JP2013056421A - Ink supply control device, printing device including the same, and ink supply control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink supply control device and a printing device including the same, capable of preventing ink whose falling state into an ink tank is determined to be not normal from being supplied to an ink head.SOLUTION: This ink supply control device comprises: an ink tank 5 at least partly formed of a transparent material; a tube 4 connecting a lower part and an upper part of the ink tank 5; a tube pump (circulation part) 6 feeding ink 20 in the tube 4; and a detection part 7 detecting the state of the ink 20 falling from a fall part 41 added to the tube 4 at the upper part of the ink tank 5 from the outside through the part formed of the transparent material of the ink tank 5.

Description

  The present invention relates to an ink supply control device that controls the supply of ink to an ink head in accordance with the ink state, a printing apparatus including the ink supply control device, and an ink supply control method.

  Ink ejection devices that print by ejecting ink from the nozzles of the ink head have ink particle components (pigments, metal particles, etc.) settled, aggregated, deposited, settled, etc. (hereinafter, settled, etc.) inside the ink tank. There was a risk. When the ink particle component settles, etc., it becomes difficult to maintain the printing quality, such as ink becoming highly viscous and causing clogging of the nozzles of the ink head, resulting in unstable ink ejection. There was a problem.

  Therefore, in Patent Document 1, a magnetic stirrer rotor for stirring ink is provided at the bottom of the ink tank, and the ink in the ink tank can be stirred by rotation of the magnetic stirrer rotor. An ink tank is disclosed. In the ink tank for an ink jet recording apparatus disclosed in Patent Document 1, it is possible to eliminate sedimentation or the like of the ink particle component that tends to stay at the bottom.

JP-A-60-110458

  The ink tank for an ink jet recording apparatus disclosed in Patent Document 1 has a problem that a broken piece or the like of a magnetic stirrer rotor is mixed with ink and easily causes clogging of nozzles of an ink head. In particular, when the ink is a ferromagnetic material, there is a problem that the ink tends to adhere to the magnetic stirrer rotor and the ink particle components tend to aggregate.

  Further, it has not been possible to determine whether or not the sedimentation of the ink particle component has been eliminated until the ink is actually ejected from the ink head. Therefore, it is necessary to take an excessive measure for suppressing the sedimentation of the ink particle component, and there is a problem that it is difficult to reduce the cost.

  The present invention has been made in view of such circumstances, and an ink supply control device capable of preventing ink that has been determined to be in an abnormal drop state from being supplied to an ink head. It is an object of the present invention to provide a printing apparatus provided with a supply control device and an ink supply control method.

  In order to achieve the above object, an ink supply control device according to a first aspect of the present invention is an ink supply control device that controls the supply of ink to an ink head, wherein the ink tank is formed of at least a part of a transparent material, A tube connecting the lower part and the upper part of the ink tank, a circulation part for sending out the ink in the tube, and a part formed of a transparent material of the ink tank are added to the tube at the upper part of the ink tank. And a detection unit that detects the state of ink falling from the drop unit from the outside.

  In the first invention, at least a part of the ink tank formed of a transparent material, a tube connecting the lower and upper portions of the ink tank, a circulating portion for sending ink in the tube, and a transparent ink tank And a detection unit that detects the state of ink falling from a dropping unit added to a tube at the top of the ink tank through a portion formed of a material. Since it is possible to determine whether or not the state of ink falling without ejecting ink from the ink head is normal, the user determined that the state of ink falling is not normal based on the detection result In this case, by operating so as not to supply ink from the ink tank to the ink head, it is possible to prevent clogging of the nozzles of the ink head and to stably discharge ink. In addition, for ink circulated through the tube, it is possible to determine whether or not the sedimentation of the ink particle component of the ink head has been eliminated. Can be minimized. Further, since the ink falls on the liquid surface of the ink in the ink tank, it is possible to promote stirring of the particle component of the ink and suppress sedimentation of the particle component.

  The ink supply control device according to a second aspect of the present invention includes a determination unit that determines whether or not the state of the falling ink is normal based on the result detected by the detection unit. When it is determined by the means that the state of the ink falling is not normal, control is performed so that ink is not supplied from the ink tank to the ink head.

  In the second invention, based on the detected result, it is determined whether or not the state of the falling ink is normal, and if it is determined that the state of the falling ink is not normal, the ink is supplied from the ink tank to the ink head. Control not to. Since it is possible to determine whether or not the state of ink falling without ejecting ink from the ink head is normal, based on the detected result, when it is determined that the state of falling ink is not normal, By controlling the operation so that ink is not supplied from the ink tank to the ink head, clogging of the nozzles of the ink head can be prevented and ink can be ejected stably. In addition, for ink circulated through the tube, it is possible to determine whether or not the sedimentation of the ink particle component of the ink head has been eliminated. Can be minimized. Further, since the ink falls on the liquid surface of the ink in the ink tank, it is possible to promote stirring of the particle component of the ink and suppress sedimentation of the particle component.

  The ink supply control device according to a third aspect of the present invention is the ink supply control device according to the first or second aspect, wherein the detection unit is an image pickup device, and the determination unit is configured to drop ink based on a change in an image picked up by the image pickup device. It is characterized by determining whether or not the state is normal.

  In the third invention, since it is determined whether or not the state of the falling ink is normal based on the change of the image captured by the imaging device, it is possible to grasp the change in the shape, color tone, width, etc. of the falling ink. It is possible to determine whether or not the degree of dispersion of the ink particle components has changed.

  In the ink supply control apparatus according to a fourth aspect of the present invention, in the first or second aspect, the detection unit is an optical sensor, and the determination unit is configured to detect ink that falls based on a change in a value detected by the optical sensor. It is characterized by determining whether or not the state is normal.

  In the fourth aspect of the invention, since it is determined whether or not the state of the falling ink is normal based on the change in the value detected by the optical sensor, it is possible to grasp the change in the shape, color tone, width, etc. of the falling ink. It is possible to determine whether or not the degree of dispersion of the ink particle components has changed.

  According to a fifth aspect of the present invention, there is provided a printing apparatus comprising the ink supply control device according to any one of the first to fourth aspects.

  In the fifth invention, since the ink supply control device described above is provided, it is possible to determine (determine) whether or not the state of ink falling without ejecting ink from the ink head is normal. Based on the result, when it is determined (determined) that the state of the falling ink is not normal, the user operates (controls the operation) so as not to supply ink from the ink tank to the ink head. It is possible to prevent clogging and stably discharge ink. In addition, since it is possible to determine (determine) whether or not the ink particle component has settled or not for the ink circulated through the tube, the time required for the ink particle component to settle or the like is eliminated. Can be minimized. Further, since the ink falls on the liquid surface of the ink in the ink tank, it is possible to promote stirring of the particle component of the ink and suppress sedimentation of the particle component.

  Next, in order to achieve the above object, an ink supply control method according to a sixth aspect of the invention is an ink supply control method for controlling supply of ink from an ink tank to an ink head, which is stored in the ink tank. A step of sending ink from the bottom to the top and dropping the ink onto the ink surface from above, a step of determining whether the ink is normal by detecting the state of the dropped ink, and the ink And a step of controlling the supply of ink from the ink tank to the ink head based on whether the state is normal.

  In the sixth aspect of the invention, the ink stored in the ink tank is sent out from below to drop the ink onto the ink surface from above. By detecting the state of the dropped ink, it is determined whether or not the ink state is normal, and the ink supply from the ink tank to the ink head is determined based on whether or not the ink state is normal. Control. Since it is possible to determine (determine) whether or not the state of ink falling without ejecting ink from the ink head is normal, it is determined that the state of falling ink is not normal based on the detected result When (determination) is performed, the user operates (controls the operation) not to supply ink from the ink tank to the ink head, thereby preventing clogging of the nozzles of the ink head and discharging ink stably. It becomes possible. In addition, since it is possible to determine (determine) whether or not the ink particle component has settled or not for the ink circulated through the tube, the time required for the ink particle component to settle or the like is eliminated. Can be minimized. Further, since the ink falls on the liquid surface of the ink in the ink tank, it is possible to promote stirring of the particle component of the ink and suppress sedimentation of the particle component.

  According to the above configuration, since it is possible to determine (determine) whether or not the state of the ink falling without ejecting ink from the ink head is normal, the state of the ink falling based on the detected result If it is determined that the ink is not normal, the user operates (controls the operation) not to supply ink from the ink tank to the ink head, thereby preventing clogging of the nozzles of the ink head and discharging the ink. It becomes possible to carry out stably. In addition, since it is possible to determine (determine) whether or not the ink particle component has settled or not for the ink circulated through the tube, the time required for the ink particle component to settle or the like is eliminated. Can be minimized. Further, since the ink falls on the liquid surface of the ink in the ink tank, it is possible to promote stirring of the particle component of the ink and suppress sedimentation of the particle component.

It is a schematic diagram which shows schematic structure of an ink jet type printing apparatus provided with the ink supply control apparatus which concerns on Embodiment 1 of this invention. It is a schematic diagram which shows the structure of the ink tank of the ink supply control apparatus which concerns on Embodiment 1 of this invention. It is a schematic diagram which shows the other structure of the ink tank of the ink supply control apparatus which concerns on Embodiment 1 of this invention. It is an expanded sectional view showing typically composition of a dropping part added to a tube of an ink supply control device concerning Embodiment 1 of the present invention. It is a schematic diagram which shows the other structure of the ink tank of the ink supply control apparatus which concerns on Embodiment 1 of this invention. It is a schematic diagram which shows the structure of the tube pump of the ink supply control apparatus which concerns on Embodiment 1 of this invention. It is a schematic diagram explaining the state of the falling ink of the ink supply control apparatus which concerns on Embodiment 1 of this invention. It is the schematic which shows typically the structure of the inkjet type printing apparatus provided with the ink supply control apparatus which concerns on Embodiment 2 of this invention. It is the schematic which shows typically the structure in the case of providing an ink supply on-off valve of the inkjet printing apparatus provided with the ink supply control apparatus which concerns on Embodiment 2 of this invention.

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

(Embodiment 1)
FIG. 1 is a schematic diagram illustrating a schematic configuration of an ink jet printing apparatus including an ink supply control apparatus according to Embodiment 1 of the present invention. An ink jet printing apparatus 1 illustrated in FIG. 1 includes an ink supply control device 10 including an ink head 2, an ink tank 5, a tube 4, a tube pump (circulation unit) 6, and an imaging device 7, a vacuum pump 35, and compressed air. A supply source 36 and a control device 37 are provided. The ink head 2 has openings 22 of a plurality of nozzles 21 that discharge the ink 20 formed on one surface, and the ink 20 in the nozzles 21 is pushed out by a piezoelectric element or the like, so that the ink is discharged from the openings 22 of the nozzles 21. 20 is discharged. The piezoelectric element and the like are driven and controlled by the control device 37. The size of the ink head 2 is, for example, approximately 120 mm in length, approximately 10 mm in width, and approximately 100 mm in height. The number of the nozzles 21 varies depending on the object to be printed by ejecting the ink 20, and is about several tens to several hundreds, and the pitch of the nozzles 21 is as wide as about 1 mm. The arrangement of the openings 22 of the nozzles 21 may be a single row or a plurality of rows. Further, it is not necessary that all the openings 22 of the plurality of nozzles 21 are continuously arranged.

  The ink tank 5 stores the ink 20 to be supplied to the ink head 2. The ink 20 used in the inkjet printing apparatus 1 is, for example, pigment-based ink, metal particles (electrode materials Au, Ag, Cu, Pd, Ni), or ink containing conductive particles. Ingredients (pigments, metal particles, etc.) are dispersed. The ink 20 may contain ceramic, resin, etc. in addition to metal particles. Further, the viscosity of the ink 20 is preferably a low viscosity of 40 mPa · s or less, and particularly preferably a viscosity of 10 mPa · s to 25 mPa · s. The capacity of the ink tank 5 is, for example, 50 mL. A supply port 8 serving as an inlet of a passage for supplying the ink 20 to the ink head 2 is provided below the ink tank 5.

  FIG. 2 is a schematic diagram showing the configuration of the ink tank 5 of the ink supply control device 10 according to the first embodiment of the present invention. As shown in FIG. 2, the ink tank 5 is formed in a columnar shape, and the tube 4 connects the lower part and the upper part of the ink tank 5. The tube 4 is fixed to the upper side surface of the ink tank 5 and extends into the ink tank 5. A portion extending inside the ink tank 5 is defined as a drop portion 41 of the tube 4. A predetermined distance is provided between the lower end of the dropping unit 41 and the liquid level of the ink 20 in the ink tank 5, and the ink 20 is dropped from the lower end of the dropping unit 41 onto the liquid level of the ink 20.

  FIG. 3 is a schematic diagram illustrating another configuration of the ink tank 5 of the ink supply control device 10 according to the first embodiment of the present invention. As shown in FIG. 3, the dropping portion 41 may be an L-shaped stainless steel pipe, which is fixed to the side surface of the ink tank 5 with a barb joint 9 and added to the tube 4.

  FIG. 4 is an enlarged cross-sectional view schematically showing the configuration of the dropping unit 41 added to the tube 4 of the ink supply control device 10 according to Embodiment 1 of the present invention. In the configuration of FIG. 4A, the dropping part 41 is protruded below the upper inner wall of the ink tank 5. Further, in the configuration of FIG. 4B, an opening obtained by performing a liquid repellent process on the peripheral portion of the upper inner wall of the ink tank 5 is used as the dropping portion 41. Thereby, the ink 20 can be reliably dropped into the ink tank 5.

  The ink tank 5 is formed of a transparent material such as polypropylene or glass, and the inside can be seen from the outside through a portion formed of the transparent material. Of course, the entire surface of the ink tank 5 does not have to be transparent, and it is only necessary to detect the state of the falling ink 20 from the outside using a detection unit such as the imaging device 7 described later.

  FIG. 5 is a schematic diagram showing another configuration of the ink tank 5 of the ink supply control device 10 according to the first embodiment of the present invention. As in FIG. 2, the ink tank 5 is formed in a columnar shape, and the tube 4 connects the lower part and the upper part of the ink tank 5. The ink tank 5 shown in FIG. 5 is provided with a part of an observation window 51 so that an image can be taken by the image pickup device (detection unit) 7. Through the observation window 51, the state of the falling ink 20 can be detected from the outside.

  The tube 4 is a silicon-based tube, and is not particularly limited as long as the tube 4 is made of a material that deforms in response to an external pressing force. In the present embodiment, the inner diameter of the tube 4 is 3 mm, for example.

  In the middle of the tube 4, a tube pump 6 is provided as a circulation unit that sends out the ink 20 in the tube 4. The operation of the tube pump 6 is controlled by the control device 37. FIG. 6 is a schematic diagram showing the configuration of the tube pump 6 of the ink supply control device 10 according to Embodiment 1 of the present invention.

  The tube pump 6 has a pair of rollers 62 provided at positions opposite to each other of a rotor 61 that rotates at the center, with the elastic tube 4 disposed along the inner periphery of a casing 63 having a substantially circular inner periphery. To press the tube 4. The pair of rollers 62 is moved by the rotation of the rotor 61, and the ink 20 is sent out by pressing the ink 20 in the tube 4 along the tube 4. In the example of FIG. 6, since the rotor 61 rotates clockwise, the ink 20 is sucked from the lower part of the ink tank 5 to which the tube 4 is connected, and is sent out to the upper part of the connected ink tank 5.

  After the pair of rollers 62 passes, the pressed portion of the tube 4 returns to its original shape by the restoring force, and the volume returns to the original. When the volume of the tube 4 is restored, the ink 20 is continuously sucked from the lower part of the ink tank 5.

  Since the tube pump 6 does not use a valve, it is suitable for transferring a viscous liquid such as the ink 20 and has high maintainability that only the tube 4 which is the only consumable item needs to be replaced. doing. Of course, the actuator is not limited to the tube pump 6 having the configuration shown in FIG. 6, and any actuator that can reliably circulate the ink 20 may be used.

  Returning to FIG. 1, on the side of the ink tank 5, an imaging device (detecting unit) 7 capable of imaging the inside of the ink tank 5 is provided. Image data captured by the imaging device 7 is transmitted to the control device 37, and the user determines whether or not the degree of dispersion of the particle components of the ink 20 in the ink tank 5 has changed based on the image data.

  Specifically, the user determines a change in the falling state with reference to the state of the ink 20 falling from the dropping portion 41 to the liquid level of the ink 20 immediately after supplying the ink 20 to the ink tank 5. FIG. 7 is a schematic diagram for explaining the state of the falling ink 20 of the ink supply control device 10 according to the first embodiment of the present invention.

  FIG. 7A shows the state of the ink 20 falling from the dropping portion 41 immediately after the ink 20 is supplied to the ink tank 5. In this case, since the sedimentation of the particle component of the ink 20 has not been eliminated, the ink 20 falls continuously from the dropping portion 41 with a certain width.

  On the other hand, when the particle component of the ink 20 gradually settles or the like, it drops intermittently as shown in FIG. 7B due to retention in the lower part of the ink tank 5 to which the tube 4 is connected. Alternatively, as shown in FIG. 7C, the width W becomes wider than that in FIG. Further, when the ink 20 is deteriorated, the color of the ink 20 may change as shown in FIG.

  In this way, based on the image data captured by the imaging device 7, the state of the falling ink 20 is confirmed, the presence or absence of the continuity of the falling ink 20, the width, the change in color tone, and the like are calculated. If it is determined that the value has changed by about 10% from the value calculated immediately after the ink 20 is supplied to the ink tank 5, it is determined that the ink 20 is not in a normal drop state.

  Returning to FIG. 1, a vacuum path 31 for sucking air in the ink tank 5 to bring the inside into a negative pressure state (1 to 3 kPa) and compressed air (compressed gas) are provided in the upper part of the ink tank 5. A gas supply path 32 for supply is connected. The upper part of the sealed ink tank 5 is in a negative pressure state so that the ink 20 does not spill from the nozzle 21 constantly. Accordingly, the supply of the ink 20 to the ink head 2 can be stopped by the negative pressure, and the ink 20 in the ink tank 5 can be continuously circulated until the sedimentation of the particle component of the ink 20 is eliminated. it can.

  On the other hand, when the ink 20 is discharged in a larger amount than the amount discharged from the nozzle 21 during printing (when purging), the negative pressure on-off valve 33 provided in the vacuum path 31 is closed and the compression provided in the gas supply path 32 is closed. Compressed air is supplied into the ink tank 5 by opening the open / close valve 34 for air. By supplying compressed air into the ink tank 5, the ink 20 in the ink tank 5 can be pushed out from the opening 22 of the nozzle 21, and the ink 20 can be discharged in a larger amount than the amount discharged from the nozzle 21 during printing. (Purge operation). The on / off valve 33 for negative pressure is connected to the vacuum pump 35 via a pressure regulating valve. The compressed air open / close valve 34 is connected to a compressed air supply source 36 via a pressure regulating valve. Further, the opening / closing valve 33 for negative pressure and the opening / closing valve 34 for compressed air are controlled by a control device 37.

  Below the ink head 2, a stage 72 on which a substrate 73 is placed is disposed. The substrate 73 is attracted to the stage 72 and fixed so as not to move with respect to the stage 72. The stage 72 can move in three axial directions, and moves the placed printing material 73 in accordance with the position of the ink 20 ejected from the nozzles 21 of the ink head 2. Note that the movement of the stage 72 is controlled by the control device 37.

  Hereinafter, an ink supply control operation of the ink jet printing apparatus 1 including the ink supply control apparatus 10 according to the first embodiment of the present invention will be described. First, the on-off valve 34 for compressed air provided in the gas supply path 32 is closed, the on-off valve 33 for negative pressure provided in the vacuum path 31 is opened, and the upper part of the ink tank 5 is brought into a negative pressure state. In this state, the tube pump 6 is activated and the tube 4 is pressed to feed the ink 20 in the tube 4 from the lower side to the upper side of the ink tank 5.

  The ink 20 in the tube 4 moves in the tube 4 and falls from the dropping portion 41 to the liquid level of the ink 20 in the ink tank 5. Immediately after the ink 20 is supplied to the ink tank 5, the ink 20 does not deteriorate and the sedimentation of the particle components has been eliminated, so that the ink 20 continuously falls from the dropping portion 41 with a constant width.

  The control device 37 appropriately closes the open / close valve 33 for negative pressure provided in the vacuum path 31, opens the open / close valve 34 for compressed air provided in the gas supply path 32, and stores it in the ink tank 5. A certain ink 20 is supplied to the ink head 2. That is, the amount of ink 20 necessary for printing can be supplied to the ink head 2 by adjusting the degree of suction according to how the on-off valve 33 is closed.

  The imaging device 7 images the ink 20 falling from the dropping unit 41. Based on the captured image data, the user confirms whether or not the falling ink 20 has continuity, changes in width, changes in color tone, and the like. For example, the value 10 calculated from the value calculated immediately after the ink 20 is supplied to the ink tank 5. %, It is determined that the ink 20 is not in a normal drop state. In this case, the control device 37 receives an input from an input device (not shown) by the user, and closes the on-off valve 34 and opens the on-off valve 33 so that the ink 20 is not supplied from the ink tank 5 to the ink head 2. .

  As described above, according to the first embodiment, it is possible to determine whether or not the state of the ink 20 that falls without ejecting the ink 20 from the ink head 2 is normal. Therefore, based on the detected result. When the user determines that the state of the falling ink 20 is not normal, the operation of not supplying the ink 20 from the ink tank 5 to the ink head 2 prevents clogging of the nozzles 21 of the ink head 2. Ink 20 can be stably discharged. Further, since it can be determined whether or not the sedimentation of the particle component of the ink 20 has been eliminated for the ink 20 circulated through the tube 4, it is necessary to eliminate the sedimentation of the particle component of the ink 20. Time can be minimized. Furthermore, since the ink 20 falls on the liquid surface of the ink 20 in the ink tank 5, the stirring of the particle component of the ink 20 is promoted, and the sedimentation of the particle component can be suppressed. Further, since the circulation path of the ink 20 is formed by a loop closed by the ink tank 5 and the tube 4, it goes without saying that there is no possibility of contamination from the outside.

(Embodiment 2)
Since the schematic configuration of the ink jet printing apparatus 1 including the ink supply control apparatus according to the second embodiment is the same as that of the first embodiment, detailed description thereof is omitted by attaching the same reference numerals. In the second embodiment, when the control device 37 determines whether or not the state of the ink 20 is normal according to the state of the falling ink 20 and determines that the ink 20 is not normal, the ink head 2 is automatically selected. The second embodiment is different from the first embodiment in that the operation is controlled so as not to supply the ink 20 to the head.

  FIG. 8 is a schematic diagram schematically illustrating the configuration of the ink jet printing apparatus 1 including the ink supply control apparatus 10 according to the second embodiment of the present invention. As shown in FIG. 8, the ink tank 5 is formed in a columnar shape, and the tube 4 connects the lower part and the upper part of the ink tank 5. The tube 4 extends from the top to the inside of the ink tank 5, and the ink 20 falls from the dropping portion 41 to the liquid level of the ink 20 in the ink tank 5.

  The ink tank 5 is made of a transparent material such as polypropylene or glass, and the inside can be seen from the outside. Of course, the entire surface of the ink tank 5 does not have to be transparent, as long as it is possible to image the state of the ink 20 falling by the imaging device 7.

  In the middle of the tube 4, a tube pump 6 is provided as a circulation unit that sends out the ink 20 in the tube 4. The operation of the tube pump 6 is controlled by the control device 37. Of course, the actuator is not limited to the tube pump 6, and any actuator that can reliably circulate the ink 20 may be used.

  On the side of the ink tank 5, there is provided an imaging device (detecting unit) 7 capable of imaging the inside of the ink tank 5. The image data picked up by the image pickup device 7 is transmitted to the control device 37, and the control device 37 functions as a determination unit, and whether the degree of dispersion of the particle components of the ink 20 in the ink tank 5 has changed based on the image data. Determine whether or not.

  Specifically, the control device 37 determines a change in the drop state based on the state of the ink 20 falling from the drop portion 41 with respect to the liquid level of the ink 20 immediately after supplying the ink 20 to the ink tank 5. . The control device 37 stores the image data picked up by the image pickup device 7 immediately after supplying the ink 20 to the ink tank 5 and compares it with the image data picked up thereafter.

  For example, when the particle component of the ink 20 settles or the like, the control device 37 determines whether or not the falling ink 20 is continuous. Here, the image data stored in advance and the captured image data are compared to determine whether or not the falling ink 20 is continuous. When it is determined that the ink 20 is not continuous, the on-off valve 34 is set. The operation is controlled to close and open the on-off valve 33. As a result, the upper portion of the ink tank 5 is in a negative pressure state, and the ink 20 is not supplied to the ink head 2.

  Further, the control device 37 determines whether or not the width of the falling ink 20 has changed. Here, the width of the ink 20 in the stored image data is compared with the width of the ink 20 in the captured image data, and when it is determined that the change has occurred by 10% or more, the on-off valve 34 is closed and the on-off valve 33 is opened. Control the action to open. As a result, the upper portion of the ink tank 5 is in a negative pressure state, and the ink 20 is not supplied to the ink head 2.

  Further, the control device 37 determines whether or not the color tone of the falling ink 20 has changed. Here, color image data is captured and the color tone (lightness, saturation, etc.) of the falling ink 20 in the stored color image data and the color tone (lightness, saturation) of the falling ink 20 in the captured image data are stored. The operation is controlled so that the on-off valve 34 is closed and the on-off valve 33 is opened when it is determined that the change has occurred by 10% or more. As a result, the upper portion of the ink tank 5 is in a negative pressure state, and the ink 20 is not supplied to the ink head 2.

  The operation is not limited to closing the opening / closing valve 34 of the vacuum pump 35 and opening the opening / closing valve 33, but an ink supply opening / closing valve is provided between the ink tank 5 and the ink head 2. The opening / closing operation of the supply opening / closing valve may be controlled. FIG. 9 is a schematic diagram schematically illustrating a configuration of the ink jet printing apparatus 1 including the ink supply control apparatus 10 according to the second embodiment of the present invention when an ink supply opening / closing valve is provided.

  As shown in FIG. 9, the ink tank 5 is formed in a columnar shape, and the tube 4 connects the lower part and the upper part of the ink tank 5. On the side of the ink tank 5, an imaging device (detection unit) 7 capable of imaging the inside of the cylindrical body 5 is provided. Image data captured by the imaging device 7 is transmitted to the control device 37, and the control device 37 determines whether or not the degree of dispersion of the particle components of the ink 20 in the ink tank 5 has changed based on the image data.

  Specifically, a change in the falling state is determined with reference to the state of the ink 20 falling from the dropping portion 41 to the liquid level of the ink 20 immediately after the ink 20 is supplied to the ink tank 5. The control device 37 stores the image data picked up by the image pickup device 7 immediately after supplying the ink 20 to the ink tank 5 and compares it with the image data picked up thereafter.

  For example, when the particle component of the ink 20 settles or the like, the control device 37 determines whether or not the falling ink 20 is continuous. Here, the image data stored in advance and the captured image data are compared to determine whether or not the falling ink 20 is continuous. If it is determined that the ink 20 is not continuous, the on-off valve 39 is set. Control the action to close. As a result, the flow path to the ink head 2 is closed, and the ink 20 is not supplied to the ink head 2.

  Further, the control device 37 determines whether or not the width of the falling ink 20 has changed. Here, the control device 37 compares the width of the falling ink 20 in the stored image data with the width of the falling ink 20 in the captured image data, and opens and closes when it is determined that the change has occurred by 10% or more. The operation is controlled to close the valve 39. As a result, the flow path to the ink head 2 is closed, and the ink 20 is not supplied to the ink head 2.

  Further, the control device 37 determines whether or not the color tone of the falling ink 20 has changed. Here, the color tone (lightness, saturation, etc.) of the falling ink 20 in the color image data stored as color image data and the color tone (lightness, saturation) of the falling ink 20 in the imaged image data are stored. The operation is controlled to close the on-off valve 39 when it is determined that the change has occurred by 10% or more. As a result, the flow path to the ink head 2 is closed, and the ink 20 is not supplied to the ink head 2.

  As described above, according to the second embodiment, it is possible to determine whether or not the state of the falling ink 20 is normal by the control device 37 functioning as a determination unit. In this case, by controlling the operation so that the ink 20 is not supplied from the ink tank 5 to the ink head 2, it is possible to prevent clogging of the nozzles 21 of the ink head 2 and to stably discharge the ink 20. Become. Further, since it is possible to determine whether or not the sedimentation of the particle component of the ink 20 has been eliminated for the ink 20 circulated through the tube 4, it is necessary to eliminate the sedimentation of the particle component of the ink 20. Time can be minimized. Furthermore, since the ink 20 falls on the liquid surface of the ink 20 in the ink tank 5, the stirring of the particle component of the ink 20 is promoted, and the sedimentation of the particle component can be suppressed.

  In the first and second embodiments, an optical sensor may be used instead of the imaging device 7. In this case, it is possible to determine whether or not the falling ink 20 is continuous depending on whether or not light is transmitted. It is also possible to determine whether or not the width of the falling ink 20 has changed based on the light receiving range of the reflected light. Furthermore, it is possible to determine whether the color tone (lightness, saturation, etc.) of the falling ink 20 has changed, whether the transmittance has changed, and the like, based on the spectrum of the reflected light.

  In addition, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications and substitutions are possible within the scope of the gist of the present invention. For example, the ink supply control device 10 according to the present invention is not limited to use in the ink jet printing apparatus 1, and the same effect can be expected when used in, for example, a jet dispenser, a wet electrophotographic apparatus, and the like.

DESCRIPTION OF SYMBOLS 1 Inkjet printer 2 Ink head 4 Tube 5 Ink tank 6 Tube pump (circulation part)
7 Imaging device (detection unit)
DESCRIPTION OF SYMBOLS 8 Supply port 10 Ink supply control apparatus 20 Ink 33, 34, 39 On-off valve 35 Vacuum pump 36 Compressed air supply source 37 Control apparatus (discriminating means)
41 Falling part

Claims (6)

In an ink supply control device that controls supply of ink to an ink head,
An ink tank at least partially formed of a transparent material;
A tube connecting the lower and upper portions of the ink tank;
A circulation part for sending out the ink in the tube;
An ink comprising: a detection unit that detects, from the outside, a state of ink falling from a dropping unit added to the tube at the top of the ink tank through a portion formed of a transparent material of the ink tank. Supply control device. A discriminating means for discriminating whether or not the state of the falling ink is normal based on a result detected by the detection unit;
2. The ink supply control device according to claim 1, wherein when the state of the ink falling by the determination unit is determined to be not normal, control is performed so that ink is not supplied from the ink tank to the ink head.   The detection unit is an imaging device, and the determination unit determines whether or not the state of ink falling is normal based on a change in an image captured by the imaging device. 2. An ink supply control device according to 1.   3. The detection unit according to claim 1, wherein the detection unit is an optical sensor, and the determination unit determines whether or not the state of ink falling is normal based on a change in a value detected by the optical sensor. 2. An ink supply control device according to 1.   A printing apparatus comprising the ink supply control device according to claim 1. An ink supply control method for controlling supply of ink from an ink tank to an ink head,
Sending the ink stored in the ink tank from below to above and dropping the ink from above onto the ink surface;
Determining whether the ink state is normal by detecting the state of the dropped ink; and
Controlling the supply of ink from the ink tank to the ink head based on whether the state of the ink is normal or not.

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