Recording device and method for controlling the recording device

Abstract

This suppresses changes in the properties of the liquid after the recording operation is complete. [Solution] The recording device comprises a recording head, a liquid storage unit, a circulation channel, a circulation drive unit, a ventilation unit, a first temperature detection unit for detecting the temperature of the recording unit, a second temperature detection unit for detecting the liquid temperature in the circulation channel, and a control unit for controlling the circulation drive unit and the ventilation unit. If the difference between the temperature detected by the first temperature detection unit and the temperature detected by the second temperature detection unit is greater than or equal to a first temperature difference, and a first time has not elapsed since the recording operation of the recording head was completed, the control unit drives the circulation drive unit and the ventilation unit.

Description

Technical Field

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[0001] The present disclosure relates to a recording apparatus and a method for controlling the recording apparatus.

Background Art

[0002] In a recording apparatus, control adapted to the temperature around the apparatus may be performed.

[0003] In an inkjet recording apparatus, an ink circulation channel configuration is used as a means for ensuring the ejection stability of a recording head that is continuously driven. In the ink circulation channel, ink is circulated between the inside of the nozzle and the storage unit, and a method has been proposed in which the temperature is constantly controlled using a heat exchanger or the like to stably eject the ink. Patent Document 1 discloses a temperature control method based on the temperature inside and around the circulation channel during recording.

[0004] According to the recording apparatus of Patent Document 1, it is possible to implement dew condensation prevention measures adapted to the environment around the apparatus.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, even if the recording apparatus is stopped immediately after the recording operation ends, the temperature of the heat source that was driven when the recording apparatus was performing the recording operation does not immediately drop. Therefore, after the recording operation ends, the recording apparatus and its surroundings may remain in a high-temperature state. If the high-temperature state continues for a long time after the recording operation ends, the liquid present inside the recording apparatus may be warmed, and there is a risk that the properties of the liquid will change.

[0007] Therefore, this disclosure aims to provide a technology that suppresses changes in the properties of a liquid after the recording operation is completed. [Means for solving the problem]

[0008] The recording device comprises a recording head equipped with a recording element that generates energy for ejecting liquid; a liquid storage section for storing liquid; a circulation channel for supplying liquid from the liquid storage section to the recording head and returning it to the liquid storage section; a circulation drive section for circulating the liquid in the circulation channel; a ventilation section for ventilating the air inside the recording section where the recording head and the circulation channel are provided; a first temperature detection section for detecting the temperature of the recording section; a second temperature detection section for detecting the liquid temperature in the circulation channel; and a control unit for controlling the driving of the circulation drive section and the driving of the ventilation section. The control unit drives the circulation drive section and the ventilation section if the difference between the temperature detected by the first temperature detection section and the temperature detected by the second temperature detection section is greater than or equal to a first temperature difference, and a first time has not elapsed since the recording operation of the recording head was completed. [Effects of the Invention]

[0009] According to the technology disclosed herein, it is possible to suppress changes in the properties of the ink after the recording operation is completed. [Brief explanation of the drawing]

[0010] [Figure 1] A schematic cross-sectional view showing the internal configuration of a recording device applicable to one embodiment. [Figure 2] A block diagram of a recording device applicable to one embodiment. [Figure 3] A diagram showing the surrounding configuration of a recording unit that can be applied to one embodiment. [Figure 4] A schematic diagram showing the configuration of an ink supply channel that can be applied to one embodiment. [Figure 5] A diagram showing a head lifting mechanism applicable to one embodiment. [Figure 6]A graph showing a reference example of the changes in the output values ​​of the first and second temperature sensors. [Figure 7] A flowchart illustrating a cooling operation determination method applicable to one embodiment. [Figure 8] A diagram showing the S705 subroutine that can be applied to one embodiment. [Figure 9] A graph showing another trend in the output values ​​of the first and second temperature sensors in this embodiment. [Figure 10] A schematic cross-sectional view showing the internal configuration of a recording device applicable to one embodiment. [Figure 11] A diagram showing the S705 subroutine that can be applied to one embodiment. [Modes for carrying out the invention]

[0011] [First Embodiment] <Recording device 1> Figure 1 is a schematic cross-sectional view showing the internal configuration of the recording device 1. In Figure 1, the vertical direction (height direction) is defined as the Z direction, the horizontal direction (longitudinal direction) is defined as the X direction, and the direction perpendicular to the height direction and the longitudinal direction (i.e., the direction from the front to the back of the paper in Figure 1) is defined as the Y direction. Furthermore, the following describes a line printer that records images using ink on a recording medium S wound in a roll. However, the technology of this disclosure is not limited to devices that use a recording medium S wound in a roll, but can also be applied to line printers that record images on cut paper.

[0012] In this disclosure, “recording” does not mean only forming meaningful information (e.g., letters or figures that are made visible to human eyes). “Recording” also means forming meaningless information. Furthermore, in this disclosure, “recording” broadly means forming images, patterns, structures, or combinations thereof on a recording medium, or processing the medium.

[0013] In addition, the "recording medium" includes not only the above-mentioned paper, but also materials such as cloth, plastic film, metal plate, glass, ceramics, resin, wood, leather, etc. that can receive ink. That is, the recording medium S is not limited as long as recording can be performed.

[0014] As shown in FIG. 1, the recording apparatus 1 includes a pay-out roll unit 2, a first dancer unit 3, a first main conveyance unit 4, a meandering correction unit 5, a conveyance detection unit 6, a mark sensor unit 7, and a recording unit 8 inside it. The recording apparatus 1 includes a first scanner unit 9, a first drying unit 10, a second drying unit 11, a cooling unit 12, a second scanner unit 13, a second main conveyance unit 14, a second dancer unit 15, a take-up roll unit 16, and a maintenance tray 17 as units in the subsequent stage of the recording unit 8. The recording medium S is conveyed along the conveyance path indicated by the solid line in the figure. In each of the above-mentioned units, processing on the recording medium S is performed.

[0015] The recording apparatus 1 includes an apparatus control unit 21 that comprehensively controls the operation of the recording apparatus 1. The apparatus control unit 21 includes an operation unit 24 that receives operations from the user. The operation unit 24 is configured to be able to transmit and receive various information with a host apparatus 25 provided outside the recording apparatus 1.

[0016] The pay-out roll unit 2 is a unit for holding and supplying the roll-shaped recording medium S. The pay-out roll unit 2 is configured to be able to store the pay-out roll and pull out and supply the recording medium S. In this embodiment, the number of rolls that can be stored is one. However, the number of rolls that can be stored is not limited to one. The pay-out roll unit 2 may be configured to be able to store two or three or more rolls and selectively pull out and supply the recording medium S from among the plurality of rolls.

[0017] The first dancer unit 3 is a unit for applying a certain tension between the pay-out roll unit 2 and the first main conveyance unit 4. In the first dancer unit 3, tension is applied by a tension applying unit (not shown).

[0018] The first main transport unit 4 is a unit that feeds the recording medium S to the subsequent unit and, in cooperation with the second main transport unit 14, applies a predetermined tension to the recording medium S. The first main transport unit 4 rotates by driving a motor (not shown) and transports the recording medium S while applying tension to it.

[0019] The meandering correction unit 5 is a unit for correcting meandering in the Y direction when transporting a recording medium S under tension. The meandering correction unit 5 comprises a meandering correction roller 5a and a meandering detection sensor (not shown) for detecting meandering of the recording medium S. The meandering correction roller 5a can change the tilt of the recording medium S by a motor (not shown), and corrects the meandering of the recording medium S based on the measurement result of the meandering detection sensor. At this time, the meandering correction function can be enhanced by wrapping the recording medium S around the meandering correction roller 5a. The meandering correction unit 5 can return the transport direction of the meandering recording medium S to the normal transport direction.

[0020] The transport detection unit 6 is a unit for detecting tension when transporting a recording medium S under tension between the first main transport unit 4 and the second main transport unit 14. The transport detection unit 6 is also a unit for detecting the speed of the recording medium S in order to control the recording timing of the recording unit 8.

[0021] The mark sensor unit 7 is a unit for detecting marks that have been previously recorded on the recording medium S in order to control the recording timing of the recording unit 8.

[0022] The recording unit 8 is a unit for recording on the transported recording medium S. The recording unit 8 records an image by ejecting ink from above onto the recording medium S using the recording head 22. The transport path in the recording unit 8 is formed by a plurality of guide rollers 23 arranged in an upwardly convex arc shape. In the transport path of the recording unit 8, a certain tension is applied to the recording medium S to ensure clearance with the recording head 22.

[0023] The recording head 22 consists of multiple recording heads arranged along the transport direction. In this embodiment, the recording device 1 is equipped with a total of eight line-type recording heads corresponding to the four colors Bk (black), Y (yellow), M (magenta), and C (cyan), as well as the reaction solution and three special colors.

[0024] Furthermore, the number of colors is not limited to four. The number of recording heads is not limited to eight. The inkjet method applied to the recording head 22 can be a method using a heating element, a piezoelectric element, an electrostatic element, or a MEMS element, etc. Ink for each color is supplied to the recording head 22 via ink tubes from the corresponding ink pack 51 (see Figure 4).

[0025] The first scanner unit 9 is a unit that reads the image recorded on the recording medium S by the recording unit 8 and detects image misalignment and density. The detection results of the first scanner unit 9 are used for correction. For example, the detection results of the first scanner unit 9 are used to perform position correction and color tone correction.

[0026] The first drying unit 10 and the second drying unit 11 are units that reduce the liquid content in the ink applied to the recording medium S by the recording unit 8, thereby improving the fixation between the recording medium S and the ink. The second drying unit 11 is located downstream of the first drying unit 10 in the transport direction of the recording medium S. The first drying unit 10 and the second drying unit 11 heat the recorded recording medium S to dry the applied ink. Inside the first drying unit 10 and the second drying unit 11, hot air is applied to the passing recording medium S from at least the ink-applied surface side to dry the ink-applied surface.

[0027] Furthermore, the drying method is not limited to the application of hot air. In addition, a method of irradiating the surface of the recording medium S with electromagnetic waves (ultraviolet or infrared rays, etc.) and a conductive heat transfer method using contact with a heating element may be combined.

[0028] The winding guide roller 31 is a roller that winds the surface of the recording medium S opposite to the ink-applied surface at a constant winding angle on the downstream side of the recording unit 8 in the transport direction. With this configuration, it is possible to block the hot air generated in the first drying unit 10 and suppress its effect on the recording unit 8. In this embodiment, two winding guide rollers 31 are arranged between the first scanner unit 9 and the first drying unit 10. The recording medium S is folded back so that it is substantially parallel to the top and bottom of the device. The first drying unit 10 is located below the recording unit 8. The second drying unit 11 is located below the transport detection unit 6 and the mark sensor unit 7.

[0029] The cooling unit 12 cools the recording medium S on which the ink has been fixed in the first drying unit 10 and the second drying unit 11, solidifying the softened ink and suppressing temperature changes of the recording medium S throughout the processes of each unit downstream in the transport direction of the recording device 1. Inside the cooling unit 12, the ink-applied surface of the recording medium S is cooled by applying air at a temperature lower than that of the recording medium S, at least from the ink-applied surface side. Note that the cooling method is not limited to applying air. The cooling method may also be a conductive heat transfer method through contact with a heat dissipation member. The cooling method may also be a combination of the air-applied method and the conductive heat transfer method through contact with a heat dissipation member.

[0030] The second scanner unit 13 is a unit that reads the test image recorded on the recording medium S by the recording unit 8 before the actual recording, and detects image misalignment and density. The detection results of the second scanner unit 13 are used for correction during the actual recording after the test image has been recorded.

[0031] The second main transport unit 14 functions by operating together with the first main transport unit 4. The second main transport unit 14 is a unit for transporting the recording medium S while applying tension to the recording medium S and for adjusting the tension of the recording medium S. The second main transport unit 14 rotates by being driven by a motor (not shown). The tension of the recording medium S is adjusted by a clutch (not shown) that can control the torque driven by it, based on a tension value detected by a tension control unit (not shown).

[0032] Furthermore, as an additional configuration for adjusting the tension of the recording medium S, a configuration may be added to control the speed of the second main conveying unit 14 based on the detection result of the conveying detection unit 6. As a way to realize this configuration, it is conceivable to use either a torque control method that controls the value of the torque transmitted from the clutch, or a speed control method that controls the roller speed of the second main conveying unit 14. Alternatively, these two methods may be switched between depending on the purpose, or both may be used simultaneously.

[0033] The second dancer unit 15 is a unit for applying a constant tension between the second main transport unit 14 and the winding roll unit 16. In the second dancer unit 15, a constant tension is applied to the recording medium S by a tension-applying unit (not shown).

[0034] The winding roll unit 16 is a unit for winding the recorded recording medium S onto a winding core. In Figure 1, there is one recoverable roll, but the number of recoverable rolls is not limited to one. The winding roll unit 16 may be configured to recover the recording medium S by selectively switching between two or three or more winding cores. Depending on the post-recording processing, it may not be necessary to wind the recording medium S onto a winding core. For example, the recording medium S may be cut using a cutter, and the cut recording medium S may be loaded.

[0035] The maintenance tray 17 is a unit equipped with a mechanism for restoring the ejection performance of the recording head 22. Examples of such mechanisms include a cap mechanism to protect the ink ejection surface of the recording head 22, a wiping mechanism (so-called wiping mechanism) that wipes the ink ejection surface using a blade or the like, and a suction mechanism that sucks ink from the nozzle out of the ink ejection surface using negative pressure.

[0036] Figure 2 is a block diagram of the control unit for controlling each unit of the recording device 1.

[0037] As shown in Figure 2, the device control unit 21 comprises a CPU 41, memory 42, storage device 43, and an operation unit 24. The operation unit 24 includes an I / F for communication with the control units of individual units, and an external I / F for connecting to a host device 25 such as an external host computer. The device control unit 21 receives instructions from the host device 25 or the operation unit 24 and transmits control commands to each unit of the recording device 1. The control program and control parameters for executing the control commands are stored in the memory 42 or storage device 43. The CPU 41 reads these control programs and control parameters and executes the control program.

[0038] In this embodiment, the first temperature sensor 32 detects the temperature of the recording unit 8 (the "head temperature TP" described later) in real time. The first temperature sensor 32 may also detect the humidity of the recording unit 8 in real time along with the temperature of the recording unit 8. The second temperature sensor 61 detects the temperature of the ink inside the circulation channel (described later) in real time. Information showing the changes in these temperatures is stored in the memory 42. That is, the memory 42 stores information showing the temperatures of the first temperature sensor 32 and the second temperature sensor 61 for a predetermined time (for example, the second time (tmin) described later). This information may also be stored in the storage device 43 (see Figure 2).

[0039] The recording control unit 44 starts the recording preparation operation based on the recording instruction received from the device control unit 21. At this time, the transport control unit 45, which transports the recording medium S, controls each drive unit so that the recording medium S is transported at a specified speed, and the maintenance mechanism control unit 46 moves the recording head 22 away from the cap (not shown) and moves the maintenance tray 17 to the retracted position. Furthermore, the drying control unit 48 controls the first drying unit 10, the second drying unit 11, and the cooling unit 12 (see Figure 1) to bring them to a specified temperature. The ink supply control unit 47 drives the upstream circulation pump 55 and the downstream circulation pump 56 to circulate the ink, and feeds back the detection results from the pressure sensor 60 and the flow rate sensor 62 to adjust the amount of drive of the upstream circulation pump 55 and the downstream circulation pump 56. Hereinafter, when there is no need to distinguish between the upstream circulation pump 55 and the downstream circulation pump 56, they will be referred to as the "circulation pump". After the above preparation operations are completed, the recording control unit 44 lowers the recording head 22 to the recording position. Subsequently, the recording data generated by the device control unit 21 is converted into drive signals for the recording head 22 on the head control board 49 of each color, and the recording element is driven by applying a drive voltage.

[0040] Figure 3 shows the configuration around the recording unit 8 of the recording device 1.

[0041] As shown in Figure 3, the recording unit 8 includes a recording head holder 26 on which the recording head 22 is mounted and a lifting frame 28 at the top. Below this, the first drying unit 10 is located. At the bottom, a transport roller 38 is located for transporting the recording medium S after it has passed through the second drying unit 11 and the cooling unit 12. Around the recording unit 8, the temperature rises not only due to the heat dissipated from the first drying unit 10, but also due to the heat generated by the head control board 49 (see Figure 2) provided on the recording head holder 26. For this reason, a ventilation mechanism including an intake fan 33 and an exhaust fan 34 is provided to ventilate the air around the recording unit 8. Hereinafter, unless there is a need to distinguish between the intake fan 33 and the exhaust fan 34, they will be referred to as "fans" as appropriate.

[0042] Furthermore, a board cooling fan 36 is provided in the recording head holding unit 26 to cool the head control board 49. In addition, a partition member 35 is provided between the recording unit 8 and the exhaust fan 34 to efficiently ventilate the inside of the device. With this configuration, the air taken in from the outside by the intake fan 33 passes through the recording unit 8 and is guided to the exhaust fan 34. Furthermore, in order to detect the temperature and humidity around the recording unit 8 during recording operation and maintain an appropriate environment, the first temperature sensor 32 is positioned near the guide roller 23 that transports the recording medium S.

[0043] Furthermore, the hot air from the first drying section 10 and the second drying section 11 (see Figure 1) is discharged through the exhaust ports provided in each of them. Therefore, there is no temperature influence on the recording section 8 due to the intrusion of hot air. As the temperature of the first drying section 10 and the second drying section 11 rises, the overall temperature inside the recording device 1 rises.

[0044] Figure 4 is a schematic diagram showing the configuration of the ink supply channel in this embodiment.

[0045] As shown in Figure 4, a supply channel 73 is provided to supply ink from the ink pack 51 to the buffer tank 53. When the supply pump 54 of the supply channel 73 is driven, the ink stored inside the ink pack 51 is supplied inside the buffer tank 53. In this embodiment, the ink pack 51 stores ink in an aluminum pillow bag. One end of the supply channel 73 is connected to the supply port of the ink pack 51 via a joint 52.

[0046] Furthermore, an outer covering member may be provided to cover the ink pack 51. In this embodiment, the form of the ink pack 51 is pillow-shaped, but the form of the ink pack 51 is not limited to this. For example, the form of the ink pack 51 may be tank-shaped or bottle-shaped. Also, in this embodiment, the material of the ink pack 51 is aluminum, but the material of the ink pack 51 is not limited to aluminum. For example, the material of the ink pack 51 may be polypropylene or the like.

[0047] The buffer tank 53 is a container for storing ink. To suppress pressure fluctuations caused by increases and decreases in ink within the ink supply channel, an atmospheric communication channel 69 is connected to the buffer tank 53. To suppress the ingress of foreign matter such as dust when air is drawn into the buffer tank 53, the atmospheric communication channel 69 is equipped with an air filter 67.

[0048] A circulating upstream channel 70 that supplies ink to the recording head 22 and a circulating downstream channel 71 that returns ink from the recording head 22 to the buffer tank 53 are connected to the buffer tank 53. Hereinafter, the circulating upstream channel 70 and the circulating downstream channel 71 will be collectively referred to as the "circulating channel". The ink supplied to the buffer tank 53 is sent to the recording head 22 by the upstream circulation pump 55 provided in the circulating upstream channel 70. A heat exchanger 57, a degassing module 58, and a filter 59 are provided between the buffer tank 53 and the upstream circulation pump 55.

[0049] The heat exchanger 57 is a device that uses circulating water at a constant temperature supplied from a chiller (not shown) installed outside the recording device 1 to maintain a constant temperature of the ink supplied from the buffer tank 53 to the recording head 22.

[0050] The degassing module 58 is a device that discharges gas dissolved inside the ink into a gas chamber that is depressurized at the interface with the gas-liquid exchange membrane as the ink passes through it. This reduces the amount of gas dissolved inside the ink.

[0051] The filter 59 traps foreign matter contained in the ink (fragments of components in the flow path or dust) and aggregates derived from the ink's components (pigments or solid materials such as resin). This helps to suppress nozzle clogging in the recording head 22.

[0052] In this embodiment, there is one upstream circulation pump 55. However, the number of upstream circulation pumps 55 is not limited to one. Multiple upstream circulation pumps 55 may be installed in parallel. The connection order of the heat exchanger 57, degassing module 58, and filter 59 is not limited to this order.

[0053] When ink is sent from the upstream circulation pump 55, the upstream circulation channel 70 is pressurized and ink is supplied to the recording head 22. However, if excessive pressure is applied to the head supply port 20 provided in the recording head 22, there is a risk that a pressure control valve provided inside the recording head 22 will open and ink will leak out of the nozzle. For this reason, a relief channel 72 equipped with a relief valve 63 is provided before the head supply port 20. As a result, any excess ink supplied is returned to the buffer tank 53 via the relief channel 72.

[0054] Furthermore, even when ink circulation is stopped, the upstream circulation channel 70 remains pressurized. This continued pressure could cause ink to leak from the channel. To prevent this, one end of the upstream pressure release channel 74 is connected downstream of the upstream circulation pump 55, and the other end of the upstream pressure release channel 74 is connected to the buffer tank 53. With this configuration, when circulation stops, the upstream pressure release valve 65 in the upstream pressure release channel 74 opens, releasing the pressure in the upstream circulation channel 70. This prevents ink from leaking from the channel when circulation stops.

[0055] Furthermore, in the relief channel 72, a second temperature sensor 61 and a pressure sensor 60 are provided before the head supply port 20. The second temperature sensor 61 measures the temperature of the ink supplied to the recording head 22 (the "circulation channel temperature TI" described later). The pressure sensor 60 measures the pressure of the ink supplied to the recording head 22. Based on these measurement results, the drive amount of the upstream circulation pump 55 is adjusted and controlled so that the pressure and temperature of the ink supplied to the recording head 22 are maintained at a constant level. One end of the downstream circulation channel 71, which returns the ink to the buffer tank 53, is connected to the head outlet 40 provided on the recording head 22. A downstream circulation pump 56 is provided in the middle of the downstream circulation channel 71.

[0056] Furthermore, a flow sensor 62 is provided downstream of the downstream circulation pump 56. The flow sensor 62 detects the amount of ink discharged from the recording head 22 when the downstream circulation pump 56 is driven. This allows monitoring of the amount of ink flowing through the circulation channel and controlling the flow rate by adjusting the amount driven by the downstream circulation pump 56.

[0057] Furthermore, by installing a flow sensor 62 in the downstream circulation channel 71, it becomes possible to measure the circulation flow rate excluding the amount of ink used for image recording from the recording head 22.

[0058] Furthermore, the other end of the circulating downstream channel 71 is connected to the buffer tank 53. In the circulating downstream channel 71, one end of a downstream pressure release channel 75 equipped with a downstream pressure release valve 66 is connected between the head outlet 40 and the downstream circulation pump 56. The other end of the downstream pressure release channel 75 is connected to the buffer tank 53. The downstream pressure release valve 66 is configured to release the pressure in the channel provided on the recording head 22 side from the downstream circulation pump 56 when there is no circulation. As a result, excessive negative pressure is applied in the circulating downstream channel 71, which destroys the meniscus formed in the nozzle of the recording head 22 and suppresses the intrusion of air.

[0059] The ink supply unit (not shown) that supplies ink to the recording head 22 is located only inside the recording unit 8. The buffer tank 53, upstream circulation pump 55, and downstream circulation pump 56, etc., are located outside the recording unit 8 to minimize the effects of temperature rise.

[0060] With the above flow path configuration, ink circulates between the buffer tank 53 and the recording head 22. The temperature of the circulating ink is kept constant, and the amount of dissolved gas is kept low. In this way, the effects of temperature fluctuations when the ink is ejected from the recording head 22 are suppressed, and the ink ejection characteristics are kept constant. Furthermore, by suppressing the elution of gas, ejection failures caused by obstruction of ink supply can be suppressed.

[0061] Figure 5 shows a head lifting mechanism that mounts a recording head 22 and changes the position of the recording head 22 in accordance with the recording operation.

[0062] As shown in Figure 5, the recording head 22 is pivotally supported by a recording head holding unit 26, which holds the recording head 22 and moves it up and down, with the recording head support shaft 27 supporting it from below. The recording head holding unit 26 moves up and down along a lifting rail 29 provided inside the lifting frame 28 by a drive unit including a lifting motor 30 (see Figure 2).

[0063] The upstream circulation channel 70, the downstream circulation channel 71, and the relief channel 72 (see Figure 4) are connected to the recording head holding section 26 along the circulation channel support member 37. When the recording head 22 moves up and down, the circulation channel support member 37 holds the channel with an appropriate curvature, thereby suppressing blockage due to buckling and twisting of the channel.

[0064] In this embodiment, the bending angle of the circulation channel support member 37 is limited by a chain link. However, a metal guide member or a film-like member may be used to prevent buckling and twisting of the channel.

[0065] The recording head holding unit 26 houses not only the recording head 22, but also a head control board 49, a pressure sensor 60 on the supply channel side, a second temperature sensor 61, and a relief valve 63. The head control board 49 generates drive signals to drive the recording elements of the recording head 22, which generates heat. A board cooling fan 36 is provided in the recording head holding unit 26 to cool this heat.

[0066] In this embodiment, an image is formed by using the hot air from the first drying section 10 and the second drying section 11 to melt the thermoplastic resin contained in the ink and fixing the ink to the recording medium S (see Figure 1). However, if the water contained in the ink evaporates due to drying, or if the temperature of the ink rises significantly, there is a risk that aggregates will form as the thermoplastic resin contained in the ink fuses with each other.

[0067] To suppress this, during the recording operation when the temperature of the recording unit 8 rises, the heat exchanger 57 (see Figure 4) is operated to maintain a constant ink temperature in the circulation path. Then, a cooling operation is performed by operating the intake fan 33, exhaust fan 34, and substrate cooling fan 36 to suppress the temperature rise inside the machine. By performing this cooling operation, the heat generated by the head control board 49 subsides after the recording is completed. Also, since the operation of the first drying unit 10 and the second drying unit 11 stops, the temperature inside the machine gradually decreases.

[0068] However, once the head control board 49, the first drying section 10, and the second drying section 11 have heated up, they do not cool down immediately. Therefore, if the fans and ink circulation are stopped prematurely, the temperature of the ink in the upstream circulation channel 70, the downstream circulation channel 71, and the relief channel 72 located inside the recording section 8 (see Figure 1, etc.) will continue to rise. In particular, the temperature of the ink in the channels located near the head control board 49, which is a heat source, will rise significantly, which may cause aggregates to form in the ink.

[0069] Figure 6 is a graph showing a reference example of the changes in the output values ​​of the first temperature sensor 32 and the second temperature sensor 61 (see Figure 2, etc.).

[0070] In Figure 6, the dashed line shows the output value of the first temperature sensor 32. The solid line shows the output value of the second temperature sensor 61. The dotted line shows the ambient temperature TE around the recording device. In this embodiment, no dedicated sensor is provided for detecting the ambient temperature TE. The ambient temperature TE is adjusted to be between 20°C and 27°C.

[0071] Furthermore, the temperature at which the ink circulates is pre-set to 22°C by the user. Hereafter, this pre-set ink circulating temperature will be referred to as the "circulation setting temperature TC".

[0072] In Figure 6, the dot pattern indicates the time period during which the cooling operation is performed. In the example in Figure 6, the cooling operation is performed from the start of the recording operation (not shown) until the end of the recording operation TX. In other words, in the example in Figure 6, the cooling operation is not performed after the end of the recording operation.

[0073] During recording, circulation occurs via the heat exchanger 57 (see Figure 4), so the temperature of the ink inside the circulation channel (hereinafter referred to as "circulation channel temperature TI") becomes the same as the circulation set temperature TC (for example, 22°C). On the other hand, the temperature of the recording unit 8 (see Figure 3, etc.) is brought into equilibrium between the amount of heat generated and the amount of heat dissipated by the fan.

[0074] During recording, the temperature of the recording unit 8 (head temperature TP) becomes relatively high due to the heat generated by the head control board 49 (see Figure 5, etc.), the first drying unit 10, and the second drying unit 11 (see Figure 1, etc.). For example, if the ambient temperature TE is 25°C, the head temperature TP will be approximately 35°C. The higher the ambient temperature TE, the higher the head temperature TP will be. The head temperature TP also changes depending on the recording conditions and drying temperature conditions.

[0075] After recording is complete and the image recorded on the recording medium S (see Figure 1) reaches the winding roll section 16 (see Figure 1), the heaters in the first drying section 10 and the second drying section 11, respectively, and the recording control unit 44 (see Figure 2) are stopped.

[0076] After the recording operation is complete, the heaters in the first drying section 10 and the second drying section 11 are stopped. However, heat is dissipated in the first drying section 10 and the second drying section 11 to lower the temperature of each heater. The first drying section 10 and the second drying section 11 are configured so that the heat released from each heater does not affect the head temperature TP.

[0077] When the cooling operation stops at the end of the recording operation, the ventilation rate in the recording unit 8 decreases. Then, the head temperature TP rises as the heat transfer from the head control board 49 and the first drying unit 10 and second drying unit 11 becomes dominant. Although it depends on the temperature of each heat source at the end of the recording operation, the increase in head temperature TP at the end of the recording operation is at most about 10°C or less.

[0078] The heat inside the recording unit 8 is discharged to the outside through the housing. As a result, as the temperature of the heat source decreases, the head temperature TP gradually decreases to approach the ambient temperature TE. At this time, the circulation channel temperature TI also changes in line with the head temperature TP, via the ink circulating between the recording head 22 and the buffer tank 53. As a result, after the recording operation is completed, the circulation channel temperature TI rises significantly, and as described above, there is a risk of ink condensation.

[0079] To avoid ink aggregation, it is conceivable to perform a cooling operation until the temperature of the recording unit 8 drops to a certain level, and then stop the cooling operation. However, in the recording unit 8, the first temperature sensor 32 is provided in only one location. Therefore, if the temperature of a component located far from the first temperature sensor 32 is high, or if the cooling of the head control board 49 is insufficient, the circulation channel temperature TI may rise again.

[0080] Furthermore, by providing sensors to detect the temperature of all components constituting the recording unit 8 and all head control boards 49, it is possible to understand the temperature decrease in detail. However, this configuration requires a large number of sensors, leading to increased costs and complex control.

[0081] Furthermore, after the recording operation is completed, it is conceivable to suppress the rise in head temperature TP and circulation channel temperature TI by continuing the cooling operation until the heat source located near the recording unit 8 has cooled sufficiently. However, this cooling method would require running the fan and circulation pump for a long time, resulting in excessive cooling operation. In other words, continuously performing the cooling operation until the heat source has cooled sufficiently would lead to problems such as a shortened lifespan of the fan and circulation pump, and an increase in power consumption. Therefore, in this embodiment, after the recording operation is completed, the fan and circulation pump are appropriately driven so that the circulation channel temperature TI does not rise significantly, thereby suppressing ink temperature fluctuations without performing excessive cooling operations.

[0082] Figure 7 is a flowchart illustrating the cooling method of the recording unit 8 after recording is complete in this embodiment. This flowchart is performed by the CPU 41 loading the program code stored in memory 42 into the storage device 43 (see Figure 2) and executing it. This flowchart is triggered when the recording operation is completed. The symbol "S" in Figure 7 represents a step. This is also the case in other drawings.

[0083] In S701, the CPU 41 stops the temperature control of the recording head 22 (see Figure 2, etc.) via the head control board 49.

[0084] In step S702, the CPU 41 stops the heater of the first drying unit 10 and the heater of the second drying unit 11 (see Figure 1, etc.) via the drying control unit 48.

[0085] In this embodiment, after an image is formed on the recording medium S (see Figure 1, etc.) in the recording unit 8, the portion on which the image is formed passes through the first drying unit 10 and the second drying unit 11. Therefore, no particular problem occurs even if the heat retention control of the recording head 22 is stopped before the first drying unit 10 and the second drying unit 11. For this reason, in this embodiment, S701 is performed before S702.

[0086] In S703, the CPU 41 caps the recording head 22. For example, the maintenance mechanism control unit 46 (see Figure 2) moves the maintenance tray 17 (see Figure 1) to a position where the recording head 22 and the cap face each other. Then, the recording control unit 44 (see Figure 2) operates the lifting motor 30 to bring the recording head 22 into contact with the cap. This prevents the ink inside the nozzle from drying out.

[0087] In S704, the CPU 41 starts counting a first timer that measures the time the cooling operation is continuously running or continuously stopped, and a second timer that measures the elapsed time since the recording operation stopped. For example, the device control unit 21 (see Figure 1) sets the values ​​of the first timer and the second timer to "0" and starts counting up. The first elapsed time t1 counted by the first timer and the second elapsed time t2 counted by the second timer are stored in the memory 42. These times may also be stored in the storage device 43.

[0088] In S705, CPU41 executes a temperature determination sequence.

[0089] Figure 8 is a flowchart of the S705 subroutine.

[0090] In S801, the CPU 41 acquires the current head temperature TP detected by the first temperature sensor 32 (see Figure 2) via the recording control unit 44.

[0091] In step S802, the CPU 41 obtains the circulation channel temperature TI via the ink supply control unit 47. In this embodiment, as described above, there are multiple recording heads 22. In step S802, the highest temperature among the circulation channel temperatures TI detected by the second temperature sensor 61 (see Figure 2) provided in the circulation channel of each recording head 22 is obtained via the ink supply control unit 47 (see Figure 2).

[0092] In S803, the CPU 41 determines whether the value obtained by subtracting the circulation channel temperature TI acquired in S802 from the head temperature TP acquired in S801 is lower than the first temperature difference (Tth1). For example, when the following formula 1 holds, the CPU 41 determines that the difference between the head temperature TP and the circulation channel temperature TI (see FIG. 6 etc.) is small, and the influence of increasing the temperature of the ink in the channel is small. In the present embodiment, Tth1 = 3°C, and it is determined whether the temperature obtained by subtracting the circulation channel temperature TI from the head temperature TP is less than 3°C.

[0093] TP - TI < Tth1…(Formula 1)

[0094] When the temperature difference obtained by subtracting the circulation channel temperature TI from the head temperature TP is greater than or equal to the first temperature difference (Tth1) (NO in S803), the CPU 41 executes the process of S804. On the other hand, when the temperature difference obtained by subtracting the circulation channel temperature TI from the head temperature TP is less than the first temperature difference (Tth1) (YES in S803), the CPU 41 executes the process of S806.

[0095] In S804, the CPU 41 reads the memory 42 and determines whether the first elapsed time (t1) counted by the first timer is greater than or equal to the second time (tmin). In the present embodiment, the second time (tmin) is set to 3 minutes, and the CPU 41 determines whether the first elapsed time (t1) is 3 minutes or more. Here, the second time corresponds to the elapsed time from the recording stop required to determine the cooling state in the circulation channel based on the temperature transition of the recording unit.

[0096] When the first elapsed time (t1) is greater than or equal to the second time (tmin) (YES in S804), the CPU 41 executes the process of S805. On the other hand, when the first elapsed time (t1) is less than the second time (tmin) (NO in S804), the CPU 41 executes the process of S808.

[0097] In S805, the CPU 41 determines whether the absolute value of the difference between the temperature of the recording unit 8 (head temperature TP’) at a time point that is 2nd time (tmin) back from the current time point and the current head temperature TP is smaller than the 2nd temperature difference Tth2. As described above, information indicating the temperature transition of the recording unit 8 is stored in the memory 42. The CPU 41 reads the memory 42 to obtain the head temperature TP’, and determines whether the absolute value obtained by subtracting the head temperature TP acquired in S801 from the head temperature TP’ is smaller than the 2nd temperature difference Tth2.

[0098] When the following formula 2 holds, the CPU 41 determines that the difference between the head temperature TP and the circulation channel temperature TI is small, and the influence of increasing the temperature of the ink in the channel is small.

[0099] |TP’ - TP| < Tth2 … (Formula 2)

[0100] In the present embodiment, the 2nd temperature difference Tth2 is set to 0.5°C. That is, in the present embodiment, it is determined whether the absolute value obtained by subtracting the temperature of the recording unit 8 at a time point 3 minutes before the current time point from the temperature of the recording unit 8 at the current time point is less than 0.5.

[0101] When the temperature obtained by subtracting the head temperature TP from the head temperature TP’ is less than the 2nd temperature difference Tth2 (YES in S805), the CPU 41 executes the process of S806. On the other hand, when the temperature obtained by subtracting the head temperature TP from the head temperature TP’ is greater than or equal to the 2nd temperature difference Tth2 (NO in S805), the CPU 41 executes the process of S807.

[0102] In S806, the CPU 41 allows the cooling operation to stop.

[0103] In S807, the CPU 41 does not allow the cooling operation to stop.

[0104] In S808, CPU41 maintains the result of the determination regarding whether or not to stop the cooling operation. Specifically, if the cooling operation is being performed while S808 is processing, stopping the cooling operation is not permitted, and the cooling operation continues. For example, in the first cycle of this flowchart, there is a high probability that the cooling operation is being performed while S808 is processing. Therefore, in S808 during the first cycle of this flowchart, the determination result that does not allow stopping the cooling operation is maintained, and the cooling operation continues. On the other hand, if the cooling operation is stopped while S808 is processing, the determination result that allows stopping the cooling operation is maintained, and the state in which the cooling operation is stopped is maintained.

[0105] After the completion of S806, S807, or S808, CPU 41 executes the process of S706 (see Figure 7).

[0106] In S706, the CPU 41 determines whether or not to stop the cooling operation based on the result of the judgment in S705 performed immediately before. If stopping the cooling operation is permitted (i.e., if the process performed immediately before S706 was S806, or if the judgment result in S808 indicating that stopping the cooling operation is permitted is maintained), the CPU 41 executes the process in S707. On the other hand, if stopping the cooling operation is not permitted (i.e., if the process performed immediately before S706 was S807, or if the judgment result in S808 indicating that stopping the cooling operation is not permitted is maintained), the CPU 41 executes the process in S710.

[0107] In S707, the CPU 41 acquires information indicating the operating status of the recording control unit 44 and the ink supply control unit 47 using a known method, and determines whether or not a cooling operation is being performed based on that information.

[0108] If the recording control unit 44, the ink supply control unit 47, or both are operating (YES in S707), the CPU 41 executes the process in S708. On the other hand, if neither the recording control unit 44 nor the ink supply control unit 47 is operating (NO in S707), the CPU 41 executes the process in S713. In this case, the cooling operation remains stopped, and the count of the first timer continues.

[0109] In S708, CPU41 stops its cooling operation.

[0110] In S709, the count of the first timer is reset to "0", and a new count is started to count the time the cooling operation is stopped.

[0111] In S710, the CPU 41 obtains information indicating the operating status of the recording control unit 44 and the ink supply control unit 47 using a known method, and determines whether or not a cooling operation is being performed based on that information. If a cooling operation is being performed (YES in S710), the CPU 41 executes the process in S713. In this case, the cooling operation continues, and the count of the first timer also continues. On the other hand, if a cooling operation is not being performed (NO in S710), the CPU 41 executes the process in S711.

[0112] In S711, CPU41 starts the cooling operation.

[0113] In S712, CPU41 resets the first timer count to "0" and starts a new count to count the duration of the cooling operation.

[0114] In S713, the CPU 41 determines whether the time elapsed since the end of the recording operation is longer than a predetermined time. Specifically, the CPU 41 reads memory 42 and obtains the second elapsed time t2 and the first time (tMAX) counted by the second timer. Then, the CPU 41 compares the second elapsed time t2 and the first time (tMAX) and determines whether the second elapsed time t2 is longer than the first time (tMAX). The first time (tMAX) is a time that can be arbitrarily set by the user.

[0115] In this embodiment, the first time (tMAX) is 30 minutes. If the second elapsed time t2 is 30 minutes or less (NO in S713), the CPU 41 executes the process in S714. On the other hand, if the time elapsed since the end of the recording operation exceeds 30 minutes (YES in S713), the CPU 41 executes the process in S715.

[0116] In S714, the CPU 41 waits for a predetermined time (Δt). In this embodiment, the predetermined time (Δt) is 1 minute. This configuration ensures sufficient processing time when the processes from S705 to S713 are repeated after S714. After S714, the CPU 41 executes the process of S705 again.

[0117] In S715, the CPU 41 acquires information indicating the operating status of the recording control unit 44 and the ink supply control unit 47 using a known method, and determines whether or not a cooling operation is being performed based on that information. If a cooling operation is being performed (YES in S715), the CPU 41 executes the process in S716. On the other hand, if a cooling operation is not being performed (NO in S715), the CPU 41 terminates the process in this flowchart.

[0118] At S716, CPU41 stops the cooling operation. After S716, CPU41 terminates the processing of this flowchart.

[0119] As explained above, in this embodiment, for example, if the difference between the temperature of the recording unit 8 and the temperature of the ink in the circulation channel is less than 3°C, and the time elapsed since the end of the recording operation exceeds 30 minutes, the cooling operation may be stopped. Alternatively, if the difference between the temperature of the recording unit 8 and the temperature of the ink in the circulation channel is 3°C or more, the difference between the current temperature of the recording unit 8 and the temperature 3 minutes ago is less than 0.5°C, and the time elapsed since the end of the recording operation exceeds 30 minutes, the cooling operation may also be stopped. This is because it can be determined that the temperature in the circulation channel will not change significantly thereafter. On the other hand, if the above conditions are not met, the cooling operation may not be stopped because the temperature in the circulation channel may still change.

[0120] In other words, in this embodiment, if there is a high probability that the temperature of the recording unit 8 has decreased sufficiently, the cooling operation may be stopped. On the other hand, if there is a low probability that the temperature of the recording unit 8 has decreased sufficiently, the cooling operation may not be stopped, and the cooling operation will be performed.

[0121] This prevents a significant rise in ink temperature within the circulation channel after the recording operation is completed. Consequently, ink aggregation within the circulation channel can be suppressed. Furthermore, by avoiding unnecessary cooling operations, the shortening of the lifespan of the intake fan 33, exhaust fan 34, substrate cooling fan 36, upstream circulation pump 55, and downstream circulation pump 56 (see Figure 2, etc.) can be suppressed, and power consumption can also be reduced.

[0122] Figures 9(a) and 9(b) are graphs showing different trends in the output values ​​of the first temperature sensor 32 and the second temperature sensor 61 in this embodiment. Figure 9(a) shows the temperature trend when the circulation channel temperature TI is lower than the ambient temperature TE. Figure 9(b) shows the temperature trend when the circulation channel temperature TI is equal to or greater than the ambient temperature TE.

[0123] In both Figure 9(a) and Figure 9(b), similar to Figure 6, the head temperature TP is kept approximately constant during the recording operation, and the circulation channel temperature TI is kept at the circulation set temperature TC. Immediately after the end of the recording operation, the head temperature TP is relatively high, and the cooling operation continues for a relatively short period of time (NO in S803, YES in S804). At this time, the amount of heat dissipated from the head control board 49 (see Figure 2) and the first drying section 10 and the second drying section 11 (see Figure 1) gradually decreases, so over time, the head temperature TP decreases to approach the ambient temperature TE. Meanwhile, during the cooling operation, the circulation channel temperature TI is kept at the circulation set temperature TC.

[0124] As shown in Figure 9(a), during the cooling operation, as time passes, the head temperature TP gradually approaches the ambient temperature TE, and the amount of change in the head temperature TP becomes small. When the value obtained by subtracting the circulation channel temperature TI from the head temperature TP falls below the first temperature difference (Tth1), the cooling operation can be stopped (S806). That is, if the difference between the head temperature TP and the circulation channel temperature TI is sufficiently small, it is judged that the increase in both the head temperature TP and the circulation channel temperature TI will be small even if the cooling operation is stopped.

[0125] If the value obtained by subtracting the circulation channel temperature TI from the head temperature TP is greater than or equal to the first temperature difference (Tth1), it is determined whether the time elapsed since the end of the recording operation is greater than or equal to the second time (tmin) (S804). If the time elapsed since the end of the recording operation is greater than or equal to the second time (tmin) (YES in S804), it is determined whether the amount of temperature change of the recording unit 8 during the second time (tmin) is lower than the second temperature difference Tth2 (S805).

[0126] If the cooling operation is progressing and the temperature change of the recording unit 8 is small (YES in S805), the cooling operation may be stopped (S806). On the other hand, if this is not the case (NO in S805), the cooling operation continues (S807). After the cooling operation stops, the head temperature TP may rise slightly depending on the amount of temperature decrease in the head control board 49 and the first drying unit 10 and the second drying unit 11.

[0127] Furthermore, after the cooling operation stops, the circulation channel temperature TI approaches the head temperature TP. If the rise in head temperature TP at this time is large, there is a risk that the circulation channel temperature TI will exceed the ambient temperature TE and rise significantly. For this reason, if the change in temperature of the recording unit 8 during the second time period (tmin) is greater than or equal to the second temperature difference Tth2 (NO in S805), stopping the cooling operation is not permitted (S807). When the cooling operation is restarted, the head temperature TP and circulation channel temperature TI will decrease, and the cooling operation will continue until the temperature fluctuations become small again.

[0128] In this way, the temperature determination process is repeated until the increase in head temperature TP after the cooling operation stops falls below the second temperature difference Tth2, thereby suppressing the rise in circulation channel temperature TI after the cooling operation stops.

[0129] When the circulation channel temperature TI is equal to or greater than the ambient temperature TE, a different process is performed than when the circulation channel temperature TI is less than the ambient temperature TE.

[0130] As shown in Figure 9(b), when the head temperature TP decreases due to the cooling operation, at a certain point the difference between the head temperature TP and the circulation channel temperature TI becomes less than the first temperature difference (Tth1). That is, the circulation channel temperature TI has come close enough to the head temperature TP (YES in S803), so the cooling operation can be stopped (S806).

[0131] If the heat source is not sufficiently cooled after the cooling operation is stopped, the head temperature TP will rise again. However, the cooling operation is repeated until the S805 process, which is performed again, yields a negative result (until NO is determined in S805) (S806). As this process is repeated, even after the first time (tMAX) has elapsed from the end of the recording operation TX, the head temperature TP remains lower than the circulation channel temperature TI, even if the cooling operation is stopped. This sustained state suppresses the rise in the circulation channel temperature TI.

[0132] As described above, according to the recording device 1 of this embodiment, if the temperature difference between the recording unit and the ink flow path is less than a predetermined value (for example, 3°C), the cooling operation (for example, ventilation of the recording unit 8) is permitted to be stopped.

[0133] Alternatively, even if the difference between the head temperature TP and the circulation channel temperature TI is greater than or equal to the first temperature difference (Tth1), if the time counted by the timer is less than or equal to a predetermined time, and the temperature change of the recording unit during that predetermined time is less than a predetermined value, the cooling operation may be stopped.

[0134] For example, if the temperature difference between the recording unit and the ink flow path exceeds a predetermined value, and the elapsed time since the start of the first timer's count is 3 minutes or less, and the temperature change of the recording unit during those 3 minutes is less than 0.5°C, then the cooling operation may be stopped. Furthermore, if the above conditions are met and the elapsed time since the start of the first timer's count exceeds a predetermined time (for example, 30 minutes), the cooling operation is stopped. On the other hand, if the above conditions are not met, stopping the cooling operation is not permitted, and the cooling operation is performed.

[0135] Therefore, according to the recording device 1 of this embodiment, the temperature of the recording unit and the flow path rises after the recording operation is completed, and the ink remaining inside them aggregates, preventing the formation of solid aggregates.

[0136] Therefore, according to the recording device 1 of this embodiment, it is possible to suppress changes in the properties of the ink after the recording operation is completed.

[0137] [Second Embodiment] A second embodiment of the technology of this disclosure will be described below with reference to the drawings. The objective of this embodiment is to provide a recording device 1 that can more accurately suppress changes in the properties of the ink after the completion of the recording operation. In the following description, components that are the same as or corresponding to the first embodiment will be denoted by the same reference numerals and their descriptions will be omitted, and the differences will be described mainly.

[0138] Figure 10 is a schematic cross-sectional view showing the internal configuration of a recording device 1 that can be applied to this embodiment.

[0139] As shown in Figure 10, the recording device 1 includes a first dancer unit 3. In this embodiment, the first dancer unit 3 includes an ambient temperature sensor 100 for measuring the ambient temperature around the recording device 1.

[0140] Furthermore, the location where the ambient temperature sensor 100 is installed is not limited to the first dancer section 3, as long as it is not a location affected by the heat generated by the recording operation. For example, the ambient temperature sensor 100 may be installed in the unwinding roll section 2. However, it is preferable not to install the ambient temperature sensor 100 in the heat source (for example, the recording section 8, the first drying section 10, or the second drying section 11).

[0141] Furthermore, it is preferable not to install the ambient temperature sensor 100 in a location affected by the airflow from the intake fan 33, exhaust fan 34, and substrate cooling fan 36. This is because if the ambient temperature sensor 100 is installed in these locations, it will be affected by the heat generated or exhausted during recording operations, making it difficult to detect the correct ambient temperature around the recording device 1.

[0142] Furthermore, it is preferable not to install the ambient temperature sensor 100 downstream of the first drying section 10 (for example, in the winding roll section 16) in the transport path of the recording medium S. This is because if the ambient temperature sensor 100 is installed in this position, it will be affected by the recording medium S heated by the first drying section 10, etc., making it difficult to detect the correct ambient temperature inside the recording device 1.

[0143] Figure 11 is a flowchart of the S705 subroutine that can be applied to this embodiment.

[0144] As shown in Figure 11, in S705 of this embodiment (see Figure 7), the flowchart in Figure 11 is performed instead of the flowchart in Figure 8. In this embodiment, after S802, the CPU 41 (see Figure 2) performs the process in S1101.

[0145] In S1101, CPU41 (see Figure 2) acquires the ambient temperature TE.

[0146] In S1102, the CPU 41 compares the temperature obtained by subtracting the ambient temperature TE from the head temperature TP with a third temperature difference (Tth3) to determine whether the value obtained by subtracting the ambient temperature TE from the head temperature TP is less than the third temperature difference (Tth3). For example, the CPU 41 determines whether the temperature obtained by subtracting the ambient temperature TE from the head temperature TP is less than 4°C. However, the example of the third temperature difference (Tth3) is not limited to 4°C. For example, the third temperature difference (Tth3) can be set appropriately within the range of 3°C to 5°C.

[0147] If the temperature obtained by subtracting the ambient temperature TE from the head temperature TP is less than the third temperature difference (Tth3) (YES in S1304), the CPU 41 executes the process in S1103. On the other hand, if the temperature obtained by subtracting the ambient temperature TE from the head temperature TP is greater than or equal to the third temperature difference (Tth3) (NO in S1304), the CPU 41 executes the process in S807.

[0148] In S1103, the CPU 41 determines whether the circulation channel temperature TI is lower than the ambient temperature TE. If the circulation channel temperature TI is lower than the ambient temperature TE, the CPU 41 executes the process in S806. On the other hand, if the circulation channel temperature TI is equal to or greater than the ambient temperature TE, the CPU 41 executes the process in S807.

[0149] As explained above, in this embodiment, when determining whether or not to stop the cooling operation, the ambient temperature TE is also considered as a determination factor in addition to the head temperature TP and the circulation channel temperature TI.

[0150] Therefore, if there is a risk that the ink temperature will rise due to the influence of the ambient temperature TE after the recording operation is completed, stopping the cooling operation is not permitted.

[0151] Therefore, according to the recording device 1 of this embodiment, it is possible to suppress changes in the properties of the ink after the recording operation is completed with greater accuracy.

[0152] [Modified version of the second embodiment] In step S1103 described above, it was determined whether the circulation channel temperature TI was lower than the ambient temperature TE. However, the examples of comparison targets for the circulation channel temperature TI are not limited to the ambient temperature TE.

[0153] For example, the CPU 41 may acquire the circulation setting temperature TC set by the user, and determine whether the circulation channel temperature TI is less than or equal to the circulation setting temperature TC. If the circulation channel temperature TI is less than or equal to the circulation setting temperature TC, the CPU 41 may execute the process in S806, and if the circulation channel temperature TI is greater than the circulation setting temperature TC, the CPU 41 may execute the process in S807.

[0154] On the other hand, if the circulation setting temperature TC is higher than the circulation channel temperature TI and the ambient temperature TE, the risk of the ink temperature exceeding the circulation setting temperature TC (e.g., 22°C) is extremely low (see Figure 9(b)).

[0155] Therefore, in this case, even if the cooling operation is stopped, there is little risk of the ink's properties changing.

[0156] Therefore, this configuration also makes it possible to suppress changes in the properties of the ink after the recording operation is completed with greater precision.

[0157] [Other embodiments] In the first and second embodiments, the multiple recording heads 22 were located inside a single recording unit 8. However, the inside of a single recording unit 8 may be divided into multiple sections. Each of these sections may be equipped with a recording head 22, an upstream circulation pump 55, a downstream circulation pump 56, an intake fan 33, an exhaust fan 34, and the like. In this configuration, the first temperature sensor 32 detects the temperature of each of the multiple sections. The CPU 41 then controls the operation of the upstream circulation pump 55, the downstream circulation pump 56, the intake fan 33, and the exhaust fan 34 for each of the multiple sections.

[0158] This configuration allows for the acquisition of a narrower temperature range, thus enabling more accurate suppression of changes in ink properties after the recording operation is complete.

[0159] Furthermore, in the first and second embodiments, the description assumed that the recording device 1 is a line-type inkjet printer equipped with a recording head 22 having a size greater than or equal to the width of the recording medium S. However, the technology of this disclosure can also be applied to serial-type inkjet printers that perform recording while moving back and forth along the scanning direction, as long as they are configured to allow comparison between the ink temperature in the circulation path and the ambient temperature.

[0160] Furthermore, while ink was used as the liquid in the first and second embodiments, the liquids that can be used in the technology of this disclosure are not limited to ink. In addition to ink, various recording liquids can be used as liquids, including processing liquids used to improve ink fixation on recording media, reduce gloss unevenness, and improve scratch resistance.

[0161] This technology can also be implemented by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. Furthermore, this technology can also be implemented by a circuit (e.g., an ASIC) that implements one or more functions.

[0162] This disclosure includes the following configuration and method:

[0163] [Configuration 1] A recording head equipped with a recording element that generates energy for ejecting liquid, A liquid storage section for storing liquid, A circulation channel that supplies liquid from the liquid storage section to the recording head and returns it to the liquid storage section, A circulation drive unit that circulates the liquid in the aforementioned circulation channel, A ventilation unit for ventilating the air inside the recording unit where the recording head and the circulation channel are provided, A first temperature detection unit for detecting the temperature of the recording unit, A second temperature detection unit for detecting the liquid temperature in the circulation channel, A control unit that controls the drive of the circulation drive unit and the drive of the ventilation unit, Equipped with, If the difference between the temperature detected by the first temperature detection unit and the temperature detected by the second temperature detection unit is greater than or equal to the first temperature difference, and if the first time has not elapsed since the recording operation of the recording head was completed, the control unit drives the circulation drive unit and the ventilation unit. A recording device characterized by the following features.

[0164] [Configuration 2] If the difference between the temperature detected by the first temperature detection unit and the temperature detected by the second temperature detection unit is less than the first temperature difference, and the first time has elapsed since the recording operation of the recording head was completed, the control unit stops the circulation drive unit and the ventilation unit. The recording device described in Configuration 1.

[0165] [Configuration 3] If the first time has not elapsed since the recording operation of the recording head was completed, and the difference between the current temperature of the recording unit and the temperature of the recording unit at a point in time two hours prior to the current time is less than the second temperature difference, the control unit stops the circulation drive unit and the ventilation unit. A recording device as described in configuration 1 or 2.

[0166] [Structure 4] If the first time has not elapsed since the recording operation of the recording head was completed, and the difference between the current temperature of the recording unit and the temperature of the recording unit at a point in time two hours prior to the current time is greater than or equal to the second temperature difference, the control unit drives the circulation drive unit and the ventilation unit. The recording device described in Configuration 3.

[0167] [Composition 5] A recording head equipped with a recording element that generates energy for ejecting liquid, A liquid storage section for storing liquid, A circulation channel that supplies liquid from the liquid storage section to the recording head and returns it to the liquid storage section, A circulation drive unit that circulates the liquid in the aforementioned circulation channel, A ventilation unit for ventilating the air inside the recording unit where the recording head and the circulation channel are provided, A first temperature detection unit for detecting the temperature of the recording unit, A second temperature detection unit for detecting the liquid temperature in the circulation channel, A third temperature detection unit detects the ambient temperature around the recording unit, A control unit that controls the drive of the circulation drive unit and the drive of the ventilation unit, Equipped with, If the first time has not elapsed since the recording operation of the recording head was completed, and the difference between the temperature detected by the third temperature detection unit and the temperature detected by the second temperature detection unit is less than the third temperature difference, and the temperature detected by the first temperature detection unit is lower than the temperature detected by the third temperature detection unit, the control unit stops the circulation drive unit and the ventilation unit. A recording device characterized by the following features.

[0168] [Composition 6] If the first time has not elapsed since the recording operation of the recording head was completed, and the difference between the temperature detected by the third temperature detection unit and the temperature detected by the second temperature detection unit is greater than or equal to the third temperature difference, the control unit drives the circulation drive unit and the ventilation unit. The recording device described in Configuration 5.

[0169] [Composition 7] The interior of the recording unit includes multiple areas, Each of the plurality of areas is provided with the recording head, the circulation drive unit, and the ventilation unit. The second temperature detection unit detects the temperature of each of the areas, The control unit controls the operation of the circulation drive unit and the ventilation unit for each of the plurality of areas. A recording device as described in configuration 5 or 6.

[0170] [Structure 8] The system includes a plurality of sets of the circulation channel and the first temperature sensing unit, If the difference between the temperature detected by the second temperature detection unit and the highest temperature among the plurality of first temperature detection units is greater than or equal to the first temperature difference, and the first time has not elapsed since the recording operation of the recording head was completed, the control unit drives the circulation drive unit and the ventilation unit. A recording device as described in any one of items 1 to 7 of the configuration.

[0171] [Composition 9] The liquid is an ink containing a thermoplastic resin. A recording device as described in any one of items 1 to 8 of the configuration.

[0172] [Configuration 10] The aforementioned circulation channel is A first channel for supplying liquid from the liquid storage unit to the recording head, A second channel for recovering liquid from the recording head to the liquid storage section, Includes, The aforementioned circulation drive unit is A first pump provided in the first flow path for supplying liquid from the liquid storage unit to the recording head, A second pump is provided in the second flow path for recovering liquid from the recording head to the liquid storage section, including, A recording device as described in any one of items 1 to 9 of the configuration.

[0173] [Composition 11] The aforementioned ventilation unit is An intake fan draws air from the outside to the inside of the recording unit, An exhaust fan that exhausts air from the inside of the recording unit to the outside, including, A recording device as described in any one of items 1 to 10 of the configuration.

[0174] [Composition 12] The system further includes a temperature control unit for adjusting the liquid in the circulation channel to a predetermined temperature range, The control unit drives the temperature control unit together with the circulation drive unit. A recording device as described in any one of items 1 to 11 of the configuration.

[0175] [Composition 13] The temperature control unit is a heat exchanger. The recording device described in configuration 12.

[0176] [Composition 14] The system further includes a temperature control unit for adjusting the liquid in the circulation channel to a predetermined temperature range, The control unit drives the temperature control unit together with the circulation drive unit. A recording device as described in any one of items 1 to 11 of the configuration.

[0177] [Composition 15] The temperature control unit is a heat exchanger. The recording device described in configuration 14.

[0178] [Method 16] A recording head equipped with a recording element that generates energy for ejecting liquid, A liquid storage section for storing liquid, A circulation channel that supplies liquid from the liquid storage section to the recording head and returns it to the liquid storage section, A circulation drive unit that circulates the liquid in the aforementioned circulation channel, A ventilation unit for ventilating the air inside the recording unit where the recording head and the circulation channel are provided, A first temperature detection unit for detecting the temperature of the recording unit, A second temperature detection unit for detecting the liquid temperature in the circulation channel, A control method for a recording device comprising, If the difference between the temperature detected by the first temperature detection unit and the temperature detected by the second temperature detection unit is greater than or equal to the first temperature difference, and if the first time has not elapsed since the recording operation of the recording head was completed, the circulation drive unit and the ventilation unit are driven. A control method characterized by the following:

[0179] [Method 17] A recording head equipped with a recording element that generates energy for ejecting liquid, A recording head equipped with a recording element that generates energy for ejecting liquid, A liquid storage section for storing liquid, A circulation channel that supplies liquid from the liquid storage section to the recording head and returns it to the liquid storage section, A circulation drive unit that circulates the liquid in the aforementioned circulation channel, A ventilation unit for ventilating the air inside the recording unit where the recording head and the circulation channel are provided, A first temperature detection unit for detecting the temperature of the recording unit, A second temperature detection unit for detecting the liquid temperature in the circulation channel, A third temperature detection unit detects the ambient temperature around the recording unit, A control method for a recording device comprising, If the first time has not elapsed since the recording operation of the recording head was completed, and the difference between the temperature detected by the third temperature detection unit and the temperature detected by the second temperature detection unit is less than the third temperature difference, and the temperature detected by the first temperature detection unit is lower than the temperature detected by the third temperature detection unit, then the circulation drive unit and the ventilation unit are stopped. A control method characterized by the following:

Claims

1. A recording head equipped with a recording element that generates energy for ejecting liquid, A liquid storage section for storing liquid, A circulation channel that supplies liquid from the liquid storage section to the recording head and returns it to the liquid storage section, A circulation drive unit that circulates the liquid in the aforementioned circulation channel, A ventilation unit for ventilating the air inside the recording unit where the recording head and the circulation channel are provided, A first temperature detection unit for detecting the temperature of the recording unit, A second temperature detection unit for detecting the liquid temperature in the circulation channel, A control unit that controls the drive of the circulation drive unit and the drive of the ventilation unit, Equipped with, If the difference between the temperature detected by the first temperature detection unit and the temperature detected by the second temperature detection unit is greater than or equal to the first temperature difference, and if the first time has not elapsed since the recording operation of the recording head was completed, the control unit drives the circulation drive unit and the ventilation unit. A recording device characterized by the following features.

2. If the difference between the temperature detected by the first temperature detection unit and the temperature detected by the second temperature detection unit is less than the first temperature difference, and the first time has elapsed since the recording operation of the recording head was completed, the control unit stops the circulation drive unit and the ventilation unit. The recording device according to claim 1.

3. If the first time has not elapsed since the recording operation of the recording head was completed, and the difference between the current temperature of the recording unit and the temperature of the recording unit at a point in time two hours prior to the current time is less than the second temperature difference, the control unit stops the circulation drive unit and the ventilation unit. The recording device according to claim 1.

4. If the first time has not elapsed since the recording operation of the recording head was completed, and the difference between the current temperature of the recording unit and the temperature of the recording unit at a point in time two hours prior to the current time is greater than or equal to the second temperature difference, the control unit drives the circulation drive unit and the ventilation unit. The recording device according to claim 3.

5. A recording head equipped with a recording element that generates energy for ejecting liquid, A liquid storage section for storing liquid, A circulation channel that supplies liquid from the liquid storage section to the recording head and returns it to the liquid storage section, A circulation drive unit that circulates the liquid in the aforementioned circulation channel, A ventilation unit for ventilating the air inside the recording unit where the recording head and the circulation channel are provided, A first temperature detection unit for detecting the temperature of the recording unit, A second temperature detection unit for detecting the liquid temperature in the circulation channel, A third temperature detection unit detects the ambient temperature around the recording unit, A control unit that controls the drive of the circulation drive unit and the drive of the ventilation unit, Equipped with, If the first time has not elapsed since the recording operation of the recording head was completed, and the difference between the temperature detected by the third temperature detection unit and the temperature detected by the second temperature detection unit is less than the third temperature difference, and the temperature detected by the first temperature detection unit is lower than the temperature detected by the third temperature detection unit, the control unit stops the circulation drive unit and the ventilation unit. A recording device characterized by the following features.

6. If the first time has not elapsed since the recording operation of the recording head was completed, and the difference between the temperature detected by the third temperature detection unit and the temperature detected by the second temperature detection unit is greater than or equal to the third temperature difference, the control unit drives the circulation drive unit and the ventilation unit. The recording device according to claim 5.

7. The interior of the recording unit includes multiple areas, Each of the plurality of areas is provided with the recording head, the circulation drive unit, and the ventilation unit. The second temperature detection unit detects the temperature of each of the areas, The control unit controls the operation of the circulation drive unit and the ventilation unit for each of the plurality of areas. The recording device according to claim 5.

8. The system includes a plurality of sets of the circulation channel and the first temperature sensing unit, If the difference between the temperature detected by the second temperature detection unit and the highest temperature among the plurality of first temperature detection units is greater than or equal to the first temperature difference, and the first time has not elapsed since the recording operation of the recording head was completed, the control unit drives the circulation drive unit and the ventilation unit. A recording device according to claim 1 or 5.

9. The liquid is an ink containing a thermoplastic resin. A recording device according to claim 1 or 5.

10. The aforementioned circulation channel is A first channel for supplying liquid from the liquid storage unit to the recording head, A second channel for recovering liquid from the recording head to the liquid storage section, Includes, The aforementioned circulation drive unit is A first pump provided in the first flow path supplies liquid from the liquid storage unit to the recording head, A second pump is provided in the second flow path for recovering liquid from the recording head to the liquid storage section, including, A recording device according to claim 1 or 5.

11. The aforementioned ventilation section is An intake fan draws air from the outside to the inside of the recording unit, An exhaust fan that exhausts air from the inside of the recording unit to the outside, including, A recording device according to claim 1 or 5.

12. The system further includes a temperature control unit for adjusting the liquid in the circulation channel to a predetermined temperature range, The control unit drives the temperature control unit together with the circulation drive unit. The recording device according to claim 1.

13. The temperature control unit is a heat exchanger. The recording device according to claim 12.

14. The system further includes a temperature control unit for adjusting the liquid in the circulation channel to a predetermined temperature range, The control unit drives the temperature control unit together with the circulation drive unit. The recording device according to claim 5.

15. The temperature control unit is a heat exchanger. The recording device according to claim 14.

16. A recording head equipped with a recording element that generates energy for ejecting liquid, A liquid storage section for storing liquid, A circulation channel that supplies liquid from the liquid storage section to the recording head and returns it to the liquid storage section, A circulation drive unit that circulates the liquid in the aforementioned circulation channel, A ventilation unit for ventilating the air inside the recording unit where the recording head and the circulation channel are provided, A first temperature detection unit for detecting the temperature of the recording unit, A second temperature detection unit for detecting the liquid temperature in the circulation channel, A control method for a recording device comprising, If the difference between the temperature detected by the first temperature detection unit and the temperature detected by the second temperature detection unit is greater than or equal to the first temperature difference, and if the first time has not elapsed since the recording operation of the recording head was completed, the circulation drive unit and the ventilation unit are driven. A control method characterized by the following:

17. A recording head equipped with a recording element that generates energy for ejecting liquid, A recording head equipped with a recording element that generates energy for ejecting liquid, A liquid storage section for storing liquid, A circulation channel that supplies liquid from the liquid storage section to the recording head and returns it to the liquid storage section, A circulation drive unit that circulates the liquid in the aforementioned circulation channel, A ventilation unit for ventilating the air inside the recording unit where the recording head and the circulation channel are provided, A first temperature detection unit for detecting the temperature of the recording unit, A second temperature detection unit for detecting the liquid temperature in the circulation channel, A third temperature detection unit detects the ambient temperature around the recording unit, A control method for a recording device comprising, If the first time has not elapsed since the recording operation of the recording head was completed, and the difference between the temperature detected by the third temperature detection unit and the temperature detected by the second temperature detection unit is less than the third temperature difference, and the temperature detected by the first temperature detection unit is lower than the temperature detected by the third temperature detection unit, the circulation drive unit and the ventilation unit are stopped. A control method characterized by the following:

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