JP2019084772A - Ink circulation system, ink jet printer and parameter setting method of ink circulation system - Google Patents

Abstract

To provide an ink circulation system which stops with the ink pressure in an ink head maintained at the proper pressure.SOLUTION: An ink circulation system 40a includes an annular circulation channel 43, an ink head 42, a first pump 44 delivering ink to the ink head 42 and a second pump 46 recovering the ink from the ink head 42. A control device stops the first pump 44 after the first time and stops the second pump 46 after the second time when stopping circulation. The first time and second time are set to the time of converging the ink pressure in the ink head 42 after the stop of the circulation within the first pressure range. The first pressure range is the pressure range in which the ink is not drawn into the ink head 42, and stays in a nozzle 42a without protruding from the nozzle 42a.SELECTED DRAWING: Figure 8A

Description

  The present invention relates to an ink circulation system, an inkjet printer provided with the ink circulation system, and a parameter setting method of the ink circulation system.

  Conventionally, an ink supply system provided with a circulation flow path for circulating the ink, and an ink jet printer provided with such an ink supply system are known. For example, Patent Document 1 discloses an ink jet recording apparatus provided with an ink return path. When the ink is a pigment-based ink containing a pigment, if the ink is allowed to stand without moving, the pigment may settle in the ink or the ink may thicken, and print quality such as color unevenness or ejection failure Easily lead to The circulation of the ink is to prevent sedimentation of the pigment and thickening of the ink.

JP, 2009-279932, A

  By the way, even in the case of the ink supply system provided with the circulation flow channel as described above, the ink is not circulated in all cases, and the circulation may be stopped. For example, it is when moving the installation place of an inkjet printer. However, if the pump is simply stopped when stopping the circulation of ink, in many cases, the pressure of ink in the ink head will change from that during circulation. The ink pressure in the ink head during circulation is controlled within the appropriate pressure range held in the nozzle in a state in which ink can be discharged, but the ink pressure greatly fluctuates due to the suspension of circulation and the appropriate pressure range If it is removed from the inside, the air from the nozzle will be sucked or the ink will drip from the nozzle. Such a situation is of course not desirable.

  The present invention has been made in view of the foregoing, and an object thereof is to provide an ink circulation system that stops while maintaining the ink pressure in the ink head at an appropriate pressure, and an ink jet printer provided with such an ink circulation system. It is to provide. Another object of the present invention is to provide a parameter setting method of the ink circulation system in which the circulation is stopped while maintaining the ink pressure in the ink head at an appropriate pressure.

  The ink circulation system according to the present invention has an annular circulation flow passage through which the ink is circulated, a nozzle through which the ink is ejected, and an ink head provided in the circulation passage, and is provided in the circulation passage. A first pump that delivers the ink to the ink head, a second pump that is provided in the circulation flow path and that recovers the ink from the ink head, and are communicably connected to the first pump and the second pump And a controller. The control device controls the first pump and the second pump to circulate the ink in the circulation flow path and adjust the pressure of the ink in the ink head, and the circulation control unit. And a stop control unit for stopping the The stop control unit is set to stop the first pump after a first time and stop the second pump after a second time when stopping the circulation. The first time and the second time are set such that the pressure of the ink in the ink head after the circulation is stopped converges within a predetermined first pressure range. The first pressure range is a pressure range in which the ink does not get drawn into the ink head and remains in the nozzle without protruding from the nozzle.

  According to the above ink circulation system, the pressure in the ink flowing into the ink head is controlled by the first pump, and the pressure in the ink flowing out of the ink head is controlled by the second pump. Adjustment of ink pressure is possible. Therefore, even when the circulation is stopped, the time until the first pump is stopped (= first time) and the time until the second pump is stopped (= second time) are adjusted, and in some cases the first time The ink pressure in the ink head can be adjusted by providing an appropriate time difference with the second time. In the above-described ink circulation system, the ink pressure in the ink head after the circulation is stopped does not cause the ink to be drawn into the ink head and the ink does not protrude from the nozzle, and the pressure range in which the ink remains in the nozzle The first time and the second time are adjusted to be within (= first pressure range). Therefore, according to the ink circulation system, the circulation can be stopped while maintaining an appropriate ink pressure. In the above, the state in which the ink is "protruding" means the state in which the ink is hanging from the nozzle without remaining in the nozzle, and the state in which the ink is "pulled in" means the ink It means that it is inhaled from the nozzle with the outside air without staying in the air. Therefore, "the state in which the ink pressure in the ink head has converged within the first pressure range" is better than the state in which the ink is sucked into the ink head together with the external air, and the ink is discharged from the nozzle Including all states better than the drooping state.

  Further, in the parameter setting method of the ink circulation system according to the present invention, an annular circulation flow passage through which the ink is circulated, an ink head having a nozzle through which the ink is ejected, and an ink head provided in the circulation passage An ink circulation system comprising: a first pump provided in a circulation flow path for delivering the ink to the ink head; and a second pump provided in the circulation flow path for recovering the ink from the ink head A method of setting a parameter for stopping the circulation of ink, wherein the parameter includes a time for stopping the first pump and a time for stopping the second pump. In the parameter setting method of the ink circulation system according to the present invention, the pressure of the ink in the ink head is confirmed after the first pump is stopped after the first time and the second pump is stopped after the second time. And the second time is relative to the first time if the pressure of the ink in the ink head as determined in the first step exceeds a predetermined first pressure range. And a second step of extending the first time relative to the second time if the pressure of the ink in the ink head confirmed in the first step falls below the first pressure range; and including. The first pressure range is a pressure range in which the ink does not get drawn into the ink head and remains in the nozzle without protruding from the nozzle.

  According to the parameter setting method of the ink circulation system, when the ink pressure in the ink head after the circulation stoppage exceeds the first pressure range, the stop time of the second pump is set to the stop time of the first pump Relatively extending, if the ink pressure in the ink head after the circulation stop falls below the first pressure range, the process of extending the stop time of the first pump relative to the stop time of the second pump is repeated. The ink pressure in the ink head after circulation is stopped is adjusted to fall within the first pressure range. That is, when the ink pressure in the ink head after the circulation stop is high, the stop of the second pump on the outflow side is delayed to lower the ink pressure, and the ink pressure in the ink head after the circulation stop is low. The ink pressure in the ink head is adjusted by delaying the stop of the first pump on the inflow side to raise the ink pressure. The first pressure range is a pressure range in which the ink does not get drawn into the ink head and remains in the nozzle without protruding from the nozzle. With such a method, it is possible to find a parameter that causes the ink circulation system to stop while maintaining the ink pressure in the ink head properly. The above-mentioned parameters are, specifically, the stop time of the first pump and the stop time of the second pump.

1 is a front view of an ink jet printer according to an embodiment. It is a schematic diagram which shows the structure of a carriage lower surface. It is a schematic diagram which shows the structure of an ink system. It is a sectional view showing typically the internal structure of the upper stream side damper. It is sectional drawing which shows the internal structure of nozzle vicinity typically. It is a block diagram of a printer. It is a schematic diagram which shows the state in which the ink is circulated in the ink circulation system. It is a schematic diagram which shows the step in stopping circulation of an ink in an ink circulation system, Comprising: It is a figure which shows the first step. It is a schematic diagram which shows the step in stopping circulation of an ink in an ink circulation system, Comprising: It is a figure which shows a 2nd step. It is a schematic diagram which shows the ink circulation system at the time of being simply stopped from the circulation state shown by FIG. It is a flowchart which shows the adjustment method of delay time.

  Hereinafter, an ink system and an ink jet printer provided with the ink system according to some embodiments will be described with reference to the drawings. The embodiments described herein are, of course, not intended to specifically limit the present invention. In addition, the same reference numerals are given to members and portions having the same effect, and the overlapping description will be appropriately omitted or simplified. In the following description, when the ink jet printer is viewed from the front, the one moving away from the ink jet printer is referred to as the front, and the one approaching the ink jet printer is as the rear. The symbols F, Rr, L, R, U, and D in the drawings indicate front, rear, left, right, top, and bottom, respectively. However, these are merely directions for the convenience of description and do not limit the installation mode and the like of the ink jet printer. Further, in the drawings, the symbol Y indicates the main scanning direction, and the symbol X indicates the sub-scanning direction X orthogonal to the main scanning direction Y.

  FIG. 1 is a front view of a large-format ink jet printer (hereinafter referred to as “printer”) 10 according to an embodiment. The printer 10 sequentially moves the roll-shaped recording medium 5 forward and ejects ink from a plurality of ink heads 42 (see FIG. 2) mounted on a carriage 25 moving in the main scanning direction Y. The image is printed on the medium 5.

  The recording medium 5 is an object on which an image is to be printed. The recording medium 5 is not particularly limited. The recording medium 5 may be, for example, paper such as plain paper or printing paper for inkjet, or may be a transparent sheet made of resin or glass, or a sheet made of metal or rubber It may be

  As shown in FIG. 1, the printer 10 includes a printer body 10a and legs 11 for supporting the printer body 10a. The printer body 10 a extends in the main scanning direction Y. The printer body 10 a includes a guide rail 21 and a carriage 25 engaged with the guide rail 21. The guide rail 21 extends in the main scanning direction Y. The guide rails 21 guide the movement of the carriage 25 in the main scanning direction Y. An endless belt 22 is fixed to the carriage 25. The belt 22 is wound around a pulley 23a provided on the right side of the guide rail 21 and a pulley 23b provided on the left side. A carriage motor 24 is attached to the pulley 23a on the right side. The carriage motor 24 is electrically connected to the control device 100. The carriage motor 24 is controlled by the control device 100. When the carriage motor 24 is driven, the pulley 23a rotates and the belt 22 travels. As a result, the carriage 25 moves in the main scanning direction Y along the guide rail 21. As described above, when the carriage 25 moves in the main scanning direction Y, the plurality of ink heads 42 also move in the main scanning direction Y.

  Below the carriage 25, a platen 12 is disposed. The platen 12 extends in the main scanning direction Y. The recording medium 5 is placed on the platen 12. Above the platen 12, a pinch roller 31 for pressing the recording medium 5 from above is provided. The pinch roller 31 is disposed rearward of the carriage 25. The platen 12 is provided with a grit roller 32. The grit roller 32 is disposed below the pinch roller 31. The grit roller 32 is provided at a position facing the pinch roller 31. The grit roller 32 is connected to a feed motor 33 (see FIG. 6). The grit roller 32 is rotatably formed in response to the driving force of the feed motor 33. The feed motor 33 is electrically connected to the control device 100. The feed motor 33 is controlled by the controller 100. When the grit roller 32 rotates while the recording medium 5 is nipped between the pinch roller 31 and the grit roller 32, the recording medium 5 is conveyed in the sub-scanning direction X.

  FIG. 2 is a schematic view showing the configuration of the surface (the lower surface in the present embodiment) of the carriage 25 facing the recording medium 5. As shown in FIG. 2, a plurality of ink heads 42 are provided on the lower surface of the carriage 25. Here, the number of ink heads 42 is “8”. Each of the plurality of ink heads 42 ejects process color ink for forming a color image or special color ink for applying a special visual effect to the image. The process color ink is, for example, cyan ink, magenta ink, yellow ink, black ink, gray ink, light cyan ink, light magenta ink, and the like. The special color ink is, for example, clear ink, white ink, or the like. However, the number of ink heads 42 is not limited to eight, and the color tone of the ink is not limited at all. Further, the material of the ink is not limited at all, and various materials conventionally used as the material of the ink of the ink jet printer can be used.

  As shown in FIG. 2, in the carriage 25, the plurality of ink heads 42 are arranged side by side in the main scanning direction Y. In each ink head 42, a plurality of nozzles 42a are formed. The plurality of nozzles 42 a are arranged in a line in the sub scanning direction X. However, the arrangement of the nozzles 42 a is not limited to one row, and a plurality of rows may be formed for one ink head 42. Further, the number of nozzles 42 a in the ink head 42 is not limited. Although ten nozzles 42 a are illustrated in each of the plurality of ink heads 42 in FIG. 2, actually more (for example, 300) nozzles are formed.

  One ink system is connected to each of the plurality of ink heads 42. FIG. 3 is a schematic view showing the configuration of the ink system 35. As shown in FIG. As shown in FIG. 3, the ink system 35 according to this embodiment includes an ink supply system 40, a capping system 60, and an ejection system 70.

  The ink supply system 40 is a system for supplying the ink to the ink head 42. The ink supply system 40 is provided for each ink head 42. The plurality of ink supply systems 40 have a common configuration except for the type of ink to be supplied and some settings described later. As shown in FIG. 3, the ink supply system 40 includes the ink cartridge 41, the ink head 42, the circulation flow path 43, the upstream pump 44, the upstream damper 45, the downstream pump 46, and the downstream side. A damper 47, an air trap 48, and a circulation valve 49 are provided.

  The ink cartridge 41 is a member that stores ink. The ink cartridge 41 is detachably provided, for example, on the printer body 10a. However, the position at which the ink cartridge 41 is disposed is not limited. For example, the ink cartridge 41 may be provided detachably on the carriage 25. The ink cartridge 41 stores one kind of ink among the various inks described above. Among them, for example, a white ink etc. is one of the inks which contains a pigment and which tends to settle when left to stand.

  The circulation channel 43 is a channel that circulates the ink so that the components of the ink do not settle. Further, the circulation flow path 43 is a flow path for supplying the ink to the ink head 42 at the time of printing. Therefore, the ink cartridge 41 is connected to the circulation flow path 43 via the supply flow path 43a. Although the type and material of the circulation flow path 43 and the supply flow path 43a are not limited, for example, a flexible tube is used. In the circulation flow channel 43, an upstream pump 44 is provided downstream of a connection point C1 between the circulation flow channel 43 and the supply flow channel 43a. An upstream damper 45 is provided downstream of the upstream pump 44. An ink head 42 is provided downstream of the upstream damper 45. The upstream pump 44 is set to send liquid from the ink cartridge 41 in the direction toward the ink head 42, and controls the flow rate of the ink supplied to the ink head 42. A downstream damper 47 is provided downstream of the ink head 42. Downstream of the downstream damper 47, a downstream pump 46 is provided. The downstream pump 46 is set to send liquid in the direction of leaving the ink head 42 and controls the return flow rate of the ink from the ink head 42. An air trap 48 is disposed downstream of the downstream pump 46. Further downstream of the air trap 48, a circulation valve 49 is provided. Downstream of the circulation valve 49, the circulation flow path 43 returns to the connection point C1 with the supply flow path 43a.

  In the following, among the above configurations, the configurations provided in the circulation channel 43 and the circulation channel 43 (upstream pump 44, upstream damper 45, ink head 42, downstream damper 47, downstream pump 46, The air trap 48 and the circulation valve 49 may be referred to as an ink circulation system 40a. The ink circulation system 40a is a system related to ink circulation.

  The upstream pump 44 and the downstream pump 46 circulate the ink in the circulation flow path 43 and adjust the ink pressure in the ink head 42 to an appropriate pressure range. The upstream pump 44 adjusts the ink pressure on the upstream side by adjusting the supply flow rate of ink. The downstream pump 46 regulates the downstream ink pressure by regulating the ink return flow rate. By adjusting the upstream ink pressure and the downstream ink pressure of the ink head 42, the ink pressure in the ink head 42 is adjusted. The types of the upstream pump 44 and the downstream pump 46 are not particularly limited. The upstream pump 44 and the downstream pump 46 are, for example, a tube pump, a diaphragm pump, and the like.

  The upstream damper 45 and the downstream damper 47 are members for alleviating ink pressure fluctuations to stabilize the ink discharge operation of the ink head 42 and adjusting the pressure of ink in the ink head 42 to a desired pressure. is there. FIG. 4 is a cross-sectional view schematically showing an internal structure of the upstream damper 45. As shown in FIG. As shown in FIG. 4, the upstream damper 45 includes a storage chamber 45a for storing ink, a film 45b forming one surface of the storage chamber 45a, a coil spring 45c, a pressing body 45d, and a photo sensor 45e. ing. The film 45b is, for example, a flexible resin film. The film 45b is attached to one surface of the storage chamber 45a with such a tension that the film 45b can be bent to the inside and the outside of the storage chamber 45a. The film 45 b constitutes one surface of the storage chamber 45 a. The coil spring 45c is an example of an elastic body that presses the film 45b via the pressing body 45d. In the present embodiment, the coil spring 45c is maintained in a compressed state. Therefore, the film 45b is always in a state of being pressed toward the outside (right side in FIG. 4) of the storage chamber 45a. The volume of the storage chamber 45a can be changed by the expansion and contraction of the coil spring 45c and bending of the film 45b. The pressing body 45 d is a member provided so that the coil spring 45 c can press the film 45 b uniformly. The configuration of the pressing body 45d is not particularly limited, and is, for example, a flat member made of metal.

  The photo sensor 45 e is a member that detects the ink pressure in the storage chamber 45 a. In the present embodiment, the photosensor 45e is provided outside the film 45b, and detects an ink pressure in the storage chamber 45a from a change in position of the film 45b. When the pressure of the ink stored in the storage chamber 45a decreases, the film 45b bends inside the storage chamber 45a. The deflection of the film 45b is optically detected by the photo sensor 45e. When the inward deflection of the film 45b becomes equal to or more than a predetermined amount, the photosensor 45e recognizes that the ink pressure in the storage chamber 45a has become equal to or less than a predetermined pressure. When the photosensor 45 e recognizes that the ink pressure in the storage chamber 45 a has become equal to or less than a predetermined value, the photosensor 45 e transmits a signal to the control device 100. In response to this signal, the control device 100 drives the upstream pump 44. When the upstream pump 44 is driven to increase the ink pressure in the storage chamber 45a and the inward deflection of the film 45b falls below a predetermined amount, the photosensor 45e detects that the ink pressure in the storage chamber 45a has a predetermined pressure. Recognize that it exceeded. When the photosensor 45 e recognizes that the ink pressure in the storage chamber 45 a exceeds a predetermined pressure, the photosensor 45 e stops transmitting a signal to the control device 100, and the control device 100 stops the upstream pump 44. The upstream damper 45 controls the drive of the upstream pump 44 via the control device 100 in this manner. The above-described drive control of the upstream pump 44 controls the ink pressure on the upstream side of the ink head 42 within a desired pressure range.

  The downstream damper 47 also has the same structure as the upstream damper 45, and controls the drive of the downstream pump 46 via the control device 100. The downstream damper 47 also includes a photo sensor 47 e (see FIGS. 3 and 6). The ink pressure on the downstream side of the ink head 42 is adjusted by control based on the detection result of the photo sensor 47 e. However, the set values of the downstream ink pressure and the upstream ink pressure are different. Therefore, the restoring force of the membrane or the coil spring is different.

  The ink head 42 is a member that discharges the ink toward the recording medium 5. The ink is discharged downward from the nozzles 42 a of the ink head 42. FIG. 5 is a cross-sectional view schematically showing an internal structure in the vicinity of the nozzle 42a. As shown in FIG. 5, the ink head 42 includes a pressure chamber 42 b and an actuator 42 c for each nozzle 42 a. The nozzle 42 a is a minute hole formed on the lower surface of the ink head 42 and is a portion from which the ink is discharged. A pressure chamber 42b is provided above the nozzle 42a. The pressure chamber 42b and the nozzle 42a communicate with each other. Ink is stored in the pressure chamber 42b. The pressure chamber 42b is provided with an inlet 42d, and the ink is supplied to the pressure chamber 42b from the inlet 42d. An actuator 42c is attached to the outside of the pressure chamber 42b. The actuator 42c is, for example, a piezoelectric element. A piezoelectric element is an element that contracts when a voltage is applied. The actuator 42 c is electrically connected to the control device 100. The operation of the actuator 42c is controlled by the control device 100.

  During printing standby, that is, when printing is not performed, the ink pressure in the pressure chamber 42b is determined by the upstream ink pressure controlled by the upstream pump 44 and the downstream ink pressure controlled by the downstream pump 46. ing. In the printer 10 according to the present embodiment, the ink pressure in the pressure chamber 42 b is substantially an intermediate value between the upstream ink pressure and the downstream ink pressure. However, the relationship between the ink pressure in the pressure chamber 42b and the upstream ink pressure and the downstream ink pressure may vary depending on the design of the ink circulation system, and is not necessarily the relationship described above. The ink pressure in the pressure chamber 42b at the time of printing standby is maintained at, for example, a negative pressure of about -3 kPa to -0.5 kPa. The ink pressure in the pressure chamber 42b is a pressure which is held in the nozzle 42a at least without the ink being drawn into the ink head 42 and without protruding from the nozzle 42a. Here, the state in which the ink is "pulled in" means the state in which the ink is sucked from the nozzle 42a together with the external air without staying in the nozzle 42a, and the state in which the ink is "protruding" This means that ink is dripping from the nozzle 42a without remaining in the nozzle 42a. The pressure range (hereinafter referred to as an allowable pressure range as appropriate) in which the ink does not protrude or be drawn in as described above and remains in the nozzle 42 a is determined by the ink head 42. When the ink pressure in the ink head 42 is higher than this allowable pressure range, the ink protrudes from the nozzle 42a and drips toward the outside (M1 in FIG. 4). When the ink pressure in the ink head 42 is lower than this allowable pressure range, the ink recedes to the pressure chamber 42b side and is sucked with the external air toward the pressure chamber 42b (M2 in FIG. 4). The allowable pressure range is a pressure range in which the pressure immediately before ink starts to be drawn into the ink head 42 is the lower limit, and the pressure immediately before the ink starts to drop out of the nozzle 42a is the upper limit. The ink pressure in the pressure chamber 42b at the time of printing standby is set within the allowable pressure range.

  At the time of printing, the pressure chamber 42b is contracted / expanded by the actuator 42c. Thus, the ink is ejected from the nozzle 42a. At the time of ink discharge, the actuator 42c is displaced in the direction to contract the pressure chamber 42b, and the displacement of the actuator 42c reduces the volume of the pressure chamber 42b. The ink corresponding to the volume reduction of the pressure chamber 42b is discharged from the nozzle 42a in communication with the pressure chamber 42b. After the ink ejection, the actuator 42c is displaced in the opposite direction to that at the time of ejection, and the pressure chamber 42b is expanded. By this expansion, the ink is supplied from the inflow port 42d to the pressure chamber 42b. The drive of the actuator 42 c is controlled by the control device 100.

  The air trap 48 is a device for capturing the air contained in the ink. The air trap 48 is, for example, a gas-liquid separator. The air trap 48 includes, for example, a capture chamber having an ink inlet and an outlet, and captures air mixed in the ink passing through the capture chamber. When the air mixed in the ink passes through the capture chamber, it is released to a space above the ink surface of the capture chamber. The air trap 48 captures the air entrained in the ink in the circulation flow path 43 in this manner. The trapped air is periodically exhausted by the exhaust system 70.

  The circulation valve 49 is a valve that opens / closes the circulation flow path 43. The circulation valve 49 is electrically connected to the control device 100. The circulation valve 49 is open during printing standby and printing. The circulation valve 49 is closed when ink in the circulation channel 43 is discharged by the discharge system 70.

  As shown in FIG. 3, the ink system 35 according to the present embodiment includes a capping system 60. The capping system 60 includes a cap 61, a cap moving mechanism 62, and a suction pump 63. The cap 61 is disposed below a home position (not shown) located at the right end of the guide rail 21. The home position is a position at which the carriage 25 stands by at the time of printing standby. The cap 61 is a member that prevents the ink attached to the nozzle 42 a of the ink head 42 from curing and clogging the nozzle 42 a. The cap 61 is attached to the ink head 42 so as to cover the nozzle surface of the ink head 42 at the time of printing standby. The cap moving mechanism 62 is connected to the cap 61. The cap moving mechanism 62 is a mechanism for moving the cap 61 up and down toward the nozzle surface of the ink head 42 at the home position. Although the configuration of the cap moving mechanism 62 is not particularly limited, for example, a drive motor is provided. The cap moving mechanism 62 moves the cap 61 up and down by driving the drive motor.

  The suction pump 63 is a member that sucks the ink in the ink head 42 in a state where the cap 61 is attached to the ink head 42. Suction is also an operation for preventing clogging of the nozzle 42 a of the ink head 42. One end of a suction flow path 64 is connected to the cap 61, and a waste liquid tank 65 is connected to the other end of the suction flow path 64. The suction pump 63 is provided in the suction flow channel 64 and suctions the ink in the ink head 42 via the suction flow channel 64. The ink sucked by the suction pump 63 is discarded to the waste liquid tank 65.

  As shown in FIG. 3, the ink system 35 according to the present embodiment includes an ejection system 70. The discharge system 70 is a system for discharging air and ink from the inside of the ink circulation system 40a. The discharge system 70 according to the present embodiment includes a discharge flow path 71, a discharge valve 72, and a discharge pump 73.

  As shown in FIG. 3, one end of the discharge flow path 71 is connected to the air trap 48, and the other end is connected to the waste liquid tank 65. The discharge flow path 71 connects the air trap 48 and the waste liquid tank 65. A discharge valve 72 is provided in the middle of the discharge flow path 71. A discharge pump 73 is provided downstream of the discharge valve 72 in the discharge flow path 71. During the discharge operation, the discharge valve 72 is opened, and the discharge pump 73 discharges air and ink from the air trap 48. Air and ink discharged by the discharge pump 73 are discarded to the waste tank 65.

  Although the suction pump 63 and the discharge pump 73 are provided for each ink supply system 40 in FIG. 3, the invention is not limited thereto. The suction pump 63 and the discharge pump 73 may be one in the printer 10 or one for the plurality of ink supply systems 40. The types and materials of the suction flow channel 64 and the discharge flow channel 71 are also not limited. The suction flow channel 64 and the discharge flow channel 71 are, for example, flexible tubes. The types of the suction pump 63 and the discharge pump 73 are not limited, but may be a tube pump, a diaphragm pump or the like.

  As shown in FIG. 1, an operation panel 110 is provided at the right end of the printer body 10a. The operation panel 110 is provided with a display unit for displaying an apparatus state, an input key operated by a user, and the like. Inside the operation panel 110, a control device 100 for controlling various operations of the printer 10 is accommodated. FIG. 6 is a block diagram of the printer 10 according to the present embodiment. As shown in FIG. 6, the control device 100 includes a carriage motor 24, a feed motor 33, an actuator 42c, an upstream pump 44, a downstream pump 46, a circulation valve 49, a cap moving mechanism 62, a suction pump 63, a discharge valve 72, And the discharge pump 73 are communicably connected to each other, and are configured to be able to control them. Further, the control device 100 is electrically connected to the photosensor 45 e of the upstream damper 45 and the photosensor 47 e of the downstream damper 47, and receives signals from them. The control device 100 includes an ink circulation control unit 101, a print control unit 102, a capping control unit 103, and a discharge control unit 104.

  The configuration of the control device 100 is not particularly limited. The control device 100 is, for example, a microcomputer. The hardware configuration of the microcomputer is not particularly limited. For example, an interface (I / F) that receives print data and the like from an external device such as a host computer, and a central processing unit (CPU: central) that executes control program instructions processing unit), ROM (read only memory) storing a program to be executed by the CPU, RAM (random access memory) used as a working area for expanding a program, and a memory for storing the program and various data And a storage device. The control device 100 does not necessarily have to be provided inside the printer main body 10a. For example, a computer or the like installed outside the printer main body 10a and communicably connected to the printer main body 10a via wire or wireless. It may be

  The ink circulation control unit 101 is a part that controls the circulation of the ink in the ink circulation system 40a. The ink circulation control unit 101 includes a circulation control unit 101a and a stop control unit 101b. The circulation control unit 101a controls the upstream pump 44 and the downstream pump 46 to circulate the ink and control the ink pressure in the ink head 42 to a predetermined pressure. The circulation control unit 101a controls the drive of the upstream pump 44 based on the signal from the photo sensor 45e, and controls the upstream ink pressure within a predetermined pressure range. Further, the circulation control unit 101a controls the driving of the downstream pump 46 based on the signal from the photo sensor 47e, and controls the downstream ink pressure within a predetermined pressure range. The details of the control are as described above. The circulation control unit 101a indirectly controls the ink pressure in the ink head 42 by controlling the upstream ink pressure and the downstream ink pressure.

  The stop control unit 101 b is a part that controls the operation of each unit when stopping the circulation of the ink in the circulation flow channel 43. The circulation of the ink is stopped, for example, when moving the installation place of the printer 10. The stop control unit 101b includes a stop time input unit 101c. The stop time input unit 101c receives a time from when a command to stop the circulation of ink is issued until the upstream pump 44 is stopped, and a time until the downstream pump 46 is stopped. The stop control unit 101b is communicably connected to the upstream pump 44 and the downstream pump 46, and controls their movement. Details of control at the time of circulation stop will be described later.

  The print control unit 102 is a part that controls printing of an image on the recording medium 5. The print control unit 102 causes ink to be ejected from the nozzles 42 a to drive printing while driving the carriage motor 24. The recording medium 5 is fixed at one position in the sub scanning direction X, and in this state, the carriage 25 reciprocates in the main scanning direction Y one or more times to perform printing. When printing is completed at the position of the one sub scanning direction X, the print control unit 102 drives the feed motor 33 to send the recording medium 5 forward by a predetermined distance. The print control unit 102 prints an image on the recording medium 5 by repeating the above.

  The capping control unit 103 controls the capping system 60 to perform capping and cleaning of the ink head 42. At the time of printing standby, the capping control unit 103 drives the cap moving mechanism 62 to move the cap 61 upward, and causes the ink head 42 to attach the cap 61. Further, the capping control unit 103 drives the suction pump 63 to suction ink when the cap 61 is attached. Furthermore, the capping control unit 103 performs flushing in which the ink is ejected from the ink head 42 when the cap 61 is attached. By periodically performing the flushing, the discharge of the ink from the ink head 42 can be maintained in a good state.

  The discharge control unit 104 is a part that controls the discharge operation of air and ink from the air trap 48. The discharge control unit 104 is communicably connected to the circulation valve 49, the discharge valve 72, and the discharge pump 73 to control the operation thereof. During the discharge operation, the discharge control unit 104 closes the circulation valve 49 and opens the discharge valve 72. Further, at the time of discharge operation, the discharge control unit 104 drives the discharge pump 73 to send out air and ink from the air trap 48 toward the waste liquid tank 65.

(Process at the time of circulation stop)
Below, the process at the time of stopping circulation of the ink in the printer 10 which concerns on this embodiment is demonstrated. As described above, in the conventional ink supply system provided with the circulation flow path for circulating the ink, there is a problem that the ink pressure in the ink head is not necessarily within the appropriate pressure range and stopped at the time of the circulation stop. there were. The proper range of the ink pressure in the ink head is a pressure range in which the ink is held in the nozzle without at least the ink dripping from the nozzle and without the external air being sucked into the nozzle. The ink circulation system 40a according to the present embodiment is provided with two pumps, the upstream pump 44 and the downstream pump 46, in the circulation flow path 43 in order to cope with the problem when the circulation is stopped as described above. The stop control unit 101b controls the two pumps to stop.

  FIG. 7 is a schematic view showing a state in which the ink is circulated in the ink circulation system 40a according to the present embodiment. In FIG. 7, the pumps being driven and the valves that are open are hatched. Stopped pumps and closed valves are not hatched. 8A and 8B are schematic views showing two steps when stopping the circulation of the ink in the ink circulation system 40a according to the present embodiment. Of FIGS. 8A and 8B, FIG. 8A shows the first step and FIG. 8B shows the second step. That is, the ink circulation system 40a according to the present embodiment reaches the circulation stop state from the circulation state by reaching the state of FIG. 8B from the state of FIG. 7 through the state of FIG. 8A. FIG. 8B illustrates the circulation stop state. Also in FIGS. 8A and 8B, the driving pump and the open valve are hatched.

  As shown in FIG. 7, during the ink circulation, in the ink circulation system 40a, the upstream pump 44 and the downstream pump 46 are driven, and the circulation valve 49 is opened. As described above, in the ink circulation system 40a according to the present embodiment, the upstream pump 44 and the downstream pump 46 are controlled independently, and as a result, the ink pressure in the ink head 42 is maintained at an appropriate pressure. It is supposed to be The upstream ink pressure and the downstream ink pressure may be set arbitrarily as long as the pressure in the ink head 42 is maintained at an appropriate pressure, but as shown in FIG. 7, in one preferred example, the upstream side The ink pressure P1 is about 3 kPa, and the downstream ink pressure P2 is about −6 kPa. As described above, in the ink circulation system 40a according to the present embodiment, the upstream ink pressure P1 is controlled to a positive pressure. The downstream ink pressure P2 is controlled to a negative pressure. Note that since the upstream damper 45 and the downstream damper 47 according to the present embodiment are both located above the ink head 42, between the upstream ink pressure P1 = 3 kPa and the downstream ink pressure P2 = -6 kPa described above. The pressure difference includes the pressure difference due to the water head difference between the upstream damper 45 and the downstream damper 47. In the ink circulation system 40a according to the present embodiment, the ink pressure Ph in the ink head 42 is around the middle value between the upstream ink pressure P1 and the downstream ink pressure P2, so Ph = about -1.5 kPa. . The ink pressure Ph in the ink head 42 is within a pressure range in which the ink remains in the nozzle 42 a and the ink can be ejected immediately.

  When it is intended to stop the circulation from the ink circulation state shown in FIG. 7, the ink circulation system 40a according to the present embodiment first shifts to the state shown in FIG. 8A. As shown in FIG. 8A, in the first step of the circulation stop, the downstream pump 46 is stopped. At this time, the upstream pump 44 is driven, and the circulation valve 49 is open. Therefore, in the first step of the circulation stop, the ink circulates in the circulation flow path 43 only by the feed of the upstream pump 44. In one preferred embodiment, this state is continued for several seconds.

  After the state shown in FIG. 8A is continued for a predetermined time, the ink circulation system 40a shifts to the second step shown in FIG. 8B. In the second step, the upstream pump 44 is stopped. In the second step, all pumps related to the ink circulation system 40a (here, the upstream pump 44 and the downstream pump 46) are stopped. By stopping all the pumps, the state of the ink in the ink circulation system 40a is fixed as the final stop state. The two-stage stop shown in FIGS. 8A and 8B is different from a simple immediate stop (hereinafter referred to as a “simple stop”) in that the stop of the upstream pump 44 is for the stop of the downstream pump 46. It is a point delayed for a fixed time. In other words, it is a point that only the upstream pump 44 is driving for a fixed time. Here, “a simple stop” means a stop method in which the stop of the upstream pump 44 and the stop of the downstream pump 46 are simultaneously performed.

(In the case of a simple stop)
FIG. 9 is a schematic view showing the ink circulation system 40a in the case where it is simply stopped from the circulation state shown in FIG. As shown in FIG. 9, in the ink circulation system 40a according to the present embodiment, when the circulation of ink is simply stopped, for example, the ink is drawn into the ink head 42 from the nozzle 42a together with the external air, and the upstream damper The upstream ink pressure P1 in 45, the downstream ink pressure P2 in the downstream damper 47, and the ink pressure Ph in the ink head 42 finally converge to a negative pressure of about -3 kPa. However, this numerical value is one example, and the upstream ink pressure P1 after the simple stop, the downstream ink pressure P2, and the ink pressure Ph in the ink head 42 depend on the configuration and setting of the ink circulation system 40a. . Since the ink is stationary in the state of FIG. 9, the upstream ink pressure P1, the downstream ink pressure P2, and the ink pressure Ph in the ink head 42 have the same pressure. The ink pressure Ph is a pressure lower than the allowable pressure range in which the ink remains in the nozzle 42a.

  Whether the pressure of the ink in the ink head 42 rises or falls after the circulation is stopped depends on the amount of change in the amount of ink stored in the upstream damper 45 and the amount of ink stored in the downstream damper 47. It relates to the magnitude relationship with the amount of change. According to the knowledge of the present inventors, if the amount of decrease of the ink in the storage chamber 45a of the upstream damper 45 is larger than the amount of the increase of the ink in the storage chamber 47a of the downstream damper 47, the circulation is stopped. The ink pressure Ph in the later ink head 42 rises more than during circulation. Conversely, if the increase in the ink in the storage chamber 47a of the downstream damper 47 is larger than the decrease in the ink in the storage chamber 45a of the upstream damper 45, the inside of the ink head 42 after the circulation stop is The ink pressure Ph drops more than during circulation. The case shown in FIG. 9 is the case where the change in the amount of ink in the storage chamber 47a of the downstream damper 47 is larger than the change in the amount of ink in the storage chamber 45a of the upstream damper 45. The ink pressure Ph in the ink head 42 after stopping is lower than that during circulation.

  Furthermore, the magnitude relationship between the amount of change in the amount of ink stored in the upstream damper 45 and the amount of change in the amount of ink stored in the downstream damper 47 before and after the circulation stop is the upstream ink pressure P1 during circulation. It relates to the magnitude relationship between the absolute value of and the absolute value of the downstream side ink pressure P2. The standard (that is, zero) of the absolute value of the ink pressure here is the atmospheric pressure. Therefore, for example, in the case of FIG. 7, the absolute value of the upstream ink pressure P1 is 3 kPa, and the absolute value of the downstream ink pressure P2 is 6 kPa. According to the findings of the present inventors, if the absolute value of the upstream ink pressure P1 during circulation is larger than the absolute value of the downstream ink pressure P2, the amount of reduction of the ink in the storage chamber 45a is Is larger than the increase amount of the ink in the storage chamber 47a. Therefore, the ink pressure Ph in the ink head 42 after the circulation is stopped is higher than that during the circulation. Conversely, when the absolute value of the downstream ink pressure P2 is larger than the absolute value of the upstream ink pressure P1, the amount of increase in the ink in the storage chamber 47a is the amount of decrease in the ink in the storage chamber 45a. It becomes bigger than. Therefore, the ink pressure Ph in the ink head 42 after the circulation is stopped drops more than during the circulation. The upstream ink pressure P1 and the downstream ink pressure P2 during circulation are the pressure characteristics of the ink head 42, the length and thickness of the circulation flow path 43, the characteristics of the upstream pump 44 and the downstream pump 46, the upstream damper It is determined in consideration of the flow path resistance between 45 and the ink head 42, the flow path resistance between the ink head 42 and the downstream side damper 47, and the like.

(Setting of delay time)
In the ink circulation system 40a according to the present embodiment, when the ink pressure in the ink head 42 after the simple stop deviates from the allowable pressure range, the delay time of the stop of the downstream pump 46 with respect to the stop of the upstream pump 44 or The delay time of the upstream pump 44 stop with respect to the stop of the pump 46 is adjusted. Specifically, when the ink circulation system 40a is simply stopped and the ink pressure in the ink head 42 after the stop exceeds the allowable pressure range, the stop of the downstream pump 46 is delayed with respect to the stop of the upstream pump 44. . Conversely, when the simple stop causes the ink pressure in the ink head 42 after the stop to fall below the allowable pressure range, the stop of the upstream pump 44 is delayed with respect to the stop of the downstream pump 46.

  FIG. 10 is a flowchart showing an example of the method of adjusting the delay time. Adjustment of the delay time is performed by repeating the process shown in FIG. In step S01 of FIG. 10, a time from the instruction to stop the circulation to stopping the upstream pump 44 (hereinafter referred to as a first time) and a time until stopping the downstream pump 46 (hereinafter referred to as the second). Each time is referred to as time) is set to an initial value. The initial value of the first time and the initial value of the second time are both 0, for example. However, the initial value of the first time and the initial value of the second time may be set to a time other than zero. Also, the initial value of the first time and the initial value of the second time may be set to different times.

  In the following steps S02 and S03, the ink is actually circulated in the ink circulation system 40a (step S02), and then the circulation is stopped (step S03). In step S03, the upstream pump 44 is stopped a first time after the instruction to stop the circulation. The downstream pump 46 is stopped a second time after the circulation stop command. In steps S04 and S05, it is determined whether the ink pressure in the ink head 42 after the circulation stop is within the allowable pressure range.

  In step S04, it is determined whether the ink protrudes to the outside of the ink head 42. If "YES" in the step S04, it is determined that the ink pressure in the ink head 42 after the circulation is stopped exceeds the allowable pressure range. In that case, the process proceeds to step S06. In step S06, the second time is changed to a time longer than the initial value. However, this is only one preferred method, and the second time may be extended relative to the first time in step S06. For example, in step S06, the first time may be shorter than the initial value if possible. Furthermore, both the extension of the second time and the shortening of the first time may be performed.

  If the step S04 is "NO", the step proceeds to the step S05, and it is determined whether the ink is drawn toward the inside of the ink head 42 or not. If "YES" in the step S05, it is determined that the ink pressure in the ink head 42 after the circulation stop is below the allowable pressure range, and the first time is set to be longer than the initial value in the step S07. Also in step S07, as in step S06, the second time may be shorter than the initial value, or both the extension of the first time and the shortening of the second time may be performed. When the process proceeds to any one of step S06 and step S07, the step returns to before step S02, and the ink circulation, the circulation stop, the confirmation of the ink pressure, and the adjustment of the first time or the second time are executed again. .

  When the step S05 is "NO", the ink does not protrude from the nozzle 42a, and the ink is not drawn into the ink head 42. In that case, it is determined that the ink pressure in the ink head 42 after the circulation stop is within the allowable pressure range. Therefore, the first time and the second time are both determined to be the values at that time.

  If the above steps are applied to the case shown in FIG. 9, for example, if the initial value of the first time and the initial value of the second time are the same time, the process proceeds from step S05 to step S07, and adjustment is performed. Is performed in the direction to extend the first time. The delay time of the upstream pump 44 stop with respect to the stop of the downstream pump 46 is, in this case, the time obtained by subtracting the second time from the first time, and the delay time is consequently extended in step S07. In addition, when the initial value of 1st time and 2nd time is not the same, adjustment may be performed by the step different from the above, and 1st time and 2nd time which are finally obtained differ. It can be a value. However, the delay times obtained are approximately the same value.

  Each step shown in FIG. 10 is typically a step performed by a developer at the time of development of the ink circulation system. In the same type of printer, the delay time is basically a common parameter. However, this does not exclude an embodiment in which the delay time is adjusted individually for each printer. It is not limited whether the adjustment of the delay time is performed for each model or for each aircraft.

  Also, in the present embodiment, as shown in steps S04 and S05, the ink pressure in the ink head 42 after the circulation stop is estimated by the state of the ink in the nozzle 42a, but such a method A special measuring device for measuring the ink pressure in 42 is unnecessary and simple. Also, the results are direct and reliable.

  The first time and the second time determined as described above are input to the stop time input unit 101c of the stop control unit 101b and registered. The stop control unit 101b stops the upstream pump 44 at the first time input to the stop time input unit 101c. The downstream pump 46 is stopped at the second time input to the stop time input unit 101c.

  In the present embodiment, the first time and the second time are determined based on whether the ink protrudes from the nozzle 42a (step S04) and whether the ink is drawn into the ink head 42 (step S05). Although the necessity of the adjustment of is determined, it is not necessary to necessarily depend on such a criterion. The above two criteria are respectively the upper limit and the lower limit in the allowable pressure range, and they do not disturb the setting of the more stringent criteria. The target value of the ink pressure in the ink head may be arbitrarily set as long as it is within the allowable pressure range. For example, the ink does not drip from the nozzle 42a but is positioned below the fixed position of the nozzle 42a, or the ink is not drawn into the ink head 42 but positioned above the fixed position of the nozzle 42a. The state or the like may be determined to be out of the proper pressure range (= pressure range requiring adjustment).

(Effect of two-step stop)
In the ink circulation system 40a in which the first time and the second time are set as described above, the state shown in FIG. 8A corresponds to the delay time (here, delay time = first time--) during the process of stopping circulation. Continue for the second time). In the state shown in FIG. 8A, the upstream pump 44 is operating and continues to supply the ink into the ink head 42. On the other hand, the downstream pump 46 is stopped, and the return of the ink from the ink head 42 is stopped. Therefore, as compared with the case where the first time and the second time are set equal to each other in the ink head 42, the ink is additionally supplied by an amount corresponding to the delay time. Thus, during the delay time, the pressure of the ink in the ink head 42 rises and eventually converges within the allowable pressure range. For example, in one preferable example, as shown in FIG. 8B, the upstream ink pressure P1, the downstream ink pressure P2, and the ink pressure Ph in the ink head 42 converge to −1 kPa. Conversely, the first time and the second time are times set such that the pressure Ph of the ink in the ink head 42 converges at least within the allowable pressure range.

  Contrary to the above embodiment, in the ink circulation system in which the ink pressure in the ink head 42 exceeds the allowable pressure range when the simple stop is performed, the second time is set longer than the first time, and the ink head 42 is Increase the flow of ink from the ink by the delay time. Therefore, during the delay time, the pressure of the ink in the ink head 42 drops and eventually converges within the allowable pressure range.

  In the ink circulation system 40a according to the present embodiment, the decrease in the amount of ink in the storage chamber 45a of the upstream damper 45 when the simple stop occurs increases the amount of ink in the storage chamber 47a of the downstream damper 47. If the amount is larger than the amount, the ink pressure Ph in the ink head 42 after the circulation is stopped increases. Therefore, if the second time is set to be longer than the first time so as to cancel it, the rise of the ink pressure Ph in the ink head 42 at the time of the circulation stop can be suppressed smaller than in the case of the simple stop. As a result, the ink pressure Ph in the ink head 42 can be converged within the allowable pressure range. Conversely, when the increase in the amount of ink in the storage chamber 47a of the downstream damper 47 when the simple stop is larger than the decrease in the amount of ink in the storage chamber 45a of the upstream damper 45, the circulation stop is performed. The ink pressure Ph in the later ink head 42 drops. Therefore, if the first time is set to be longer than the second time so as to cancel it, the drop of the ink pressure Ph in the ink head 42 at the time of the circulation stop can be suppressed smaller than in the case of the simple stop. The ink pressure Ph in the ink head 42 can be converged within the allowable pressure range.

  Furthermore, according to the findings of the present inventors, the decrease in the amount of ink in the storage chamber 45a of the upstream damper 45 and the increase in the amount of ink in the storage chamber 47a of the downstream damper 47 when the simple stop is performed. Is the same as the magnitude relationship between the absolute value of the upstream ink pressure P1 and the absolute value of the downstream ink pressure P2 during circulation. That is, if the absolute value of the upstream ink pressure P1 at the time of circulation is larger than the absolute value of the downstream ink pressure P2, the amount of reduction of the amount of ink in the storage chamber 45a of the upstream damper 45 is stored in the downstream damper 47. It becomes larger than the increase amount of the amount of ink in the chamber 47a, and the ink pressure Ph in the ink head 42 after the circulation is stopped increases. If the absolute value of the downstream ink pressure P2 is larger than the absolute value of the upstream ink pressure P1, the amount of increase in the amount of ink in the reservoir chamber 47a of the downstream damper 47 is the ink in the reservoir chamber 45a of the upstream damper 45 The ink pressure Ph in the ink head 42 after the circulation is stopped decreases. Therefore, when the absolute value of the upstream ink pressure P1 is set larger than the absolute value of the downstream ink pressure P2, the second time is set longer than the first time. If the absolute value of the downstream ink pressure P2 is set larger than the absolute value of the upstream ink pressure P1, the first time is set longer than the second time. By setting in this manner, the ink pressure in the ink head 42 after the circulation stop can be converged within the allowable pressure range.

  Furthermore, as described above, the method of adjusting the ink pressure Ph in the ink head 42 after the circulation stop by the two-step stop within the allowable pressure range is the ink pressure in the ink head 42 within the allowable pressure range at the simple stop. It is much easier than letting it converge. In order to make the ink pressure in the ink head 42 converge within the allowable pressure range in the simple stop, it is necessary to consider the configuration of the circulation channel 43 and the characteristics of the pump, etc., and the adjustment is very complicated. Conceivable. Also, it is not always adjustable. However, according to the above-described two-stage stop, the ink in the ink head 42 after the circulation is stopped is almost any ink circulation system provided with pumps on the upstream side and the downstream side of the ink head. The pressure can be adjusted within the desired pressure range within the allowable pressure range.

(Fine adjustment by the type of ink)
The stop times of the upstream pump 44 and the downstream pump 46 may be set to the same value in all the ink circulation systems 40 a of one printer 10 or may be set to different values. The printer 10 according to the present embodiment includes eight ink circulation systems 40 a and ejects a plurality of types of ink. Therefore, the stop times of the upstream pump 44 and the downstream pump 46 may be set for each type of ink, for example. According to the findings of the inventor of the present invention, when the other conditions are the same, the higher the viscosity of the circulating ink, the longer the suitable delay time tends to be. Therefore, the delay time may be set long in the ink circulation system 40a for circulating the high viscosity ink, and may be set short in the ink circulation system 40a for circulating the low viscosity ink.

  The preferred embodiment of the present invention has been described above. However, the above-described embodiments are merely illustrative, and the present invention can be embodied in other various forms.

  For example, in the above-described embodiment, the ink pressure in the ink head after the circulation stop is estimated based on the state of the ink in the nozzles, but may be measured directly by a pressure sensor or the like. The method of checking the ink pressure in the ink head is not limited in the parameter setting of the ink circulation system.

  Further, in the above-described embodiment, the ink pressures in the upstream damper and the downstream damper are respectively detected by the photosensors, but the invention is not limited thereto. For example, the upstream damper and the downstream damper may each be provided with a pressure sensor of an actual measurement method. Moreover, those outputs may not be ON / OFF signals which a photo sensor emits, for example, may be an analog output.

  In the above-described embodiment, the method of discharging the ink is a so-called piezo drive method, but the ink discharge method is not limited. As the ink discharge method of the printer, for example, various continuous methods such as binary deflection method or continuous deflection method, and various on-demand methods such as thermal method can be used. The ink supply system is also not limited to the above-described configuration, and members such as valves may be added or changed as needed, or members may be deleted. Further, the configuration of the printer is not limited to the above-described configuration, and the technology disclosed herein can be applied to various printers such as a line head method and a flat bed method.

  Furthermore, the technology disclosed herein can be applied not only to inkjet printers, but also to various devices equipped with an ink circulation system. For example, the technology disclosed herein is also applicable to a binder jet type three-dimensional modeling apparatus and the like. Also, the printer is not limited to one used alone as an independent printer, and may be combined with another device. For example, the printer may be a print and cut device or the like provided with a cutting device.

10 Printer (ink jet printer)
40a Ink circulation system 42 Ink head 42a Nozzle 44 Upstream pump (first pump)
45 upstream damper (first damper)
45a Reservoir (First Reservoir)
45e Photo sensor (1st pressure sensor)
46 downstream pump (second pump)
47 downstream damper (second damper)
47a Reservoir (Second Reservoir)
47e Photo sensor (second pressure sensor)
100 control device 101a circulation control unit 101b stop control unit 101c stop time input unit (input unit)
P1 Upstream ink pressure P2 Downstream ink pressure Ph Ink pressure in the ink head

Claims (11)

An annular circulation channel through which the ink is circulated;
An ink head having a nozzle from which the ink is ejected, and provided in the circulation channel;
A first pump provided in the circulation channel and delivering the ink to the ink head;
A second pump provided in the circulation channel and recovering the ink from the ink head;
A controller communicably connected to the first pump and the second pump;
Equipped with
The controller is
A circulation control unit that controls the first pump and the second pump to circulate the ink in the circulation flow path and adjust the pressure of the ink in the ink head;
A stop control unit for stopping the circulation;
Equipped with
The stop control unit is set to stop the first pump after a first time and stop the second pump after a second time when stopping the circulation.
The first time and the second time are set such that the pressure of the ink in the ink head after the circulation is stopped converges within a predetermined first pressure range.
The first pressure range is a pressure range in which the ink does not get drawn into the ink head and does not protrude from the nozzle.
Ink circulation system. If the time when the first pump is stopped and the time when the second pump is stopped are set equal, the pressure of the ink in the ink head after the circulation is stopped exceeds the first pressure range. An ink circulation system configured to
The second time is set to a time longer than the first time,
The ink circulation system according to claim 1. A first damper provided between the first pump and the ink head in the circulation flow path, the first damper comprising a first storage chamber for storing the ink;
A second damper provided between the ink head of the circulation flow path and the second pump and including a second storage chamber for storing the ink;
A first pressure sensor provided in the first damper for detecting the pressure of the ink in the first storage chamber;
A second pressure sensor provided in the second damper for detecting the pressure of the ink in the second storage chamber;
Equipped with
The circulation control unit controls the first pump to maintain the pressure of the ink in the first storage chamber at a predetermined first pressure based on the detection result of the first pressure sensor, and the second pressure The second pump is controlled to maintain the pressure of the ink in the second storage chamber at a predetermined second pressure based on the detection result of a sensor.
The absolute value of the first pressure is greater than the absolute value of the second pressure,
The ink circulation system according to claim 2. In the first reservoir, when the time when the first pump is stopped and the time when the second pump is stopped are set equal, the circulation is stopped and then the ink in the ink head is stopped. The amount of stored ink decreases by the first volume until the pressure converges,
In the second reservoir, when the time when the first pump is stopped and the time when the second pump is stopped are set equal, the circulation is stopped and then the ink in the ink head is stopped. Until the pressure converges, the ink storage amount increases by a second volume smaller than the first volume,
The ink circulation system according to claim 3. If the time when the first pump is stopped and the time when the second pump is stopped are set equal, the pressure of the ink in the ink head after the circulation is stopped falls below the first pressure range. An ink circulation system configured to
The first time is set to be longer than the second time,
The ink circulation system according to claim 1. A first damper provided between the first pump and the ink head in the circulation flow path, the first damper comprising a first storage chamber for storing the ink;
A second damper provided between the ink head of the circulation flow path and the second pump and including a second storage chamber for storing the ink;
A first pressure sensor provided in the first damper for detecting the pressure of the ink in the first storage chamber;
A second pressure sensor provided in the second damper for detecting the pressure of the ink in the second storage chamber;
Equipped with
The circulation control unit controls the first pump to maintain the pressure of the ink in the first storage chamber at a predetermined first pressure based on the detection result of the first pressure sensor, and the second pressure The second pump is controlled to maintain the pressure of the ink in the second storage chamber at a predetermined second pressure based on the detection result of a sensor.
The absolute value of the second pressure is greater than the absolute value of the first pressure,
The ink circulation system according to claim 5. In the first reservoir, when the time when the first pump is stopped and the time when the second pump is stopped are set equal, the circulation is stopped and then the ink in the ink head is stopped. The amount of stored ink decreases by the first volume until the pressure converges,
In the second reservoir, when the time when the first pump is stopped and the time when the second pump is stopped are set equal, the circulation is stopped and then the ink in the ink head is stopped. Until the pressure converges, the ink storage amount increases by a second volume that is larger than the first volume,
The ink circulation system according to claim 6. The stop control unit includes an input unit to which the first time and the second time are input.
The ink circulation system according to any one of claims 1 to 7. The ink circulation system according to any one of claims 1 to 8.
Inkjet printer. An annular circulation flow channel through which the ink is circulated, an ink head having a nozzle through which the ink is ejected, an ink head provided in the circulation flow channel, and the ink flow is provided in the circulation flow channel and the ink head A method for setting parameters for stopping circulation of ink in an ink circulation system comprising a first pump, and a second pump provided in the circulation flow path and recovering the ink from the ink head. ,
The parameters include a time for stopping the first pump and a time for stopping the second pump,
A first step of checking the pressure of the ink in the ink head after stopping the first pump after a first time and stopping the second pump after a second time;
When the pressure of the ink in the ink head confirmed in the first step exceeds a predetermined first pressure range, the second time is extended relative to the first time, and the first step And a second step of extending the first time relative to the second time if the pressure of the ink in the ink head confirmed at the point below the first pressure range.
Including
The first pressure range is a pressure range in which the ink does not get drawn into the ink head and does not protrude from the nozzle.
Parameter setting method of ink circulation system. In the first step, the pressure of the ink in the ink head is confirmed based on the state of the ink at the nozzle,
When the ink protrudes from the nozzle, it is determined that the pressure of the ink in the ink head exceeds the first pressure range,
When the ink is drawn into the ink head, it is determined that the pressure of the ink in the ink head is lower than the first pressure range.
The parameter setting method of the ink circulation system according to claim 10.

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