JPWO2016208533A1 - Inkjet printing apparatus and printing method - Google Patents

Abstract

An ink jet printing apparatus capable of reducing the number of pumps is provided. An inkjet printing apparatus 1 using a plurality of inkjet heads 11 and 12. The liquid supply source, the flow path 3 connected to the liquid supply source, the plurality of inkjet heads 11 and 12 connected to the flow path 3, the liquid feed pump 6, and the downstream of the plurality of inkjet heads 11 and 12. In the side portion, suction pumps 25 and 26 for sucking liquid from the plurality of inkjet heads 11 and 12 are provided, and the number of the liquid feed pump 6 or the suction pumps 25 and 26 is larger than the number of the inkjet heads 11 and 12. Less inkjet printing apparatus 1.

Description

  The present invention relates to a printing apparatus and a printing method using an inkjet head.

  Conventionally, various ink jet printing apparatuses using an ink jet head have been proposed. In the following Patent Document 1, a plurality of inkjet heads are connected between a liquid supply tank and a storage tank as a waste liquid tank. Ink from the supply tank is supplied to the plurality of inkjet heads, and excess ink from the inkjet heads is collected in the storage tank. In Patent Document 2, a regulator is provided in the flow path so that liquid leakage does not occur in the inkjet head when driving is started.

  On the other hand, Patent Document 3 below also discloses an inkjet printing apparatus in which a plurality of inkjet heads are connected to a flow path. In Patent Document 3, a suction pump is connected to a downstream flow path in order to supply liquid to a plurality of ink jet heads by a liquid feed pump and collect excess liquid from the ink jet heads. One pressure pump is used for liquid feeding, and one suction pump is used for suction.

Patent No. 5084609 Japanese Patent No. 5554759 Japanese Patent No. 5577388

  In Patent Document 3, one liquid feed pump and one suction pump are used for a plurality of ink jet heads. In such a configuration, the viscosity of the liquid at room temperature is high, and when ink is used that is heated at the time of printing and lowered to a viscosity that can be ejected by inkjet, the liquid is applied to a plurality of inkjet heads at the start of circulation. Could not be delivered smoothly. This is because the previous liquid remains in the flow path at the start of supply and its viscosity is high. In particular, when a flow path is branched to supply liquid to a plurality of ink jet heads, the liquid may flow only to the branch flow path side with a low resistance, and the liquid may not flow to the branch flow path with a high resistance side. . This phenomenon occurs remarkably in inks that are heated at a high temperature at room temperature and are lowered to a viscosity that can be ejected by inkjet. In such a case, a complicated operation such as using a regulator or providing a valve in each branch channel to turn on or off the branch channel is forced.

  Further, in the structure in which the regulator or the valve is provided in each branch flow path, the structure of the ink jet printing apparatus becomes complicated and there is a possibility that the structure becomes large. Furthermore, when the number of liquid feeding pumps and suction pumps is simply increased in order to increase the driving force of liquid feeding, there is a possibility that the inkjet printing apparatus becomes larger.

  An object of the present invention is to provide an ink jet printing apparatus and a printing method capable of reducing the number of pumps.

  The inkjet printing apparatus of the present invention is an apparatus using an inkjet head, and is connected to a liquid supply source, the liquid supply source, a flow path for supplying liquid from the liquid supply source, and the flow. A plurality of inkjet heads that are connected to a channel and to which the liquid is supplied; a liquid feeding pump that is connected to an upstream side portion of the plurality of inkjet heads in the flow path; and A suction pump for sucking the liquid from the plurality of ink jet heads in a portion downstream of the plurality of ink jet heads, wherein the number of the liquid feed pumps or the number of the suction pumps is greater than the number of the ink jet heads; There are few.

  In a specific aspect of the ink jet printing apparatus according to the present invention, one liquid feeding pump is provided for one ink jet head. In this case, even when a high-viscosity liquid is used, the liquid can be smoothly supplied to the plurality of inkjet heads.

  In another specific aspect of the inkjet printing apparatus according to the present invention, the liquid supply source is a closed tank, and the suction pump is connected to the tank so as to adjust the atmospheric pressure in the tank. The number of suction pumps is less than the number of ink jet heads.

  In still another specific aspect of the ink jet printing apparatus according to the present invention, one suction pump is provided for one ink jet head. In this case, even when a high-viscosity liquid is used, the liquid can be smoothly supplied to the plurality of inkjet heads.

  In still another specific aspect of the inkjet printing apparatus according to the present invention, the downstream portion of the flow path includes a plurality of first downstream flow path portions each having one end connected to the plurality of inkjet heads. Have.

  In another specific aspect of the inkjet printing apparatus according to the present invention, the downstream portion of the flow path includes a plurality of first downstream flow path portions each having one end connected to the plurality of inkjet heads. The suction pump is connected to each first downstream flow path portion.

  In another specific aspect of the inkjet printing apparatus according to the present invention, a plurality of the first downstream flow path portions are joined downstream of the suction pump.

  In another specific aspect of the ink jet printing apparatus according to the present invention, the upstream portion of the flow path connects the liquid supply source and the liquid feed pump, the first upstream flow path section, A liquid feed pump and a second upstream flow path connecting the plurality of inkjet heads, and the second upstream flow path is branched so as to be connected to the plurality of inkjet heads Has been.

  In still another specific aspect of the ink jet printing apparatus according to the present invention, in the second upstream flow path portion of the upstream flow path portion, the liquid feeding pump and the second upstream flow path portion are branched. A first flow path switching member is connected between the first flow path switching member and the first upstream flow path portion and the second upstream flow path portion. A liquid supply flow path state connecting the branched portions of the first flow path, a first upstream flow path portion, and a bypass flow path state connecting the first downstream flow path portions. It is comprised so that a flow path state can be switched between.

  In still another specific aspect of the inkjet printing apparatus according to the present invention, a second channel switching member is provided in each of the first downstream channel portions connecting the plurality of inkjet heads and the suction pump. The second flow path switching member is connected between a suction state connecting the inkjet head and the suction pump and a bypass flow path state connecting the bypass flow path and the suction pump. It is comprised so that a road state can be switched.

  A printing method according to the present invention is a printing method using an ink jet printing apparatus configured according to the present invention, and drives the liquid feeding pump of the ink jet printing apparatus and drives the suction pump to pass through the flow path. A step of feeding a liquid from the liquid supply source; and a step of discharging the supplied liquid from the inkjet head and printing.

  In a specific aspect of the printing method according to the present invention, when the liquid is started to flow into the flow path by the ink jet printing apparatus, the liquid is supplied from the liquid feed pump so as to bypass the plurality of ink jet heads. There is further provided a step of feeding liquid to the suction pump side through the flow path.

  According to the ink jet printing apparatus and the printing method of the present invention, the number of pumps can be reduced.

FIG. 1 is a schematic configuration diagram illustrating an ink jet printing apparatus according to a first embodiment of the present invention. FIG. 2 is a schematic configuration diagram showing an ink jet printing apparatus according to the second embodiment of the present invention. FIG. 3 is a schematic configuration diagram showing an ink jet printing apparatus according to the third embodiment of the present invention. FIG. 4 is a schematic configuration diagram showing an ink jet printing apparatus according to the fourth embodiment of the present invention.

  Hereinafter, the present invention will be clarified by describing specific embodiments of the present invention with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of an ink jet printing apparatus according to the first embodiment of the present invention.

  The ink jet printing apparatus 1 has a tank 5. In this embodiment, the tank 5 is a tank in which a liquid having a relatively high viscosity as a printing material is stored. However, the physical structure of the liquid supply source is not limited to a tank shape. In addition, the inkjet printing apparatus 1 of this embodiment is used for the adhesive as a liquid having a relatively high viscosity. However, the use of the inkjet printing apparatus 1 of the present embodiment is not limited to such adhesive printing.

  The tank 5 has an outlet 5a and a recovery port 5b. The outlet 5a is provided for supplying a liquid to first and second ink jet heads 11 and 12, which will be described later. The recovery port 5b is provided for recovering the liquid sucked from the first and second inkjet heads 11 and 12. The recovered liquid is supplied to the flow path 3 from the outlet 5 a side of the tank 5.

  Further, a heating device can be provided in the tank 5 in order to heat the ink.

  The channel 3 includes an upstream channel portion 3a and a downstream channel portion 3b.

  An upstream flow path portion 3a located upstream of the inkjet heads 11 and 12 is connected to the outlet 5a. A liquid feed pump 6 is connected to the upstream flow path portion 3a. The liquid feed pump 6 is provided in order to send a liquid in a pressurized manner. The liquid feed pump 6 can be formed by an appropriate pump such as a diaphragm pump.

  A first flow path switching member 13 is connected to the downstream side of the liquid feed pump 6. The first channel switching member 13 includes a liquid supply channel state connecting the first upstream channel unit 3a1 and the second upstream channel unit 3a2, and a first upstream channel. It is comprised so that it can switch between the part 3a1 and the bypass flow path state which has connected the bypass flow path 14. FIG. Such a 1st flow-path switching member 13 is comprised by the three-way valve etc., for example.

  The second upstream flow path portion 3a2 is branched into first and second branch flow paths 3a21 and 3a22. The first inkjet head 11 is connected to the first branch flow path 3a21. The second inkjet head 12 is connected to the second branch flow path 3a22.

  The first ink jet head 11 and the second ink jet head 12 are known ink jet printing heads. A flow path portion connecting the first and second ink jet heads 11 and 12 and the recovery port 5b of the tank 5 described above is a downstream flow path portion 3b. More specifically, the downstream flow path portion 3b includes a plurality of first downstream flow path portions 3b1 and 3b2. The first downstream flow path portion 3 b 1 is connected to the outlet of the first inkjet head 11. The first downstream flow path portion 3 b 2 is connected to the outlet of the second inkjet head 12.

  The plurality of first downstream flow path portions 3b1 and 3b2 are connected to the second flow path switching members 21 and 22, respectively. The second flow path switching member 21 is a three-way valve. However, an appropriate flow path switching device that can similarly switch the flow path state other than the three-way valve can be used. The second flow path switching member 21 has a first port connected to the bypass flow path 14 described above. The second port is connected to the first downstream flow path portion 3b1. The third port is connected to the second downstream channel portion 3b3.

  In addition, the 1st suction pump 25 is connected to the 2nd downstream flow path part 3b3.

  The second flow path switching member 21 includes a bypass flow path state connecting the bypass flow path 14 and the second downstream flow path portion 3b3, and thus the first suction pump 25, and the first downstream side. It is configured to be able to be switched between a flow path state (suction state) connecting the flow path part 3b1 and the second downstream flow path part 3b3, and thus the first suction pump 25.

  Similarly, the second flow path switching member 22 also has first to third ports, and connects the bypass flow path 14 to the second downstream flow path portion 3b4, and thus the second suction pump 26. Between the first bypass channel portion 3b2 and the second downstream channel portion 3b4, and thus the second suction pump 26. The state is switched.

  The first and second suction pumps 25 and 26 can be formed by appropriate pumps such as a diaphragm-type pump and a roller pump.

  The first and second suction pumps 25 and 26 are connected to the recovery port 5 b of the tank 5.

  A feature of the present embodiment is that one first suction pump 25 is connected to the first inkjet head 11, while one second suction pump is connected to the second inkjet head 12. 26 is connected.

  That is, in the inkjet printing apparatus 1, one independent suction pump 25 or 26 is connected to the inkjet head. That is, the suction pumps 25 and 26 are independently connected to the first and second inkjet heads 11 and 12, respectively. Therefore, as is apparent from the following description of the printing method, even when printing is performed using a high-viscosity liquid, printing can be started and completed without requiring complicated operations.

  In addition, the above-described effect can be obtained even though the number of liquid feed pumps 6 is smaller than the number of first and second inkjet heads 11 and 12. That is, the number of pumps can be reduced and the above effects can be obtained.

  The printing method of this embodiment will be described with reference to FIG.

  In the inkjet printing apparatus 1, the first flow path switching member 13 and the second flow path switching members 21 and 22 are set in a bypass flow path state. In this state, the liquid feed pump 6 and the first and second suction pumps 25 and 26 are driven. Accordingly, the liquid flows out of the flow path 3. The liquid in the tank 5 reaches the first flow path switching member 13. Since the first flow path switching member 13 is in the bypass flow path state and the second flow path switching members 21 and 22 are also in the bypass flow path state, the liquid is bypassed immediately after driving. The fluid passes through the passage 14 and is sucked by the first and second suction pumps 25 and 26 and is collected from the downstream flow path portion 3b1 to the tank 5.

  Next, another flow path switching member 13 is set to a flow path state in which the upstream flow path portion 3a is connected to the first and second branch flow paths 3a21 and 3a22. Similarly, the second flow path switching members 21 and 22 are in a flow path state in which the first and second inkjet heads 11 and 12 are connected to the first and second suction pumps 25 and 26. In this state, printing is enabled by the first and second inkjet heads 11 and 12. That is, since the liquid is supplied to the first and second ink jet heads 11 and 12, printing can be performed by the first and second ink jet heads 11 and 12.

  Excess liquid is sucked from the first and second suction pumps 25 and 26 through the second downstream flow path portions 3b3 and 3b4 and collected.

  Since the independent first and second suction pumps 25 and 26 are connected to the first and second inkjet heads 11 and 12, respectively, liquid can be supplied to the first and second inkjet heads 11 and 12 without difficulty. Can be supplied. This is because, in the first inkjet head 11, not only the liquid is conveyed by the pressure applied by the liquid feeding pump 6 but also the liquid is conveyed by the suction force of the independent first suction pump 25, and the second inkjet head 12. Even on the side, not only the pressure of the liquid feed pump 6 but also the liquid is conveyed by the second suction pump 26 provided independently.

  Therefore, even if the resistance of the portion where the liquid flows is different between the first inkjet head 11 side and the second inkjet head 12 side, or even if the liquid to be printed has a high viscosity, it is ensured. In addition, the liquid can be smoothly supplied to the first and second inkjet heads 11 and 12.

  The present invention is not limited to the structure of the above embodiment. Hereinafter, preferred modifications of the ink jet printing apparatus of the above embodiment will be described in detail.

  In the above embodiment, the tank 5 is used as the liquid supply source. However, a liquid supply source may be further arranged on the upstream side of the tank 5, and the liquid may be supplied from the liquid supply source into the tank 5. In that case, a liquid feed pump for supplying a liquid may be connected between the liquid supply source and the tank 5.

  Moreover, in the upstream flow path portion 3a, it is preferable to connect a buffer tank to the downstream side of the liquid feed pump 6. Thereby, pulsation can be suppressed. As the buffer tank, an appropriate buffer tank capable of suppressing pulsation can be used.

  In addition, it is preferable that a temperature raising unit is connected to the downstream side of the liquid feed pump 6 in the upstream flow path portion 3a. By providing the temperature raising unit, the temperature of the liquid can be raised and the viscosity can be lowered. Therefore, it is possible to easily carry the liquid immediately after driving. About this temperature rising unit, it can comprise by attaching a suitable heater and a heating jacket.

  Moreover, it is preferable to wind a heat insulating material in the part which cannot be heated.

  Moreover, it is also preferable to connect a filter for removing dust, impurities, and the like to the upstream channel portion 3a and the downstream channel portion 3b. In particular, it is preferable to provide a filter in the upstream flow path portion 3a upstream of the inkjet heads 11 and 12. Thereby, contamination of the inkjet heads 11 and 12 can be suppressed.

  Moreover, it is desirable to provide a pressure sensor for appropriately detecting the pressure of the liquid in the upstream flow path portion 3a and the downstream flow path portion 3b. In particular, it is preferable to connect a pressure sensor to each of the first and second branch flow paths 3a21 and 3a22 and the first downstream flow path portions 3b1 and 3b2. As the pressure sensor, an appropriate liquid detection pressure sensor such as one using a piezoelectric element can be used.

  In the second downstream flow path portions 3b3 and 3b4, a buffer tank is preferably connected to the upstream side of the first and second suction pumps 25 and 26. Thereby, the influence of pulsation can be suppressed.

  Further, a flow path switching member may be further connected between the first and second suction pumps 25 and 26 and the tank 5. That is, it is preferable to connect a flow path switching member having an inlet port connected to the first and second suction pumps 25, 26, an outlet port connected to the recovery port 5b, and a waste liquid port. By using such a flow path switching member, the flow path can be switched between a flow path state in which the liquid is collected in the recovery port 5b and a waste liquid flow path state in which the used liquid is discharged from the waste liquid port. .

  In the above embodiment, the first and second inkjet heads 11 and 12 are used, but three or more inkjet heads may be connected. Even in this case, the same effect as that of the above embodiment can be obtained if one suction pump is connected to one inkjet head.

  In addition, like the said embodiment, size reduction can be achieved by using the one liquid feeding pump 6 with respect to the some inkjet heads 11 and 12. FIG.

  FIG. 2 is a schematic configuration diagram of an ink jet printing apparatus according to the second embodiment.

  The ink jet printing apparatus 31 includes a plurality of upstream flow path portions 33aA and 33aB. Each upstream flow path portion 33aA, 33aB does not have the first and second branch flow paths, and each is connected to one inkjet head. More specifically, in the upstream channel portion 33aA, the first inkjet head 11 and the first liquid feed pump 36A are connected via the first channel switching member 13A. In the upstream flow path portion 33aB, the second ink jet head 12 and the second liquid feed pump 36B are connected via the first flow path switching member 13B.

  On the other hand, the downstream flow path portion 33b has one first downstream flow path portion 33b1 and a second downstream flow path portion 3b3 connected to the first downstream flow path portion 33b1. The first downstream channel portion 33b1 and the second downstream channel portion 3b3 are connected via the second channel switching member 21.

  The first downstream channel portion 33b1 has first and second branch channels 33b11 and 33b12. The first branch channel 33 b 11 is connected to the first inkjet head 11. The second branch flow path 33b12 is connected to the second inkjet head 12.

  In each upstream channel portion 33aA, 33aB, the bypass channel state and the liquid supply channel state can be switched. Also in the downstream channel portion 33b, the bypass channel state and the suction state can be switched.

  Similar to the first embodiment, when the inkjet printing apparatus 31 is used, even when a relatively high viscosity is supplied, the liquid can be smoothly supplied to the plurality of inkjet heads, and no complicated operation is required.

  In the present embodiment, the number of suction pumps 35 is different from the number of first and second inkjet heads 11 and 12. More specifically, the number of suction pumps 35 is smaller than the number of first and second inkjet heads 11 and 12. Therefore, the number of pumps can be reduced and the above effects can be obtained.

  Although a plurality of suction pumps may be provided, in this case as well, it is preferable that the number of suction pumps is smaller than the number of the plurality of inkjet heads. However, in the inkjet printing apparatus 31, since the number of suction pumps 35 is one, the number of pumps can be reduced particularly effectively.

  FIG. 3 is a schematic configuration diagram of an ink jet printing apparatus according to the third embodiment.

  The ink jet printing apparatus 41 includes a plurality of tanks 45A and 45B. The tank 45 </ b> A is a liquid supply source that supplies liquid to the first inkjet head 11. The tank 45 </ b> B is a liquid supply source that supplies liquid to the second inkjet head 12. Thus, in this embodiment, each inkjet head has a liquid supply source.

  The outlet 5a of the tank 45A is connected to the upstream channel portion 43aA. The upstream flow path portion 43aA connects the tank 45A to the first inkjet head 11 via the first liquid feed pump 36A and the first flow path switching member 13A. The first inkjet head 11 is connected to the downstream flow path portion 43bA. The downstream flow path portion 43bA connects the first inkjet head 11 to the recovery port 5b of the tank 45A via the second flow path switching member 21.

  A pressure sensor 44 </ b> Aa is connected between the first flow path switching member 13 </ b> A and the first inkjet head 11. A pressure sensor 44Ab is connected between the first inkjet head 11 and the second flow path switching member 21. The pressure sent to the first inkjet head 11 can be measured by the pressure sensor 44Aa, and the pressure at which the liquid is recovered from the first inkjet head 11 can be measured by the pressure sensor 44Ab. Accordingly, printing can be performed while adjusting the flow rate of the liquid.

  The tank 45A is a closed float tank. The tank 45A has a suction port 45c. The suction port 45c is connected to a suction pump 35 for adjusting the atmospheric pressure in the tank 45A. The flow rate of the liquid can be adjusted by adjusting the air pressure in the tank 45A.

  The tank 45A is also connected to a supply pump 46 for supplying liquid to the tank 45A. The supply pump 46 is connected to, for example, a supply bottle that supplies liquid.

  On the other hand, the tank 45B is also a closed float tank. Similarly to the tank 45A, the tank 45B is connected to the second inkjet head 12 via the second liquid feed pump 36B, the first flow path switching member 13B, and the pressure sensor 44Ba by the upstream flow path portion 43aB. ing. The second inkjet head 12 is connected to the tank 45B via the pressure sensor 44Bb and the second flow path switching member 22 by the downstream flow path portion 43bB.

  The suction port 45c of the tank 45B is connected to the suction pump 35 to which the tank 45A is connected. A switching member 47 is connected between the tanks 45 </ b> A and 45 </ b> B and the suction pump 35. A three-way valve or the like can be used for the switching member 47. The switching member 47 can switch the suction state of only the tank 45A, the suction state of only the tank 45B, and the suction state of both the tanks 45A and 45B.

  The supply port 45d of the tank 45B is connected to the supply pump 46 to which the tank 45A is connected. A third flow path switching member 48 is connected between the tanks 45A and 45B and the supply pump 46. A three-way valve or the like can be used for the third flow path switching member 48. The third flow path switching member 48 can switch the supply state of only the tank 45A, the supply state of only the tank 45B, and the supply state of both the tanks 45A and 45B.

  Also in the present embodiment, the liquid supply flow path state and suction state in the flow paths on the first ink jet head 11 side and the second ink jet head 12 side can be switched to the bypass flow path state.

  Similar to the first embodiment, when the inkjet printing apparatus 41 is used, even when a relatively high viscosity is supplied, the liquid can be smoothly supplied to the plurality of inkjet heads, and no complicated operation is required.

  In addition, if the pressure in the tanks 45A and 45B is low, the liquid is sucked into the tanks 45A and 45B. Therefore, the liquid is more reliably transported. Therefore, even when the resistance of the portion where the liquid flows is different between the first inkjet head 11 side and the second inkjet head 12 side, the liquid is more reliably applied to the first and second inkjet heads 11 and 12. Can be supplied.

  The number of suction pumps 35 is smaller than the number of first and second inkjet heads 11 and 12. Therefore, the number of pumps can be reduced.

  FIG. 4 is a schematic configuration diagram of an ink jet printing apparatus according to the fourth embodiment.

  The ink jet printing apparatus 51 is different from the third embodiment in that there is one tank 55. Except for the above points, the inkjet printing apparatus 51 has the same configuration as the inkjet printing apparatus 41 of the third embodiment.

  The tank 55 has two recovery ports 55bA and 55bB. The recovery port 55bA is connected to the downstream flow path portion 43bA on the first inkjet head 11 side. The recovery port 55bB is connected to the downstream flow path portion 43bB on the second inkjet head 12 side. The outlet 5a of the tank 55 is connected to both the upstream flow path portion 43aA on the first inkjet head 11 side and the upstream flow path portion 43aB on the second inkjet head 12 side.

  In the present embodiment, the number of tanks 55 can be reduced. Further, similarly to the third embodiment, even when a relatively high viscosity is supplied, liquid can be smoothly supplied to a plurality of inkjet heads, no complicated operation is required, and the number of pumps is reduced. Can do.

  A preferred printing method will be described by taking a printing method using the inkjet printing apparatus 1 of the first embodiment shown in FIG. 1 as an example. At the start of printing, it is preferable that the following warm-up process, head temperature raising process, and printing process are sequentially performed. In the warm-up process, in the bypass flow path state, the first and second suction pumps 25 and 26 are driven, and the liquid feeding pump 6 is also driven. In this case, the liquid passes through the bypass channel 14 and does not pass through the inkjet heads 11 and 12. Therefore, there is no possibility that excess ink leaks from the inkjet heads 11 and 12. Since there is no possibility that the ink leaks, the liquid can be sufficiently circulated in the flow path 3 and can be sufficiently heated. Thereby, the viscosity of the liquid flowing through the entire flow path 3 can be reduced.

  In the first and second suction pumps 25 and 26, when the pump discharge amount changes according to the drive voltage, the drive voltages of the first and second suction pumps 25 and 26 are preferably set to the same value. . Further, since the liquid feed pump 6 is used in combination with the first and second suction pumps 25 and 26, when the liquid feed pump and the suction pump are the same pump, the drive voltage of the liquid feed pump 6 is It is desirable that the driving voltage of the first and second suction pumps 25 and 26 is doubled.

  Next, a head temperature raising operation is performed. That is, the flow path 3 is switched from the bypass flow path state to a head-routed flow path state in which liquid flows through the first and second inkjet heads 11 and 12. Thereby, the liquid is supplied to the first and second ink jet heads 11 and 12, and the ink jet heads 11 and 12 are warmed. In this case, since the flow path portion connected to the first and second ink jet heads 11 and 12 and the first and second ink jet heads 11 and 12 are initially at a low temperature, the liquid feeding resistance is high. For this reason, if the liquid feeding pressure becomes too high, there is a risk that the liquid may sag from the first and second inkjet heads 11 and 12. In order to suppress this, it is desirable to lower the drive voltages of the first and second suction pumps 25 and 26 and the liquid feed pump 6 once at the start of the head temperature raising operation.

  It is desirable to gradually increase the voltages of the liquid feed pump 6 and the first and second suction pumps 25 and 26 after a predetermined time has elapsed after changing the flow path state. In this case, it is preferable that the total driving voltage of the first and second suction pumps 25 and 26 is higher than the driving voltage of the liquid feeding pump 6. As a result, the liquid is supplied more smoothly by the first and second inkjet heads 11 and 12.

  In the printing process, it is preferable to transport the liquid using a pressure sensor while measuring the pressure of the liquid supplied to or recovered from the inkjet heads 11 and 12. Moreover, it is preferable that there is no temperature difference between the temperature of the first inkjet head 11 and the temperature of the second inkjet head 12 in the printing process. Therefore, for example, it is preferable to use a temperature sensor to detect the temperatures of the first inkjet head 11 and the second inkjet head 12 and adjust the liquid feeding so that the temperature difference between the two becomes small. For example, for the inkjet head on the lower temperature side, it is desirable to increase the driving voltage of the connected suction pump and increase the liquid feeding speed. Thereby, the temperature of the inkjet head on the relatively low temperature side can be increased. Alternatively, the voltage of the suction pump connected to the inkjet head on the relatively high temperature side may be lowered. Further, both of these operations may be combined. In this way, the temperature difference between the first and second inkjet heads 11 and 12 can be reduced. Preferably, the temperature difference between the plurality of inkjet heads is desirably within 2 ° C., and more desirably within 1 ° C.

  As described above, by adjusting the drive voltages of the first and second suction pumps 25 and 26, the temperature difference between the first and second inkjet heads 11 and 12 can be controlled within 2 ° C., for example. . In this way, printing can be performed with high accuracy using the plurality of first and second inkjet heads 11 and 12.

  Moreover, in the inkjet printing apparatus 1 and the printing method of the present embodiment, as described above, a high-viscosity liquid, for example, an E-type viscometer (“TVE22L” manufactured by Toki Sangyo Co., Ltd.) is used to comply with JIS K2283. Thus, printing can be performed using a liquid having a high viscosity such that the viscosity at 25 ° C. and 10 rpm is 160 mPa · s or higher, preferably 200 to 1600 mPa · s. When a high-viscosity liquid is used, printing accuracy and resolution can be effectively increased. Therefore, fine printing can be performed with high accuracy. As described above, the ink jet printing apparatus 1 of the above embodiment is suitably used for printing an adhesive having a high viscosity. Therefore, a high-viscosity liquid such as a high-viscosity adhesive can be printed with high accuracy on a wafer used for mass production of electronic components, for example. However, the inkjet printing apparatus 1 is not limited to such an adhesive, and can be used for printing various liquid materials other than high viscosity liquid resin materials and high viscosity resins.

DESCRIPTION OF SYMBOLS 1 ... Inkjet printer 3 ... Flow path 3a ... Upstream flow path part 3a1, 3a2 ... 1st, 2nd upstream flow path part 3a21, 3a22 ... 1st, 2nd branch flow path 3b ... Downstream flow path Portions 3b1, 3b2 ... first downstream flow path portions 3b3, 3b4 ... second downstream flow path portions 5 ... tank 5a ... outlet 5b ... recovery port 6 ... feed pumps 11, 12 ... first and second Inkjet heads 13, 13A, 13B ... first flow path switching member 14 ... bypass flow paths 21, 22 ... second flow path switching members 25, 26 ... first and second suction pumps 31 ... ink jet printer 33aA, 33aB ... upstream channel portion 33b ... downstream channel portion 33b1 ... first downstream channel portions 33b11, 33b12 ... first and second branch channels 35 ... suction pumps 36A, 36B ... first and second Liquid feed pump 41 ... inkjet mark Apparatus 43aA, 43aB ... Upstream flow path portion 43bA, 43bB ... Downstream flow path portion 44Aa, 44Ab, 44Ba, 44Bb ... Pressure sensor 45c ... Suction port 45d ... Supply port 45A, 45B ... Tank 46 ... Supply pump 47 ... Switching member 48 ... Third flow path switching member 51 ... Inkjet printer 55 ... Tanks 55bA, 55bB ... Recovery port

Claims (12)

An inkjet printing apparatus using an inkjet head,
A liquid supply source, a flow path connected to the liquid supply source, for supplying liquid from the liquid supply source,
A plurality of inkjet heads connected to the flow path and supplied with the liquid;
A liquid feed pump connected to an upstream side portion of the plurality of inkjet heads in the flow path;
A suction pump for sucking the liquid from the plurality of inkjet heads in the flow path, on a downstream side of the plurality of inkjet heads;
An ink jet printing apparatus, wherein the number of liquid feeding pumps or the number of suction pumps is smaller than the number of ink jet heads.   The inkjet printing apparatus according to claim 1, wherein one liquid feeding pump is provided for one inkjet head.   The liquid supply source is a closed tank, the suction pump is connected to the tank so as to adjust the atmospheric pressure in the tank, and the number of the suction pumps is smaller than the number of the inkjet heads; The ink jet printing apparatus according to claim 1 or 2.   The inkjet printing apparatus according to claim 1, wherein one suction pump is provided for one inkjet head.   The inkjet according to any one of claims 1 to 3, wherein the downstream portion of the flow path includes a plurality of first downstream flow path portions each having one end connected to the plurality of inkjet heads. Printing device.   The downstream portion of the flow path has a plurality of first downstream flow path portions whose one ends are respectively connected to the plurality of inkjet heads, and the suction is applied to each first downstream flow path portion. The inkjet printing apparatus of Claim 4 with which the pump is connected.   The inkjet printing apparatus according to claim 6, wherein the plurality of first downstream flow path portions are merged downstream of the suction pump.   The upstream portion of the flow path connects the first upstream flow path section connecting the liquid supply source and the liquid feed pump, the liquid feed pump, and the plurality of inkjet heads. 8, and the second upstream flow path portion is branched so as to be connected to the plurality of ink jet heads. The inkjet printing apparatus of Claim 1.   In the second upstream flow path portion of the upstream flow path portion, a first flow path switching member is provided between the liquid feed pump and the branched portion of the second upstream flow path portion. The first flow path switching member is connected, and the liquid supply flow path connects the first upstream flow path section and the branched portion of the second upstream flow path section. A flow path state can be switched between a state and a bypass flow path state connecting the first upstream flow path portion and each first downstream flow path portion. Item 9. The inkjet printing apparatus according to Item 8.   A second flow path switching member is connected to each of the first downstream flow path portions connecting the plurality of inkjet heads and the suction pump, and the second flow path switching member is The flow path state can be switched between a suction state connecting the inkjet head and the suction pump and a bypass flow path state connecting the bypass flow path and the suction pump. The inkjet printing apparatus as described. A printing method using the inkjet printing apparatus according to any one of claims 1 to 10,
Driving the liquid feeding pump of the ink jet printing apparatus and driving the suction pump, and feeding liquid from the liquid supply source to the flow path;
And a step of ejecting the supplied liquid from the inkjet head and printing.   When starting to send the liquid to the flow path by the ink jet printing apparatus, the liquid is sent from the liquid feed pump to the suction pump side via the flow path so as to bypass the plurality of ink jet heads. The printing method using the inkjet printing apparatus according to claim 11, further comprising a step.

Images