumatic pump and the sub tank 120, etc. Consists of In FIG. 1, a portion surrounded by a frame C is provided in the carriage 40, and a portion outside the frame is a device provided in the apparatus main body 1.

  The air chamber 142 is connected to the suction port 161 of the pneumatic pump via a line 147a, and the air in the chamber is exhausted and reduced to a negative pressure state by the operation of the pneumatic pump 160. The volume of the air chamber 142 is set to about 1/10 to 1/50 of the intake / exhaust amount per process of the air feed pump 160. For example, when the intake / exhaust amount per stroke of the air pump 160 is 2 cc, the pulsation of the intake air due to the pump operation can be reduced to 1/25 or less by using a 50 cc air chamber. The air chamber 142 is provided with an air introduction line 147i that introduces air into the chamber decompressed to a negative pressure state, and a flow rate adjustment valve 143a that adjusts the flow rate of the air flowing in through the air introduction line 147i. An air filter 143b is provided for removing dust from the introduced air.

  The flow rate adjustment valve 143a makes the internal pressure of the air chamber 142 constant by adjusting the flow rate of air flowing into the air chamber 142 in a state where the air pump 160 and the sub tank 120 are connected via the negative pressure circuit 141. As a result, the internal pressure of the ink storage chamber 123 becomes a predetermined negative pressure (for example, negative pressure of -1.2 kPa: hereinafter referred to as “set negative pressure”) appropriate for meniscus formation in the nozzle portion. Is set as follows. As described above, the air chamber 142 functions as a buffer tank that absorbs the pulsation of the intake air due to the operation of the air pump 160 and holds the internal pressure of the sub tank 120 at a constant set negative pressure.

  The negative pressure control valve 145 is provided between the air chamber 142 and the sub tank 120 and is provided in the carriage 40. The negative pressure control valve 145 establishes a communication state between the line 147c on the air chamber 142 side and the line 147d on the sub tank 120 side. It is a solenoid valve to switch to. In the present embodiment, a configuration using a three-way valve as the negative pressure control valve 145 is illustrated, and a line 147c is connected to the common port (COM) of the negative pressure control valve 145, and a line 147d is connected to the normal open port (NO). The normally closed port (NC) is open to the atmosphere via the line 147x and the silencer 148.

  For this reason, when the negative pressure control valve 145 is off (during normal operation such as during printing or standby), the line 147c and the line 147d are connected, and the negative pressure circuit 141 is set in a communication state so The suction port 161 of the pump 160 and the sub tank 120 are connected via a junction circuit 171 described later. On the other hand, when the negative pressure control valve 145 is on (during ink filling or cleaning), the connection between the line 147c and the line 147d is disconnected, the negative pressure circuit 141 is shut off, and the line 147c is changed to the line 147x. As a result, the circuit on the suction port side of the pneumatic pump 160 is opened to the atmosphere. The negative pressure control valve 145 is connected to the control unit 80 and is on / off controlled by the control unit 80.

  The pressure sensor 144 is a gauge pressure type pressure sensor having a detection region of about ± 5 kPa and provided between the air chamber 142 and the negative pressure control valve 145, and detects the pressure of the line 147 near the sub tank. Specifically, in a state where the negative pressure control valve 145 is turned off and the pneumatic pump 160 and the sub tank 120 are connected by the negative pressure circuit 141, the pressure of the line up to the sub tank 120 is set to the set negative pressure described above. A pressure (for example, a pressure of about −1.3 kPa) taking loss into account is detected by the pressure sensor 144. Paradoxically, by adjusting and setting (initial setting) the flow rate adjustment valve 143a so that the pressure detected by the pressure sensor 144 becomes the above pressure value, the internal pressure of the ink storage chamber 123 becomes the set negative pressure. Is set. Therefore, by monitoring the pressure detected by the pressure sensor 144, it is possible to detect whether or not the pressure in the ink storage chamber 123 has been set to the set negative pressure. A detection signal of the pressure sensor 144 is input to the control unit 80.

  The sub tank pressurizing unit 150 is formed by a positive pressure circuit 151 that connects between the sub tank 120 and the discharge port 162 of the pneumatic pump 160. The positive pressure circuit 151 is a flow control valve 153a for adjusting the flow rate of the air flowing through the positive pressure circuit 151 and air toward the sub tank 120, as shown in FIG. An air filter 153b that removes dust, a pressure sensor 154 that detects the pressure of the positive pressure circuit 141, a positive pressure control valve 155 that opens and closes the positive pressure circuit 151, and a discharge tank 162 and a sub tank of the pneumatic pump by connecting these devices. It is composed of a line 157 (157a, 157b, 157c, 157d) formed by a tube connecting to 120.

  The flow rate adjustment valve 153a increases the internal pressure of the ink storage chamber 123 to a predetermined level or more by adjusting the flow rate of air flowing through the positive pressure circuit 151 in a state where the air feed pump 160 and the sub tank 120 are connected by the positive pressure circuit 151. This valve is adjusted so that the internal pressure of the sub tank 120 is about 20 kPa.

  The positive pressure control valve 155 is provided between the flow adjustment valve 153a and the sub tank 120 in the carriage 40, and is an electromagnetic valve that switches the line 157c and the line 157d between a communication state and a cutoff state. In the present embodiment, a configuration using a three-way valve as the positive pressure control valve 155 is illustrated, and a line 157c is connected to the common port (COM) of the positive pressure control valve 155, and a line 157d is connected to the normal close port (NC). The normally open port (NO) is open to the atmosphere via the line 157x and the silencer 158.

  Therefore, when the positive pressure control valve 155 is off (during normal operation such as printing or standby), the connection between the line 157c and the line 157d is disconnected, the positive pressure circuit 151 is shut off, and the line 157c is disconnected. Is connected to the line 157x, and the positive pressure circuit on the discharge port side of the pneumatic pump 160 is opened to the atmosphere. On the other hand, when the positive pressure control valve 155 is on (when ink is filled, cleaning, etc.), the line 157c and the line 157d are connected and the positive pressure circuit 151 is set in a communication state, and the air pump 160 discharges. The outlet 162 and the sub-tank 120 are connected via the junction circuit 171. The positive pressure control valve 155 is connected to the control unit 80 and is on / off controlled by the control unit 80.

  The pressure sensor 154 is a gauge pressure type pressure sensor provided in the carriage 40 with a detection region of about ± 50 kPa, and detects the pressure of the line 157 near the sub tank. Specifically, the pressure applied to the sub tank 120 is detected in a state where the positive pressure control valve 155 is set to ON and the pneumatic pump 160 and the sub tank 120 are connected by the positive pressure circuit 151. Therefore, by monitoring the pressure detected by the pressure sensor 154, it is possible to detect whether or not the pressure of the ink storage chamber 123 has been set to a predetermined positive pressure state. A detection signal of the pressure sensor 154 is input to the control unit 80.

  The air feed pump 160 is a pump that sucks air from the negative pressure circuit 141 connected to the suction port 161 and pumps the sucked air to the positive pressure circuit 151 connected to the discharge port 162. A pump that generates a predetermined positive / negative pressure at the port 161 is used. That is, a negative pressure of a predetermined pressure is generated at the suction port 161 when the negative pressure circuit 141 is closed, and a positive pressure of a predetermined pressure is generated at the discharge port 162 when the positive pressure circuit 151 is closed. As such a pump, for example, a diaphragm pump that generates a positive / negative pressure of about ± 40 kPA is preferably used.

  Thus, the negative pressure circuit 141 and the positive pressure circuit 151 are both connected to the pneumatic pump 160 at the base end side, and the subtank decompression unit 140 and the subtank pressurization unit 150 are operated to suck and discharge the single pneumatic pump 160. It is configured using. For this reason, the configuration of both the subtank decompression unit 140 and the subtank pressurization unit 150 can be simplified, the entire ink supply device can be rationally simplified and miniaturized, and a pump is provided for each of the subtank decompression unit 140 and the subtank pressurization unit 150. Therefore, it is not necessary to perform start / stop control, and the control burden can be reduced. Furthermore, the maintenance work for the pump may be performed for one pneumatic pump 160, and the maintenance man-hours can be reduced.

  The negative pressure circuit 141 and the positive pressure circuit 151 merge on the way to the sub tank 120, and a merge circuit 171 is formed. The merging circuit 171 is formed by merging the negative pressure circuit line 147d and the positive pressure circuit line 157d, and the 177 connected to the sub tank and the merging circuit opening / closing provided on the line 177 for opening and closing the merging circuit 171. And a valve 175. The junction circuit open / close valve 175 is provided corresponding to the sub-tank 120. In this embodiment, the junction circuit open / close valve 175 branches the junction circuit 171 (line 177) into four, and each branch junction is divided. Circuits (lines 177C, 177M, 177Y, 177K, part of which are omitted) can be opened and closed individually.

  That is, the junction circuit opening / closing valve 175 is a manifold type electromagnetic opening / closing valve having a common input port connected to the line 177, four valves provided corresponding to the four sub tanks, and an output port. The first to fourth junction circuit opening / closing valves 175C, 175M, 175Y, and 175K corresponding to the fourth sub tanks 120C, 120M, 120Y, and 120K can open and close the junction circuit 171 independently. With such a configuration, it is possible to simplify the configuration around the printer head by reducing the number of piping members provided in the carriage 40, and it is possible to pressurize or depressurize by selecting one or more arbitrary subtanks (printer heads). . The operation of the junction circuit opening / closing valve 175 is controlled by the control unit 80.

  The number of branches of the junction circuit 171 can be arbitrarily set according to the number of printer heads 60 provided. For example, when the printer head 60 has a single head configuration, the junction circuit opening / closing valve 175 is A single-valve electromagnetic on-off valve may be used. In a printer apparatus having eight printer heads, as shown in FIG. 1, an 8-unit type electromagnetic on-off valve is used (or a 4-unit type electromagnetic on-off valve is installed). For example, by using two).

  In this way, the negative pressure circuit 141 and the positive pressure circuit 151 are connected to the pneumatic pump 160 to form one continuous circuit, and the leading ends of both circuits are assembled to form a closed loop pressure increasing / decreasing circuit. The A merging circuit 171 in which both circuits are assembled is connected to the sub tank 120 via a merging circuit on / off valve 175, and the negative pressure control valve 145 and the positive pressure control valve 155 are switched to control the ink storage chamber 123 of the sub tank. It is configured to be changeable between a reduced pressure state and a pressurized state.

  In the ink supply device 100 configured as described above, the operation of the liquid feed pump 118, the negative pressure control valve 145, the positive pressure control valve 155, and the air feed pump 160 is controlled by the control unit 80 as follows. . As is clear from the above description, the UV ink supply system is the same for the four systems (C, M, Y, K), and therefore, the items common to each system are subscripted. The description is omitted.

(Control during normal operation)
When the main power supply of the printer device P is turned on, the control unit 80 reads the control program stored in the ROM 81 and controls the operation of each part of the printer device based on the read control program. For the ink supply device 100, electric power is supplied to the air feed pump 160 to be in a rotational drive state, and all the junction circuit open / close valves 175 are turned on. At this time, both the negative pressure control valve 145 and the positive pressure control valve 155 remain off. As a result, in the negative pressure circuit 141, the line 147c and the line 147d communicate with each other, the suction port 161 of the air pump 160 and the ink storage chamber 123 of the sub tank 120 are connected by the line 147 and the line 177, and the positive pressure circuit 151 The line 157c and the line 157x are connected to open the circuit on the discharge port side of the air feed pump 160 to the atmosphere.

  Therefore, the air in the line 147 connected to the suction port 161 of the pneumatic pump is sucked and the air chamber 142 is decompressed to a negative pressure, and the inflow air flow rate adjusted by the flow rate adjusting valve 143a and the pneumatic pump 160 are used. Stable at a substantially constant pressure determined by the balance with the amount of air sucked. As described above, this pressure is set to a predetermined negative pressure of about −1 to −2 kPa (for example, a set negative pressure of −1.2 kPa) appropriate for meniscus formation in the nozzle portion of the printer head 60. The internal pressures of the ink storage chambers 123 of the two sub-tanks are stably held in a state where all the internal negative pressures are set to the same set negative pressure.

  At this time, in the positive pressure circuit 151, the circuit on the discharge port side of the air feed pump 160 is opened to the atmosphere, and the air sucked from the negative pressure circuit 141 is opened to the atmosphere via the air filter 158. For this reason, the negative pressure state can be stably maintained without the pressure (back pressure) of the positive pressure circuit 151 increasing and the intake efficiency of the pneumatic pump 160 being lowered.

  Whether or not the internal pressure of the ink storage chamber 123 is maintained at the set negative pressure can be determined by a detection signal input from the pressure sensor 144 to the control unit 80, and the pressure detected by the pressure sensor 144 is set. When deviating from the negative pressure by a certain level or more, for example, when it is determined that the detected pressure exceeds the range of ± 20% with respect to the set negative pressure, the control unit 80 indicates that (the pressure of the negative pressure circuit). (Abnormal) alarm display can be performed. In this case, it is possible to obtain an appropriate set negative pressure by checking the presence / absence of abnormality in each part of the negative pressure circuit and adjusting the flow rate adjustment valve 143a if there is no abnormality.

  During normal operation, UV ink is stored to some extent in the ink storage chamber 123 of the sub tank 120. However, the UV ink stored in the ink storage chamber 123 is discharged and consumed from the nozzles of the printer head 60 by executing a printing program or the like, and the stored UV ink gradually decreases. Therefore, the ink supply device 100 is provided with a sub-tank storage detection unit 130, and when the UV ink stored in the ink storage chamber 123 becomes a predetermined amount or less, the UV ink stored in the main tank 110 is the ink. The ink is supplied to the sub tank by the transfer unit 115 and replenished with UV ink.

  Specifically, when the UV ink stored in the ink storage chamber 123 decreases and the residual amount of the UV ink becomes equal to or less than a predetermined amount, the float 134 that moves up and down with the liquid level of the UV ink moves to the liquid level detection substrate 135. Detected by the Lo detection sensor 136L provided in. Receiving the detection signal of the Lo detection sensor 136L from the liquid level detection substrate 135, the control unit 80 activates the liquid feed pump 118 in a state where the ink storage chamber 123 is depressurized to a negative pressure state. The UV ink delivered from the main tank 110 by the liquid feed pump is supplied from the tube connector 128 to the ink storage chamber 123 through the line 117b, and the amount of stored ink in the chamber increases. Then, when the float 134 is detected by the Hi detection sensor 136H, the liquid feed pump 118 is stopped, whereby the ink storage chamber 123 is replenished with UV ink.

  As described above, the replenishment of the UV ink to the sub tank 120 is performed in a state where the ink storage chamber 123 is decompressed. Therefore, the UV ink can be reliably transferred even with a small liquid feed pump, and the printer is replenished when the UV ink is replenished. UV ink does not leak from the nozzles of the head 60. In the case where the pressure of the ink storage chamber 123 rises at the time of ink replenishment due to the relationship between the capacity of the ink storage chamber 123 and the capacity of the air chamber 142, at the time of ink replenishment, depending on the detected pressure of the pressure sensor 144. By increasing the number of revolutions of the air feed pump 160, decreasing the valve opening degree of the flow rate adjusting valve 143a, or both, the pressure in the ink storage chamber 123 can be controlled to be constant without increasing. Is possible.

  When the printer device P is started in this manner, the air feed pump 160 is continuously operated thereafter, and the internal pressure of the sub tank 120 is constantly maintained at the set negative pressure regardless of whether the printing program is being executed or is on standby. Therefore, a large main tank can be disposed at an arbitrary position within the apparatus main body 1 within the range of the head of the liquid feed pump 118, and both downsizing the printer P and facilitating ink replacement work can be achieved. it can. Further, as shown in FIGS. 5 and 6, the sub tank 120 is formed in a rectangular box shape that is thin on the left and right and long in the vertical direction in a side view, and is provided directly above the printer head 60. For this reason, there is little change in the liquid level accompanying the left / right movement of the carriage 40, and it is hardly affected by the acceleration accompanying the acceleration / deceleration of the carriage. Therefore, even if the carriage 40 is moved left and right at a high scanning speed, stable ink ejection can be realized from the printer head 60, thereby improving the throughput.

(Control when filling ink)
At the initial filling of the UV ink or at the start-up after the nozzle cleaning using the cleaning liquid, the UV ink is not present in the ink chamber of the printer head 60 or the line 117 of the main supply circuit, and is left for a certain period. There may be a case where bubbles are mixed in the UV ink at the time of subsequent restarting or at the time of restarting after replacing the main tank. Therefore, in such a case, ink filling control is executed as follows based on the ink filling command input from the operation panel 88 to the control unit 80. A flowchart of the ink filling program PG set and stored in the ROM 81 for this ink filling control is shown in FIG.

  When the “ink filling” process is selected on the operation panel 88 by, for example, selecting a function key and the printer head 60 is specified to the control unit 80 and an ink filling execution command is input, the arithmetic processing unit 83 In accordance with the ink filling program, ink filling should be executed in a state where the subtank internal pressure is maintained at the set negative pressure during normal operation in step S10 (that is, both the negative pressure control valve 145 and the positive pressure control valve 155 are off). A process (negative pressure maintaining process) for holding the junction circuit opening / closing valve corresponding to the printer head on and holding the other junction circuit opening / closing valve off is executed, and the process proceeds to step S20. For example, when ink filling is selected only for the first printer head 60C on the operation panel 88, only the first junction circuit opening / closing valve 175C corresponding to the first printer head 60 is kept on, and the second to second The second to fourth junction circuit opening / closing valves 175M, 175Y, and 175K corresponding to the four printer heads are turned off (this case will be described below).

  In step S20, UV ink is transferred from the first main tank 110C to the decompressed first sub tank 120C to replenish the first sub tank 120C with ink (ink replenishment process). That is, when only the liquid feed pump 118C corresponding to the first sub tank 120C is activated to supply the UV ink stored in the first main tank 110C to the first sub tank 120C, and the float 134 is detected by the Hi detection sensor 136H. The liquid feed pump 118C is stopped. Accordingly, a sufficient amount of UV ink is stored in the ink storage chamber 123 of the first sub tank 120C. If it is determined that the float 134 has already been detected by the Hi detection sensor 136H and the UV ink has been stored up to the reference filling height at the start of execution of the ink replenishment process, this step is skipped. Proceed to S30.

  Next, in step S30, the negative pressure circuit 141 is shut off, the internal pressure of the first sub tank 120C is pressurized to a positive pressure state by the sub tank pressurizing unit 150, and a part of the UV ink stored in the first sub tank 120C is supplied to the first sub tank 120C. Flow out from one printer head 60C (printer head ink filling process). Specifically, the control unit 80 turns on the negative pressure control valve 145 to cut off the communication between the line 147c and the line 147d, connects the line 147c to the line 147x, and connects the suction side circuit of the air feed pump 160 to the atmosphere. To open. Further, the positive pressure control valve 155 is turned on, and the line 157c and the line 157d are connected to connect the discharge port 162 of the air feed pump and the ink storage chamber 123 of the first sub tank 60c.

  By this switching control, the connection between the pneumatic pump 160 and the first sub tank 120C through the negative pressure circuit 141 is cut off, while the pneumatic pump 160 and the first sub tank 120C are connected through the positive pressure circuit 151 from the discharge port 162 of the pneumatic pump 160. The discharged air is supplied to the ink storage chamber 123 of the first sub tank 120C through the line 157, the line 177, and the line 177c. As described above, the liquid feed pump 118 is a pump capable of interrupting the pressure acting from the ink suction line 117a side or the ink delivery line 117b side across the liquid feed pump 118. Therefore, the UV ink in the first sub tank 120C does not flow back to the first main tank 110C, and the internal pressure of the first sub tank 120C rises to a pressure (for example, about 20 kPa) set by adjusting the flow rate adjustment valve 153a. Positive pressure is reached. As a result, the UV ink stored in the ink storage chamber 123 of the first sub-tank 120C is pushed out from the first outlet path 126a and the second outlet path 126b at the lower end of the tank and supplied to the first printer head 120C. The ink flows out from the nozzle of the head 120 </ b> C and is received by the ink tray 180.

  At this time, in the negative pressure circuit 141, the circuit on the suction side of the pneumatic pump 160 is opened to the atmosphere, and the pneumatic pump 160 is operated with almost no load on the suction side. For this reason, it is possible to reliably fill the ink chamber of the first printer head 60C with UV ink without lowering the discharge efficiency due to a decrease in the intake pressure of the pneumatic pump. Furthermore, the first sub tank 120C can be easily changed from the depressurized state to the pressurized state by simple control of turning on both the negative pressure control valve 145 and the positive pressure control valve 155 while rotating the pneumatic pump 160 in a certain direction. You can switch to

  This step S30 is continued until the ink chamber is filled with UV ink and the UV ink flows out from the nozzles on the lower surface of the head even when the ink chamber of the first printer head 60C is in a color state. For example, the duration of this step is set as a timer based on the time required to supply UV ink to the first printer head 60C with the ink chamber in the empty state by pressurizing the first sub tank and let it flow out from the nozzles to a certain extent. This is defined by the setting (time setting) or until the UV ink stored in the ink storage chamber 123 flows out and the float 134 is detected by the Lo detection sensor 136L provided on the liquid level detection substrate 135. (Ink amount).

  By this step S30, UV ink is filled from the ink storage chamber 123 of the first sub-tank 120C to the nozzles of the first printer head 60C. If bubbles exist in this path, the bubbles are pushed away from the nozzles. The UV ink is filled from the first sub tank 120C to the nozzles of the first printer head 60C, and the process proceeds to the next step S40. At this time, the junction circuit opening / closing valve 175 is in a closed state except for the first junction circuit opening / closing valve 175C, and the internal pressure of the second to fourth sub tanks is maintained at the initial set negative pressure.

  In step S40, the positive pressure circuit 141 is shut off, the internal pressure of the first subtank 120C is reduced to a negative pressure state by the subtank pressure reducing unit 140, and the first subtank 120C is reduced from the first main tank 110C by the ink transfer unit 115. The ink is transferred to fill the first sub tank 120C with ink (sub tank ink filling process). That is, the control unit 80 turns off the positive pressure control valve 155, cuts off the communication between the line 157c and the line 157d, connects the line 157c to the line 157x, and opens the discharge side circuit of the pneumatic pump 160 to the atmosphere. To do. Further, the negative pressure control valve 145 is also turned off, the line 147c and the line 147d are brought into communication, and the suction port 161 of the air feed pump 160 and the ink storage chamber 123 of the first sub tank 120C are connected.

  By this switching control, the positive pressure circuit 151 disconnects the connection between the pneumatic pump 160 and the first sub tank 120C, while the negative pressure circuit 141 connects the pneumatic pump 160 and the first sub tank 120C, and the first sub tank. The air in the ink storage chamber 123 is sucked into the air feed pump 160 via the line 177c, the line 177, and the line 147. For this reason, the internal pressure of the first sub-tank 120C decreases and changes from the positive pressure state to the negative pressure state. The control unit 80 activates the liquid feed pump 118C when the pressure detected by the pressure sensor 144 becomes a predetermined negative pressure (for example, −0.8 kPa or lower), and the float 134 is detected by the Hi detection sensor 136H. The liquid feed pump 118C is stopped. As a result, the UV ink stored in the first main tank 110C is supplied to the ink storage chamber 123 of the first sub tank 120C, and the ink ink is filled into the ink storage chamber 123 of the first sub tank 120C to the reference filling height.

  In the subsequent step S50, the internal pressure of the first sub tank 120C detected by the pressure sensor 144 is reduced until it reaches the vicinity of the set negative pressure (for example, about −1.0 kPa). The closed second to fourth junction circuit open / close valves 175M, 175Y, and 175K are turned on to open the valves so that all of the first to fourth sub tanks are held in the negative pressure state of the set negative pressure ( (Negative pressure maintaining process), the process proceeds to step S60, and the ink filling program PG is terminated. As a result, the first printer head 60C selected on the operation panel 88 is filled with ink, and all the subtanks including the first subtank are set to a predetermined set negative pressure and held on standby. Even when the ink filling process is executed for a plurality of printer heads, the same process as described above is performed with the merging on / off valve on which the process is executed turned on.

  As described above, according to the ink supply method executed based on the ink filling program PG, the sub tank 120 is provided close to the printer head 60, and the internal pressure of the sub tank is connected to one air pump 160. By switching and controlling the negative pressure control valve 145 of the negative pressure circuit 141 and the positive pressure control valve 155 of the positive pressure circuit 151, the negative pressure state and the positive pressure state can be switched to the negative pressure holding and ink of the printer head 60. Filling or the like is performed. For this reason, in the printer device P, it is not necessary to provide a suction circuit for capping the bottom surface of the printer head and performing vacuum suction, and the ink filling failure caused by deterioration of the rubber cap or adhesion of dust is eliminated. Stable ink ejection can be performed immediately after filling. In addition, for the configuration in which the negative pressure state can be switched between the negative pressure state and the positive pressure state by switching the negative pressure control valve 145 and the positive pressure control valve 155 while the single pneumatic pump 160 is rotated in a certain direction, The overall configuration of the ink supply device 100 can be simplified and reduced in size, and the control burden and maintenance man-hours can be reduced.

  In the embodiment described above, a three-way valve is used as the negative pressure control valve 145 and the positive pressure control valve 155, and switching between communication / blocking of each circuit and release to the atmosphere are realized by turning on / off one valve. However, it is also possible to use a two-way valve dedicated for opening and closing that switches each circuit between a communication state and a shut-off state, and a two-way valve dedicated to opening and closing each circuit that opens to the atmosphere. . Further, in the embodiment, the configuration in which the pneumatic pump 160 is continuously rotated at a constant speed in principle for the sake of simplicity of the control configuration has been described. However, for example, the pneumatic pump is divided into a process of depressurizing and pressurizing the sub tank 120. You may comprise so that the rotation speed of the pump 160 may be changed or the rotation speed of the pneumatic pump 160 may be changed according to the pressure detected by the pressure sensors 144 and 154 provided in each circuit. Further, in the ink filling to the printer head 60, the method of directly pushing out UV ink by stopping the liquid feed pump 118 and increasing the internal pressure of the sub tank 120 by the sub tank pressurizing unit 150 has been described. After the internal pressure is set to a positive pressure state, the merging on-off valve 175 may be closed, and ink may be supplied to the sub tank 120 by the liquid feed pump 118, and the UV ink may be pushed out by the increase in internal pressure at this time.

  In the embodiments, as an example of an inkjet printer to which the present invention is applied, a configuration example applied to a UV curable inkjet printer of a uniaxial printing medium movement type and a uniaxial printer head movement type has been described. It can be applied to a printer, for example, a biaxial printer head moving type ink jet printer or a biaxial printing medium moving type ink jet printer, and other types of inks such as dyes and pigments are used as inks to be used. It can be applied to an ink jet printer.

It is a systematic diagram of an ink supply apparatus. FIG. 3 is an external perspective view of a printer apparatus as an application example of the present invention from an oblique front. FIG. 2 is an external perspective view of the printer device from an oblique rear side. It is a front view which shows the principal part structure of the apparatus main body in the said printer apparatus. It is a perspective view of the periphery of a carriage in the printer apparatus. It is an external appearance perspective view of the sub tank provided in the carriage. It is a schematic block diagram of an ink supply apparatus. It is a flowchart of an ink filling program.

Explanation of symbols

M Print medium P Printer device (inkjet printer)
1 Device body (main body member)
20 Platen (medium support part)
30 Media moving mechanism 40 Carriage 50 Carriage moving mechanism 60 Printer head (60C: first printer head, 60M: second printer head, 60Y: third printer head, 60K: fourth printer head)
80 Control unit 100 Ink supply device 110 Main tank (110C: first main tank, 110M: second main tank, 110Y: third main tank, 110K: fourth main tank)
115 Ink transfer unit (ink transfer means)
116 Main supply circuit 118 Liquid feed pump 120 Sub tank (120C: first sub tank, 120M: second sub tank, 120Y: third sub tank, 120K: fourth sub tank)
123 Ink storage chamber 140 Subtank decompression section (subtank decompression means)
141 Negative pressure circuit 145 Negative pressure control valve (negative pressure circuit opening means)
150 Sub tank pressurizing part (sub tank pressurizing means)
151 Positive pressure circuit 155 Positive pressure control valve (positive pressure circuit opening means)
160 Pneumatic pump (pump)
161 Suction port 162 Discharge port 171 Junction circuit 175 Junction circuit on / off valve (175C: first junction circuit on / off valve, 175M: second junction circuit on / off valve, 175Y: third junction circuit on / off valve, 175K: fourth junction circuit on / off valve )

Claims (5)

Is connected to the printer head for ejecting ink, and the sub tank for storing ink to be supplied to the printer head,
A main tank for storing ink connected to the sub tank and supplied to the sub tank;
Sub-tank pressure reducing means for reducing the internal pressure of the sub-tank to a negative pressure state;
Sub tank pressurizing means for pressurizing the internal pressure of the sub tank to a positive pressure state,
It said sub-tank pressure reducing means and the sub tank pressurizing unit utilizes suction and discharge action of one of the air pump is constructed an internal pressure of the sub tank to press vacuum or pressure,
The sub-tank pressure reducing means opens and closes the negative pressure circuit that connects the air pump suction port and the sub tank, and closes the negative pressure circuit to cut off the connection between the air pump suction port and the sub tank. A negative pressure circuit opening and closing means for opening the circuit on the suction port side of the air pump to the atmosphere sometimes,
The sub-tank pressurizing means opens and closes the positive pressure circuit, and closes the positive pressure circuit to cut off the connection between the discharge port of the air pump and the sub tank. A positive pressure circuit opening and closing means for opening the circuit on the discharge port side of the air pump to the atmosphere when
The air pump is driven to rotate in a certain direction, and the negative pressure circuit opening / closing means and the positive pressure circuit opening / closing means are used to switch between the negative pressure circuit and the positive pressure circuit, thereby reducing or increasing the internal pressure of the sub tank. An ink supply device for an ink jet printer, characterized by being configured as described above . When the internal pressure of the sub tank is reduced to a negative pressure state, the negative pressure circuit opening / closing means opens the negative pressure circuit to connect the air pump inlet and the sub tank, and uses the positive pressure circuit opening / closing means. Disconnecting the connection between the discharge port of the air pump and the sub-tank to open the circuit on the discharge port side of the air pump to the atmosphere,
When pressurizing the internal pressure of the sub tank to a positive pressure state, the positive pressure circuit opening / closing means opens the positive pressure circuit to connect the discharge port of the air pump and the sub tank, and uses the negative pressure circuit opening / closing means. 2. The ink supply device for an ink jet printer according to claim 1, wherein the connection between the suction port of the air pump and the sub tank is cut off to open a circuit on the suction port side of the air pump to the atmosphere . The positive pressure circuit and the negative pressure circuit merge to form a merge circuit,
The junction circuit is connected to the sub-tank;
The ink supply device for an ink jet printer according to claim 1 , wherein the junction circuit is provided with a junction circuit on-off valve that opens and closes the junction circuit. A plurality of the printer head and the sub tank are provided,
4. The ink supply device for an ink jet printer according to claim 3 , wherein the merging circuit opening / closing valve is configured to individually open and close the merging circuits branched corresponding to the plurality of sub tanks. The inkjet printer includes a main body member provided with a medium support portion for supporting a print medium, and a carriage provided movably on the main body member so as to face the print medium supported by the medium support portion,
The main tank is provided in the body member;
The ink supply device for an ink jet printer according to claim 1, wherein the printer head and the sub tank are provided in the carriage.

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