Inkjet recording device, temperature control method, and program

Abstract

The goal is to reduce ink bubbles during the printing process. [Solution] The inkjet recording device comprises an inkjet head 24a, a liquid delivery unit 40, heaters 4213h and 412h as adjustment units, and a control unit. The inkjet head 24a ejects ink. The liquid delivery unit 40 delivers ink. The heaters 4213h and 412h adjust the temperature of the ink in the liquid delivery unit 40 upstream of the inkjet head 24a. The control unit adjusts the temperature of the ink in the upstream liquid delivery unit 40 using the heaters 4213h and 412h to eliminate air bubbles in the ink.

Description

Technical Field

[0001] The present disclosure relates to an inkjet recording apparatus, a temperature control method, and a program.

Background Art

[0002] Conventionally, a droplet discharge apparatus (inkjet recording apparatus) that discharges droplets from a droplet discharge head is known. The droplet discharge apparatus includes a plurality of tanks each containing a liquid. For example, a float switch is provided in the tank as a measuring unit that measures the liquid level height of the liquid.

[0003] When ink is heated in an ink supply flow path, air dissolved in the ink and air taken in a dispersed state during stirring in the ink tank are released into the flow path as bubbles when the liquid is fed and heated. In this way, bubble accumulation may occur in the flow path and in the tank. When ink foams, its density decreases. For this reason, the buoyancy acting on the float switch decreases, and as a result, the measuring unit may erroneously detect the liquid level height. As bubble growth progresses, there is a risk that the pressure-adjusting air flow path provided at the upper part of the tank may be contaminated, so it is necessary to suppress apparatus troubles and quality degradation caused by bubbles.

[0004] Since the ink flow rate varies depending on the printing pattern, foaming cannot be reduced with a fixed temperature setting. For this reason, there is known a recording head cartridge that stores residual bubbles in an ink flow path at high temperature, collects and discharges the coalesced bubbles (see Patent Document 1). There is also known a print head assembly for an inkjet printer that applies pressure and temperature to phase-change ink to move and discharge bubbles (see Patent Document 2). The print head assembly forms a liquid phase and a solid phase of ink in the flow path by setting a temperature gradient in the ink flow path. The print head assembly fills voids existing in the solid phase by allowing liquid to penetrate into the voids via a pressure difference generated by a temperature difference and applied pressure.

Prior Art Literature

Patent Literature

[0005] [Patent Document 1] Japanese Patent Publication No. 2011-224851 [Patent Document 2] Japanese Patent Publication No. 2012-162078 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, the above-mentioned recording head cartridge has a strong maintenance component and cannot remove air bubbles generated during the ink heating process during continuous printing without interrupting printing. Furthermore, the above-mentioned print head assembly may be effective during maintenance while warming up, but may not be effective during printing. In addition, Patent Document 2 describes removing air from the free surface of the head along with the ink, which suggests that air bubbles are being ejected along with the ink, potentially affecting print quality. For this reason, there is a risk in releasing air from the head. Moreover, even during printing, with ink flow rate and head temperature changing, it may not be possible to adequately control the degree of air bubble removal by controlling pressure and temperature.

[0007] The objective of this disclosure is to reduce ink bubbles even during printing. [Means for solving the problem]

[0008] To solve the above problems, the inkjet recording apparatus disclosed in claim 1 is An inkjet head that ejects ink, A liquid supply unit that delivers the aforementioned ink, An adjustment unit for adjusting the ink temperature within the liquid delivery section upstream of the inkjet head, The system includes a control unit that adjusts the temperature of the ink in the upstream liquid supply unit using the adjustment unit, thereby eliminating air bubbles in the ink.

[0009] The disclosure described in claim 2 relates to the inkjet recording apparatus described in claim 1, The aforementioned liquid delivery unit is A storage unit for storing the aforementioned ink, The liquid flow path of the aforementioned ink, Dissolving unit for dissolving the aforementioned ink, A heat-insulating section for keeping the ink warm is provided in order from the upstream side to the inkjet head. The control unit defoams the ink from the dissolving section to the heat retention section by adjusting the temperature of the adjustment unit.

[0010] The disclosure described in claim 3 relates to the inkjet recording apparatus described in claim 2, The aforementioned heat-retaining section is equipped with a first temperature detection unit that detects the ink temperature, The adjustment unit has a first heating unit that heats the ink in the dissolving unit, During the printing operation, the control unit changes the set temperature of the first heating unit so that the detected ink temperature of the heat-retaining unit reaches the target temperature.

[0011] The disclosure described in claim 4 relates to the inkjet recording apparatus described in claim 2 or 3, It is equipped with a second temperature detection unit that detects the ink temperature of the dissolving unit, The adjustment unit has a second heating unit that heats the ink in the heat retention unit. During the printing operation, the control unit changes the set temperature of the second heating unit so that the detected ink temperature of the dissolving unit reaches the target temperature.

[0012] The disclosure described in claim 5 relates to the inkjet recording apparatus described in claim 4, The control unit changes the set temperature of the second heating unit based on a time constant calculated from the ink flow volume and ink flow rate from the melting unit to the heat retention unit, according to the detected ink temperature of the melting unit.

[0013] The disclosure described in claim 6 relates to the inkjet recording apparatus described in claim 5, The control unit acquires the ink flow rate from a flow rate measurement unit that measures the ink flow rate from the dissolving unit to the heat retention unit, or calculates the ink flow rate from image data difference.

[0014] The disclosure according to claim 7 provides the inkjet recording apparatus according to claim 2, wherein: The adjustment unit includes a first heating unit that heats ink in the dissolving unit, and a second heating unit that heats ink in the heat retention unit, a third temperature detection unit that detects an ink temperature or a tank temperature of the dissolving unit, and a fourth temperature detection unit that detects an ink temperature or a tank temperature of the heat retention unit, The control unit performs temperature control on the first heating unit such that the detected ink temperature or tank temperature of the dissolving unit reaches a target temperature, and performs temperature control on the second heating unit such that the detected ink temperature or tank temperature of the heat retention unit reaches a target temperature, during a period other than a printing operation.

[0015] The disclosure according to claim 8 provides the inkjet recording apparatus according to claim 1 or 2, wherein: The ink is UV ink.

[0016] The disclosure according to claim 9 provides the inkjet recording apparatus according to claim 1 or 2, wherein: The ink is phase-change gel ink.

[0017] The temperature control method of the disclosure according to claim 10 is: an inkjet head that ejects ink, a liquid feeding unit that feeds the ink, a temperature control method for an inkjet recording apparatus, comprising: an adjustment unit that adjusts a temperature of ink in the liquid feeding unit on an upstream side of the inkjet head, the method comprises a control step of adjusting a temperature of ink in the upstream liquid feeding unit by the adjustment unit to defoam bubbles contained in the ink.

[0018] The program of the disclosure according to claim 11 is: An inkjet head that ejects ink, A liquid supply unit that delivers the aforementioned ink, A computer for an inkjet recording device, comprising an adjustment unit for adjusting the temperature of the ink in the liquid delivery unit upstream of the inkjet head, The control unit adjusts the temperature of the ink in the upstream liquid supply section using the adjustment unit to eliminate air bubbles in the ink. To make it function as such. [Effects of the Invention]

[0019] According to this disclosure, ink bubbles can be reduced even during printing. [Brief explanation of the drawing]

[0020] [Figure 1] This is a side view of an inkjet recording apparatus according to an embodiment of the present disclosure. [Figure 2] This is a schematic diagram showing the liquid delivery section. [Figure 3] This is a block diagram showing a part of the fluid delivery section. [Figure 4] This is a block diagram showing the functional configuration of an inkjet recording device. [Figure 5] This is a flowchart showing the temperature control process. [Figure 6] This is a diagram showing the settings table. [Figure 7] This is a diagram showing the settings table. [Figure 8] This figure shows the characteristics of the dissolution section ink setting temperature corresponding to the first sub-tank ink temperature. [Figure 9] This figure shows the characteristics of the first sub-tank ink setting temperature corresponding to the dissolution ink temperature. [Figure 10] This figure shows the relationship between ink temperature and ink discharge time in the example. [Figure 11] This figure shows the relationship between ink temperature and ink discharge time for the comparative example. [Figure 12]This figure shows an example of the time characteristics of the dissolution section ink temperature, the first sub-tank ink setting temperature, and the dissolution section ink setting temperature. [Modes for carrying out the invention]

[0021] The advantages and features provided by one or more embodiments of this disclosure will be better understood from the following detailed description and accompanying drawings. However, these drawings are for illustrative purposes only and are not intended to define the limits of this disclosure. Embodiments of this disclosure will be described below with reference to the drawings. However, the scope of this disclosure is not limited to the embodiments disclosed.

[0022] A first embodiment of the present disclosure will be described with reference to Figures 1 to 12. First, the configuration of the inkjet recording apparatus 1 of this embodiment will be described with reference to Figures 1 to 4. Figure 1 is a side view showing the inkjet recording apparatus 1 of this embodiment. Figure 2 is a schematic diagram showing the liquid supply unit 40. Figure 3 is a block diagram showing a part of the liquid supply unit 40. Figure 4 is a block diagram showing the functional configuration of the inkjet recording apparatus 1.

[0023] Referring to Figure 1, the overall configuration of the inkjet recording device 1 will be described. The inkjet recording device 1 comprises a paper feeding unit 10, an image forming unit 20, and a paper discharge unit 30. The inkjet recording device 1 transports the recording medium P from the paper feeding unit 10 to the image forming unit 20. The image forming unit 20 forms an image on the recording medium P using ink supplied from the liquid supply unit 40 (see Figures 2 to 4). After image formation, the paper discharge unit 30 control unit 50 discharges the recording medium P into the paper discharge tray 31.

[0024] The recording medium P is, but is not limited to, paper such as plain paper or coated paper. Various media capable of fixing ink deposited on their surface can be used as the recording medium P, such as cloth or sheet-like resin.

[0025] Furthermore, Figure 1 shows the three-dimensional X, Y, and Z axes. The +X, +Y, and +Z directions will also be referred to as the width direction, transport direction, and height direction, respectively.

[0026] The paper feeding unit 10 stores recording media P before image formation and transports the recording media P to the image forming unit 20. The paper feeding unit 10 comprises a paper feeding tray 11 and a transport unit 12. The paper feeding tray 11 is a plate-shaped member for storing recording media P. The paper feeding tray 11 is provided so that one or more recording media P can be placed on it. The paper feeding tray 11 moves up and down according to the amount of recording media P placed on it. Through this up and down movement, the paper feeding tray 11 is held in a position where the uppermost recording media P is transported by the transport unit 12.

[0027] The transport unit 12 transports the recording medium P from the paper feed tray 11 to the image forming unit 20. The transport unit 12 is equipped with a transport mechanism. The transport mechanism drives a belt 123 to transport the recording medium P on the belt 123. The belt 123 is ring-shaped, and the inside of the ring is supported by a plurality of rollers 121 and 122. The transport unit 12 transfers the uppermost recording medium P placed on the paper feed tray 11 onto the belt 123 and transports the recording medium P along the belt 123.

[0028] The image forming unit 20 works in cooperation with the liquid delivery unit 40 to record an image on the recording medium P. The image forming unit 20 includes an image forming drum 21, a transfer unit 22, a paper heating unit 23, a head unit 24, an irradiation unit 25, a delivery unit 26, and the like.

[0029] The image forming drum 21 carries the recording medium P along its cylindrical outer surface and transports the recording medium P as it rotates. The transport surface of the image forming drum 21 faces the paper heating unit 23, the head unit 24, and the irradiation unit 25, and performs image forming processing on the transported recording medium P.

[0030] The transfer unit 22 is positioned between the transport unit 12 and the image forming drum 21. The transfer unit 22 includes a claw portion 221, a transfer drum 222, and the like. The claw portion 221 is a cylindrical member that supports one end of the recording medium P transported by the transport unit 12. The transfer drum 222 is a member that guides the recording medium P supported by the claw portion 221. The transfer unit 22 picks up the recording medium P on the transport unit 12 with the claw portion 221 and guides it along the outer surface of the transfer drum 222. Through this operation, the transfer unit 22 transfers the recording medium P to the image forming drum 21.

[0031] The paper heating unit 23 is equipped with a heating element and generates heat in response to the application of electricity. The paper heating unit 23 is controlled by the control unit 50 and generates heat so that the recording medium P passing near it reaches a predetermined temperature. The paper heating unit 23 is located near the outer surface of the image forming drum 21 and is positioned upstream of the head unit 24 in the transport direction of the recording medium P. A temperature sensor (not shown) is provided near the paper heating unit 23. The control unit 50 (see Figure 4) detects the temperature near the paper heating unit 23 using the temperature sensor. Based on the detected temperature, the control unit 50 controls the heat generation of the paper heating unit 23.

[0032] The head unit 24 is composed of, for example, multiple inkjet heads 24a and a carriage on which the inkjet heads 24a are mounted. The head unit 24 ejects ink droplets from nozzles onto the recording medium P to form an image. Head units 24 are provided, each corresponding to a different color: C (cyan), M (magenta), Y (yellow), and K (black). In Figure 1, the head units 24 corresponding to the colors Y, M, C, and K are arranged in order from upstream in the transport direction of the recording medium P.

[0033] In this embodiment, the head unit 24 is arranged in multiple configurations with a length (width) that covers the entire recording medium P in the width direction. That is, the inkjet recording device 1 is a one-pass line-head type inkjet recording device. The head unit 24 is composed of multiple inkjet heads 24a arranged in the transport direction. The number of head units 24 may be five or more, or three or fewer. Alternatively, a single inkjet head 24a may constitute the head unit 24.

[0034] The ink ejected by the head unit 24 is, for example, an ultraviolet-curable ink (UV (Ultra Violet) ink). The ultraviolet-curable ink includes, for example, an ultraviolet-curable resin. The ultraviolet-curable resin includes a monomer and a polymerization initiator. When the ink containing the ultraviolet-curable resin is irradiated with ultraviolet light, the monomer polymerizes and hardens due to the action of the polymerization initiator, and the ink is fixed to the recording medium P.

[0035] The ink ejected by the head unit 24 may be a phase-change gel ink containing a gelling agent. Phase-change gel ink undergoes a phase change between a gel state (solid phase) and a liquid (sol) state (liquid phase) depending on the temperature. Gel ink has a phase change temperature of, for example, 40 to 100°C, and uniformly liquefies (solifies) when heated above the phase change temperature. On the other hand, gel ink gels at normal room temperature, i.e., around 0 to 30°C. Therefore, the ink in the head unit 24 is heated to an appropriate temperature by an ink heater (not shown) or the like to become a sol. Then, after being ejected and landing on the recording medium P, it transitions to a gel state appropriately while being transported by the image forming drum 21.

[0036] The irradiation unit 25 is equipped with a fluorescent tube such as a low-pressure mercury lamp. The irradiation unit 25 irradiates energy rays such as ultraviolet rays through the emission of light from the fluorescent tube. The irradiation unit 25 is provided near the outer surface of the image forming drum 21. Furthermore, the irradiation unit 25 is provided so as to be located downstream of the head unit 24 in the transport direction of the recording medium P. The irradiation unit 25 irradiates the recording medium P on which the ink has been ejected with energy rays. If the ink on the recording medium P is UV ink, it hardens due to the action of these energy rays.

[0037] Furthermore, the fluorescent tubes that emit ultraviolet light are not limited to low-pressure mercury lamps. The fluorescent tubes may be, for example, mercury lamps with an operating pressure of several hundred Pa to approximately 1 MPa. Alternatively, the fluorescent tubes may be light sources usable as germicidal lamps, such as cold cathode fluorescent lamps, ultraviolet laser light sources, metal halide lamps, or light-emitting diodes. Among these, it is desirable that the fluorescent tubes be light sources capable of emitting ultraviolet light at a higher intensity and with low power consumption. Examples of such fluorescent tubes include light-emitting diodes. The energy rays are not limited to ultraviolet light; any energy ray that has the property of curing ink, depending on the properties of the ink, is acceptable. The light source is also substituted according to the energy ray.

[0038] In the above example, the head unit 24 ejects UV ink or phase-change gel ink, but it is not limited to this. The ink ejected by the head unit 24 may be water-based ink or other inks having different physical properties.

[0039] The delivery unit 26 includes a transport mechanism. The transport mechanism transports the recording medium P by driving a ring-shaped belt 263, which is supported on the inside by a plurality of rollers 261, 262. The delivery unit 26 includes a cylindrical transfer roller 264. The transfer roller 264 transfers the recording medium P from the image forming drum 21 to the transport mechanism. The delivery unit 26 transports the recording medium P that has been transferred onto the belt 263 by the transfer roller 264 and sends it to the paper discharge unit 30.

[0040] The paper output unit 30 receives the recording medium P from which the image has been formed in the image forming unit 20. The paper output unit 30 includes a plate-shaped paper output tray 31, etc. The recording medium P sent out from the image forming unit 20 by the delivery unit 26 is placed on the paper output tray 31. The paper output unit 30 stores the recording medium P until the user removes it.

[0041] Next, the liquid supply unit 40 will be described with reference to Figures 2 and 3. Note that in Figure 2, multiple inkjet heads 24a are omitted, and one inkjet head 24a is shown as a representative example. The liquid supply unit 40 includes a tank 41, a liquid flow path 42, a temperature sensing unit 43, and a flow rate measuring unit 44 (see Figure 4 for both).

[0042] Tank 41 stores ink. Tank 41 is made of metal, for example, and has a rigid, sealed structure. Tank 41 comprises a main tank 411, a first sub-tank 412, and a second sub-tank 413. Main tank 411 contains ink of each color supplied to each part of the liquid supply unit 40. Although not shown in Figures 2 and 3, a main tank 411 is provided separately for each ink color. The ink is supplied to the inkjet head 24a sequentially via the first liquid channel 421, the first sub-tank 412, the second liquid channel 422, the second sub-tank 413, and the third liquid channel 423, which will be described later. The main tank 411 is replaceable as a whole and is formed to be detachable from the first liquid channel 421 regardless of the operating status of the first liquid supply unit 4211, which will be described later.

[0043] The first sub-tank 412 temporarily stores and maintains the temperature of the ink supplied from the main tank 411. The inclusion of the first sub-tank 412 in the liquid supply unit 40 mitigates pressure changes caused by pulsation when the first liquid supply unit 4211 supplies ink from the main tank 411. In addition, ink that is not discharged from the nozzles of the inkjet head 24a is recovered into the first sub-tank 412 from the outlet. The second sub-tank 413 temporarily stores the ink to be supplied to the inkjet head 24a. The second sub-tank 413 is provided with a back pressure adjustment means (not shown). The back pressure adjustment means prevents ink from leaking out of the inkjet head 24a by applying appropriate negative pressure to the inkjet head 24a. Hereafter, unless otherwise specified, the first sub-tank 412 and the second sub-tank 413 will simply be referred to as "sub-tanks" in the description.

[0044] The first sub-tank 412 and the second sub-tank 413 are each equipped with liquid level sensors F1 and F2. Liquid level sensors F1 and F2 measure information about the amount of ink in the attached sub-tanks. Specifically, liquid level sensors F1 and F2 each measure the liquid level position in the sub-tank and transmit this data to the control unit 50. Based on this data, the control unit 50 obtains the liquid level height in the sub-tank. Liquid level sensors F1 and F2 are float sensors comprising a float, a magnetic sensor, and a magnetic material (none of which are shown). Note that liquid level sensors F1 and F2 are not limited to float sensors. For example, the liquid level height in the sub-tank may be measured using a capacitive sensor that utilizes an electric field.

[0045] Furthermore, the sub-tank is equipped with a heating unit to maintain the ink inside at an appropriate temperature. As shown in Figure 3, the first sub-tank 412 has a heater 412h as a second heating unit. The heater 412h heats the ink stored in the first sub-tank 412 under the control of the control unit 50. The heater 412h consists of a heater body, a heat transfer member that transmits heat from the heater body to the ink side, and the like. The heater body is, for example, an electric heating wire that generates Joule heat when energized. The heat transfer member is a heat conductive plate made of a material with high thermal conductivity, for example, a heat conductive plate made of various metals (alloys).

[0046] Furthermore, the sub-tanks are equipped with a pressure sensor (not shown) capable of measuring the internal pressure value and an air path as shown in Figure 2. The air path is equipped with a pneumatic pump (not shown) capable of sucking air from each sub-tank and reducing the pressure under the control of the control unit 50, thereby controlling the pressure in each sub-tank. In particular, the control unit 50, for example, sends air from the second sub-tank 413 to the first sub-tank 412, thereby making the pressure inside the first sub-tank 412 higher than that inside the second sub-tank 413, and sending the ink in the first sub-tank 412 to the second sub-tank 413.

[0047] The liquid channel 42 is an ink channel that allows for recirculation from the main tank 411 to the inkjet head 24a. The liquid channel 42 comprises a first liquid channel 421, a second liquid channel 422, a third liquid channel 423, and a fourth liquid channel 424. The liquid channel 42 preferably has ink resistance and has a hollow, annular tube structure.

[0048] The first liquid channel 421 connects the main tank 411 and the first sub-tank 412. The first liquid channel 421 is equipped with a first liquid delivery unit 4211, a supply valve 4212, and a dissolving unit 4213. The first liquid delivery unit 4211 delivers ink from the main tank 411 to the first sub-tank 412. When the control unit 50 detects, based on the measurement results of the liquid level sensor F1, that the liquid level in the first sub-tank 412 is at a predetermined lower limit, it drives the first liquid delivery unit 4211 for a predetermined time to deliver ink from the main tank 411 to the first sub-tank 412.

[0049] The first liquid delivery unit 4211 is, for example, a pump, but is not limited thereto. If the first liquid delivery unit 4211 is a pump, it is preferably a diaphragm pump from the viewpoint of durability, cost, size, and variety. The supply valve 4212 is, for example, a solenoid valve. Under the control of the control unit 50, the supply valve 4212 selectively opens the first liquid flow path 421 when the first liquid delivery unit 4211 is driven.

[0050] The dissolution unit 4213 is a heating unit that stores the ink sent from the main tank 411 in the tank and heats and dissolves it. Under the control of the control unit 50, the dissolution unit 4213 heats the ink flowing in the first liquid channel 421 to a predetermined temperature and reduces its viscosity. As shown in Figure 3, the dissolution unit 4213 has a heater 4213h as a first heating unit. Under the control of the control unit 50, the heater 4213h heats the ink stored in the tank of the dissolution unit 4213. The heater 4213h has a configuration similar to, for example, the heater 412h.

[0051] The second liquid passage 422 is a passage that connects the first sub-tank 412 and the second sub-tank 413. The second liquid passage 422 is provided with a degassing section 4221, a second liquid supply section 4222, a circulation passage 4223, and a circulation valve 4224. The degassing section 4221 is a degassing module that removes gas dissolved in the ink that has passed through it. The degassing section 4221 has a gas permeable membrane that is depressurized by drawing in air from inside while it is in an airtight state. The degassing section 4221 removes the gas dissolved in the ink that has passed through it by bringing the ink into contact with the gas permeable membrane, thereby causing the dissolved gas in the ink to pass through the gas permeable membrane due to the pressure difference.

[0052] The second liquid supply unit 4222 supplies ink from the first sub-tank 412 to the second sub-tank 413. When the control unit 50 detects, based on the measurement results of the liquid level sensor F2, that the liquid level in the second sub-tank 413 is at a predetermined lower limit, it drives the second liquid supply unit 4222 for a predetermined time to supply ink from the first sub-tank 412. For the same reasons as the first liquid supply unit 4211, the second liquid supply unit 4222 is a pump, and if it is a pump, it is especially a diaphragm pump. It is preferable to do so.

[0053] The circulation channel 4223 is a channel provided to branch off from downstream of the second liquid delivery unit 4222 in the liquid delivery direction and upstream of the circulation valve 4224 in the liquid delivery direction. The circulation channel 4223 has a channel that communicates with the first liquid channel 421 between the supply valve 4212 and the dissolution unit 4213. With this configuration, when the control unit 50 closes the circulation valve 4224 and drives the second liquid delivery unit 4222, the ink delivered from the first sub-tank 412 passes through the dissolution unit 4213 and returns to the first sub-tank 412. Therefore, when the ink supply is stopped, it is possible to suppress a drop in ink temperature or uneven temperature distribution. The circulation valve 4224 is a solenoid valve that selectively opens the second liquid channel 422 when the second liquid delivery unit 4222 is driven.

[0054] Furthermore, upstream of the second liquid delivery section 4222 in the liquid delivery direction of the second liquid flow path 422, a known degassing module for removing air from the ink and a known filter for collecting foreign matter in the ink may be provided. Providing these configurations can suppress deterioration of the second liquid delivery section 4222. In addition, as described above, foreign matter in the ink can be removed when the ink is circulated.

[0055] The third liquid channel 423 is a channel that connects the second sub-tank 413 and the inlet of the inkjet head 24a. The fourth liquid channel 424 is a channel that connects the outlet of the inkjet head 24a and the first sub-tank 412. The fourth liquid channel 424 is provided with a second circulation valve 4241, which is a solenoid valve. Under the control of the control unit 50, the second circulation valve 4241 selectively opens the fourth liquid channel 424 when circulating ink from the inkjet head 24a to the first sub-tank 412.

[0056] The temperature detection unit 43 detects the temperature of the ink inside the dissolution unit 4213 and the first sub-tank 412. As shown in Figure 3, the temperature detection unit 43 has temperature detection units 431, 432, 433, and 434. The temperature detection unit 431, as the second temperature detection unit, is located near the outlet of the dissolution unit 4213 tank, detects the temperature of the supplied ink, and outputs the detected temperature information to the control unit 50. The temperature detection unit 432, as the first temperature detection unit, is located in the tank of the dissolution unit 4213, detects the temperature of the tank, and outputs the detected temperature information to the control unit 50. The temperature detection unit 433 is located in the tank of the dissolution unit 4213, detects the temperature of the tank, and outputs the detected temperature information to the control unit 50. The temperature detection unit 432 is located in the tank of the first sub-tank 412, detects the temperature of the tank, and outputs the detected temperature information to the control unit 50.

[0057] The flow rate measuring unit 44 measures the ink flow rate of the ink being supplied from the dissolution unit 4213 to the first sub-tank 412. The flow rate measuring unit 44 is composed of, for example, a clamp-type flow meter. The flow rate measuring unit 44 measures the ink flow rate [cc / s] supplied from the dissolution unit 4213 and outputs the measured ink flow rate to the control unit 50.

[0058] Referring to Figure 4, the internal functional configuration of the inkjet recording device 1 will be explained. The inkjet recording device 1 includes a paper feeding unit 10, an image forming unit 20, a paper discharge unit 30, a liquid delivery unit 40, a control unit 50, a storage unit 60, an operation panel 70, a communication unit 80, and the like. Each part of the inkjet recording device 1 is connected via a bus. The operation panel 70 includes a display unit 71 and an operation unit 72.

[0059] The control unit 50 includes a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), etc. The control unit 50 comprehensively controls the operation of each part of the inkjet recording device 1. The CPU reads various programs stored in the ROM, loads them into the RAM, and executes various processes in cooperation with the loaded programs. The RAM provides the CPU with a working memory space to temporarily store data. The ROM stores various programs and setting data. In particular, the ROM stores a temperature control program for executing the temperature control process described later. The ROM may also be a storage unit that can read information, such as flash memory.

[0060] The paper feeding unit 10 feeds the recording medium P to the image forming unit 20 according to the control unit 50. The image forming unit 20 forms an image on the recording medium P fed by the paper feeding unit 10 using an inkjet recording method, according to the control unit 50. The paper discharge unit 30 discharges the recording medium P on which the image has been formed by the image forming unit 20, according to the control unit 50. The ink supply unit 40 supplies ink to the inkjet head 24a of the image forming unit 20, according to the control unit 50.

[0061] The storage unit 60 stores print jobs and image data input from external devices such as PCs (Personal Computers) via the communication unit 80. In particular, the storage unit 60 stores setting tables 610 and 620 related to temperature settings during printing, which will be described later. The storage unit 60 also stores the target temperatures for the dissolving tank ink temperature and the first sub-tank ink temperature during standby. Alternatively, the storage unit 60 may store the target temperatures for the dissolving tank temperature and the first sub-tank temperature during standby instead of the target temperatures for the dissolving tank ink temperature and the first sub-tank ink temperature during standby.

[0062] The control panel 70 includes a display unit 71 that displays various information to the user and an operation unit 72 that receives operation input from the user. The display unit 71 is composed of an LCD (liquid crystal display), an ELD (electroluminescent display), etc. The display unit 71 displays display information input from the control unit 50. The display information includes various setting screens, various buttons, and the operating status of each function. The operation unit 72 includes a touchscreen provided on the screen of the display unit 71 and various hard keys arranged around the screen of the display unit 71. The operation unit 72 receives touch input and press input from the user and outputs the operation information to the control unit 50. In particular, the operation unit 72 has a power key that receives input for turning the power on and off of the inkjet recording device 1.

[0063] The communication unit 80 is a communication module connected to an external device or a communication network such as a LAN (Local Area Network). The communication unit 80 consists of input / output interfaces and a network card. The control unit 50 transmits and receives information to and from the external device or an external device on the communication network via the communication unit 80.

[0064] Next, the operation of the inkjet recording device 1 will be explained with reference to Figures 5 to 12. Figure 5 is a flowchart of the temperature control process. Figure 6 is a diagram of the setting table 610. Figure 7 is a diagram of the setting table 620. Figure 8 is a diagram showing the characteristics of the dissolution section ink setting temperature corresponding to the first sub-tank ink temperature. Figure 9 is a diagram showing the characteristics of the first sub-tank ink setting temperature corresponding to the dissolution section ink temperature. Figure 10 is a diagram showing the ink temperature as a function of ink discharge time in the example. Figure 11 is a diagram showing the ink temperature as a function of ink discharge time in the comparative example. Figure 12 is a diagram showing an example of the time characteristics of the dissolution section ink temperature, the first sub-tank ink setting temperature, the first sub-tank ink temperature, and the dissolution section ink setting temperature.

[0065] First, let's explain the foaming mechanism of ink. Foaming is a state in which dispersed gases dissolved in a liquid are released as bubbles when the temperature of the liquid ink is increased. In UV inks and phase-change gel inks used with heating, as in this embodiment, foaming is inevitable. Regarding the viscosity of the ink, the stability of the bubbles is related to the viscoelasticity of the thin foam film (lamellae) within the foam, and the higher the liquid viscosity, the more stable the bubbles become. Therefore, raising the ink temperature tends to decrease the viscosity, leading to instability and inducing defoaming.

[0066] Furthermore, regarding the interfacial tension of the ink, as the ink temperature rises, the interfacial tension decreases, making it more prone to foaming. Although it becomes easier to foam, the bubbles are coarse and large, so they come into contact with air and the bubble film is more likely to burst. It is thought that ink foaming occurs when a foam-breaking agent with low surface tension penetrates the foam film, causing a localized decrease in surface tension in that area. This decreased tension is then pulled by the surrounding foam film with higher surface tension, causing the bubbles to burst. For these reasons, it is preferable to control the ink temperature to one that is appropriate for defoaming.

[0067] Referring to Figure 5, the temperature control process performed in the inkjet recording device 1 will be explained. The temperature control process is a process that controls the temperature of the dissolution unit 4213 and the first sub-tank 412 when the inkjet recording device 1 is in standby mode and when printing (inkjet image formation). The setting tables 610 and 620, and the flow path volume [cc] in the flow path between the dissolution unit 4213 and the first sub-tank 412, which is being measured, are stored in the storage unit 60 in advance.

[0068] In the inkjet recording device 1, the user inputs a power-on instruction via the power key on the operation unit 72. Triggered by this instruction, the control unit 50 executes temperature control processing according to the temperature control program stored in the ROM.

[0069] In parallel with the temperature control process, the control unit 50 performs a print standby process and a print process. The standby process is the process of controlling the paper feed unit 10, image forming unit 20, paper discharge unit 30, and liquid supply unit 40 to a standby state after a power-on input from the user or after the print process is completed. The print process is the process of controlling the paper feed unit 10, image forming unit 20, paper discharge unit 30, and liquid supply unit 40 after a print command input from the user to form an image on the recording medium P based on the specified image data. However, the standby process and the print process do not include temperature control of the dissolution unit 4213 and the first sub-tank 412 in the temperature control process.

[0070] First, the control unit 50 determines whether or not printing has started due to the printing process (step S11). If the printer is in a standby state and printing has not started (step S11; NO), the control unit 50 has the temperature detection unit 433 detect and acquire the temperature of the first sub-tank ink (step S12). The control unit 50 reads the target temperature of the first sub-tank ink during standby from the storage unit 60 (step S13). In step S13, the control unit 50 controls the heater 412h so that the acquired temperature of the first sub-tank ink becomes the target temperature of the first sub-tank ink during standby. The heater 412h is controlled to either heat up or stop.

[0071] In step S12, the control unit 50 may have the temperature detection unit 434 detect and acquire the temperature of the first sub-tank. In this case, in step S13, the control unit 50 reads the target temperature of the first sub-tank during standby from the storage unit 60. The control unit 50 controls the heater 412h so that the acquired temperature of the first sub-tank becomes the set temperature of the first sub-tank during standby.

[0072] Then, the control unit 50 has the temperature detection unit 431 detect and acquire the dissolving ink temperature (step S14). The control unit 50 reads the target temperature for the dissolving ink temperature during standby from the storage unit 60 (step S15). In step S15, the control unit 50 controls the heater 4213h so that the acquired dissolving ink temperature becomes the target temperature for the dissolving ink temperature during standby. The heater 4213h is controlled to either heat up or stop.

[0073] In step S14, the control unit 50 may have the temperature detection unit 432 detect and acquire the melting tank temperature. In this case, in step S15, the control unit 50 reads the target temperature for the melting tank temperature during standby from the storage unit 60. The control unit 50 controls the heater 4213h so that the acquired melting tank temperature becomes the target temperature for the melting tank temperature during standby.

[0074] The control unit 50 determines whether to terminate the temperature control process based on the power off input from the user via the power key on the operation unit 72 (step S16). If the process is not terminated (step S16; NO), the process proceeds to step S11. If the process is terminated (step S16; YES), the temperature control process is terminated.

[0075] When printing is started by executing the print process (step S11; YES), the control unit 50 has the temperature detection unit 433 detect and acquire the first sub-tank ink temperature (step S17). The control unit 50 reads the setting table 610 from the storage unit 60 (step S18). The setting table 610 will now be explained with reference to Figure 6. The setting table 610 is a table that stores the dissolution unit ink setting temperatures corresponding to each range of the first sub-tank ink temperature [°C] according to a plurality of conditions 1 to 5. Temperature a [°C] is the target temperature of the ink. Temperature b [°C] is the initial value of the dissolution unit ink setting temperature. The setting table 610 is for performing temperature control corresponding to the linear L1 in the relationship between the first sub-tank ink temperature and the dissolution unit ink setting temperature shown in Figure 8. In the linear L1, if the first sub-tank ink temperature is lower than the target temperature a, the dissolution unit ink setting temperature is raised from temperature b to heat the dissolution unit 4213. In the linear L1, if the first sub-tank ink temperature is higher than the target temperature a, the dissolution section ink setting temperature is lowered from temperature b to stop heating the dissolution section 4213.

[0076] In step S18, the control unit 50 determines whether to change the currently set dissolving ink setting temperature to a different value in the setting table 610 corresponding to the acquired first sub-tank ink temperature. When step S18 is executed for the first time, it is assumed that the dissolving ink setting temperature is set to the initial value temperature b.

[0077] If the dissolution ink setting temperature is changed to a different one (step S18; YES), the process proceeds to step S19. In step S19, the control unit 50 changes the dissolution ink setting temperature to the value in the setting table 610 corresponding to the acquired first sub-tank ink temperature. In step S19, the control unit 50 controls the heater 4213h so that the dissolution ink temperature becomes the dissolution ink setting temperature for printing. The heater 4213h is controlled to either heat up or stop.

[0078] The control unit 50 then obtains the dissolution ink temperature by having the temperature detection unit 431 detect it (step S20). If the dissolution ink setting temperature is not changed to a different one (step S18; NO), the process proceeds to step S20. The control unit 50 reads the setting table 620 from the storage unit 60 (step S21). The setting table 620 will now be explained with reference to Figure 7. The setting table 620 is a table that stores the first sub-tank ink setting temperatures corresponding to each range of dissolution ink temperature [°C] according to multiple conditions 1 to 5. Temperature c [°C] is the initial value of the first sub-tank ink setting temperature. The setting table 620 is for performing temperature control corresponding to the straight line L2 in the relationship between the dissolution ink temperature and the first sub-tank ink setting temperature shown in Figure 9. In the straight line L2, if the dissolution ink temperature is lower than the target temperature a, the first sub-tank ink setting temperature is raised from temperature c to heat the first sub-tank 412. In the linear L2, if the dissolution ink temperature is higher than the target temperature a, the first sub-tank ink setting temperature is lowered from temperature c and the heating of the first sub-tank 412 is stopped. When step S21 is executed for the first time, the first sub-tank ink setting temperature is assumed to be set to the initial value temperature c.

[0079] In step S21, the control unit 50 determines whether to change the setting temperature of the first sub-tank ink that is currently being set to a different value in the setting table 620 corresponding to the acquired dissolution unit ink temperature. If the setting temperature of the first sub-tank ink is changed to a different value (step S21; YES), the process proceeds to step S22. In step S22, the control unit 50 reads the flow path volume from the storage unit 60 and obtains the ink flow rate by having the flow rate measuring unit 44 measure it. In step S23, the control unit 50 calculates a time constant indicating the time it takes to deliver ink from the dissolution unit 4213 to the first sub-tank 413 using the following equation (1). Time constant [s] = Flow channel volume [cc] ÷ Ink flow rate [cc / s] …(1)

[0080] Examples of time constants [s] are shown in Table I below. [Table 1] The control unit 50 may also be configured to calculate the time constant from the difference in image data.

[0081] In step S22, the control unit 50 takes a time constant into account (for example, after the time constant) and changes the first sub-tank ink setting temperature to the value in the setting table 620 corresponding to the acquired dissolution ink temperature. In step S22, the control unit 50 controls the heater 412h so that the first sub-tank ink temperature becomes the first sub-tank ink setting temperature during printing. The heater 412h is controlled to either heat up or stop.

[0082] The control unit 50 determines whether the printing process is complete or not (step S23). If the setting temperature of the first sub-tank ink is not changed to a different temperature (step S22; NO), the process proceeds to step S23. If the printing process is not complete (step S23; NO), the process proceeds to step S17. If the printing process is complete (step S23; YES), the process proceeds to step S16. Note that in step S23; NO, the control unit 50 may set the setting temperature of the dissolution section ink during printing to an initial value (e.g., temperature b). The control unit 50 may also set the setting temperature of the first sub-tank ink during printing to an initial value (e.g., temperature c).

[0083] Here, with reference to Figures 10 and 11, the effect of controlling the dissolution section set temperature according to the first sub-tank ink temperature will be explained. Referring to Figure 10, an embodiment of this example will be described. Figure 10 shows the ink temperature [°C] of the liquid delivery section 40 as a function of the ink discharge time [s] during the temperature control process of the inkjet recording device 1. At this time, the ink flow rate is 6.1 [cc / s]. The ink temperature [°C] of the liquid delivery section 40 is the dissolution section ink temperature [°C], the first sub-tank ink temperature [°C], and the dissolution section ink set temperature [°C]. Each value in Figure 10 is the control value or measured value during the execution of the temperature control process and the printing process in the inkjet recording device 1.

[0084] As shown in Figure 10, first, in steps S17 and S18, the temperature of the first sub-tank ink decreases from the target temperature. In step S19, the set temperature of the dissolving section ink is raised, and the heater 4213h is heated. By repeatedly executing steps S17 to S19, the set temperature of the dissolving section ink is raised in steps multiple times. Due to the heating control at this time, the temperature of the dissolving section ink also rises in accordance with the rise in the set temperature of the dissolving section ink.

[0085] As the ink temperature in the dissolution section rises, the heated ink is transferred from the dissolution section 4213 to the first sub-tank 412, causing the ink temperature in the first sub-tank to rise to the target temperature. When the temperature of the first sub-tank recovers, the defoaming ability is restored, the defoaming rate equals the foaming rate, and the ink in the first sub-tank 412 is defoamed.

[0086] A comparative example of the above embodiment will be described with reference to Figure 11. Similar to the above embodiment, Figure 11 shows the ink temperature [°C] of the liquid delivery unit 40 relative to the ink discharge time [s] in the temperature control of the comparative example of the inkjet recording device 1. At this time, the ink flow rate is 6.0 [cc / s]. The temperature control of the comparative example is a method in which the ink temperature of the dissolution unit is detected even during the printing process, and the heater 4213h of the dissolution unit 4213 is controlled to bring the ink temperature of the dissolution unit closer to the target temperature.

[0087] As shown in Figure 11, first, the ink temperature of the first sub-tank drops below the target temperature. Then, since the ink temperature of the dissolution section does not drop below the target temperature, the set temperature of the dissolution section ink is not changed, and the first sub-tank 412 is not heated. When the ink temperature of the first sub-tank drops, the defoaming ability decreases, the defoaming rate becomes less than the foaming rate, and the ink in the first sub-tank 412 foams.

[0088] Next, referring to Figure 12, the effect of controlling the first sub-tank set temperature according to the dissolution ink temperature will be explained. Figure 12 shows the various temperatures of the liquid delivery unit 40 over time during the temperature control process of the inkjet recording device 1. The various temperatures of the liquid delivery unit 40 are the dissolution ink temperature, the first sub-tank ink set temperature, the first sub-tank ink temperature, and the dissolution ink set temperature. The values ​​in Figure 12 are the control values ​​or measured values ​​during the execution of the temperature control process and the printing process in the inkjet recording device 1.

[0089] As shown in Figure 12, first, in steps S20 and S21, a decrease occurs in the ink temperature of the dissolution section from the target temperature. In step S22, to compensate for the temperature drop of the ink in the dissolution section 4213, the first sub-tank ink setting temperature is raised from the initial temperature, taking into account a time constant, and the heater 412h is heated. At this time, the ink in the dissolution section 4213 flows into the first sub-tank 412 with a time delay corresponding to the time constant. As a result, the ink that flows in with a time delay is heated according to the raised first sub-tank ink setting temperature, and the temperature fluctuation from the target temperature is reduced. In accordance with the reduction in the temperature fluctuation of the first sub-tank 412, the dissolution section ink setting temperature is adjusted in steps S17 to S19, and the dissolution section ink temperature is also adjusted.

[0090] As described above, according to this embodiment, the inkjet recording device 1 comprises an inkjet head 24a, a liquid delivery unit 40, heaters 4213h and 412h as adjustment units, and a control unit 50. The inkjet head 24a ejects ink. The liquid delivery unit 40 delivers ink. The heaters 4213h and 412h adjust the temperature of the ink in the liquid delivery unit 40 upstream of the inkjet head 24a. The control unit 50 adjusts the temperature of the ink in the liquid delivery unit 40 upstream of the heaters 4213h and 412h to defoam air bubbles in the ink. Therefore, by controlling the ink temperature in the flow path and defoaming the air bubbles in the ink, it is possible to reduce air bubbles even during printing without interrupting printing. Thus, device troubles caused by air bubbles and deterioration of print quality can be suppressed. Device troubles caused by air bubbles include false detection of the liquid level in the first sub-tank 412 due to air bubbles in ink adhering to the float of the liquid level sensor F1. The degradation in print quality is suppressed because air bubbles are not discharged from the nozzles of the inkjet head 24a.

[0091] The liquid supply unit 40 is equipped with a main tank 411 as a storage unit, a liquid flow path 42, a dissolution unit 4213, and a first sub-tank 412 as a heat retention unit, in order from the upstream side to the inkjet head 24a. The main tank 411 stores the ink. The dissolution unit 4213 dissolves the ink. The first sub-tank 412 keeps the ink warm. The control unit 50 defoams the ink from the dissolution unit 4213 to the first sub-tank 412 by adjusting the temperature of heaters 4213h and 412h. As a result, the ink temperature in the flow path up to the inkjet head 24a can be effectively controlled, reducing bubbles even during printing and suppressing equipment troubles and deterioration of print quality caused by bubbles.

[0092] The inkjet recording device 1 includes a temperature detection unit 433 that detects the ink temperature of the first sub-tank 412. The heater 4213h heats the ink in the dissolution unit 4213. During printing, the control unit 50 changes the set temperature of the heater 4213h so that the detected ink temperature of the first sub-tank 412 reaches the target temperature. In this way, the ink in the upstream dissolution unit 4213 is preheated to an appropriate temperature in response to changes in the ink temperature of the first sub-tank 412, and the ink flowing into the first sub-tank 412 is heated to an appropriate temperature in the dissolution unit 4213 to eliminate air bubbles.

[0093] The inkjet recording device 1 includes a temperature detection unit 431 that detects the ink temperature of the dissolution unit 4213. The heater 412h heats the ink in the first sub-tank 412. During printing, the control unit 50 changes the set temperature of the heater 412h so that the detected ink temperature in the dissolution unit 4213 reaches the target temperature. In this way, in response to the change in the ink temperature of the dissolution unit 4213, the ink flowing into the downstream first sub-tank 412 is heated to an appropriate temperature in the first sub-tank 412, and air bubbles are eliminated.

[0094] The control unit 50 changes the set temperature of the heater 412h based on a time constant calculated from the ink flow volume and ink flow rate from the dissolving unit 4213 to the first sub-tank 412, according to the detected ink temperature of the dissolving unit 4213. In this way, the ink flowing into the downstream first sub-tank 412 can be heated to an appropriate temperature at the time of inflow in response to the change in ink temperature of the dissolving unit 4213, thereby eliminating bubbles.

[0095] The control unit 50 obtains the ink flow rate from the flow rate measuring unit 44, which measures the ink flow rate from the dissolution unit 4213 to the first sub-tank 412. This allows for the calculation of an accurate time constant, and the ink temperature can be adjusted at the precise timing using this accurate time constant to eliminate bubbles.

[0096] The inkjet recording device 1 includes temperature detection units 431 and 432 as third temperature detection units, and temperature detection units 433 and 434 as fourth temperature detection units. Temperature detection unit 431 detects the melting unit ink temperature of the melting unit 4213. Temperature detection unit 432 detects the melting unit tank temperature of the melting unit 4213. Temperature detection unit 433 detects the first subtank ink temperature of the first subtank 412. Temperature detection unit 434 detects the first subtank temperature of the first subtank 412. The control unit 50 controls the heater 4213h so that the detected melting unit ink temperature or melting unit tank temperature of the melting unit 4213 reaches the target temperature when not in printing operation. The control unit 50 controls the heater 412h so that the detected first subtank ink temperature or first subtank temperature of the first subtank 412 reaches the target temperature when not in printing operation (standby). Therefore, if ink does not flow in the liquid supply unit 40 during standby, the dissolving unit 4213 or the first sub-tank 412 can appropriately adjust the temperature of the ink in its own section according to the detected temperature.

[0097] The ink is either UV ink or phase-change gel ink. Therefore, it can effectively defoam bubbles in UV ink or phase-change gel ink that require heating.

[0098] The above description discloses an example in which ROM is used as a computer-readable medium for the program relating to this disclosure, but is not limited to this example. Other computer-readable mediums that can be used include non-volatile memory such as flash memory and portable recording media such as CD-ROM. Furthermore, carrier waves can also be used as a medium for providing the data of the program relating to this disclosure via a communication line, and this disclosure is applicable.

[0099] The above-described embodiments are merely examples of the inkjet recording apparatus, temperature control method, and program related to this disclosure, and are not limited thereto.

[0100] While embodiments of this disclosure have been described and illustrated in detail, the disclosed embodiments are for illustrative and illustrative purposes only and are not limiting. The scope of this disclosure should be construed by the terms of the appended claims. [Explanation of symbols]

[0101] 1. Inkjet recording device 10 Paper feed section 11 Paper feed tray 12 Conveying section 121,122 Rollers 123 belt 20 Image forming unit 21 Image forming drum 22 Transfer Unit 221 Nail area 222 Transfer Drum 23 Paper heating section 24 Head Units 24a inkjet head 25 Irradiation area 26 Delivery Department 261,262 rollers 263 belt 264 Transfer Roller 30 Paper output section 31 Paper output tray 40 Liquid delivery section 41 tanks 411 Main Tank 412 First Sub-tank 412h Heater 413 Second Sub-tank 42 Liquid flow path 421 First liquid channel 4211 First Liquid Transfer Unit 4212 Supply valve 4213 Melting part 4213h Heater 422 Second liquid channel 4221 Degassing section 4222 Second Liquid Transfer Section 4223 Circulation channel 4224 Circulation valve 423 Third liquid channel 424 Fourth liquid channel 4241 Second circulation valve 43, 431, 432, 433, 434 Temperature detection unit 44 Flow measurement section 50 Control Unit 60 Storage section 70 Control Panel 80 Communications Department P recording medium

Claims

1. An inkjet head that ejects ink, A liquid supply unit that delivers the aforementioned ink, An adjustment unit for adjusting the ink temperature within the liquid delivery section upstream of the inkjet head, An inkjet recording apparatus comprising: a control unit that adjusts the temperature of the ink in the upstream liquid supply unit using the adjustment unit to de-foam air bubbles in the ink.

2. The aforementioned liquid delivery unit is A storage unit for storing the aforementioned ink, The liquid flow path of the aforementioned ink, Dissolving unit for dissolving the aforementioned ink, A heat-insulating section for keeping the ink warm is provided in order from the upstream side to the inkjet head. The control unit defoams the ink by adjusting the temperature of the adjustment unit from the dissolving unit to the heat retention unit, as described in claim 1.

3. The aforementioned heat-retaining section is equipped with a first temperature detection unit that detects the ink temperature, The adjustment unit has a first heating unit that heats the ink in the dissolution unit, The inkjet recording apparatus according to claim 2, wherein the control unit changes the set temperature of the first heating unit so that the detected ink temperature of the heat-retaining unit reaches the target temperature during printing.

4. The system includes a second temperature detection unit that detects the ink temperature of the dissolving section, The adjustment unit has a second heating unit that heats the ink in the heat retention unit. The inkjet recording apparatus according to claim 2 or 3, wherein the control unit changes the set temperature of the second heating unit so that the detected ink temperature of the dissolving unit becomes the target temperature during the printing operation.

5. The inkjet recording apparatus according to claim 4, wherein the control unit changes the set temperature of the second heating unit based on a time constant calculated from the ink flow path volume and ink flow rate from the dissolving unit to the heat retention unit, according to the detected ink temperature of the dissolving unit.

6. The inkjet recording apparatus according to claim 5, wherein the control unit obtains the ink flow rate from a flow rate measuring unit that measures the ink flow rate from the dissolution unit to the heat retention unit, or calculates it from the difference in image data.

7. The adjustment unit includes a first heating unit that heats the ink in the dissolving unit, It has a second heating section for heating the ink in the heat-retaining section, A third temperature detection unit for detecting the ink temperature or tank temperature of the dissolving section, It comprises a fourth temperature detection unit that detects the ink temperature or tank temperature of the heat-retaining unit, The inkjet recording apparatus according to claim 2, wherein the control unit controls the temperature of the first heating unit so that the detected ink temperature or tank temperature of the dissolving unit reaches a target temperature, and controls the temperature of the second heating unit so that the detected ink temperature or tank temperature of the heat retention unit reaches a target temperature, except during printing operations.

8. The inkjet recording apparatus according to claim 1 or 2, wherein the ink is UV ink.

9. The inkjet recording apparatus according to claim 1 or 2, wherein the ink is a phase-change gel ink.

10. An inkjet head that ejects ink, A liquid supply unit that delivers the aforementioned ink, A temperature control method for an inkjet recording apparatus, comprising an adjustment unit for adjusting the temperature of the ink in the liquid supply unit upstream of the inkjet head, A temperature control method including a control step of adjusting the temperature of the ink in the upstream liquid supply section using the adjustment section to eliminate air bubbles in the ink.

11. An inkjet head that ejects ink, A liquid supply unit that delivers the aforementioned ink, A computer for an inkjet recording device, comprising an adjustment unit for adjusting the temperature of the ink in the liquid delivery unit upstream of the inkjet head, The control unit adjusts the temperature of the ink in the upstream liquid supply section using the adjustment unit to eliminate air bubbles in the ink. A program designed to function as such.

Images