Inkjet printer

Abstract

To stir ink in an ink container.SOLUTION: An inkjet printer includes an ink container 61 storing ink, an ink head for discharging ink, an ink flow channel 62 for connecting the ink container 61 and the ink head, and a stirring device 80 for stirring the ink in the ink container 61. The ink container 61 includes a cylindrical side face extending in a vertical direction. The stirring device 80 includes a heater 81 for heating a part 61R in a circumferential direction out of side faces of the ink container 61 from outside, and a control device 84 for controlling the heater 81 so as to repeat activation and stop.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an inkjet printer. [Background technology]

[0002] Inkjet printers that print by ejecting ink from an ink head have been known for some time. For example, Patent Document 1 discloses an inkjet printer that includes an ink cartridge that stores ink, an ink head that ejects ink, an ink flow path that connects the ink cartridge and the ink head, and a liquid feed pump that sends ink through the ink flow path. The inkjet printer described in Patent Document 1 includes a circulation flow path that circulates the ink in the ink flow path. The inkjet printer described in Patent Document 1 is configured to circulate the ink within the circulation flow path by driving the liquid feed pump. As a result, the inkjet printer described in Patent Document 1 suppresses or eliminates pigment sedimentation in inks that are prone to pigment sedimentation, such as white ink. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-081945 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the inkjet printer described in Patent Document 1, the ink in the ink flow path can be agitated by circulating the ink in the circulation flow path. However, in this type of inkjet printer, the ink in the ink cartridge is not agitated.

[0005] SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide an inkjet printer that can agitate ink in an ink container. [Means for solving the problem]

[0006] The inkjet printer disclosed herein includes an ink container containing ink, an ink head from which the ink is ejected, an ink flow path connecting the ink container and the ink head, and an agitator for agitating the ink in the ink container. The ink container has a cylindrical side surface extending in the vertical direction. The agitator includes a heater that heats a portion of the side surface of the ink container along the circumferential direction from the outside, and a control device that controls the heater to repeatedly activate and deactivate.

[0007] In the inkjet printer, the agitator heats a portion of the side of the ink container with a heater. This creates a temperature difference between the ink near the heated portion of the side and the ink near the unheated portion, causing convection. This convection agitates the ink. By stopping the heater to lower the ink temperature and then heating the ink again, ink convection is repeatedly generated. This causes the ink to be repeatedly agitated, and the agitated state of the ink continues. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a front view of a printer according to an embodiment. [Figure 2] FIG. 2 is a schematic diagram illustrating a configuration of an ink supply system. [Figure 3] FIG. 2 is a schematic front view of a cartridge holder and a stirring device. [Figure 4] FIG. 2 is a schematic, partially cutaway side view of a cartridge holder and a stirring device. [Figure 5] 10 is a time chart showing the ON / OFF of a heater, the ON / OFF of a cooling device, and the change in measured temperature over time. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Inkjet printer configuration] An inkjet printer according to one embodiment will be described below with reference to the drawings. It should be noted that the embodiment described here is not intended to limit the present invention. Furthermore, the same reference numerals are used to designate components and parts that perform the same functions, and redundant descriptions will be omitted or simplified as appropriate. In the following description, when viewing the inkjet printer from the front, the side away from the inkjet printer is referred to as the front, and the side approaching the inkjet printer is referred to as the rear. Furthermore, the reference numerals F, Rr, L, R, U, and D in the drawings represent the front, rear, left, right, top, and bottom, respectively. However, these directions are merely provided for the convenience of explanation and do not limit the installation manner of the inkjet printer, etc.

[0010] 1 is a front view of a large-format inkjet printer (hereinafter referred to as "printer") 10 according to one embodiment. The printer 10 prints an image on the recording medium 5 by moving a roll-shaped recording medium 5 in the front-to-rear direction and ejecting ink from an ink head 50 mounted on a carriage 20 that moves in the left-to-right direction.

[0011] The recording medium 5 is an object onto which an image is printed. There are no particular limitations on the recording medium 5. For example, the recording medium 5 may be paper such as plain paper or inkjet printing paper, or may be a transparent sheet made of resin or glass. The recording medium 5 may also be a sheet made of metal or rubber. It may also be fabric.

[0012] As shown in FIG. 1, the printer 10 includes a platen 12, a carriage 20, a carriage moving device 30, a transport device 40, an ink head 50, and an ink supply system 60.

[0013] The carriage moving device 30 moves the carriage 20 left and right, thereby moving the ink head 50 mounted on the carriage 20 left and right. The carriage moving device 30 includes a guide rail 31, a belt 32, left and right pulleys 33a and 33b, and a carriage motor 34. The carriage 20 is slidably engaged with the guide rail 31. The guide rail 31 extends left and right. The guide rail 31 guides the left and right movement of the carriage 20. The belt 32 is fixed to the carriage 20. The belt 32 is an endless belt. The belt 32 is wound around a pulley 33a on the right side of the guide rail 31 and a pulley 33b on the left side. A carriage motor 34 is attached to the right pulley 33a. When the carriage motor 34 is driven, the pulley 33a rotates, causing the belt 32 to run. As a result, the carriage 20 moves left and right along the guide rail 31 .

[0014] The platen 12 supports the recording medium 5. The recording medium 5 on the platen 12 is moved in the front-to-rear direction by a conveying device 40. The conveying device 40 includes a pinch roller 41, a grit roller 42, and a feed motor 43. The pinch roller 41 is provided above the platen 12 and presses down on the recording medium 5 from above. The pinch roller 41 is located behind the carriage 20. The platen 12 is provided with a grit roller 42. The grit roller 42 is located below the pinch roller 41. The grit roller 42 is located in a position facing the pinch roller 41. The grit roller 42 is connected to the feed motor 43. The grit roller 42 is formed to be rotatable by receiving a driving force from the feed motor 43. When the grit roller 42 rotates with the recording medium 5 sandwiched between the pinch roller 41 and the grit roller 42, the recording medium 5 is conveyed in the front-to-rear direction.

[0015] A plurality of ink heads 50 are provided on the underside of the carriage 20. The ink heads 50 are configured to eject ink. The plurality of ink heads 50 are arranged side by side in the left-right direction on the carriage 20. A nozzle row 51 is formed on the underside of each of the plurality of ink heads 50 (see FIG. 2). The nozzle row 51 is made up of a plurality of nozzles 52 arranged in the front-to-rear direction. The nozzles 52 are minute holes through which ink is ejected. In this example, the ink head 50 is a piezo-driven inkjet head. However, the method by which the ink head 50 ejects ink is not limited to the piezo-driven method, and may be, for example, a thermal method.

[0016] As shown in FIG. 1, ink is supplied to the ink head 50 by an ink supply system 60. FIG. 2 is a schematic diagram showing the configuration of the ink supply system 60. In this embodiment, an ink supply system 60 is provided for each nozzle row 51. As shown in FIG. 2, each ink supply system 60 includes an ink cartridge 61, an ink flow path 62, a main valve 63, a bypass valve 64, a liquid feed pump 65, and a damper 66. However, details of all but one ink supply system 60 are omitted in FIG. 2.

[0017] The ink cartridge 61 is an example of an ink container that contains ink. One ink cartridge 61 stores, for example, one of a process color ink and a spot color ink. In this embodiment, the multiple types of ink include white ink. White ink is a pigment ink in which a white pigment is dispersed in a solvent. White ink is an example of an ink in which the pigment is prone to settling. If white ink is left as is, the white pigment will settle, making it impossible to form a white image with the desired density. Therefore, it is preferable to stir the white ink periodically or as needed. However, the ink material is not particularly limited. The ink may be, for example, a solvent-based pigment ink or an aqueous pigment ink. Alternatively, it may be an aqueous dye ink or an ultraviolet-curable pigment ink that hardens when exposed to ultraviolet light.

[0018] As shown in FIG. 1, the ink cartridge 61 is held by a cartridge holder 70. Here, the ink cartridge 61 is inserted into the cartridge holder 70 from the front side toward the rear side of the printer 10. However, the insertion and removal direction (insertion and removal direction) of the ink cartridge 61 is not limited to the front-to-rear direction. As shown in FIG. 2, the printer 10 according to this embodiment is equipped with an agitator 80 that agitates the ink in the ink cartridge 61 while it is held by the cartridge holder 70. The agitator 80 agitates the ink in the ink cartridge 61 by heating and cooling the ink in the ink cartridge 61 via the cartridge holder 70. The configurations of the cartridge holder 70 and the agitator 80 will be described later.

[0019] The ink flow path 62 connects the ink cartridge 61 and the ink head 50. Ink is supplied from the ink cartridge 61 to the ink head 50 through the ink flow path 62. The configuration of the ink flow path 62 is not limited, but may include, for example, a flexible tube.

[0020] In this embodiment, the ink flow path 62 includes a circulation flow path 62a for circulating ink. As shown in Fig. 2, the ink flow path 62 includes an annular circulation flow path 62a, an upstream flow path 62b having one end connected to the ink cartridge 61 and the other end connected to the circulation flow path 62a, and a downstream flow path 62c having one end connected to the circulation flow path 62a and the other end connected to the ink head 50 via a damper 66. The circulation flow path 62a branches off at a connection with the upstream flow path 62b and includes a main flow path 62d and a bypass flow path 62e that merge at a connection with the downstream flow path 62c.

[0021] The main valve 63 is provided in the upstream flow path 62b. The main valve 63 opens and closes the upstream flow path 62b. The bypass valve 64 is provided in the bypass flow path 62e. The bypass valve 64 opens and closes the bypass flow path 62e. The main valve 63 and the bypass valve 64 are, for example, solenoid valves. However, the types of the main valve 63 and the bypass valve 64 are not limited, and they may be, for example, air-driven valves.

[0022] The liquid feed pump 65 is provided in the main flow path 62d. When driven, the liquid feed pump 65 feeds ink in the direction from the ink cartridge 61 toward the ink head 50. In this embodiment, the liquid feed pump 65 is a tube pump. However, the type of the liquid feed pump 65 is not limited, and it may be, for example, a diaphragm pump.

[0023] The damper 66 is provided immediately before the ink head 50. The damper 66 is connected to the ink head 50 and the downstream flow path 62c. The damper 66 has a storage chamber 66a in which ink is temporarily stored. The damper 66 reduces fluctuations in ink pressure by temporarily storing ink in the storage chamber 66a. The damper 66 has a pressure sensor 66b that detects the ink pressure in the storage chamber 66a. The configuration of the pressure sensor 66b is not limited. The pressure sensor 66b may be a sensor that directly measures the ink pressure, or may be a sensor that detects the ink pressure by detecting the expansion and contraction of a flexible membrane that forms part of the wall surface of the storage chamber 66a, for example.

[0024] When ink is consumed by image formation or the like and the pressure detected by the pressure sensor 66b drops, the liquid feed pump 65 is driven and ink is supplied to the damper 66. When ink is supplied, the main valve 63 is opened and the bypass valve 64 is closed. When ink is circulated to suppress or eliminate pigment sedimentation, the main valve 63 is closed, the bypass valve 64 is opened, and the liquid feed pump 65 is driven.

[0025] [Configuration of the mixing device] The configuration of the agitator 80 will be described in detail below. The configurations of the ink cartridge 61 and cartridge holder 70 will also be described below. Figure 3 is a schematic front view of the cartridge holder 70 and the agitator 80. Figure 4 is a schematic, partially cutaway side view of the cartridge holder 70 and the agitator 80. As shown in Figures 3 and 4, the ink cartridge 61 includes a pouch 61a that contains ink, and a case 61b that houses the pouch 61a.

[0026] The pouch 61a is flexible and expands and contracts depending on the amount of ink remaining. The case 61b has a fixed shape. Here, the case 61b (ink cartridge 61) is configured as a flat, approximately rectangular parallelepiped. The case 61b (ink cartridge 61) has a bottom surface 61D, cylindrical side surfaces (consisting of a front surface 61F, a left side surface 61L, a right side surface 61R, and a rear surface 61Rr) connected to the bottom surface 61D and extending in the vertical direction, and a top surface 61U. The front surface 61F, the left side surface 61L, the right side surface 61R, and the rear surface 61Rr extend upward from the front end, left end, right end, and rear end of the bottom surface 61D, respectively. The top surface 61U is connected to the upper ends of the front surface 61F, the left side surface 61L, the right side surface 61R, and the rear surface 61Rr.

[0027] The left side surface 61L and the right side surface 61R are wide surfaces of the ink cartridge 61, defined by the longest side 61b1 and the second long side 61b2 of the ink cartridge 61. The other surfaces of the ink cartridge 61, namely the bottom surface 61D, the top surface 61U, the front surface 61F, and the back surface 61Rr, are narrow surfaces with areas smaller than the wide surfaces. The longest side 61b1 of the ink cartridge 61 extends in the insertion / removal direction of the ink cartridge 61 (the front-to-rear direction in this case). The second long side 61b2 of the ink cartridge 61 extends in the up-down direction. The shortest side 61b3 of the ink cartridge 61 extends in the left-to-right direction. The back surface of the case 61b is provided with an opening (not shown) through which a needle 72 (described below) of the cartridge holder 70 passes when the needle 72 is inserted into the pouch 61a.

[0028] The cartridge holder 70 is box-shaped with an open front. The cartridge holder 70 surrounds the ink cartridge 61 from above, below, left, right, and rear. The cartridge holder 70 has a bottom surface 70D, a top surface 70U, a left side surface 70L, a right side surface 70R, and a rear surface 70Rr. The left side surface 70L, the right side surface 70R, and the rear surface 70Rr extend upward from the left end, right end, and rear end of the bottom surface 70D, respectively. The top surface 70U is connected to the upper ends of the left side surface 70L, the right side surface 70R, and the rear surface 70Rr, and faces the bottom surface 70D. The top surface 70U and the left side surface 70L are provided with leaf springs 71U and 71L, respectively, that press the ink cartridge 61 inward. The ink cartridge 61 is pressed by the leaf springs 71U and 71L against the bottom surface 70D and right side surface 70R of the cartridge holder 70. This determines the position of the ink cartridge 61 in the cartridge holder 70 and holds the ink cartridge 61 in place.

[0029] The cartridge holder 70 is provided with a needle 72 that pierces the pouch 61a to connect the pouch 61a to the ink flow path 62. The needle 72 is provided on the rear surface 70Rr. The needle 72 is hollow. The ink flow path 62 is connected to the needle 72.

[0030] The agitation device 80 agitates the ink in the ink cartridge 61 by heating the ink in the ink cartridge 61. In this embodiment, the agitation device 80 includes a heater 81, a temperature sensor 82, a cooling device 83, and a control device 84.

[0031] The heater 81 heats a portion of the side surfaces 61F, 61L, 61R, and 61Rr of the ink cartridge 61 along the circumferential direction from the outside. In this embodiment, the heater 81 heats one of the side surfaces of the ink cartridge 61, in this case the right side surface 61R. More specifically, the heater 81 heats the right side surface 61R from its bottom to its top. The heater 81 heats almost the entire right side surface 61R. Here, the "bottom end" of the right side surface 61R refers to an area that can be considered substantially the bottom end, for example, a range from the lowest point of the right side surface 61R to within 10% of the entire height of the right side surface 61R. The "top end" of the right side surface 61R refers to an area that can be considered substantially the top end, for example, a range from the highest point of the right side surface 61R to within 10% of the entire height of the right side surface 61R. The side surface of the ink cartridge 61 that is heated is not limited to the right side surface 61R, but may be the front surface 61F, the left side surface 61L, or the rear surface 61Rr. The side surfaces of the ink cartridge 61 that are heated may be two or three of the front surface 61F, the left side surface 61L, the right side surface 61R, and the rear surface 61Rr.

[0032] In this embodiment, the heater 81 is provided so as to be in contact with the cartridge holder 70, and heats the ink cartridge 61 by heating the cartridge holder 70. More specifically, the heater 81 is provided so as to be in contact with the right side surface 70R of the cartridge holder 70, and heats the right side surface 70R. The ink cartridge 61 is placed against the right side surface 70R of the cartridge holder 70.

[0033] Here, the heater 81 is a surface heater provided so as to be in contact with the cartridge holder 70. However, the heater 81 is not limited to a surface heater and may be, for example, a wire heater or a hot air generator. In this embodiment, the front-to-rear and up-to-down lengths of the heater 81 are equal to or approximately equal to the front-to-rear and up-to-down lengths of the cartridge holder 70, respectively. The heater 81 is in contact with substantially the entire right side surface 70R of the cartridge holder 70.

[0034] The temperature sensor 82 measures the temperature of the location heated by the heater 81. In this example, the temperature sensor 82 is sandwiched between the heater 81 and the right side surface 70R of the cartridge holder 70. The temperature sensor 82 measures the surface temperature of the right side surface 70R of the cartridge holder 70. The type of the temperature sensor 82 is not particularly limited. The temperature sensor 82 may be, for example, a thermistor or a thermocouple. The temperature sensor 82 is configured to transmit a signal when the measured temperature reaches a predetermined upper limit temperature T1 (see FIG. 5) and when it falls below a predetermined heating start temperature T2 (see FIG. 5). However, the type of signal transmitted by the temperature sensor 82 is not particularly limited as long as it can determine whether the measured temperature is equal to or higher than the upper limit temperature T1 and whether it is below the predetermined heating start temperature T2. The temperature sensor 82 may be configured to transmit, for example, an analog signal corresponding to the measured temperature.

[0035] The cooling device 83 cools the ink cartridges 61. The cooling device 83 cools the cartridge holder 70, the ink cartridges 61, and the ink inside the ink cartridges 61 that have been heated by the heater 81, and ensures that the heater 81 reheats these components as scheduled. Here, the cooling device 83 is equipped with a blower fan 83a. The blower fan 83a cools the surface opposite the surface heated by the heater 81 by blowing air onto it. Here, the blower fan 83a is positioned to face the left side surface 70L of the cartridge holder 70, and blows air onto the left side surface 70L. However, the cooling device 83 is not limited to being equipped with a blower fan 83a. The cooling device 83 may also be equipped with, for example, a Peltier element. A Peltier element is a semiconductor element that changes the direction of heat transfer depending on the direction of current flow. By attaching a Peltier element to the left side surface 70L of the cartridge holder 70 and passing an electric current through the Peltier element so that heat moves from the surface in contact with the left side surface 70L to the back surface, the left side surface 70L of the cartridge holder 70, the left side surface of the ink cartridge 61, and the ink near the left side surface of the ink cartridge 61 can be cooled.

[0036] The control device 84 controls the heater 81 to repeatedly activate and deactivate. The control device 84 also controls the cooling device 83 when cooling the ink. The control device 84 is connected to the heater 81, the cooling device 83, and the temperature sensor 82. The control device 84 manages the activation and deactivation of the heater 81 over time, and also controls the heater 81 based on the temperature measured by the temperature sensor 82. The control device 84 is independent of the control device of the printer 10 that controls the ink head 50 and other components. In this embodiment, the control device 84 includes a circuit that controls the activation and deactivation of the heater 81, a circuit that controls the activation and deactivation of the cooling device 83, a circuit that receives signals from the temperature sensor 82, and a circuit that interrupts the control of the heater 81 based on the temperature measured by the temperature sensor 82. However, the configuration of the control device 84 is not limited to this. The control device 84 may include, for example, a microcomputer. The control device 84 may be part of the control device of the printer 10.

[0037] As shown in FIG. 4, the control device 84 includes a first control unit 84a, a second control unit 84b, and a third control unit 84c. The first control unit 84a repeatedly operates the heater 81 for a predetermined heating time TP1 and stops the heater 81 for a predetermined cooling time TP2. Control by the first control unit 84a is the main control of the heater 81. The second control unit 84b stops the heater 81 when the temperature measured by the temperature sensor 82 reaches a predetermined upper limit temperature T1 (see FIG. 5). Control by the second control unit 84b takes precedence over the main control by the first control unit 84a. After the predetermined heating time TP1 has elapsed and the heater 81 is stopped, the third control unit 84c stops the heater 81 until the temperature measured by the temperature sensor 82 drops below a predetermined heating start temperature T2. Control by the third control unit 84c takes precedence over the main control by the first control unit 84a.

[0038] [Agitator operation] The operation of the stirring device 80 according to this embodiment will be described below. FIG. 5 is a time chart showing the ON / OFF of the heater 81, the ON / OFF of the cooling device 83, and the change over time in the measured temperature. The upper diagram in FIG. 5 shows the ON / OFF time chart of the heater 81. The diagram in the vertical center of FIG. 5 shows the ON / OFF time chart of the cooling device 83. The lower diagram in FIG. 5 shows the time chart of the temperature measured by the temperature sensor 82. The horizontal axis in FIG. 5 is time. The vertical axis in the upper diagram in FIG. 5 is the ON / OFF of the heater 81. The vertical axis in the center diagram in FIG. 5 is the ON / OFF of the cooling device 83. The vertical axis in the lower diagram in FIG. 5 is the temperature measured by the temperature sensor 82.

[0039] As shown in the main control state S1 on the left side of Fig. 5, when only the main control is active, the heater 81 is turned on for a predetermined heating time TP1 and turned off for a predetermined cooling time TP2, and this is repeated (Fig. 5 shows only one ON / OFF cycle). Also, the cooling device 83 is turned on during the cooling time TP2.

[0040] When the heater 81 is driven, the ink in the right portion of the ink cartridge 61 is heated. The heated ink generates an upward flow F1, as shown in FIG. 3. The upward flow F1 bends to the left at the ink surface, generating a downward flow F2 along the left side of the ink cartridge 61. This generates ink convection within the ink cartridge 61. The pigment in the ink attempts to settle to the bottom of the ink cartridge 61. The pigment that is attempting to settle or has settled is stirred up by the ink convection and dispersed within the ink. This agitates the ink. At this time, the right side 70R of the cartridge holder 70, which is in contact with the ink cartridge 61, is heated, so the ink is heated more efficiently. According to experiments by the inventors of the present application, more convection is generated when only one side of the ink cartridge 61 (the left or right side, or the front or rear side) is heated than when only the bottom of the ink cartridge 61 is heated. This is because even if only the lower part of the ink cartridge 61 is heated, the ink cools down as it rises in an upward flow.

[0041] When the entire ink is heated, convection ceases to occur, so after the heating time TP1 has elapsed, the heater 81 is turned off and the cooling device 83 is turned on. At this time, the left side of the ink cartridge 61, through which the downward flow F2 mainly flows, is cooled via the left side surface 70L of the cartridge holder 70. Therefore, the ink convecting due to residual heat is gradually cooled.

[0042] When a predetermined cooling time TP2 has elapsed since the heater 81 was turned off, the cooling device 83 is turned off and the heater 81 is turned on again. In the case of main control, the heating and cooling of the ink described above is repeated.

[0043] Next, a case where temperature management control interrupts main control will be described. As shown in the upper limit temperature control state S2 in the center of FIG. 5, when the temperature measured by the temperature sensor 82 reaches a predetermined upper limit temperature T1, the agitator 80 stops the heater 81 even before the heating time TP1 has elapsed. The upper limit temperature T1 is based on the heat resistance temperature of the ink. The upper limit temperature T1 is preferably set to a temperature 10 to 20 degrees lower than the heat resistance temperature of the ink. The heat resistance temperature of the ink is, for example, 50 to 70 degrees, and in that case, the upper limit temperature T1 is, for example, 30 to 60 degrees. However, there are no particular limitations on the upper limit temperature T1 as long as it is equal to or lower than the heat resistance temperature of the ink.

[0044] The agitator 80 turns on the heater 81 again when the temperature measured by the temperature sensor 82 falls below the upper limit temperature T1. However, the agitator 80 may be configured to turn on the heater 81 when the temperature measured by the temperature sensor 82 falls below a predetermined temperature lower than the upper limit temperature T1. Alternatively, the agitator 80 may be configured to turn on the heater 81 a predetermined time after the temperature measured by the temperature sensor 82 falls below the upper limit temperature T1. In main control, the temperature of the heated ink is rapidly increased to generate stronger convection, so the output of the heater 81 is not controlled so that the measured temperature does not exceed the upper limit temperature T1. Therefore, for example, in an environment with a high ambient temperature, the temperature measured by the temperature sensor 82 may exceed the upper limit temperature T1. The upper limit temperature T1 is set so that even in such a case, the ink is not overheated to an excessively high temperature, causing deterioration.

[0045] Furthermore, as shown in the heating start temperature control state S3 on the right side of FIG. 5 , after the heating time TP1 has elapsed and the heater 81 has been stopped, the agitator 80 stops the heater 81 until the temperature measured by the temperature sensor 82 drops below a predetermined heating start temperature T2. The heating start temperature T2 is a threshold temperature at which reheating does not begin unless the measured temperature has dropped to at least that temperature. For example, in a high ambient temperature environment, as shown in FIG. 5 , the temperature measured by the temperature sensor 82 may exceed the heating start temperature T2 even after the cooling time TP2 has elapsed. The heating start temperature T2 is a threshold set to ensure the upper limit temperature at which reheating begins even in such cases, preventing ink convection from weakening with each repetition. As shown in FIG. 5 , once the cooling time TP2 has elapsed and the measured temperature has fallen below the heating start temperature T2, the heater 81 is turned on again.

[0046] [Effects of the embodiment] The following describes the effects that can be achieved by the printer 10 according to this embodiment.

[0047] The printer 10 according to this embodiment includes an ink cartridge 61 containing ink, an ink head 50 from which the ink is ejected, an ink flow path 62 connecting the ink cartridge 61 and the ink head 50, and an agitator 80 that agitates the ink in the ink cartridge 61. The ink cartridge 61 includes cylindrical side surfaces 61F, 61L, 61R, and 61Rr that extend vertically. The agitator 80 includes a heater 81 that externally heats a circumferential portion of the side surfaces 61F, 61L, 61R, and 61Rr of the ink cartridge 61 (here, the right side surface 61R), and a controller 84 that controls the heater 81 to repeatedly activate and deactivate.

[0048] According to this printer 10, the agitator 80 heats a portion of the sides 61F, 61L, 61R, and 61Rr of the ink cartridge 61 (here, the right side 61R) with the heater 81. This creates a temperature difference between the ink near the heated portion (here, the right side 61R) of the sides 61F, 61L, 61R, and 61Rr and the ink near the unheated portion, causing convection. This convection agitates the ink. By stopping the heater 81 to lower the ink temperature and then heating the ink again, ink convection is repeatedly generated. This causes the ink to be repeatedly agitated, and the agitated state of the ink continues.

[0049] In this embodiment, the ink cartridge 61 is configured as a flat, approximately rectangular parallelepiped. The heater 81 heats one of the wider sides (here, the right side 61R) of the ink cartridge 61: sides 61F, 61L, 61R, and 61Rr. With this configuration, convection occurs that swirls when viewed toward the narrow side. This makes the convection stronger. If convection were to occur that swirls when viewed toward the wide side, there would be too much unheated ink compared to the heated ink, and the convection would be weak.

[0050] In this embodiment, the heater 81 heats one side surface (here, the right side surface 61R) from the bottom to the top. As mentioned above, if only the bottom of the ink cartridge 61 is heated, the ink will cool as it rises, making it difficult for ink convection to occur. With this configuration, the ink will not cool as it rises, making it possible to generate a stronger convection.

[0051] The printer 10 according to this embodiment further includes a cartridge holder 70 that holds the ink cartridge 61. A heater 81 heats the cartridge holder 70. Since the ink cartridge 61 is replaced as the ink is consumed, it is difficult to provide a heater 81. However, with this configuration, the ink cartridge 61 can be heated indirectly via the cartridge holder 70.

[0052] In this embodiment, the heater 81 is a surface heater provided so as to be in contact with the cartridge holder 70. With this configuration, by surface-heating the cartridge holder 70, it is possible to surface-heat a desired range of the ink cartridge 61. In this embodiment, it is possible to surface-heat the entire right side surface 61R of the ink cartridge 61.

[0053] In this embodiment, the control device 84 includes a first control unit 84a that repeatedly operates the heater 81 for a predetermined heating time TP1 and stops the heater 81 for a predetermined cooling time TP2. With this configuration, ink convection can be generated by operating the heater 81 for the heating time TP1, and the ink can be cooled and prepared for reheating by stopping the heater 81 for the cooling time TP2. Furthermore, for the purpose of agitating the ink, it is not necessary to control the ink temperature with high precision. Therefore, the heating and cooling of the ink can be controlled by time, which is easier than, for example, controlling the temperature.

[0054] In this embodiment, the agitator 80 is equipped with a temperature sensor 82 that measures the temperature of a location heated by the heater 81. The control device 84 is equipped with a second control unit 84b that stops the heater 81 when the temperature measured by the temperature sensor 82 reaches a predetermined upper limit temperature T1. With this configuration, the heater 81 is stopped when the measured temperature reaches the upper limit temperature T1, preventing ink deterioration due to excessive temperature rise. The locations heated by the heater 81 may include the surfaces of the ink cartridges 61, the surface of the cartridge holder 70, and the heater 81. Therefore, the temperature sensor 82 may measure the surface temperature of the ink cartridges 61, the surface temperature of the cartridge holder 70, or the temperature of the heater 81.

[0055] The control device 84 includes a third control unit 84c that stops the heater 81 until the temperature measured by the temperature sensor 82 drops below a predetermined heating start temperature T2 after a predetermined heating time TP1 has elapsed and the heater 81 is stopped. With this configuration, the heater 81 is not reheated until the measured temperature drops below the heating start temperature T2, so even if the ink temperature is difficult to drop due to an external factor such as a high ambient temperature, the ink convection is prevented from weakening with each repetition.

[0056] In this embodiment, the stirring device 80 is equipped with a cooling device 83 that cools the ink cartridge 61. With this configuration, by cooling the ink in the ink cartridge 61, it is possible to reduce the number of cases where the heater 81 is unable to heat the ink at the scheduled time intervals, i.e., at the cooling time TP2 intervals. Note that if control by the third control unit 84c is not performed and, for example, the heating condition for the heater 81 is set to be that the measured temperature drops below the heating start temperature T2, the operation of the cooling device 83 can shorten the time interval between the ink heating / cooling cycles.

[0057] [Other embodiments] Although a preferred embodiment of the present invention has been described above, the above embodiment is merely an example, and the technology disclosed herein can be embodied in various other forms.

[0058] For example, in the above embodiment, the ink flow path 62 includes a circulation flow path 62a for preventing ink components from settling, but it is not necessary to include the circulation flow path 62a. Alternatively, the ink flow path 62 may include other components, such as a bubble separator. In the above embodiment, the ink container that stores the ink is the ink cartridge 61, but the ink container is not limited to the ink cartridge 61. The ink container may be, for example, a pouch that is not housed in a case, or a tank into which ink is replenished. In addition, the configuration of the ink supply system 60 is not limited to the above.

[0059] In the above embodiment, the agitator 80 is equipped with the cooling device 83, but it is not necessarily equipped with the cooling device 83. The part of the ink cartridge 61 that is cooled by the cooling device 83 is not limited to the surface opposite the surface heated by the heater 81. The part that is cooled by the cooling device 83 may be anywhere in the ink cartridge 61.

[0060] In the above embodiment, the heater 81 indirectly heats the ink cartridge 61 by heating the cartridge holder 70, but the heating method for the ink cartridge 61 is not limited to this. For example, the heater 81 may be provided in the cartridge holder 70 so as to abut against the ink cartridge 61 and directly heat the ink cartridge 61. The heater 81 is not limited to being a heater that abuts against an object to be heated and directly heats it, and may be configured to blow hot air onto the object to be heated, for example.

[0061] The portion of the ink cartridge 61 heated by the heater 81 is not particularly limited as long as it is a circumferential portion of the side surfaces 61F, 61L, 61R, and 61Rr of the ink cartridge 61. The portion of the ink cartridge 61 heated by the heater 81 may be, for example, a portion of any of the side surfaces 61F, 61L, 61R, and 61Rr of the ink cartridge 61. The portion of the ink cartridge 61 that is heated does not have to be the entire area from bottom to top in the vertical direction, as long as it is within a range that generates suitable ink convection.

[0062] The configuration of the inkjet printer is not limited unless otherwise specified. For example, the technology disclosed herein can be used in flatbed inkjet printers. It can also be used in devices that incorporate an inkjet printer, such as an inkjet printer with a cutting head. [Explanation of symbols]

[0063] 10 Printers 50 ink head 60 Ink supply system 61 Ink cartridges (ink containers) 62 Ink flow path 70 Cartridge holder (holder) 80 Stirring device 81 Heater 82 Temperature Sensor 83 Cooling device 84 Control device 84a First Control Section 84b Second control section 84c Third Control Section TP1 Heating time TP2 Cooling time T1 upper limit temperature T2 Heating start temperature

Claims

1. an ink container containing ink; an ink head from which ink is ejected; an ink flow path connecting the ink container and the ink head; an agitator that agitates the ink in the ink container, The ink container has a cylindrical side surface extending in a vertical direction, The stirring device is a heater that heats a portion of the side surface of the ink container along a circumferential direction from the outside; a control device that controls the heater to repeatedly activate and deactivate the heater; Inkjet printer.

2. the ink container is a flat, substantially rectangular parallelepiped ink cartridge, the heater heats one of the wider side surfaces of the ink container; 2. The inkjet printer according to claim 1.

3. The heater heats the one side surface from its lower end to its upper end.

3. The inkjet printer according to claim 2.

4. a holder for holding the ink container; The heater heats the holder.

2. The inkjet printer according to claim 1.

5. the heater is a surface heater provided in contact with the holder; 5. The inkjet printer according to claim 4.

6. The control device includes a first control unit that repeatedly operates the heater for a predetermined heating time and stops the heater for a predetermined cooling time.

2. The inkjet printer according to claim 1.

7. the stirring device includes a temperature sensor for measuring the temperature of a portion heated by the heater; The control device includes a second control unit that stops the heater when the temperature measured by the temperature sensor reaches a predetermined upper limit temperature.

7. The inkjet printer according to claim 6.

8. the stirring device includes a temperature sensor for measuring the temperature of a portion heated by the heater; The control device includes a third control unit that stops the heater after the predetermined heating time has elapsed and the heater is stopped, until the temperature measured by the temperature sensor drops below a predetermined heating start temperature.

7. The inkjet printer according to claim 6.

9. The stirring device includes a cooling device that cools the ink container.

2. The inkjet printer according to claim 1.

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