JP2010036418A - Ink supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink supply device which can adjust the pressure in an ink chamber preventing the ink in the ink chamber from flowing into a pressure adjusting means and flowing reversely. <P>SOLUTION: The ink supply device is equipped with: a sub tank 120 in which an ink storage chamber 123 is formed that temporarily storing the liquid ink supplied from a main tank and supplies it to a printer head 60; a liquid feeding pump which supplies the liquid ink from the main tank to the ink storage chamber 123; a storage detecting part 130 which detects a level height position of the liquid ink in the ink storage chamber 123; and a control unit which controls supply of the liquid ink by the liquid feeding pump according to the detection result detected by the storage detecting part 130. The control unit controls supply of the liquid ink by the liquid feeding pump so that the level of the liquid ink in the ink storage chamber 123 is located between the lowest and highest limits. An ink supply hole 128a is positioned higher than the highest limit. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ink supply device that supplies ink to a printer head that performs desired printing by discharging ink.

  An ink jet printer using the printer head is configured to perform desired printing by ejecting ink from nozzles formed on the lower surface of the printer head while moving the printer head relative to the print medium. 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. For example, 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. Ink is supplied from the tank to the printer head.

  Here, when the internal pressure of the printer head becomes higher than the atmospheric pressure, the ink is pushed out from the nozzle and dripped onto the print medium, thereby causing a problem of so-called “dropping off”. Therefore, conventionally, a configuration using an ink supply (sub tank) is known so that the internal pressure of the printer head becomes a slightly negative pressure slightly lower than the atmospheric pressure. As a configuration example of a conventional sub tank, a sub tank having a small-capacity ink chamber is provided between an ink tank (main tank) provided in a printer main body and a printer head, and the printer head and the sub tank are connected to a print medium. Some are mounted on a relatively movable carriage. A configuration in which the printer head can be brought into a slightly negative pressure state by depressurizing the ink chamber of the sub tank by the pressure adjusting means (see, for example, Patent Document 1 and Patent Document 2). For example, Patent Document 1 discloses a configuration in which a pressure pump and a pressure reduction pump are provided and these pumps are connected to each sub tank.

FIG. 9 shows a cross-sectional view of the sub-tank 500 which the applicant has invented himself and has applied for a patent, and supplies ink while maintaining the printer head 600 connected below at a slight negative pressure. Configured as follows. An ink chamber 510 that stores ink and a float storage chamber 520 that communicates with the ink chamber 510 are formed inside the sub tank 500, and ink is supplied to the printer head 600 from a supply path 590 that extends downward from the ink chamber 510. Supplied. Near the center of the ink chamber 510, an ink supply means 570 for supplying ink from a main tank (not shown) to the ink chamber 510 is connected, and a pressure adjusting means 580 is connected to the upper end. A magnet 540 fixed to the float 530 is inserted into the float storage chamber 520 so as to be movable up and down. The magnet 540 is detected to detect that the ink level is positioned at the upper limit level. A magnetic detection sensor 550 for detecting, and 560 for detecting that it is positioned at the lower limit liquid level height position are attached to the side surface of the sub tank 500. Based on the detection result of the liquid level, ink supply by the ink supply unit 570 is controlled so that the ink liquid level is positioned between the upper limit liquid level height position and the lower limit liquid level height position.
JP 2004-284207 A JP 2006-62330 A

  Incidentally, in recent years, in an industrial inkjet printer, there is a demand for moving a carriage on which a printer head and a sub tank are mounted at a high speed relative to a printing medium in order to shorten a printing time. In order to meet this requirement, for example, when the carriage is reciprocated at a high speed, the ink in the main tank may exceed the control amount via the ink supply means 570 due to the influence of inertia depending on the moving direction of the carriage. May flow into chamber 510. At this time, since the ink supply means 570 and the ink chamber 510 are connected via the ink, the ink flows into the ink chamber 510 due to the influence of inertia and the liquid level in the ink chamber 510 rises. There is a risk that the pressure will flow back into the pressure adjusting means 580 set to a pressure. In particular, in a sub-tank connected to a printer head in which ink is not ejected (printed), ink is not supplied from the supply path 590 to the printer head 600, and thus the backflow is likely to occur. If the ink flows into the pressure adjusting unit 580, for example, it is difficult to reduce the pressure in the ink chamber 510, and the above-described problem of “dropping off” may occur.

  The present invention has been made in view of the above problems, and provides an ink supply device capable of adjusting the pressure in the ink chamber without causing the ink in the ink chamber to flow back into the pressure adjusting means. Objective.

  In order to achieve the above object, an ink supply apparatus according to the present invention is configured to supply liquid ink to the printer head connected to a printer head that discharges liquid ink and performs desired printing, and the printer. A sub-tank formed with an ink chamber (for example, ink storage chamber 123 in the embodiment) that is connected to the head and temporarily supplies liquid ink supplied from a main tank in which liquid ink is stored and then supplies the ink to the printer head. An ink supply means (for example, a liquid feed pump 118 in the embodiment) connected to the sub tank and supplying liquid ink from the main tank to the ink chamber; and a liquid surface height position of the liquid ink in the ink chamber. By the liquid level detection means to detect (for example, the storage detection unit 130 in the embodiment) and the liquid level detection means Depending on the issued detection result, the supply control means for controlling the supply of liquid ink by the ink supply means (e.g., the control unit 80 in the embodiment) and a. The supply control means controls the supply of the liquid ink by the ink supply means so that the liquid level of the liquid ink in the ink chamber is located between the lower limit liquid level height position and the upper limit liquid level height position. The sub tank side connection position of the ink supply means is configured to be located above the upper limit liquid level height position.

  Further, in the ink supply device, the ink supply means is connected to a side surface side of the sub tank (for example, the front wall 121f in the embodiment), and an ink supply hole in the ink supply means opens to the ink chamber side. Pressure adjusting means for adjusting the pressure in the ink chamber (for example, the air pump 160 in the embodiment) is connected to the upper surface side of the sub tank (for example, the ceiling wall 121t in the embodiment), and the pressure in the pressure adjusting means is adjusted. A hole (for example, the gas introduction hole 129a in the embodiment) opens to the ink chamber side, and an inflow regulating member (for example, a collision in the embodiment) that extends inward of the ink chamber so as to face the ink supply hole. The plate 123a) is preferably formed so as to be positioned between the ink supply hole and the pressure adjusting hole.

  The supply control unit causes the ink supply unit to supply liquid ink when the liquid level detection unit detects that the liquid level of the liquid ink has dropped to the lower limit liquid level height position. Preferably, control is performed so that the supply of the liquid ink by the ink supply means is stopped when the liquid level detection means detects that the liquid ink level has risen to the upper limit liquid level height position. .

  In the ink supply device according to the present invention, the sub tank side connection position of the ink supply means is higher than the upper limit liquid level height position that is the liquid level height position of the ink when the maximum volume of ink is stored in the ink chamber. Is located. With this configuration, the sub tank side connection portion of the ink supply means is not filled with ink, that is, the sub tank side connection portion of the ink supply means and the ink in the ink chamber are completely separated and blocked. It can be in the state. Therefore, surface tension can be applied to the ink located at the sub tank side connection portion of the ink supply means. Therefore, even when the inertia or the like acts on the ink by performing printing while reciprocating the printer head (sub tank) at high speed, the ink in the main tank flows into the ink chamber at once through the ink supply means. Therefore, it is possible to prevent the ink in the ink chamber from flowing back into the pressure adjusting means and flowing backward, for example, and the pressure in the ink chamber can be adjusted.

  Further, it is preferable that the inflow restricting member is formed so as to face the ink supply hole and extend inward of the ink chamber and to be positioned between the ink supply hole and the pressure adjusting hole. With this configuration, for example, the ink supplied from the ink supply hole to the ink chamber can be made to flow down downward after colliding with the inflow restricting member and reliably guided to the ink chamber. Therefore, it is possible to prevent the supplied ink from flowing into the pressure adjusting means from the pressure adjusting hole and flowing backward, although the inflow restricting member that prevents the progress is provided in the middle of the ink traveling path. Furthermore, some of the ink supplied from the ink supply hole to the ink chamber changes in a mist shape. However, when the inflow chamber is set, for example, when the ink chamber is set to a negative pressure by the pressure adjusting means. In this case, it is possible to prevent the mist-like ink from being sucked into the pressure adjusting means from the pressure adjusting hole and flowing in.

  The supply control means causes the ink supply means to supply ink when it is detected that the ink level has dropped to the lower limit liquid level height position, so that the ink level is higher than the upper limit level. A configuration in which the supply of ink is stopped when it is detected that the position has been raised is preferable. When configured in this way, a constant volume of ink can be stored in the ink chamber at all times, and ink can be stably supplied without interruption to the printer head.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. As an example of an ink jet printer to which the present invention is applied, a type in which a printer head is reciprocated and printing is performed while a print medium is fed in a direction perpendicular to the printer head is taken, and an ultraviolet curable ink that is cured by being irradiated with ultraviolet light ( A configuration example applied to a UV curable inkjet printer (hereinafter referred to as a printer device) that discharges so-called UV ink from a printer head will be described. 1 and 2 are perspective views of the printer device P of the present embodiment, and FIG. 3 shows the configuration of the main part 1 of the printer device P. The entire printer device P is described with reference to these drawings. The configuration will be described. In the following description, directions indicated by arrows F, R, and U added in FIG. 1 will be referred to as front, right, and upward, respectively.

  The printer device P is broadly divided into an apparatus main body 1 supported by the support unit 2, a feed mechanism 3 that feeds an unprinted print medium M provided before and after the support unit 2, and a print medium M that has finished drawing. A winding mechanism 4 for winding is configured. In the apparatus main body 1, a horizontally long window-shaped medium insertion portion 15 that allows the print medium M to be inserted back and forth in the frame 10 is formed, and the print medium M is supported by the lower frame 10 </ b> L positioned below the media insertion portion 15. A platen 20 and a medium moving mechanism 30 for feeding the print medium M back and forth are provided (see FIG. 3). A carriage 40 that holds the printer head 60 and a carriage moving mechanism 50 that moves the carriage 40 to the left and right are provided on the upper frame 10U positioned above the media insertion portion 15. The apparatus body 1 is provided with a control unit 80 which will be described later, and an operation panel 88 provided with various operation switches and the like is disposed on the front surface of the apparatus body 1 (see FIG. 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 for horizontally supporting the print medium M is provided in the left and right belt-like drawing areas by the printer head 60. Is formed. The medium moving mechanism 30 includes a cylindrical feed roller 31 whose upper peripheral surface is exposed to the platen 20, a roller driving motor 33 that rotates the feed roller 31 via a timing belt 32, and the like. A roller assembly 35 having a pinch roller 36 rotatably supported is disposed on the left and right. The roller assembly 35 is configured to be set 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. The print medium M is sandwiched between the pinch roller 36 and the feed roller 31, the roller assembly 35 is set to the clamp position, and the roller drive motor 33 is rotationally driven to feed the print medium M forward and backward by a predetermined distance. Can do. In FIG. 3, both the clamp position and the unclamp position are shown.

  The carriage 40 is supported by a guide rail 45 attached to the upper frame 10U so as to be movable left and right, and is driven by a carriage driving mechanism 50 described later. A printer head 60 that discharges UV ink is mounted on the carriage 40 with a predetermined gap from the media support portion 21. FIG. 5 is a perspective view of the periphery of the carriage. In FIG. 5, the printer head 60 is used for each of the four colors of UV inks of cyan (C), magenta (M), yellow (Y), and black (K). The case where (first printer head 60C, second printer head 60M, third printer head 60Y, fourth printer head 60K) is provided is illustrated. The carriage 40 is provided with subtanks 120 (first subtank 120C, second subtank 120M, third subtank 120Y, and fourth subtank 120K), which will be described in detail later, corresponding to the printer head 60. Note that the printer head 60 in the present embodiment exemplifies a configuration that ejects ink by a piezo method.

  The left and right side portions of the carriage 40 are provided with a left UV light source 70L and a right UV light source 70R that irradiate ultraviolet light toward the print medium M, and are configured using, for example, a UV lamp or a UV-LED. The blinking operation of the left UV light source 70L and the right UV light source 70R is controlled by the control unit 80 in accordance with the movement of the carriage 40 and the ejection of ink from the printer head 60. The carriage moving mechanism 50 is wound around a drive pulley 51 and a driven pulley 52 provided on the left and right sides of the frame 10, a carriage drive motor 53 that rotates the drive pulley 51, and the drive pulley 51 and the driven pulley 52. The endless timing belt 55 is formed (see FIG. 3). The carriage 40 is fixed to a timing belt 55 and is moved left and right above the platen 20 along the guide rail 45 in accordance with the drive of the carriage drive motor 53.

  The control unit 80 performs arithmetic processing on a ROM 81 in which a control program for each component is written, a RAM 82 for temporarily storing the program, a program read from the RAM 82, an operation signal input from the operation panel 88, and the like. The arithmetic processing unit 83 is mainly configured. The control unit 80 controls the operation of each component such as the medium moving mechanism 30, the carriage moving mechanism 50, the printer head 60, the ink supply device 100 described later, and the like.

  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 moving mechanism 30 and the left / right movement of the carriage 40 by the carriage moving mechanism 50 are combined. The print medium M and the printer head 60 are moved relative to each other. Simultaneously with this relative movement, a UV light source (for example, the left UV light source 70L when the carriage is moved to the right) is turned on while discharging ink from each printer head 60 toward the printing medium M. Then, information corresponding to the printing program is drawn.

Thus, in the printer apparatus P schematically configured, the printer head 60 is used during printing.
UV ink is supplied from the ink supply device 100 to the printer head 60 in accordance with the amount of UV ink consumed. 4 is a system diagram of the ink supply apparatus 100, FIG. 6 is an external perspective view of the sub tank 120, FIG. 7 is a cross-sectional view taken along the line VII-VII in FIG. 6, and FIG. 6 shows a state where no UV ink is stored, and FIG. 7 shows a state where a predetermined amount of UV ink is stored.

  The ink supply device 100 includes a sub-tank 120 connected to the printer head 60, a main tank 110 storing UV ink, a sub-tank decompression unit 140 for reducing the internal pressure of the sub-tank 120 to a negative pressure state, and an internal pressure of the sub-tank 120 being a positive pressure state. A sub tank pressurizing unit 150 that pressurizes the main tank 110, an ink transfer unit 115 that transfers UV ink stored in the main tank 110 to the sub tank 120, and the like. (See FIG. 4). As the main tank 110, a tank capable of storing a capacity corresponding to the consumption amount of UV ink per unit time in the printer device P is selected. 2 shows the cartridge-type main tanks 110 (first main tank 110C, second main tank 110M, third main tank 110Y, and fourth main tank 110K) for the above four colors, respectively, on the rear surface of the apparatus main body 1. Fig. 1 shows an example of a configuration that is detachably disposed.

  As shown in FIG. 6, the sub tank 120 is made of, for example, a resin material that covers and seals the opening surface of the container member 121 on a thin rectangular box-shaped container member 121 that opens to one side (right side of the sheet). A transparent sheet member 122 is welded and sealed with the sheet member 122, thereby forming an ink storage chamber 123 and a float storage chamber 124. A thin plate member 122a made of, for example, a metal material and formed in a lattice shape is sandwiched between the opening surface of the container member 121 and the sheet member 122, and the opening surface is partially covered by the thin plate member 122a.

  The ink storage chamber 123 stores a predetermined amount of UV ink during printing, and a groove-like float storage chamber 124 that communicates with the ink storage chamber 123 and extends vertically is formed behind the ink storage chamber 123. (See FIG. 7). A disk-shaped float 134 that floats on UV ink is accommodated in the float chamber 124 so as to be movable up and down. A magnet 134 a is fixed to the center of the float 134. Note that at least one of the container member 121 and the sheet member 122 is formed using a transparent or translucent material, so that the storage state of the UV ink in the ink storage chamber 123, the floating state of the float 134, and the like from the outside. It is configured so that it can be confirmed visually.

  A short cylindrical connector portion 125 projecting downward from the bottom wall 121 b of the container member 121 is formed on the lower surface side of the sub tank 120, and the connector portion 125 and the printer head 60 are connected using a tube 69. (See FIGS. 6 and 7). A block-shaped duct portion 126 extending upward from the bottom wall 121b to the inside of the ink storage chamber 123 is formed on the upper portion of the connector portion 125. A first lead-out path 127a that penetrates the bottom wall 121b up and down is formed so as to connect the ink storage chamber 123 and the connector part 125, and a second lead-out path 126b that penetrates the duct part 126 up and down is formed. The cross-sectional area of the first lead-out path 127a is smaller than the cross-sectional area of the second lead-out path 126b. Therefore, the ink storage chamber 123 and the printer head 60 are connected via the first lead-out path 127a and the second lead-out path 126b. When printing is not being performed, the carriage 40 is controlled to move to a reference position (home position), and a bat-shaped ink tray that receives UV ink is located below the printer head 60 positioned at the reference position. 180 is provided (see FIG. 5).

  A storage detector 130 that detects the storage state of the UV ink in the ink storage chamber 123 is provided on the rear surface side of the sub tank 120. The storage detection unit 130 detects the magnetism of the float 134 and the magnet 134a, which moves up and down according to the liquid level of the UV ink in the ink storage chamber 123, to which the magnet 134a is fixed. It is comprised from the liquid level detection sensor 138 which detects thickness. On the rear wall 121r of the container member 121, a groove-shaped sensor mounting portion 131 extending in the vertical direction is formed, and the liquid level detection sensor 138 is mounted on the sensor mounting portion 131. For example, a case member 137 to be described later is attached. The liquid level detection sensor 138 is fixed to the rear wall 121r by inserting and fastening the mounting screw 139 into the hole 137a (see FIG. 7).

  The liquid level detection sensor 138 includes a liquid level detection substrate 135 to which a Hi detection sensor 136H and a Lo detection sensor 136L are attached in order from the top, and a case member 137 that accommodates the liquid level detection substrate 135. Each of the detection sensors 136H and 136L can be configured using, for example, a Faraday element or a magnetic impedance element, and a Hall element is preferably used. Various magnets can be used as the magnet 134a, and an anisotropic ferrite magnet is preferably used. As shown in FIG. 7, the liquid level detection sensor 138 is disposed opposite to the float 134 with the rear wall 121r interposed therebetween, and the magnetism of the magnet 134a is detected by the detection sensors 136H and 136L, whereby the liquid level of the UV ink is detected. It is possible to detect that is positioned at the highest position and the lowest position. The highest liquid level T is indicated by a two-dot chain line.

  A regulation rib 124a is formed above the float storage chamber 124, and regulates the float 134 from further moving beyond the highest position. As can be seen from FIG. 7, since the inner wall of the float storage chamber 124 and the front and rear side surfaces of the float 134 (magnet 134a) are close to each other, the float 134 makes the float storage chamber 124 substantially straight according to the liquid level of the UV ink. It is configured to move up and down. In this way, the liquid level height position of the UV ink detected by the liquid level detection sensor 138 is output to the control unit 80.

  An ink introduction path (not shown) penetrating the front wall 121f of the container member 121 back and forth is formed on the front side of the sub tank 120 so as to communicate with the ink storage chamber 123. A tube connector 128 is connected to the ink introduction path. Is inserted and attached. As can be seen from FIG. 7, the attachment position of the tube connector 128 to the front wall 121f is above the highest liquid level T. Further, the collision plate 123a extends downward on the ceiling wall 121t of the container member 121 so as to face the ink supply hole 128a opened to the ink storage chamber 123 side of the tube connector 128, and the ink supply hole 128a will be described later. It is formed so as to block between the gas introduction hole 129a. Further, on the upper surface side of the sub tank 120, a gas introduction path (not shown) penetrating the ceiling wall 121t up and down is formed so as to communicate with the ink storage chamber 123. A tube connector 129 in which a gas introduction hole 129a is formed is inserted and attached.

  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 includes an ink suction line 117 a connected to the main tank 110 and the liquid feed pump 118, an ink delivery line 117 b connected to the liquid feed pump 118 and the tube connector 128, and UV ink from the main tank 110 to the sub tank. The liquid feed pump 118 supplied to 120 is configured. As the liquid feed pump 118, for example, a diaphragm pump or a tube pump is preferably used. In the present embodiment, a configuration using a diaphragm pump will be described as an example.

  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, a pressure sensor 144 that detects the pressure of the negative pressure circuit 141, a negative pressure control valve 145 that opens and closes the negative pressure circuit 141, as shown by being surrounded by a frame A in FIG. 4, and A line 147 (147a, 147b, 147c, 147d) or the like connecting these devices to connect between the suction port 161 of the pneumatic pump and the sub tank 120 is configured. In FIG. 4, a portion surrounded by a frame C is provided on the carriage 40, and a portion outside the frame is a device provided on the apparatus main body 1.

  The air chamber 142 is connected to the suction port 161, and is configured such that the air in the chamber is exhausted and reduced to a negative pressure state by the operation of the air feed pump 160. An air introduction line 147i for introducing air into the inside is provided. The air introduction line 147i is provided with a flow rate adjustment valve 143a for adjusting the flow rate of air and an air filter 143b for dust removal. The flow rate adjusting valve 143a adjusts the flow rate of the 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, thereby making the internal pressure of the air chamber 142 constant.

  The negative pressure control valve 145 is located between the air chamber 142 and the sub tank 120, and is an electromagnetic valve that switches the line 147c and the line 147d between a communication state and a cutoff state. FIG. 4 exemplifies a configuration using a three-way valve as the negative pressure control valve 145. A line 147c is connected to the common port (COM), a line 147d is connected to the normally open port (NO), and a normally closed port (NC) is shown. ) Is open to the atmosphere via line 147x and silencer 148. For this reason, when the negative pressure control valve 145 is off (during normal operation such as printing or standby, and at the time of ink filling), the line 147c and the line 147d are connected to bring the negative pressure circuit 141 into a communication state. The suction port 161 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 cleaning or the like), the connection between the line 147c and the line 147d is cut off, the negative pressure circuit 141 is cut off, and the line 147c is connected to the line 147x. The circuit on the suction port side of the feed pump 160 is opened to the atmosphere.

  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 includes a flow rate adjustment valve 153a that adjusts the flow rate of air, a dust filter air filter 153b, and a pressure sensor 154 that detects the pressure of the positive pressure circuit 151, as shown by being surrounded by a frame B in FIG. From a positive pressure control valve 155 that opens and closes the positive pressure circuit 151, and a line 157 (157a, 157b, 157c, 157d) connecting these devices to connect the discharge port 162 of the air pump 160 and the sub tank 120, etc. Composed. The flow rate adjustment valve 153a is a valve that adjusts the internal pressure of the ink storage chamber 123 so as not to exceed a predetermined value in a state where the air pump 160 and the sub tank 120 are connected by the positive pressure circuit 151.

  The positive pressure control valve 155 is located between the flow rate adjustment valve 153a and the sub tank 120, and is an electromagnetic valve that switches the line 157c and the line 157d between a communication state and a cutoff state. FIG. 4 illustrates a configuration using a three-way valve as the positive pressure control valve 155. 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 a line 157x and a silencer 158. For this reason, when the positive pressure control valve 155 is off (during normal operation such as printing or standby, and at the time of ink filling), the connection between the line 157c and the line 157d is disconnected and the positive pressure circuit 151 is cut off. In addition, the line 157c is connected to the line 157x, and the positive pressure circuit on the discharge port side of the air feed pump 160 is opened to the atmosphere. On the other hand, when the positive pressure control valve 155 is on (for cleaning or the like), the line 157c and the line 157d are connected, the positive pressure circuit 151 is set in a communication state, and the discharge port 162 and the sub tank 120 are connected to the junction circuit 171. Connected through.

  The pneumatic 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 is used for the port 161. 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 junction circuit 171 includes a line 177 connected to the sub tank 120 and a junction circuit opening / closing valve 175 that opens and closes the junction circuit 171. The junction circuit open / close valve 175 is provided corresponding to the number of sub-tanks 120. In FIG. 4, the junction circuit 171 (line 177) is branched into four, and each of the branched junction circuits (lines 177C and 177M) is branched. , 177Y, 177K, part numbers omitted) are illustrated as being individually openable and closable.

  In the printer apparatus P configured as described above, as shown in FIG. 8, detection results obtained by the pressure sensors 144 and 154 and the liquid level detection sensor 138 are input to the control unit 80, and from the operation panel 88. The operation signal is input. The control unit 80 controls the operation of the liquid feed pump 118, the air feed pump 160, the negative pressure control valve 145, the positive pressure control valve 155, and the junction circuit opening / closing valve 175 based on these input results.

  Hereinafter, the operation control by the control unit 80 will be described. Since the UV ink supply system is the same for the four systems (C, M, Y, K), the items common to each system in the following description will be described by omitting these subscripts. .

  When the main power supply of the printer apparatus P is turned on, the control unit 80 drives the air feed pump 160 and turns on all the junction circuit open / close valves 175. After the junction circuit opening / closing valve 175 is turned on, the negative pressure control valve 145 and the positive pressure control valve 155 are both turned off, so that in the negative pressure circuit 141, the line 147c and the line 147d communicate with each other for suction. The port 161 and the ink storage chamber 123 are connected, and in the positive pressure circuit 151, the line 157c and the line 157x are connected, and the circuit on the discharge port side of the air feed pump 160 is opened to the atmosphere. In this way, the air feed pump 160 is continuously driven regardless of whether the printing program is being executed or on standby, and the internal pressures of the four ink storage chambers 123 are always set to the same negative pressure. Retained.

  As described above, when the internal pressure of the storage chamber 123 is set to a negative pressure, the sheet member 122 can be bent toward the inside of the sub tank 120, so that the rapid fluctuation of the internal pressure can be absorbed (relaxed). It is the structure where excessive external force does not act on each component part. Further, since the ink storage chamber 123 and the float storage chamber 124 are partially covered by the thin plate member 122a, the sheet member 122 can be prevented from being excessively bent toward the inside of the sub tank 120. Therefore, for example, the sheet member 122 and the float 134 do not come into contact with each other, and the vertical movement of the float 134 according to the liquid level height of the UV ink can be secured, so that the accurate liquid level height can be detected. Further, for example, when the UV ink in the sub tank 120 is once discharged and cleaning is performed, the internal pressure of the storage chamber 123 is set to a positive pressure, contrary to the above. In this case, the sheet member 122 is configured to be able to absorb fluctuations in its internal pressure by bending toward the outside of the sub tank 120.

  During normal printing, the control unit 80 controls each component so that a certain amount of UV ink is always stored in the ink storage chamber 123 of the sub tank 120. The control will be specifically described. The UV ink stored in the ink storage chamber 123 is discharged and consumed from the nozzles of the printer head 60 by the execution of a printing program or the like and gradually decreases. When the UV ink stored in the ink storage chamber 123 decreases, the liquid level of the UV ink decreases, and the float 134 is moved downward in the float storage chamber 124 according to the liquid level. When the magnetism of the magnet 134a is detected by the Lo detection sensor 136L and it is detected that the liquid level is positioned at the lowest position, the control unit 80 is in a state where the ink storage chamber 123 is depressurized to a negative pressure state. The liquid feed pump 118 is started.

  The UV ink sent from the main tank 110 by the driving of the liquid feed pump 118 is supplied to the ink storage chamber 123 from the ink supply hole 128a of the tube connector 128 through the line 117b. At this time, the supplied UV ink collides with the collision plate 123a, and then flows down and is stored in the ink storage chamber 123 (see FIG. 7). By providing the collision plate 123a in this way, it is possible to prevent the UV ink supplied to the ink storage chamber 123 from reaching the gas introduction hole 129a, so that the line 177 flows backward by being sucked into the gas introduction hole 129a. Can be prevented. In addition, when ink is supplied to the ink storage chamber 123, a part of the ink may become mist in the ink supply hole 128a. Even in such a case, since the collision plate 123a is formed, the ink mist is not sucked into the gas introduction hole 129a set to the negative pressure, and the pressure in the storage chamber 123 can be adjusted as set. It becomes possible.

  As described above, since the supplied UV ink flows down from the ink supply hole 128a to the ink storage chamber 123, it can be prevented from directly hitting the float 134 and pushing the float 134 into the UV ink. . Therefore, the liquid level height position of the ink storage chamber 123 can be faithfully reflected in the height position of the float 134, and the liquid level detection sensor 138 can detect the liquid level height position with high accuracy.

  By continuing the supply of UV ink to the ink storage chamber 123, the liquid level of the UV ink gradually increases, the magnetism of the magnet 134a is detected by the Hi detection sensor 136H, and the liquid level rises to the highest position. When this is detected, the control unit 80 stops the driving of the liquid feed pump 118 and the replenishment of the UV ink is completed. In this way, during normal printing, the UV ink in the ink storage chamber 123 has its liquid surface located between the lowest position and the highest position, and a predetermined amount of UV ink is always stored, so that the printer head 60 It is controlled so as to be supplied stably.

  In the printer apparatus P to which the present invention is applied, as described above, for example, a diaphragm pump is used as the liquid feed pump 118, and the ink storage chamber 123 is set to a negative pressure as described above. The liquid feed pump 118 tends to be in a slightly open state (a state in which the main tank 110 and the storage chamber 123 are connected) during printing. By the way, the tube connector 128 (ink supply hole 128a) is attached to the front wall 121f so as to be positioned further above the liquid level T at the highest position, so that the UV in the ink supply hole 128a and the ink storage chamber 123 is disposed. The ink is completely separated and blocked. Therefore, surface tension can be applied to the ink positioned in the ink supply hole 128a. Therefore, even when the inertia or the like acts on the ink by performing the printing while reciprocating the carriage 40 at a high speed, the ink in the main tank 110 is transferred from the ink supply hole 128a through the liquid supply pump 118 to the ink storage chamber 123. It is possible to prevent the ink in the ink storage chamber 123 from flowing into the gas introduction hole 129a and flowing backward.

  In the above-described embodiment, the collision plate 123a formed to extend downward from the ceiling wall 121t has been described as an example. However, the present invention is not limited to this configuration. For example, UV ink supplied from the ink supply hole 128a is guided to the ink storage chamber 123 without reaching the gas introduction hole 129a, and ink mist generated in the ink supply hole 128a is not sucked into the gas introduction hole 129a. The shape and formation position of the collision plate 123a are not limited.

  Further, in the above-described embodiment, as shown in FIG. 7, the magnet 134a is fixed to the center of the float 134, and the vertical position of the magnet 134a and the liquid surface position of the UV ink coincide with each other. It is not limited to the configuration. For example, when the float 134 having the magnet 134a fixed to the upper end portion is floated in the UV ink, the positional relationship between the liquid surface position of the UV ink and the fixing position of the magnet 134 is known. In consideration of the fixing position, a configuration in which the Hi detection sensor 136H and the Lo detection sensor 136L are disposed is also possible.

  In the above-described embodiment, as an example of the ink jet printer to which the present invention is applied, the configuration example applied to the UV curable ink jet printer of the uniaxial printing medium movement and the uniaxial printer head movement has been described. However, the present invention can also be applied to other forms of jet printers, for example, a biaxial printer head moving type or a biaxial printing medium moving type ink jet printer. The present invention can be applied to an ink jet printer using other types of ink.

It is the external appearance perspective view which showed the printer apparatus to which this invention was applied from diagonally forward. It is the external appearance perspective view which showed the said printer apparatus from diagonally backward. It is the front view which showed the principal part structure of the apparatus main body of the said printer apparatus. It is a systematic diagram of an ink supply apparatus. It is the perspective view which showed the carriage periphery of the said printer apparatus. It is the external appearance perspective view which showed the sub tank provided in the carriage. It is sectional drawing which showed the VII-VII part in FIG. It is a schematic block diagram of an ink supply apparatus. It is sectional drawing which showed the conventional subtank.

Explanation of symbols

60 printer head (60C: first printer head, 60M: second printer head, 60Y: third printer head, 60K: fourth printer head)
80 Control unit (supply control means)
100 ink supply device 110 main tank (110C: first main tank, 110M: second main tank, 110Y: third main tank, 110K: fourth main tank)
118 Liquid feed pump (ink supply means)
120 sub tanks (120C: first sub tank, 120M: second sub tank, 120Y: third sub tank, 120K: fourth sub tank)
121f Front wall (side)
121t ceiling wall (top side)
123 Ink storage chamber (ink chamber)
123a Colliding plate (inflow restricting member)
128a Ink supply hole 129a Gas introduction hole (pressure adjusting hole)
130 Storage detection unit (liquid level detection means)
160 Pneumatic pump (pressure regulation means)

Claims (3)

An ink supply device that is connected to a printer head that discharges liquid ink and performs desired printing and supplies liquid ink to the printer head,
The ink supply device comprises:
A sub-tank connected to the printer head and formed with an ink chamber for supplying the printer head after temporarily storing the liquid ink supplied from a main tank in which the liquid ink is stored;
An ink supply means connected to the sub-tank to supply liquid ink from the main tank to the ink chamber;
A liquid level detecting means for detecting a liquid level height position of the liquid ink in the ink chamber;
Supply control means for controlling the supply of liquid ink by the ink supply means according to the detection result detected by the liquid level detection means,
The supply control means controls the supply of the liquid ink by the ink supply means so that the liquid level of the liquid ink in the ink chamber is located between the lower limit liquid level height position and the upper limit liquid level height position. ,
An ink supply device, wherein a sub tank side connection position of the ink supply means is positioned above the upper limit liquid level height position. The ink supply means is connected to a side surface of the sub-tank, and an ink supply hole in the ink supply means opens to the ink chamber side;
Pressure regulating means for regulating the pressure in the ink chamber is connected to the upper surface side of the sub tank, and a pressure regulating hole in the pressure regulating means opens to the ink chamber side,
2. The inflow regulating member facing the ink supply hole and extending inward of the ink chamber is formed to be positioned between the ink supply hole and the pressure adjusting hole. The ink supply device according to 1. The supply control means includes
When the liquid level detection means detects that the liquid level of the liquid ink has dropped to the lower limit liquid level height position, the liquid supply by the ink supply means is performed,
When the liquid level detection means detects that the liquid level of the liquid ink has risen to the upper limit liquid level height position, the liquid supply control by the ink supply means is controlled to stop. The ink supply device according to claim 1 or 2.

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