Printing device and printing device control method

Abstract

A printing device according to the present invention comprise: an ink supply source; a damper that supplies ink supplied from the ink supply source to a head which discharges ink; a supply flow path that connects the ink supply source and the damper; a supply valve that is provided in the supply flow path; a circulation flow path that is connected to the damper and to the downstream side of the supply valve in the supply flow path and that circulates the ink supplied to the damper by returning the ink to the downstream side of the supply valve in the supply flow path; a circulation valve that is provided midstream in the circulation flow path; a circulation pump that is provided on the downstream side of the circulation valve in the circulation flow path and that moves the ink from the damper side to the supply flow path side; and a control unit that controls opening and closing of the supply valve and the circulation valve and the start and the stop of an operation of the circulation pump.　When starting a circulation operation, the control unit opens the supply valve and then opens the circulation valve and starts the circulation pump.

Description

Printing device and method for controlling printing device

[0001] The present invention relates to a printing device and a method for controlling a printing device.

[0002] In inkjet printing devices, when the head that ejects ink is on standby, a configuration is known in which ink is circulated within a damper that supplies ink to the head in order to prevent ink components from settling (see, for example, Patent Document 1).

[0003] International Publication No. 2015 / 174535

[0004] In the printing device described above, it is required to stably eject ink from the head while suppressing settling of ink components.

[0005] The present invention has been made in consideration of the above, and aims to provide a printing device and a method for controlling a printing device that can stably eject ink from a head while suppressing sedimentation of ink components.

[0006] a supply valve provided in the supply flow path and configured to open and close the supply flow path; a circulation flow path connected to the damper and the supply flow path downstream of the supply valve and configured to return the ink supplied to the damper to the supply flow path downstream of the supply valve, and circulate the ink; a circulation valve provided in the circulation flow path and configured to open and close the circulation flow path; a circulation pump provided in the circulation flow path downstream of the circulation valve and configured to move the ink from the damper side to the supply flow path; and a control unit that controls the opening and closing of the supply valve, the opening and closing of the circulation valve, and the start and stop of the circulation pump; when starting the circulation of the ink through the circulation flow path, the control unit opens the supply valve, then opens the circulation valve and starts the circulation pump.

[0007] a supply valve provided in the supply flow path and configured to open and close the supply flow path; a circulation flow path connected to the damper and the supply flow path downstream of the supply valve and configured to return the ink supplied to the damper to the supply flow path downstream of the supply valve, and circulate the ink; a circulation valve provided in the circulation flow path and configured to open and close the circulation flow path; a circulation pump provided in the circulation flow path downstream of the circulation valve and configured to move the ink from the damper side to the supply flow path; and a control unit that controls the opening and closing of the supply valve, the opening and closing of the circulation valve, and the start and stop of the circulation pump; and when the control unit wants to stop the circulation of the ink through the circulation flow path, it stops the circulation pump and then closes the circulation valve, and then closes the supply valve after the circulation valve has been closed.

[0008] A control method for a printing device according to the present invention is a control method for a printing device that includes an ink supply source that is a supply source of ink, a damper that supplies ink supplied from the ink supply source to a head that ejects the ink, a supply flow path that connects the ink supply source and the damper, a supply valve that is provided in the supply flow path and opens and closes the supply flow path, a circulation flow path that is connected to the damper and the supply flow path downstream of the supply valve and returns the ink supplied to the damper to the supply flow path downstream of the supply valve, and circulates the ink, a circulation valve that is provided midway in the circulation flow path and opens and closes the circulation flow path, and a circulation pump that is provided in the circulation flow path downstream of the circulation valve and moves the ink from the damper side to the supply flow path side, and the control method includes a supply valve opening step that opens the supply valve when starting the circulation operation of the ink via the circulation flow path, and a circulation step that opens the circulation valve and starts the circulation pump after performing the supply valve opening step.

[0009] a supply valve provided in the supply flow path and configured to open and close the supply flow path; a circulation flow path connected to the damper and the supply flow path downstream of the supply valve and configured to return the ink supplied to the damper to the supply flow path downstream of the supply valve, and circulate the ink; a circulation valve provided in the circulation flow path and configured to open and close the circulation flow path; and a circulation pump provided in the circulation flow path downstream of the circulation valve and configured to move the ink from the damper side to the supply flow path, the control method for a printing device according to the present invention includes, when stopping the circulation of the ink through the circulation flow path, a circulation pump stopping step of stopping the circulation pump, a circulation valve closing step of closing the circulation valve after performing the circulation pump stopping step, and a supply valve closing step of closing the supply valve after performing the circulation valve closing step.

[0010] According to the present invention, ink can be stably ejected from the head while suppressing the settling of ink components.

[0011] FIG. 1 is a functional block diagram schematically illustrating an example of a printing device according to the present embodiment. FIG. 2 is a functional block diagram illustrating an example of the configuration of a control unit according to the present embodiment. FIG. 3 is a flowchart illustrating an example of a control method for a printing device. FIG. 4 is a timing chart illustrating an example of the operation of a supply valve, a circulation valve, and a circulation pump (fixed-time circulation operation). FIG. 5 is a timing chart illustrating an example of the operation of a supply valve, multiple circulation valves, and a circulation pump (operation in which multiple circulation valves are controlled at different timings in fixed-time circulation operation). FIG. 6 is a timing chart illustrating an example of the operation of a supply valve, a circulation valve, and a circulation pump (sub-circulation operation).

[0012] Hereinafter, an embodiment of a printing device and a printing device control method according to the present invention will be described with reference to the drawings. Note that the present invention is not limited to this embodiment. Furthermore, the components in the following embodiments include those that are easily replaceable by those skilled in the art, or those that are substantially identical.

[0013] FIG. 1 is a functional block diagram schematically illustrating an example of a printing device according to this embodiment. In FIG. 1, solid arrows indicate ink flow paths, and dashed arrows indicate control signals from a control unit 80. As shown in FIG. 1, the printing device 100 includes an ink supply source 10, a supply valve 20, a damper 30, a head 40, a circulation valve 50, a filter 60, a circulation pump 70, and a control unit 80. The printing device 100 also includes a supply flow path R1 and a circulation flow path R2. The supply flow path R1 connects the ink supply source 10 and the damper 30. The circulation flow path R2 connects the damper 30 and the downstream side of the supply valve 20 in the supply flow path R1.

[0014] The ink supply source 10 is a supply source that supplies ink to the head 40. The ink supply source 10 may be configured to have one or more cartridges that contain ink.

[0015] The supply valve 20 is provided in the supply flow path R1 and opens and closes the supply flow path R1. When the supply valve 20 is open, ink flows from the ink supply source 10 to the supply flow path R1. When the supply valve 20 is closed, ink does not flow from the ink supply source 10 to the supply flow path R1. The opening and closing operation of the supply valve 20 is controlled by the control unit 80.

[0016] The damper 30 supplies ink supplied from the ink supply source 10 to the head 40. In the supply flow path R1, ink flows in a supply direction D1 from the ink supply source 10 toward the damper 30 due to, for example, a head difference between the ink supply source 10 and the damper 30. As shown in FIG. 1 , the supply flow path R1 may branch into multiple flow paths at a connection portion with the damper 30. Note that the supply flow path R1 does not have to branch into multiple flow paths at a connection portion with the damper 30.

[0017] The damper 30 has an ink chamber 31 that stores ink supplied from the supply flow path R1. The damper 30 supplies the ink stored in the ink chamber 31 to the head 40. More specifically, the damper 30 supplies the ink Q to the head 40 while adjusting the internal pressure of the head 40 to a predetermined slight negative pressure that is slightly lower than atmospheric pressure. The damper 30 forms a meniscus surface Qa of the ink Q at the tip of the nozzle 41 of the head 40 so that the meniscus surface Qa has an upwardly convex curved shape.

[0018] The ink chamber 31 is connected to a circulation flow path R2. The ink Q stored in the ink chamber 31 can flow into the circulation flow path R2. One or more circulation flow paths R2 are connected to the ink chamber 31. Note that while FIG. 1 shows a configuration in which multiple (two) circulation flow paths R2 are connected to the ink chamber 31, the present invention is not limited to this configuration, and only one circulation flow path R2 may be connected.

[0019] The head 40 has a plurality of nozzles 41 (only one is shown in FIG. 1 ) that eject ink Q. The head 40 is provided so as to be movable in the main scanning direction. The operation of the head 40 is controlled by a control unit 80.

[0020] The circulation valve 50 is provided in the circulation flow path R2 and opens and closes the circulation flow path R2. When the circulation valve 50 is opened, ink can flow through the circulation flow path R2. When the circulation valve 50 is closed, ink cannot flow through the circulation flow path R2. The opening and closing operation of the circulation valve 50 is controlled by the control unit 80. When multiple circulation flow paths R2 are provided, a circulation valve 50 is provided for each of the multiple circulation flow paths R2, as shown in FIG. 1 . In this case, the control unit 80 can synchronously control each circulation valve 50.

[0021] The filter 60 is disposed in the circulation flow path R2 downstream of the circulation valve 50. The filter 60 filters the ink Q flowing through the circulation flow path R2 to remove foreign matter from the ink Q.

[0022] The circulation pump 70 is provided in the circulation flow path R2 downstream of the circulation valve 50. In this embodiment, the circulation pump 70 is arranged in the circulation flow path R2 further downstream of the filter 60, which is arranged downstream of the circulation valve 50. The circulation pump 70 moves ink from the damper 30 side to the supply flow path R1 by generating a pressure difference.

[0023] By operating the circulation pump 70 with the circulation valve 50 open, the ink Q flows from the damper 30 into the circulation flow path R2, and the ink Q flows through the circulation flow path R2 in the circulation direction D2. This ink Q passes through the circulation valve 50, the filter 60, and the circulation pump 70, and flows into the supply flow path R1 downstream of the supply valve 20. As a result, the ink Q in the damper 30 circulates through the supply flow path R1.

[0024] The supply valve 20, the damper 30, the circulation valve 50, and the circulation pump 70 are each provided with a check valve (not shown). The check valves prevent the ink Q from flowing backward in the intended direction.

[0025] The control unit 80 comprehensively controls the operation of the printing device 100. Fig. 2 is a functional block diagram showing an example of the configuration of the control unit 80 according to this embodiment. The control unit 80 includes a communication unit 81, a processing unit 82, and a storage unit 83.

[0026] The communication unit 81 performs wired or wireless communication with external devices and includes an interface such as a network interface card.

[0027] The processing unit 82 performs various types of information processing and includes a processor such as a CPU (Central Processing Unit) and memories such as a ROM (Read Only Memory) and a RAM (Random Access Memory).

[0028] The processing unit 82 includes a print control unit 84 , a determination unit 85 , a supply valve control unit 86 , a circulation valve control unit 87 , and a circulation pump control unit 88 .

[0029] The print control unit 84 controls the operation of the head 40. The print control unit 84 outputs a control signal S1 for controlling the operation of the head 40. The print control unit 84 also controls the operation of the transport unit R (see FIG. 1 ), which transports the media M. The print control unit 84 outputs a control signal S2 for controlling the operation of the transport unit R. The determination unit 85 performs various determinations and outputs the determination results. The supply valve control unit 86 controls the opening and closing operation of the supply valve 20. The supply valve control unit 86 outputs a control signal S3 for controlling the opening and closing operation of the supply valve 20. The circulation valve control unit 87 controls the opening and closing operation of the circulation valve 50. The circulation valve control unit 87 outputs a control signal S4 for controlling the opening and closing operation of the circulation valve 50. The circulation pump control unit 88 controls the operation of the circulation pump 70. The circulation pump control unit 88 outputs a control signal S5 for controlling the operation of the circulation pump 70.

[0030] The storage unit 83 stores information such as various programs, data, etc. The storage unit 83 includes storage such as a hard disk drive (HDD) and a solid state drive (SSD).

[0031] The storage unit 83 includes, for example, an ink supply source 10 that is a supply source of ink, a damper 30 that supplies ink supplied from the ink supply source 10 to a head 40 that ejects ink, a supply flow path R1 that connects the ink supply source 10 and the damper 30, a supply valve 20 that is provided in the supply flow path R1 and opens and closes the supply flow path R1, a circulation flow path R2 that is connected to the damper 30 and the downstream side of the supply valve 20 in the supply flow path R1 and circulates the ink supplied to the damper 30 to the supply flow path R1, and a circulation flow path R2 that is provided in the circulation flow path R2 and controls the circulation A control program for a printing device (100) equipped with a circulation valve (50) that opens and closes a circulation flow path (R2), and a circulation pump (70) that is provided on the circulation flow path (R2) downstream of the circulation valve (50) and moves ink from the damper (30) side to the supply flow path (R1) side, the control program stores a program that causes a computer to execute a supply valve opening process that opens the supply valve (20) when starting the circulation operation of ink through the circulation flow path (R2), and a circulation process that opens the circulation valve (50) and starts operating the circulation pump (70) after the supply valve opening process.

[0032] The storage unit 83 also stores, for example, an ink supply source 10 that is a supply source of ink, a damper 30 that supplies ink supplied from the ink supply source 10 to a head 40 that ejects ink, a supply flow path R1 that connects the ink supply source 10 and the damper 30, a supply valve 20 that is provided in the supply flow path R1 and opens and closes the supply flow path R1, a circulation flow path R2 that is connected to the damper 30 and the supply flow path R1 on the downstream side of the supply valve 20 and circulates the ink supplied to the damper 30 to the supply flow path R1, and a circulation valve that is provided in the circulation flow path R2 and opens and closes the circulation flow path R2. A control program for a printing device (100) equipped with a lube (50) and a circulation pump (70) provided downstream of the circulation valve (50) in the circulation flow path (R2) for moving ink from the damper (30) side to the supply flow path (R1) side, the control program storing the program causes a computer to execute a circulation pump stop process for stopping the circulation pump (70) when the circulation operation of ink through the circulation flow path (R2) is to be stopped, a circulation valve closing process for closing the circulation valve (50) after the circulation pump stop process, and a supply valve closing process for closing the supply valve (20) after the circulation valve closing process.

[0033] In the control unit 80, the processor in the processing unit 82 reads out various programs and loads them into memory, thereby executing information processing corresponding to the functions of the above-mentioned units. Examples of the various programs include programs received by the communication unit 81, programs stored in the storage unit 83, and programs recorded on an external recording medium. The control unit 80 functions as an information processing device (computer) that executes various information processes. Note that the various programs may be executed by an information processing device other than the control unit 80, or the control unit 80 and the other information processing device may cooperate to execute the various programs.

[0034] Next, the operation of the printing device 100 configured as described above will be described. The printing device 100 performs a printing operation on the medium M by moving the head 40 in the main scanning direction under the control of the print control unit 84, and relatively moving the transport unit R on which the medium M is placed in the sub-scanning direction perpendicular to the main scanning direction, and ejecting ink Q from the nozzles 41. When a printing operation is not being performed, the print control unit 84 causes the head 40 to wait at a predetermined standby position.

[0035] In the printing device 100, when the head 40 is on standby, ink components may settle in, for example, the supply flow path R1 of the damper 30, the ink chamber 31, etc., resulting in uneven ink concentration. For this reason, the printing device 100 performs a circulation operation that periodically circulates the ink Q in the ink chamber 31 through the circulation flow path R2, thereby suppressing the settling of ink Q components. The circulation operation will be described below.

[0036] Fig. 3 is a flowchart showing an example of a control method for the printing apparatus 100. Fig. 4 is a timing chart showing an example of the operations of the supply valve 20, the circulation valve 50, and the circulation pump 70.

[0037] As shown in FIG. 3, the control method for the printing apparatus 100 when starting the circulation operation includes a determination step S10, a supply valve opening step S20, and a circulation step S30.

[0038] In determination step S10, the determination unit 85 of the control unit 80 determines whether or not to start the circulating operation. When making this determination, the determination unit 85 detects whether or not the timing to perform the circulating operation has arrived. An example of the timing to perform the circulating operation is the timing when a predetermined time has elapsed since the previous circulating operation. In this case, the determination unit 85 can determine that the scheduled circulating operation should be performed as the circulating operation. If the timing to perform the circulating operation has not arrived in determination step S10, the determination unit 85 determines that the circulating operation will not be performed (No in step S10), and repeats the determination in step S10.

[0039] If the timing to perform the circulation operation has arrived in determination step S10, the determination unit 85 determines that the circulation operation should be performed (Yes in step S10). If the determination unit 85 determines that the circulation operation should be performed, the supply valve opening step S20 is performed (time t1 in FIG. 4). In supply valve opening step S20, the supply valve control unit 86 opens the supply valve 20. When the supply valve 20 is opened, the ink Q flows in the supply flow path R1 in a supply direction D1 from the ink supply source 10 toward the damper 30 due to the head difference between the ink supply source 10 and the damper 30. The ink Q that flows through the supply flow path R1 and reaches the damper 30 is supplied to the ink chamber 31 and stored therein.

[0040] After the supply valve opening step S20 is performed, the circulation step S30 is performed ( FIG. 4 : time t2). In the circulation step S30, the circulation valve control unit 87 opens the circulation valve 50. The circulation pump control unit 88 also starts the operation of the circulation pump 70, causing the ink Q to circulate in the circulation direction D2 from the damper 30 side toward the supply flow path R1. By performing the circulation step S30, the ink Q stored in the ink chamber 31 flows into the circulation flow path R2. The ink Q that has flowed into the circulation flow path R2 passes through the circulation valve 50, has foreign matter removed by the filter 60, passes through the circulation pump 70, and flows into the supply flow path R1 downstream of the supply valve 20. The ink Q supplied from the ink supply source 10 to the ink chamber 31 via the supply flow path R1 circulates to the supply flow path R1 via the circulation flow path R2.

[0041] For example, if the supply valve 20, the circulation valve 50, and the circulation pump 70 are opened simultaneously during the circulation operation, the volumes of the supply flow path R1 and the circulation flow path R2 suddenly fluctuate due to the opening of the supply valve 20 and the circulation valve 50. If this sudden change in volume coincides with the pressure fluctuation caused by the start of the circulation pump 70, the internal pressure of the circulation flow path R2 suddenly drops, causing the supply flow path R1 to become less dense and experience excessive negative pressure, which may prevent the ink Q from being supplied. In contrast, in this embodiment, the circulation valve 50 is opened and the circulation pump 70 is started after the supply valve 20 is opened, thereby suppressing the sudden drop in pressure at the start of the circulation operation. Note that the timing of opening the circulation valve 50 and the timing of starting the circulation pump 70 can be set as desired. The opening of the circulation valve 50 and the starting of the circulation pump 70 may be performed first, or both may be performed simultaneously. For example, by opening the circulation valve 50 (time t2 in Figure 4) and then starting the operation of the circulation pump 70 (time t2a in Figure 4), it is possible to suppress fluctuations in pressure within the circulation flow path R2 when the circulation valve 50 is opened.

[0042] Also, as shown in FIG. 3, the control method of the printing device 100 when stopping the circulation operation includes a determination step S40, a circulation pump stopping step S50, a circulation valve closing step S60, and a supply valve closing step S70.

[0043] In the determination step S40, the determination unit 85 determines whether or not to stop the circulation operation. In making this determination, the determination unit 85 detects whether or not the timing to stop the circulation operation has arrived. The timing to stop the circulation operation can be, for example, when a predetermined time has elapsed since the start of the circulation operation. If the circulation operation is a scheduled circulation operation, the timing to stop the scheduled circulation operation can be, for example, when a first time ΔT1 has elapsed since the start of the scheduled circulation operation. The first time ΔT1 can be several minutes (for example, about 2 minutes). In the determination step S40, if the timing to stop the circulation operation has not arrived, the determination unit 85 determines not to stop the circulation operation (No in step S40) and repeats the determination in step S40.

[0044] In the determination step S40, if it is time to stop the circulation operation, the determination unit 85 determines that the circulation operation should be stopped (Yes in step S40). If it is determined that the circulation operation should be stopped, the circulation pump stop step S50 is performed ( FIG. 4 : time t3). In the circulation pump stop step S50, the circulation pump control unit 88 stops the operation of the circulation pump 70. By stopping the operation of the circulation pump 70, the negative pressure is eliminated.

[0045] After the circulation pump stop step S50 is performed, the circulation valve closing step S60 is performed ( FIG. 4 : time t4). In the circulation valve closing step S60, the circulation valve control unit 87 closes the circulation valve 50. At this time, the circulation valve control unit 87 can close the circulation valve 50, for example, about one second after the circulation pump 70 stops operating. By closing the circulation valve 50 about one second after the circulation pump 70 stops operating, the pressure in the circulation flow path R2 after the circulation operation can be kept constant or approximately constant (for example, within a range of −1 kPa to −2 kPa).

[0046] After the circulation valve closing step S60 is performed, the supply valve closing step S70 is performed ( FIG. 4 : time t5). In the supply valve closing step S70, the supply valve control unit 86 closes the supply valve 20. At this time, the supply valve control unit 86 can close the supply valve 20 approximately two seconds after the operation of the circulation pump 70 is stopped. In this way, by setting the negative pressure release time in the supply flow path R1 to approximately two seconds, the pressure in the supply flow path R1 can be made equal to or less than 0 kPa and equal to or greater than the pressure in the circulation flow path R2. This makes it possible to suppress the seeping of ink Q from the nozzles 41 of the head 40. Furthermore, since the pressure fluctuations in the supply flow path R1 can be made gentler, the loss of ink Q from the nozzles 41 can be suppressed.

[0047] For example, when stopping the circulation operation, if the circulation pump 70 is stopped, the circulation valve 50 is closed, and the supply valve 20 is closed simultaneously, the timing of each operation may vary by a minute difference of about microseconds, potentially resulting in a change in the order of the operations. For example, if the supply valve 20 and the circulation valve 50 are closed before the circulation pump 70 is stopped, the negative pressure in the supply flow path R1 and the circulation flow path R2 may vary for each circulation operation. In this case, ink Q may seep out of the nozzles 41 of the head 40 or leak from the nozzles 41. In contrast, in this embodiment, the circulation pump 70 is stopped, the circulation valve 50 is closed, and then the supply valve 20 is closed after the circulation valve 50 is closed, thereby bringing the pressure in the supply flow path R1 closer to a constant value. Furthermore, since the fluctuations in the pressure in the supply flow path R1 can be gradual, leakage of ink Q from the nozzles 41 can be suppressed. This allows ink to be stably ejected from the head 40 while suppressing sedimentation of ink components.

[0048] FIG. 5 is a timing chart showing another example of the operation of the supply valve 20, the circulation valve 50, and the circulation pump 70. The timing chart shown in FIG. 5 illustrates an example in which the opening and closing operations of multiple (two in the example of FIG. 5) circulation valves 50 are performed at different times. In this case, as shown in FIG. 5, after performing the supply valve opening step S20 (FIG. 5: time t1), first, a circulation step S30 (FIG. 5: time t2) is performed using the first circulation valve 50 (FIG. 5: circulation valve A) and the circulation pump 70, thereby performing a circulation operation using the first circulation valve 50. Thereafter, a circulation pump stopping step S50 (FIG. 5: time t3) is performed, and then a circulation valve closing step S60 (FIG. 5: time t4) is performed for the circulation valve A.

[0049] Thereafter, while the supply valve 20 remains open, a circulation step S30 ( FIG. 5 : time t5) is performed using the second circulation valve 50 ( FIG. 5 : circulation valve B) and the circulation pump 70, thereby performing a circulation operation using the second circulation valve B. Thereafter, a circulation pump stop step S50 ( FIG. 5 : time t6) is performed, and then a circulation valve closing step S60 ( FIG. 5 : time t7) is performed for the circulation valve B. After performing a circulation operation for the second circulation valve B, i.e., the last circulation valve 50 of the multiple circulation valves 50, a supply valve closing step S70 ( FIG. 5 : time t8) is performed.

[0050] In this way, when multiple circulation valves 50 are controlled at different times, efficient control of the circulation operation can be achieved by performing the supply valve closing step S70 after completing the circulation operation using each circulation valve 50.

[0051] Fig. 6 is a timing chart showing another example of the operations of the supply valve 20, the circulation valve 50, and the circulation pump 70. Specifically, Fig. 6 is a timing chart when a sub-circulation operation, which will be described later, is performed.

[0052] The timing for performing the circulation operation may be the timing of a regular circulation operation, or the timing when an operation for opening the supply valve 20 is completed, such as a printing operation or an operation for cleaning the head 40. In determination step S10, when the timing for completing the operation for opening the supply valve 20 arrives, the determination unit 85 can determine that a sub-circulation operation should be performed as the circulation operation (Yes in step S10).

[0053] If it is determined in step S10 that sub-circulation operation is to be performed, the supply valve opening step S20 (time t11 in FIG. 6) and the circulation step S30 (time t12 in FIG. 6) are performed in the same manner as if it was determined in step S10 that regular circulation operation is to be performed.

[0054] Furthermore, when the circulation operation is to be stopped, in a determination step S40, the determination unit 85 determines whether or not to stop the sub-circulation operation. In making this determination, the determination unit 85 detects whether or not the timing to stop the sub-circulation operation has arrived. The timing to stop the sub-circulation operation can be, for example, the timing when a second time ΔT2 has elapsed since the start of the sub-circulation operation. The second time ΔT2 is a time shorter than the first time ΔT1 in the scheduled circulation operation and can be several seconds (for example, 2 seconds). In a determination step S40, when the timing to perform the sub-circulation operation has not arrived, the determination unit 85 determines not to stop the sub-circulation operation (No in step S40) and repeats the determination in step S40.

[0055] In the determination step S40, if it is time to stop the sub-circulation operation, the determination unit 85 determines that the sub-circulation operation should be stopped (Yes in step S40). If it is determined that the sub-circulation operation should be stopped, the determination unit 85 performs the steps of stopping the circulation pump S50 (time t13 in FIG. 6 ), closing the circulation valve S60 (time t14 in FIG. 6 ), and closing the supply valve S70 (time t15 in FIG. 6 ), as in the case where it is determined that the scheduled circulation operation should be stopped.

[0056] In this way, the sub-circulation operation has a shorter period of time than the fixed-time circulation operation. The sub-circulation operation is not intended to circulate the ink Q, but rather to control the pressure in the supply flow path R1 and the circulation flow path R2 in a short time by performing a short-time circulation operation.

[0057] As described above, the printing device 100 according to this embodiment includes the ink supply source 10, which is a supply source of ink; the damper 30 that supplies ink supplied from the ink supply source 10 to the head 40 that ejects ink; the supply flow path R1 that connects the ink supply source 10 and the damper 30; the supply valve 20 that is provided in the supply flow path R1 and opens and closes the supply flow path R1; and the circulation valve 20 that is connected to the damper 30 and the supply flow path R1 downstream of the supply valve 20 and returns the ink supplied to the damper 30 to the supply flow path R1 downstream of the supply valve 20, thereby circulating the ink. The device comprises a flow path R2, a circulation valve 50 that is provided midway along the circulation flow path R2 and opens and closes the circulation flow path R2, a circulation pump 70 that is provided on the circulation flow path R2 downstream of the circulation valve 50 and moves ink from the damper 30 side to the supply flow path R1 side, and a control unit 80 that controls the opening and closing of the supply valve 20, the opening and closing of the circulation valve 50, and the start and stop of the operation of the circulation pump 70.When starting the circulation operation of ink via the circulation flow path R2, the control unit 80 opens the supply valve 20, then opens the circulation valve 50 and starts the circulation pump 70.

[0058] By opening the supply valve 20, and then opening the circulation valve 50 and starting the circulation pump 70, a sudden drop in pressure at the start of the circulation operation is suppressed. This allows the ink to be stably ejected from the head 40 while suppressing the settling of ink components.

[0059] In the printing device 100 according to this embodiment, the control unit 80 starts the circulation pump 70 after opening the circulation valve 50 .

[0060] According to this configuration, the circulation pump 70 is started after the circulation valve 50 is opened, thereby suppressing fluctuations in pressure within the circulation flow path R2 when the circulation valve 50 is opened.

[0061] In the printing device 100 according to this embodiment, when the control unit 80 stops the circulation operation of ink through the circulation flow path R2, it stops the circulation pump 70, then closes the circulation valve 50, and after the circulation valve 50 is closed, it closes the supply valve 20.

[0062] After stopping the circulation pump 70, the circulation valve 50 is closed, and after the circulation valve 50 is closed, the supply valve 20 is closed, thereby making it possible to bring the pressure in the supply flow path R1 close to a constant value. Furthermore, since fluctuations in the pressure in the supply flow path R1 can be made gentler, it is possible to prevent the ink Q from leaking out of the nozzles 41. This makes it possible to stably eject the ink from the head 40 while preventing the sedimentation of ink components.

[0063] The printing device 100 according to this embodiment includes an ink supply source 10 that is a supply source of ink, a damper 30 that supplies ink supplied from the ink supply source 10 to a head 40 that ejects ink, a supply flow path R1 that connects the ink supply source 10 and the damper 30, a supply valve 20 that is provided in the supply flow path R1 and opens and closes the supply flow path R1, a circulation flow path R2 that is connected to the damper 30 and the downstream side of the supply valve 20 of the supply flow path R1 and returns and circulates the ink supplied to the damper 30 to the downstream side of the supply valve 20 of the supply flow path R1, and the circulation flow path R2, and a circulation pump 70 that is provided on the circulation flow path R2 downstream of the circulation valve 50 and moves ink from the damper 30 side to the supply flow path R1 side; and a control unit 80 that controls the opening and closing of the supply valve 20, the opening and closing of the circulation valve 50, and the start and stop of the operation of the circulation pump 70. When the control unit 80 wants to stop the circulation of ink through the circulation flow path R2, it stops the circulation pump 70, then closes the circulation valve 50, and then closes the supply valve 20 after closing the circulation valve 50.

[0064] After stopping the circulation pump 70, the circulation valve 50 is closed, and after the circulation valve 50 is closed, the supply valve 20 is closed, thereby making it possible to bring the pressure in the supply flow path R1 close to a constant value. Furthermore, since fluctuations in the pressure in the supply flow path R1 can be made gentler, it is possible to prevent the ink Q from leaking out of the nozzles 41. This makes it possible to stably eject the ink from the head 40 while preventing the sedimentation of ink components.

[0065] In the printing device 100 according to this embodiment, the ink circulation operation includes at least one of a regular circulation operation that is performed at regular intervals and a sub-circulation operation that is performed after the supply valve 20 is opened.

[0066] By performing at least one of the fixed circulation operation and the sub-circulation operation, ink can be ejected from the head 40 in a stable manner.

[0067] In the printing device 100 according to this embodiment, the ink circulation operation includes both a fixed-time circulation operation that is performed at fixed times and a sub-circulation operation that is performed after the supply valve 20 is opened, and the control unit 80 shortens the operating time of the circulation pump 70 during the sub-circulation operation compared to the operating time of the circulation pump 70 during the fixed-time circulation operation.

[0068] According to this configuration, in the fixed-time circulation operation, it is possible to suppress sedimentation of ink components and stably eject ink from the head 40. Furthermore, in the sub-circulation operation, by performing a short-time circulation operation, it is possible to control the pressure in the supply flow path R1 and the circulation flow path R2 in a short time.

[0069] The control method for a printing device according to this embodiment includes an ink supply source 10 that is a supply source of ink, a damper 30 that supplies ink supplied from the ink supply source 10 to a head 40 that ejects ink, a supply flow path R1 that connects the ink supply source 10 and the damper 30, a supply valve 20 that is provided in the supply flow path R1 and opens and closes the supply flow path R1, a circulation flow path R2 that is connected to the damper 30 and the downstream side of the supply valve 20 of the supply flow path R1 and that returns and circulates the ink supplied to the damper 30 to the downstream side of the supply valve 20 of the supply flow path R1, and A control method for a printing device (100) equipped with a circulation valve (50) provided midway through a circulation flow path (R2) for opening and closing the circulation flow path (R2), and a circulation pump (70) provided downstream of the circulation valve (50) on the circulation flow path (R2) for moving ink from the damper (30) side to the supply flow path (R1) side, the control method including, when starting the circulation operation of ink via the circulation flow path (R2), a supply valve opening step (S20) for opening the supply valve (20), and a circulation step (S30) for opening the circulation valve (50) and starting operation of the circulation pump (70) after performing the supply valve opening step (S10).

[0070] According to this configuration, a sudden drop in pressure at the start of circulation operation is suppressed by opening the circulation valve 50 and starting the circulation pump 70 after opening the supply valve 20. This allows ink to be stably ejected from the head 40 while suppressing settling of ink components.

[0071] The control method for a printing device according to this embodiment includes an ink supply source 10 that is a supply source of ink, a damper 30 that supplies ink supplied from the ink supply source 10 to a head 40 that ejects ink, a supply flow path R1 that connects the ink supply source 10 and the damper 30, a supply valve 20 that is provided in the supply flow path R1 and opens and closes the supply flow path R1, a circulation flow path R2 that is connected to the damper 30 and the supply flow path R1 on the downstream side of the supply valve 20 and that returns and circulates the ink supplied to the damper 30 to the downstream side of the supply valve 20 of the supply flow path R1, and a circulation valve that is provided in the middle of the circulation flow path R2 and that A control method for a printing device (100) equipped with a circulation valve (50) that opens and closes a flow path (R2), and a circulation pump (70) that is provided on the circulation flow path (R2) downstream of the circulation valve (50) and moves ink from the damper (30) side to the supply flow path (R1) side, and when stopping the circulation operation of ink through the circulation flow path (R2), includes a circulation pump stopping step (S50) that stops the circulation pump (70), a circulation valve closing step (S60) that closes the circulation valve (50) after performing the circulation pump stopping step (S50), and a supply valve closing step (S70) that closes the supply valve (20) after performing the circulation valve closing step (S60).

[0072] After stopping the circulation pump 70, the circulation valve 50 is closed, and after the circulation valve 50 is closed, the supply valve 20 is closed, thereby making it possible to bring the pressure in the supply flow path R1 close to a constant value. Furthermore, since fluctuations in the pressure in the supply flow path R1 can be made gentler, it is possible to prevent the ink Q from leaking out of the nozzles 41. This makes it possible to stably eject the ink from the head 40 while preventing the sedimentation of ink components.

[0073] 50...circulation valve, D1...supply direction, D2...circulation direction, M...media, Q...ink, R...transport unit, R1...supply flow path, R2...circulation flow path, Qa...meniscus surface, 10...ink supply source, 20...supply valve, 30...damper, 31...ink chamber, 40...head, 41...nozzle, 60...filter, 70...circulation pump, 80...control unit, 81...communication unit, 82...processing unit, 83...storage unit, 84...printing control unit, 85...determination unit, 86...supply valve control unit, 87...circulation valve control unit, 88...circulation pump control unit, 100...printing device

Claims

a supply valve provided in the supply flow path and opening and closing the supply flow path; a circulation flow path connected to the damper and the supply flow path downstream of the supply valve, and circulating the ink supplied to the damper by returning it to the supply flow path downstream of the supply valve; a circulation valve provided in the circulation flow path and opening and closing the circulation flow path; a circulation pump provided in the circulation flow path downstream of the circulation valve, and moving the ink from the damper side to the supply flow path; and a control unit that controls the opening and closing of the supply valve, the opening and closing of the circulation valve, and the start and stop of the circulation pump, wherein when starting the circulation of the ink through the circulation flow path, the control unit opens the supply valve, then opens the circulation valve and starts the circulation pump.

2. The printing device according to claim 1, wherein the control unit starts the circulation pump after opening the circulation valve.

3. The printing device according to claim 1, wherein when the control unit stops the circulation operation of the ink through the circulation flow path, it stops the circulation pump, then closes the circulation valve, and after the circulation valve is closed, it closes the supply valve.

4. A printing device comprising: an ink supply source that supplies ink; a damper that supplies ink supplied from the ink supply source to a head that ejects the ink; a supply flow path that connects the ink supply source and the damper; a supply valve that is provided in the supply flow path and opens and closes the supply flow path; a circulation flow path that is connected to the damper and the supply flow path downstream of the supply valve and returns the ink supplied to the damper to the supply flow path downstream of the supply valve, and circulates the ink; a circulation valve that is provided midway along the circulation flow path and opens and closes the circulation flow path; a circulation pump that is provided in the circulation flow path downstream of the circulation valve and moves the ink from the damper side to the supply flow path side; and a control unit that controls the opening and closing of the supply valve, the opening and closing of the circulation valve, and the start and stop of the circulation pump, wherein when circulating the ink through the circulation flow path is to be stopped, the control unit stops the circulation pump and then closes the circulation valve, and then closes the supply valve after the circulation valve is closed.

5. A printing device according to claim 1 or claim 4, wherein the ink circulation operation includes at least one of a circulation operation performed at regular intervals and a sub-circulation operation performed after the operation of opening the supply valve has been performed.

6. The printing device described in claim 4, wherein the ink circulation operation includes both a regular circulation operation performed at regular intervals and a sub-circulation operation performed after the supply valve is opened, and the control unit makes the operating time of the circulation pump in the sub-circulation operation shorter than the operating time of the circulation pump in the regular circulation operation.

7. A control method for a printing device comprising: an ink supply source that supplies ink; a damper that supplies ink supplied from the ink supply source to a head that ejects the ink; a supply flow path that connects the ink supply source and the damper; a supply valve that is provided in the supply flow path and opens and closes the supply flow path; a circulation flow path that is connected to the damper and the supply flow path downstream of the supply valve and returns the ink supplied to the damper to the supply flow path downstream of the supply valve, and circulates the ink; a circulation valve that is provided midway in the circulation flow path and opens and closes the circulation flow path; and a circulation pump that is provided in the circulation flow path downstream of the circulation valve and moves the ink from the damper side to the supply flow path, the control method for a printing device comprising: a supply valve opening step that opens the supply valve when starting circulation of the ink via the circulation flow path; and a circulation step that opens the circulation valve and starts the circulation pump after performing the supply valve opening step.

8. A control method for a printing device comprising: an ink supply source that supplies ink; a damper that supplies ink supplied from the ink supply source to a head that ejects the ink; a supply flow path that connects the ink supply source and the damper; a supply valve that is provided in the supply flow path and opens and closes the supply flow path; a circulation flow path that is connected to the damper and the supply flow path downstream of the supply valve and returns the ink supplied to the damper to the supply flow path downstream of the supply valve, and circulates the ink; a circulation valve that is provided midway in the circulation flow path and opens and closes the circulation flow path; and a circulation pump that is provided in the circulation flow path downstream of the circulation valve and moves the ink from the damper side to the supply flow path, the control method for a printing device comprising: a circulation pump stopping step that stops the circulation pump when circulating the ink through the circulation flow path is to be stopped; a circulation valve closing step that closes the circulation valve after performing the circulation pump stopping step; and a supply valve closing step that closes the supply valve after performing the circulation valve closing step.

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