JPWO2016024455A1 - Ink jet recording apparatus and ink temperature control method - Google Patents

Abstract

An inkjet recording apparatus 1 that ejects ink that is liquefied at a temperature equal to or higher than a liquefying temperature and gels at a temperature equal to or lower than a gelling temperature that is lower than the liquefying temperature. 2421 and 3011, a second heating unit 2401, temperature detection units 2402, 2422 and 3012, and a control unit 40, and the control unit 40 uses the first heating units 2421 and 3011 and the second heating unit 2401 to perform ink. After the supply system 320 and the inkjet head 241 are heated and the temperature of the ink in the ink supply system 320 becomes equal to or higher than the liquefaction temperature, the temperature of the ink in the ink supply system 320 is higher than the gelation temperature and lower than the liquefaction temperature. The first heating units 2421 and 3011 are controlled.

Description

  The present invention relates to an ink jet recording apparatus and an ink temperature control method.

  2. Description of the Related Art Conventionally, an ink jet recording apparatus using an ink whose viscosity changes with temperature is known (see, for example, Patent Document 1). As such an ink, for example, there is an ink that is liquefied by being heated to a temperature higher than the liquefaction temperature to become a low-viscosity liquid and gelled by being cooled to a temperature lower than the gelation temperature to be high-viscosity. By using such ink, both the fluidity of ink required at the time of ejection and the fixability of ink required after adhering to the recording medium are compatible.

  In order to smoothly feed the ink from the ink tank to the ink jet head and stably discharge the ink from the ink jet head, an ink supply system for supplying ink to the ink jet head and a sub tank for temporarily storing ink are respectively used. The ink was heated above the liquefaction temperature, and the ink was held above the liquefaction temperature in the ink flow path.

  Here, the physical properties of the ink are not always constant at any temperature above the liquefaction temperature, and the physical properties such as viscosity and surface tension may change depending on the temperature even at the temperature above the liquefaction temperature. For this reason, for each type of ink, there is a temperature (head ejection temperature) that exhibits physical properties suitable for ejection from the inkjet head, and it is preferable to adjust the ink temperature to the head ejection temperature during ink ejection.

JP 2003-220714 A

  However, in the conventional inkjet recording apparatus using the ink as described above, since the inkjet head itself can generate heat when the inkjet head is driven, the temperature of the ink in the inkjet head exceeds the head discharge temperature. There is a case. In such a case, it is necessary to perform control to stand by until the ink is naturally cooled and the temperature is lowered to the head discharge temperature, which increases the time required for image formation. A countermeasure for providing a cooling mechanism in the ink jet head is also conceivable, but this is not preferable because it leads to an increase in size and cost of the apparatus.

  Therefore, an object of the present invention is to provide an ink jet recording apparatus and an ink temperature control method that can stabilize the temperature of ink in an ink jet head even during image formation.

In order to solve the above problems, the invention described in claim 1
An ink jet recording apparatus that performs image formation by discharging an ink that is liquefied at a temperature equal to or higher than a liquefying temperature and gelled at a temperature equal to or lower than the gelation temperature lower than the liquefaction temperature,
An inkjet head that ejects ink;
An ink supply system for supplying ink to the inkjet head;
A first heating unit for heating the ink supply system;
A second heating unit for heating the inkjet head;
A temperature detector for detecting the temperature of ink in the ink supply system and the inkjet head, and
A control unit for controlling the first heating unit and the second heating unit,
The control unit heats the ink supply system and the inkjet head by the first heating unit and the second heating unit, and the temperature of the ink in the ink supply system detected by the temperature detection unit is equal to or higher than the liquefaction temperature. Then, the first heating unit is controlled such that the temperature of the ink in the ink supply system detected by the temperature detection unit is higher than the gelation temperature and lower than the liquefaction temperature. .

Invention of Claim 2 is the inkjet recording device of Claim 1, Comprising:
A sub tank for storing ink supplied from an ink tank and supplying the stored ink to the ink supply system;
A third heating unit for heating the sub-tank,
The temperature detection unit further detects the temperature of the ink in the sub tank,
The control unit further controls the third heating unit, heats the sub tank by the third heating unit, and the temperature of the ink in the sub tank detected by the temperature detection unit becomes equal to or higher than the liquefaction temperature. The third heating unit is controlled such that the temperature of the ink in the sub tank detected by the temperature detection unit is higher than the gelation temperature and lower than the liquefaction temperature.

Invention of Claim 3 is an inkjet recording device of Claim 2, Comprising:
The control unit heats the sub tank by the third heating unit when the temperature of the ink in the sub tank detected by the temperature detection unit becomes equal to or lower than the gelation temperature by supplying ink to the sub tank. Then, after the temperature of the ink in the sub tank detected by the temperature detection unit becomes equal to or higher than the liquefaction temperature, the temperature of the ink in the sub tank detected by the temperature detection unit is higher than the gelation temperature and the liquefaction. The third heating unit is controlled so as to be lower than the temperature.

Invention of Claim 4 is an inkjet recording device as described in any one of Claim 1 to 3, Comprising:
The control unit controls the second heating unit such that the temperature of the ink of the inkjet head detected by the temperature detection unit becomes an ink discharge temperature higher than the liquefaction temperature.

Invention of Claim 5 is the temperature control method of the ink in the inkjet recording device as described in any one of Claim 1 to 4, Comprising:
Heating the ink supply system and the inkjet head by the first heating unit and the second heating unit, and setting the temperature of the ink in the ink supply system detected by the temperature detection unit to be equal to or higher than the liquefaction temperature;
And controlling the first heating unit such that the temperature of the ink in the ink supply system detected by the temperature detection unit is higher than the gelation temperature and lower than the liquefaction temperature. .

  According to the present invention, it is possible to provide an ink jet recording apparatus and an ink temperature control method capable of stabilizing the temperature of ink in an ink jet head even during image formation.

1 is a diagram illustrating a main configuration of an ink jet recording apparatus according to an embodiment of the present invention. FIG. 4 is a perspective view showing a positional relationship between an image forming drum and a cleaning unit and positions before and after movement of a head unit. It is a figure which shows an example of a structure of a head unit, Comprising: It is the schematic of the internal structure of a head unit at the time of seeing a head unit from the side. It is a figure which shows an example of a structure of a head unit, Comprising: It is the schematic of the internal structure of a head unit at the time of seeing a head unit from the recording medium side. It is a graph which shows the example of a change of the viscosity of the ink accompanying the temperature rise and fall of an ink. It is a side view of an inkjet head. FIG. 3 is a schematic diagram illustrating a main configuration of an ink discharge mechanism and connections between respective portions of the ink discharge mechanism. It is a block diagram of an inkjet recording device. 3 is a flowchart illustrating a method for controlling the temperature of ink. It is a graph which shows the temperature transition of the ink in the inkjet head in the inkjet recording device of this invention, and the inkjet recording device of a prior art.

  Hereinafter, an ink jet recording apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples. In addition, in the following description, what has the same function and structure attaches | subjects the same code | symbol, and abbreviate | omits the description.

  FIG. 1 is a diagram showing a main configuration of an ink jet recording apparatus 1 according to an embodiment of the present invention.

  The ink jet recording apparatus 1 includes a paper feeding unit 10, an image forming unit 20, a paper discharge unit 30, a control unit 40 (see FIG. 7), and the like. Under the control of the control unit 40, the inkjet recording apparatus 1 conveys the recording medium P stored in the paper feeding unit 10 to the image forming unit 20, and forms an image on the recording medium P with the image forming unit 20. The formed recording medium P is discharged to the paper discharge unit 30.

  The paper feed unit 10 includes a paper feed tray 11 that stores the recording medium P, and a transport unit 12 that transports the recording medium P from the paper feed tray 11 to the image forming unit 20.

  The paper feed tray 11 is a plate-like member provided so that one or a plurality of recording media P can be placed thereon. The paper feed tray 11 is provided so as to move up and down according to the amount of the recording medium P placed on the paper feed tray 11, and the uppermost recording medium P is transported by the transport unit 12 in the vertical movement direction. Held at a position.

  The transport unit 12 includes a transport mechanism that transports the recording medium P on the belt 123 by driving a ring-shaped belt 123 supported by a plurality of (for example, two) rollers 121 and 122 on the inner side, and a paper feed tray 11. A supply unit that transfers the uppermost recording medium P placed on the belt 123 onto the belt 123. The transport unit 12 transports the recording medium P transferred from the supply unit onto the belt 123 so as to follow the belt 123.

  The image forming unit 20 includes an image forming drum 21 that carries the recording medium P along a cylindrical outer peripheral surface, and a transfer unit that transfers the recording medium P conveyed by the conveying unit 12 of the paper feeding unit 10 to the image forming drum 21. 22. A sheet heating unit 23 for heating the recording medium P carried on the image forming drum 21; a head unit 24 for ejecting ink onto the recording medium P carried on the image forming drum 21; An irradiation unit 25 that irradiates an energy beam for curing the ink ejected on the head, a delivery unit 26 that transports the recording medium P irradiated by the irradiation unit 25 from the image forming drum 21 to the paper discharge unit 30, and a head unit 24. And a cleaning unit 27 (see FIG. 2) for receiving ink ejected from the head unit 24 during maintenance.

  FIG. 2 is a perspective view showing the positional relationship between the image forming drum 21 and the cleaning unit 27 and the position before and after the movement of the head unit 24.

  The image forming drum 21 includes a claw portion 211 and a suction portion 212 for carrying the recording medium P on the outer peripheral surface thereof.

  As shown in FIG. 2, the claw portion 211 has a plurality of claws provided along a rotation axis direction (X direction) of the cylindrical image forming drum 21 at a predetermined position on the outer peripheral surface of the image forming drum 21. . The claw portion 211 sandwiches and supports the vicinity of one side of the recording medium P in cooperation with the outer peripheral surface of the image forming drum 21.

  As shown in FIG. 2, the air intake portion 212 includes a plurality of air intake holes provided on the outer peripheral surface of the image forming drum 21 along which the recording medium P supported by the claw portion 211 and the vicinity of one side thereof, and the air intake holes. And a suction force generator (not shown) (for example, an air pump or a fan) that generates a suction force so as to suck the gas into the image forming drum 21. In other words, the suction unit 212 sucks the recording medium P along the outer peripheral surface of the image forming drum 21 by the suction force generated by the suction from the suction hole.

  In FIG. 2, a part of the recording medium P is turned up from the outer peripheral surface of the image forming drum 21, but this is for the purpose of illustrating the intake holes, and image formation by the image forming unit 20 is performed. Sometimes, the entire recording medium P is carried along the outer peripheral surface of the image forming drum 21.

  As shown in FIG. 1, the delivery unit 22 is provided at a position interposed between the transport unit 12 of the paper feeding unit 10 and the image forming drum 21. The delivery unit 22 includes a claw part 221 that supports one end of the recording medium P conveyed by the conveyance part 12, a cylindrical delivery drum 222 that guides the recording medium P carried by the claw part 221, and the like. The recording medium P on the portion 12 is picked up by the claw portion 221 and is moved along the outer peripheral surface of the transfer drum 222 to guide the recording medium P in the direction along the outer peripheral surface of the image forming drum 21 and transfer it to the image forming drum 21. .

  The sheet heating unit 23 includes, for example, a heating wire and generates heat in response to energization. The sheet heating unit 23 is provided in the vicinity of the outer peripheral surface of the image forming drum 21 and on the upstream side of the head unit 24 in the conveyance direction of the recording medium P by the rotation of the image forming drum 21. Heat generation of the sheet heating unit 23 is controlled by the control unit 40 so that the recording medium P carried on the image forming drum 21 and passing through the vicinity of the sheet heating unit 23 has a predetermined temperature.

  Further, a temperature sensor (not shown) is provided in the vicinity of the paper heating unit 23. Based on the temperature in the vicinity of the paper heating unit 23 detected by the temperature sensor, the control unit 40 causes the recording medium P carried on the image forming drum 21 and passing through the vicinity of the paper heating unit 23 to have a predetermined temperature. The operation of the paper heating unit 23 is controlled.

  3A and 3B are diagrams showing the internal configuration of the head unit 24. FIG. FIG. 3A is a schematic diagram of an internal configuration when the head unit 24 is viewed from the side. FIG. 3B is a schematic diagram of an internal configuration when the head unit 24 is viewed from the recording medium side. The case when viewed from the side indicates a case where the head unit 24 is viewed with the front surface of one side of the head unit 24 along the vertical direction and the X direction of the head unit 24.

The head unit 24 is disposed along the outer peripheral surface of the image forming drum 21 at a predetermined distance from the image forming drum 21.
As shown in FIGS. 3A and 3B, the head unit 24 includes a plurality of inkjet heads 241.

  Each inkjet head 241 has a plurality of nozzles 2411. The ink jet head 241 ejects ink from a plurality of nozzles 2411 to form an image on the recording medium P carried on the image forming drum 21. That is, the inkjet head 241 is provided such that the plurality of nozzles 2411 are exposed on the lower surface side of the head unit 24. The inkjet head 241 illustrated in FIG. 3B includes a plurality of nozzles 2411 arranged in two rows of nozzles along the X direction.

  For example, as shown in FIG. 3A, the plurality of inkjet heads 241 includes two inkjet heads 241 as a set, and each set of inkjet heads 241 forms a row of inkjet heads 241 provided in the X direction. Has been placed. Further, a plurality of rows of the inkjet heads 241 are provided, and the positional relationship between the pairs of the inkjet heads 241 in adjacent rows is arranged in a staggered manner in the direction orthogonal to the X direction.

  Each of the head units 24 is provided so as to be individually movable along the X direction. Specifically, as shown in FIG. 2, the head unit 24 is provided so as to be movable between a position between the image forming drum 21 and the cleaning unit 27 provided so as to be arranged in the X direction. Under the control of the control unit 40, the head unit 24 moves to a position where the lower surface faces the image forming drum 21 during image formation, and the lower surface moves to a position facing the cleaning unit 27 during various maintenance. Moving.

  The head unit 24 is individually provided for each color (CMYK) used for image formation. In the inkjet recording apparatus 1 shown in FIGS. 1 and 2, in the order of Y, M, C, and K colors from the upstream along the transport direction of the recording medium P transported as the image forming drum 21 rotates. A head unit 24 corresponding to each color is provided.

  As shown in FIG. 2, the width of the head unit 24 in the X direction is provided so as to sufficiently cover the width of the recording medium P carried and transported by the image forming drum 21 in the X direction. At this time, the position of the head unit 24 is fixed with respect to the image forming drum 21. In other words, the inkjet recording apparatus 1 is a one-pass inkjet recording apparatus, and the head unit 24 includes a plurality of nozzles 2411 of a plurality of inkjet heads 241 arranged side by side along the X direction. With respect to the direction (X direction) orthogonal to the direction in which the head 241 and the recording medium P move relatively, the number is set according to the maximum width of the recording medium P.

Here, the ink used in the inkjet recording apparatus 1 of the present invention will be described.
The ink used for image formation by the ink jet recording apparatus 1 has a property of phase change depending on the temperature of the ink.
Specifically, the ink changes in phase from gel or solid to liquid depending on the temperature. Examples of the composition of such an ink include an ink composition in which several percent of a gelling agent is added to a composition mainly composed of a polymerizable compound and a photopolymerization initiator.

Hereinafter, an example of an ink manufacturing method will be disclosed.
First, two kinds of compounds of 5 parts of Solspers 32000 (manufactured by Lubrizol) and 80 parts of HD-N (1,6-hexanediol dimethacrylate, Shin-Nakamura Chemical Co., Ltd.) are placed in a stainless steel beaker and dissolved by stirring and heating. . Then, after cooling to room temperature, 15 parts of carbon black (# 56, manufactured by Mitsubishi Chemical Corporation) was added thereto, sealed in a glass bottle with 0.5 mm zirconia beads, dispersed in a paint shaker for 10 hours, and then zirconia. What removed the bead is obtained as a pigment dispersion.
Including the pigment dispersion obtained as described above, the composition is adjusted as shown in Table 1.

  And the composition after filtering with the Teflon (trademark) 3 micrometer membrane filter by ADVATEC is obtained with respect to the composition shown in Table 1 as an ink.

  FIG. 4 shows an example of the change in ink viscosity as the ink temperature rises and falls. A line L1 shown in FIG. 4 shows an example of a change in ink viscosity when the temperature rises, and a line L2 shows an example of a change in ink viscosity when the temperature falls.

  As shown by a line L1 in FIG. 4, the ink undergoes a phase change in which the viscosity changes remarkably around 60 ° C. when the temperature rises. Specifically, an ink that was in a gel or solid state at a temperature lower than 60 ° C. becomes a liquid with a markedly reduced viscosity from around 60 ° C. due to the temperature increase. In the case of the example shown in FIG. 4, the temperature around 60 ° C. is the liquefaction temperature.

  On the other hand, as shown by the line L2 in FIG. 4, the ink undergoes a phase change whose viscosity changes remarkably as compared with the phase change at the time of temperature rise at around 45 ° C. when the temperature is lowered. Specifically, an ink that has been kept in a liquid state to a temperature exceeding 45 ° C. has a very marked increase in viscosity when it falls below 45 ° C. due to a temperature drop, and becomes a gel or solid. In the case of the example shown in FIG. 4, the gelling temperature is around 45 ° C.

  The ink is stored in the storage unit 242 and the sub tank 243 in the head unit 24. A mechanism for supplying ink from the storage unit 242 and the sub tank 243 to the inkjet head 241 will be described later.

  The irradiation unit 25 includes a fluorescent tube such as a low-pressure mercury lamp, and irradiates energy rays such as ultraviolet rays by light emitted from the fluorescent tube. The irradiation unit 25 is provided in the vicinity of the outer peripheral surface of the image forming drum 21 and on the downstream side of the head unit 24 in the conveyance direction of the recording medium P by the rotation of the image forming drum 21. The irradiation unit 25 irradiates the recording medium P carried on the image forming drum 21 and ejects the ink with an energy ray, and cures the ink on the recording medium P by the action of the energy ray.

  The fluorescent tube emitting ultraviolet light is not limited to a low-pressure mercury lamp, but a mercury lamp having an operating pressure of about several hundred Pa to 1 MPa, a light source usable as a germicidal lamp, a cold cathode tube, an ultraviolet laser light source, a metal halide lamp, and a light emitting diode. However, it is desirable that the light source is a power-saving light source (for example, a light emitting diode) that can irradiate ultraviolet rays with higher illuminance. The energy rays are not limited to ultraviolet rays, but may be any energy rays having a property of curing ink according to the properties of the ink, and the light source is replaced according to the energy rays.

  The delivery unit 26 drives a ring-shaped belt 263 supported by a plurality of (for example, two) rollers 261 and 262 on the inner side, and conveys the recording medium P on the belt 263, and the recording medium P as an image. It has a cylindrical delivery roller 264 and the like that delivers from the forming drum 21 to the transport mechanism. The delivery unit 26 conveys the recording medium P transferred on the belt 263 by the transfer roller 264 so as to be along the belt 263 and sends it to the paper discharge unit 30.

  The cleaning unit 27 includes a waste ink unit (not shown) that receives and stores ink discharged from the head unit 24 during maintenance, and the ink discharged from the head unit 24 during maintenance in the image forming unit 20 To prevent fouling.

  The paper discharge unit 30 includes a plate-shaped paper discharge tray 31 on which the recording medium P sent out from the image forming unit 20 by the delivery unit 26 is placed, and the recording medium P after image formation is taken out by the user. Store up to.

  Next, the ink ejection mechanism 300 will be described with reference to FIGS. Here, the ink ejection mechanism 300 refers to a mechanism related to an operation of ejecting ink from the plurality of nozzles 2411 of the inkjet head 241, and includes a mechanism for supplying ink from the storage unit 242 and the sub tank 243 to the inkjet head 241.

  FIG. 5 is a side view of the inkjet head 241. The side surface referred to here is a surface along one side surface of the head unit 24 described above.

  As shown in FIG. 5, the inkjet head 241 includes an upper channel portion 2412 and a lower channel portion 2413 that function as a channel for ink ejected from the inkjet head 241, and an upper channel portion 2412 and a lower channel portion 2413. An inlet 2414 into which supplied ink flows, an outlet 2415 through which ink returned from the upper flow path portion 2412 to the sub tank 243 flows, a bypass section 2416 through which ink returned from the lower flow path portion 2413 to the sub tank 243 flows, and the like.

  Each of the upper flow path portion 2412 and the lower flow path portion 2413 has a flow path for guiding the ink supplied to each of the plurality of nozzles of the inkjet head 241 to the nozzle. The flow path is a common flow path shared by a plurality of nozzles, and guides the ink flowing through the inlet 2414. That is, the ink supplied from the inlet 2414 flows through the flow paths in the upper flow path portion 2412 and the lower flow path portion 2413 and reaches a plurality of nozzles 2411.

  On the other hand, the common flow path in the upper flow path portion 2412 is also connected to the outlet 2415. That is, the ink flowing through the upper flow path portion 2412 can flow out to the outlet 2415 side. Further, the common flow path in the lower flow path portion 2413 is also connected to the bypass portion 2416. That is, the ink flowing through the lower flow path portion 2413 can also flow out to the bypass portion 2416 side.

  A filter 2417 is provided between the upper flow path portion 2412 and the lower flow path portion 2413. As a result, the ink flowing from the upper flow path portion 2412 to the lower flow path portion 2413 is filtered by the filter 2417.

  A pressure chamber 2418 is provided in the vicinity of the nozzle surface below the lower flow path portion 2413. Under the control of the control unit 40, the pressure chamber 2418 applies pressure to the nozzle corresponding to the ink ejected according to the image formed on the recording medium P, and ejects the ink.

  In addition, the ink jet head 241 includes a head control unit 2419. The head control unit 2419 is provided, for example, above the upper flow path unit 2412, and controls the operation of the pressure chamber 2418 under the control of the control unit 40.

  In addition, the inkjet head 241 has a second heating unit 2401. The 2nd heating part 2401 has a heating wire etc., for example, and generates heat according to energization. The second heating unit 2401 heats the ink in the inkjet head 241 by heating the inkjet head 241.

  In addition, the inkjet head 241 includes a temperature detection unit 2402. The control unit 40 controls the operation of the second heating unit 2401 based on the average value of the temperatures detected by the temperature detection units 2402 provided at six locations of the inkjet head 241. Here, the temperature detection unit 2402 is provided on the outer surface of the inkjet head 241 and detects the temperature of the inkjet head 241, but the control unit 40 determines the temperature detected by the temperature detection unit 2402. The operation of the second heating unit 2401 is controlled assuming that the temperature of the ink is inside. However, when the difference in ink temperature is large, it is also possible to measure the difference from the ink temperature in advance and correct it for control.

FIG. 6 is a schematic diagram showing the main configuration of the ink ejection mechanism 300 and the connections between the respective parts of the ink ejection mechanism 300. The ink ejection mechanism 300 includes an ink tank 244 that stores ink, a sub tank 243 that stores ink supplied from the ink tank 244, a storage unit 242 that stores ink supplied from the sub tank 243, and ink supplied from the storage unit 242. The ink jet head 241 for discharging the ink, the pressure control unit 305 for setting the nozzle 2411 of the ink jet head 241 to a negative pressure, the path 304 for connecting the ink tank 244 and the sub tank 243, the path 303 for connecting the sub tank 243 and the storage part 242, and the storage A supply path 301 that connects the section 242 and the inkjet head 241, a recovery path 302 that connects the inkjet head 241 and the sub tank 243, a ventilation path 306 that connects the storage section 242 and the pressure control section 305, and the like. Yes. Among these, the ink supply system 320 is configured by the path 303, the storage unit 242, and the supply path 301.
In FIG. 6 and the like, each path serving as an ink path is indicated by a broken line or the like, but the specific configuration of each path according to these descriptions is a closed path for conducting ink.

  The ink tank 244 stores the ink circulated to each part of the ink ejection mechanism 300 and supplies the stored ink to the sub tank 243.

  The sub tank 243 stores the ink supplied from the ink tank 244 and supplies the stored ink to the storage unit 242. The sub tank 243 is provided with a third heating unit 2431. The 3rd heating part 2431 has a heating wire etc., for example, and generates heat according to energization. The third heating unit 2431 heats the ink in the sub tank 243 by heating the sub tank 243. Since the non-heated ink is supplied from the ink tank 244 to the sub tank 243, the supply speed of the non-heated ink may increase depending on the ink consumption speed at the time of image formation, and the temperature in the sub tank 243 may greatly decrease.

  The sub tank 243 is provided with a temperature detection unit 2432. The control unit 40 controls the operation of the third heating unit 2431 based on the temperature of the sub tank 243 detected by the temperature detection unit 2432. Here, the temperature detection unit 2432 is provided on the outer surface of the sub tank 243 and detects the temperature of the sub tank 243, but the control unit 40 determines the temperature detected by the temperature detection unit 2432 as ink in the sub tank 243. The operation of the third heating unit 2431 is controlled as the temperature of The outer surface temperature and the ink temperature are substantially the same, but there may be a difference immediately after the normal temperature ink is supplied. For this reason, it is preferable to use a liquid contact detection unit that directly detects the ink temperature.

  The storage unit 242 stores the ink supplied from the sub tank 243 and supplies the stored ink to the inkjet head 241. The storage unit 242 is provided with a first heating unit 2421. The 1st heating part 2421 has a heating wire etc., for example, and generates heat according to energization. The first heating unit 2421 heats the ink in the storage unit 242 by heating the storage unit 242. The storage unit 242 is supplied with ink liquefied in the sub tank 243.

  The storage unit 242 is provided with a temperature detection unit 2422. The control unit 40 controls the operation of the first heating unit 2421 based on the temperature of the storage unit 242 detected by the temperature detection unit 2422. Here, the temperature detection unit 2422 is provided on the outer surface of the storage unit 242, and detects the temperature of the storage unit 242, but the control unit 40 determines the temperature detected by the temperature detection unit 2422. The operation of the first heating unit 2421 is controlled as the temperature of the ink inside.

  The pressure control unit 305 is connected to the storage unit 242 and adjusts the pressure in the storage unit 242 under the control of the control unit 40. As a result, the pressure control unit 305 sets the pressure of the nozzle 2411 of the inkjet head 241 to a negative pressure state via the storage unit 242 and the supply path 301. This prevents ink from leaking from the nozzles when image formation and various maintenance are not performed.

  Each of the supply path 301, the recovery path 302, and the paths 303 and 304 is a tube-shaped member through which ink passes. For example, the supply path 301, the recovery path 302, and the paths 303 and 304 are made of a material such as resin or a member having good heat conductivity.

  The path 304 connects the sub tank 243 and the ink tank 244, and the path 304 is provided with a pump P2. The pump P <b> 2 operates under the control of the control unit 40 and supplies ink from the ink tank 244 to the sub tank 243. For example, a positive displacement pump such as a diaphragm pump, a tube pump, or the like is used as the pump P2.

  The path 303 connects the storage unit 242 and the sub tank 243, and the path 303 is provided with a pump P1. The pump P <b> 1 operates under the control of the control unit 40 and supplies ink from the sub tank 243 to the storage unit 242. For example, a positive displacement pump such as a diaphragm pump, a tube pump, or the like is used as the pump P1.

The supply path 301 connects the inlet 2414 of the inkjet head 241 and the storage unit 242. A first heating unit 3011 is provided in the supply path 301. The 1st heating part 3011 has a heating wire etc., for example, and generates heat according to energization. The first heating unit 3011 heats the ink passing through the supply path 301 by heating the supply path 301.
The supply path 301 is provided with a temperature detection unit 3012. The control unit 40 controls the operation of the first heating unit 3011 based on the temperature of the supply path 301 detected by the temperature detection unit 3012. Here, the temperature detection unit 3012 is provided on the outer surface of the supply path 301 and detects the temperature of the supply path 301, but the control unit 40 detects the temperature detected by the temperature detection unit 3012. The operation of the first heating unit 3011 is controlled on the assumption that the temperature of the ink is inside.

  The collection path 302 connects the inkjet head 241 and the sub tank 243. In the recovery path 302, the first recovery path 3021 and the second recovery path 3022 connected to the outlet 2415 and the bypass unit 2416 of the inkjet head 241 are joined to one common recovery path 3023 and connected to the sub tank 243. It has a structure.

Further, a recovery path heating unit 3024 is provided in the recovery path 302. The recovery path heating unit 3024 has, for example, a heating wire and generates heat in response to energization. The recovery path heating unit 3024 heats the ink passing through the recovery path 302 by heating the recovery path 302.
Further, a recovery path temperature detection unit 3025 is provided in the recovery path 302. The control unit 40 controls the operation of the recovery path heating unit 3024 based on the temperature of the recovery path 302 detected by the recovery path temperature detection unit 3025. Here, the recovery path temperature detection unit 3025 is provided on the outer surface of the recovery path 302 and detects the temperature of the recovery path 302, but the control unit 40 detects the temperature detected by the recovery path temperature detection unit 3025. Is the temperature of the ink in the recovery path 302, and the operation of the recovery path heating unit 3024 is controlled.

  The air passage 306 connects the storage unit 242 and the pressure control unit 305. The air passage 306 is a tube-shaped member through which air passes, and is made of, for example, resin. The air passage 306 has a structure that branches from one common air passage 3061 connected to the pressure control unit 305 to a plurality of branch air passages 3062 connected to each of the plurality of storage units 242.

  In addition, electromagnetic valves 307, 308, 309, and 310 are provided in the first recovery path 3021, the second recovery path 3022, the path 303, and the branch ventilation path 3062, respectively. The electromagnetic valves 307 to 310 open and close the ink flow paths and the air flow paths provided under the control of the control unit 40. That is, the electromagnetic valve 307 provided in the first recovery path 3021 and the electromagnetic valve 308 provided in the second recovery path 3022 switch opening and closing of the recovery path 302. A solenoid valve 309 provided between the sub tank 243 and the pump P1 in the path 303 switches between opening and closing of the connection between the sub tank 243 and the pump P1. The electromagnetic valve 310 provided in the branch ventilation path 3062 switches between opening and closing of the connection between the storage unit 242 and the pressure control unit 305.

  In addition, the storage part 242 is a tank-shaped container sealed except said various connection location. That is, the pressure in the storage unit 242 varies depending on the degree of negative pressure applied by the pressure control unit 305, the presence or absence of ink supply from the sub tank 243, and the like. For example, when the supply of ink from the sub tank 243 is received in a state where the electromagnetic valve 310 is closed and the negative pressure applied by the pressure control unit 305 is lost, the ink amount in the storage unit 242 increases. The pressure in the reservoir 242 increases.

  On the other hand, the sub-tank 243 is a container opened to the outside, and is maintained at substantially the atmospheric pressure regardless of increase or decrease in the amount of ink.

FIG. 7 is a block diagram of the inkjet recording apparatus 1.
As shown in FIG. 7, the control unit 40 is connected to each part constituting the ink jet recording apparatus 1 and controls each part constituting the ink jet recording apparatus 1. The control unit 40 includes a CPU 41, a RAM 42, a ROM 43, and the like. The CPU 41 reads out and executes various programs, data, and the like corresponding to the processing contents from a storage device such as the ROM 43, and controls the operation of each unit of the inkjet recording apparatus 1 according to the executed processing contents. The RAM 42 temporarily stores various programs and data processed by the CPU 41. The ROM 43 stores various programs and data read by the CPU 41 and the like.

  Specifically, the control unit 40 heats the ink supply system 320, the inkjet head 241 and the sub tank 243 by the first heating units 2421 and 3011, the second heating unit 2401 and the third heating unit 2431, and the temperature detection unit 2402, Ink supply systems detected by the temperature detection units 2402, 2422, 2432, and 3012 after the ink temperatures of the ink supply system 320, the inkjet head 241 and the sub tank 243 detected by the temperature detection units 2422, 2432, and 3012 are equal to or higher than the liquefaction temperature. The first heating units 2421 and 3011 and the third heating unit 2431 are controlled so that the temperature of the ink in 320 and the sub tank 243 is higher than the gelation temperature and lower than the liquefaction temperature.

  In addition, the control unit 40 detects the ink supply system 320 detected by the temperature detection units 2402, 2422, and 3012 and the ink jet head detected by the temperature detection unit 2402 after the ink temperature of the ink jet head 241 becomes equal to or higher than the liquefaction temperature. The second heating unit 2401 is controlled so that the temperature of the ink 241 becomes an ink discharge temperature higher than the liquefaction temperature. Here, the ink discharge temperature is an ink temperature that exhibits the most suitable physical properties (viscosity, surface tension, etc.) for discharging ink from the inkjet head 241 and is a value set in advance for each type of ink. .

  Further, when the temperature of the ink in the sub tank 243 detected by the temperature detection unit 2432 becomes equal to or lower than the gelation temperature by supplying ink to the sub tank 243, the control unit 40 causes the third heating unit 2431 to set the sub tank 243. After the heating and the temperature of the ink in the sub tank 243 detected by the temperature detection unit 2432 becomes equal to or higher than the liquefaction temperature, the temperature of the ink in the sub tank 243 detected by the temperature detection unit 2432 is higher than the gelation temperature and lower than the liquefaction temperature. The third heating unit 2431 is controlled so that

  Next, an example of the ink temperature control process performed by the control unit 40 in the inkjet recording apparatus 1 configured as described above will be described with reference to FIG. FIG. 8 is a flowchart illustrating an example of the ink temperature control process.

First, the control unit 40 determines whether the user has turned on the power of the inkjet recording apparatus 1 (step S101).
When it is determined that the power of the inkjet recording apparatus 1 is not turned on (step S101; NO), the control unit 40 performs the process of step S101 again.

  On the other hand, if it is determined that the power of the ink jet recording apparatus 1 is turned on (step S101; YES), the control unit 40 causes the ink temperatures of the ink supply system 320, the ink jet head 241, and the sub tank 243 to be equal to or higher than the liquefaction temperature. In this way, the first heating units 2421 and 3011, the second heating unit 2401 and the third heating unit 2431 are controlled (step S102). Thereby, the fluidity of the ink is increased, and the ink can be smoothly fed in the ink ejection mechanism 300. As described above, the ink liquefaction temperature has a unique value depending on the type of ink, and the specific value is stored in the control unit 40 in advance.

Next, the control unit 40 determines whether or not the temperature of the ink in the ink supply system 320, the inkjet head 241 and the sub tank 243 detected by the temperature detection units 2402, 2422, 2432, and 3012 is equal to or higher than the liquefaction temperature ( Step S103).
If it is determined that the ink temperatures of the ink supply system 320, the inkjet head 241 and the sub tank 243 are not equal to or higher than the liquefaction temperature (step S103; NO), the control unit 40 performs the process of step S103 again.

  On the other hand, when it is determined that the ink temperatures of the ink supply system 320, the ink jet head 241 and the sub tank 243 have become equal to or higher than the liquefaction temperature (step S103; YES), the control unit 40 is detected by the temperature detection units 2422, 2432 and 3012. The first heating units 2421 and 3021 and the third heating unit 2431 are controlled so that the temperature of the ink in the ink supply system 320 and the sub tank 243 is higher than the gelation temperature and lower than the liquefaction temperature (step S104). Thereby, it is possible to suppress an excessive increase in the temperature of the ink in the inkjet head 241 while maintaining the fluidity of the ink in the ink supply system 320 and the sub tank 243. In addition, the amount of heat generated by the first heating units 2421 and 3021 and the third heating unit 2431 can be reduced, and the power cost in ink temperature control can be reduced. Here, as described above, the gelation temperature of the ink has a unique value depending on the type of ink, and the specific value is stored in the control unit 40 in advance.

  At this time, the control unit 40 controls the recovery path heating unit 3024 so that the temperature of the ink in the recovery path 302 detected by the recovery path temperature detection unit 3025 is higher than the gelation temperature and lower than the liquefaction temperature. . As a result, the amount of heat generated by the recovery path heating unit 3024 can also be reduced, and the power cost in ink temperature control can be further reduced.

Next, the control unit 40 controls the second heating unit 2401 so that the ink temperature of the inkjet head 241 becomes the ink discharge temperature (step S105). Thereby, ink can be rapidly ejected from the inkjet head 241. The ink discharge temperature is a value set in advance for each type of ink as described above, and the specific value is stored in the control unit 40 in advance.
In step S103, the control unit 40 determines that the ink temperatures in the ink supply system 320, the inkjet head 241 and the sub tank 243 are equal to or higher than the liquefaction temperature, and then performs the process in step S105. It is good also as what performs a process.

  In step S103, when it is determined that the temperature of the ink in the ink supply system 320, the inkjet head 241 and the sub tank 243 is equal to or higher than the liquefaction temperature, steps S104 and S105 are performed in order. When it is determined that the temperature of the ink 320 is equal to or higher than the liquefaction temperature, the first heating units 2421 and 3011 are controlled so that the temperature of the ink in the ink supply system 320 is higher than the gelation temperature and lower than the liquefaction temperature. It is good as a thing. Alternatively, the second heating unit 2401 may be controlled so that the temperature of the ink of the inkjet head 241 becomes the ink discharge temperature when it is determined that the temperature of the ink of the inkjet head 241 has become equal to or higher than the liquefaction temperature. Further, when it is determined that the temperature of the ink in the sub tank 243 is equal to or higher than the liquefaction temperature, the third heating unit 2431 is controlled so that the temperature of the ink in the sub tank 243 is higher than the gelation temperature and lower than the liquefaction temperature. It is also good. As described above, the first to third heating units 2401, 2421, 2431, and 3011 may be individually controlled in an arbitrary order.

  After performing the process of step S105, the control unit 40 controls each part of the inkjet recording apparatus 1 and starts image formation (step S106). In this way, the control unit 40, during the image formation, the first heating unit 2421, 3021 and the third heating unit so that the temperature of the ink in the ink supply system 320 and the sub tank 243 is higher than the gelation temperature and lower than the liquefaction temperature. 2431 is controlled, and the second heating unit 2401 is controlled so that the ink temperature of the inkjet head 241 becomes the ink discharge temperature.

After starting the image formation, the control unit 40 determines whether or not the temperature of the ink in the sub tank 243 detected by the temperature detection unit 2432 is equal to or lower than the gelation temperature (step S107). As a result, when the amount of ink consumed by image formation is large and the amount of ink flowing into the sub tank 243 is large, it is detected at an early stage whether or not the temperature of the ink in the sub tank 243 has become equal to or lower than the gelation temperature. The ink fluidity at 300 is prevented from being lowered.
When it is determined that the temperature of the ink in the sub tank 243 is not equal to or lower than the gelation temperature (step S107; NO), the control unit 40 performs a process of step S111 described later.

  On the other hand, when it is determined that the temperature of the ink in the sub tank 243 is equal to or lower than the gelation temperature (step S107; YES), the control unit 40 detects that the temperature of the ink in the sub tank 243 detected by the temperature detection unit 2432 is equal to or higher than the liquefaction temperature. The third heating unit 2431 is controlled so as to become (step S108).

Next, the control unit 40 determines whether or not the temperature of the ink in the sub tank 243 detected by the temperature detection unit 2432 is equal to or higher than the liquefaction temperature (step S109).
When it is determined that the temperature of the ink in the sub tank 243 is not equal to or higher than the liquefaction temperature (step S109; NO), the control unit 40 performs the process of step S109 again.

  On the other hand, when it is determined that the temperature of the ink in the sub tank 243 is equal to or higher than the liquefaction temperature (step S109; YES), the control unit 40 determines that the temperature of the ink in the sub tank 243 detected by the temperature detection unit 2432 is higher than the gelation temperature. The third heating unit 2431 is controlled to be larger and lower than the liquefaction temperature (step S110).

Next, the control unit 40 determines whether or not to end image formation (step S111).
If it is determined not to end the image formation (step S111; NO), the control unit 40 performs the process of step S107 again. As described above, the control unit 40 repeats the processes in steps S107 to S111 until the image formation is completed.

On the other hand, if it is determined that image formation is to be terminated (step S111; YES), the control unit 40 stops heating by the first to third heating units 2401, 2421, 2431, and 3011 (step S112).
In this manner, the ink temperature control process is performed.

In the temperature control process, the control of the first to third heating units 2401, 2421, 2431, and 3011 is started immediately after the power of the inkjet recording apparatus 1 is turned on. However, the present invention is not limited to this. Instead, it may start at any time before the start of image formation.
In the temperature control process, the second heating unit 2401 is controlled so that the temperature of the inkjet head 241 becomes equal to or higher than the liquefaction temperature in step S102, and the temperature of the inkjet head 241 becomes the ink discharge temperature in step S105. Although 2 heating part 2401 was controlled, it is not restricted to this. That is, the second heating unit 2401 may be controlled so that the temperature of the inkjet head 241 becomes the ink discharge temperature in step S102, and the process in step S105 may be omitted.
In the temperature control process, it is determined in step S103 whether or not the temperature of the ink in the ink supply system 320, the inkjet head 241 and the sub tank 243 is equal to or higher than the liquefaction temperature. It may be determined whether or not the temperature of the ink at 243 is equal to or higher than the liquefaction temperature.
In the temperature control process, in step S104, the temperature of the ink in the recovery path 302 detected by the recovery path temperature detection unit 3025 is higher than the gelling temperature together with the temperature control of the ink in the ink supply system 320 and the sub tank 243. Although the recovery path heating unit 3024 is controlled so as to be lower than the liquefaction temperature, the recovery path heating unit 3024 may be controlled so that the temperature of the ink in the recovery path 302 is equal to or higher than the liquefaction temperature. Further, the temperature control of the ink in the recovery path 302 may not be performed.

As described above, according to the embodiment described above, the control unit 40 heats the ink supply system 320 and the inkjet head 241 with the first heating units 2421 and 3011 and the second heating unit 2401, and the ink supply system 320 and the inkjet head. Since the first heating units 2421 and 3011 are controlled so that the temperature of the ink in the ink supply system 320 is higher than the gelation temperature and lower than the liquefaction temperature after the temperature of the ink 241 becomes equal to or higher than the liquefaction temperature, the inkjet head The temperature of the ink supplied to 241 can be set to a low temperature that can maintain fluidity. For this reason, even when the inkjet head 241 is driven to generate heat, the temperature of the ink in the inkjet head 241 can be suppressed from being excessively increased, and the ink in the inkjet head 241 can also be formed during image formation. The temperature can be stabilized. As a result, it is possible to continuously form an image without causing ink ejection failure or image deterioration, and it is not necessary to stop the image formation in order to cool the ink whose temperature has become too high. Can be shortened.
Further, since the first heating units 2401 and 3011 are controlled so that the temperature of the ink in the ink supply system 320 is higher than the gelation temperature and lower than the liquefaction temperature, the amount of heat generated by the first heating units 2401 and 3011 can be reduced. In addition, it is possible to reduce the power cost in the ink temperature control accompanying the image formation.

  The sub-tank 243 and the third heating unit 2431 are further provided, and the control unit 40 heats the ink supply system 320, the inkjet head 241 and the sub-tank 243 by the first to third heating units 2401, 2421, 2431, and 3011, After the temperature of the ink in the ink supply system 320, the inkjet head 241 and the sub tank 243 becomes equal to or higher than the liquefaction temperature, the temperature of the ink in the ink supply system 320 and the sub tank 243 is higher than the gelation temperature and lower than the liquefaction temperature. Since the first heating units 2401 and 3011 and the third heating unit 2431 are controlled, the temperature of the ink in the inkjet head 241 can be more reliably stabilized. Further, since the third heating unit 2431 is controlled so that the temperature of the ink in the sub tank 243 is higher than the gelation temperature and lower than the liquefaction temperature, the amount of heat generated by the third heating unit 2431 can be reduced, and the power cost is further increased. Can be reduced.

  In addition, when the temperature of the ink in the sub tank 243 becomes equal to or lower than the gelation temperature by supplying the ink, the control unit 40 heats the sub tank 243 by the third heating unit 2431, and the temperature of the ink in the sub tank 243 is liquefied. After the temperature exceeds the temperature, the third heating unit 2431 is controlled so that the temperature of the ink in the sub tank 243 is higher than the gelation temperature and lower than the liquefaction temperature. Even when the temperature of the ink in the sub tank 243 becomes equal to or lower than the gelation temperature due to the increase in the ink inflow amount, the sub tank 243 can be quickly heated to increase the fluidity of the ink.

  In addition, the control unit 40 controls the second heating unit 2401 so that the ink temperature of the inkjet head 241 becomes an ink discharge temperature higher than the liquefaction temperature after the temperature of the ink of the inkjet head 241 becomes equal to or higher than the liquefaction temperature. Therefore, the ink supplied to the inkjet head 241 can be heated to start image formation promptly.

  In the above-described embodiment, the ink discharge mechanism 300 includes the sub tank 243, but may not include the sub tank 243. In this case, the ink ejection mechanism 300 does not include the third heating unit 2431 and the temperature detection unit 2432, and the control unit 40 does not control the third heating unit 2431.

  Further, in the above-described embodiment, as the temperature detection units 2402, 2422, 2432, 3012 and the recovery path temperature detection unit 3025, sensors that are not in contact with ink are used, but sensors that are in contact with ink are used. It is good as a thing. In this case, temperature control with higher accuracy can be performed. In particular, since ink at normal temperature is supplied to the sub tank 243, a sensor that contacts the ink or a combination thereof is preferable.

  Using the inkjet recording apparatus 1 of the present invention configured as described above and the inkjet recording apparatus of the prior art, the temperature transition of the ink in the inkjet head was measured. In this example, an ink having a gelation temperature of 45 ° C., a liquefaction temperature of 65 ° C., and an ink discharge temperature of 70 ° C. was used.

  In the inkjet recording apparatus 1 of the present invention, the first heating units 2421 and 3011 and the third heating are performed so that the temperature of the ink in the ink supply system 320 and the sub tank 243 is higher than the gelation temperature and lower than the liquefaction temperature, that is, 60 ° C. It is assumed that the part 2431 is controlled and the second heating part 2401 is controlled such that the temperature of the ink in the inkjet head 241 is 70 ° C.

  The prior art ink jet recording apparatus has substantially the same configuration as that of the ink jet recording apparatus 1 of the present invention, and the ink supply system, the sub tank, and the ink in the ink jet head have an ink temperature of 70 ° C. respectively. The 1st-3rd heating part shall be controlled.

  FIG. 9 shows the measurement results of the temperature transition of the ink in the inkjet head in the inkjet recording apparatus 1 of the present invention and the inkjet recording apparatus of the prior art. In FIG. 9, the horizontal axis represents time, and the vertical axis represents ink temperature of the inkjet head. In FIG. 9, the temperature transition of the ink in the inkjet head 241 in the inkjet recording apparatus 1 of the present invention is represented by a solid line A, and the temperature transition of the ink in the inkjet head in the conventional inkjet recording apparatus is represented by a broken line B. Further, in FIG. 9, T1 and T2 indicate time periods in which image formation is performed by ejecting ink from the inkjet head.

As shown in FIG. 9, in the conventional inkjet recording apparatus, the ink in the inkjet head rises above the ink discharge temperature of 70 ° C. during image formation. This is presumably because the temperature of the ink supplied to the ink jet head is 70 ° C., and the ink jet head itself generates heat when the piezo element of the ink jet head is driven, so that the temperature of the ink exceeds 70 ° C. In addition, the temperature of the ink in the ink-jet head has dropped to around 68 ° C after the end of image formation. This is because the temperature control of the ink-jet head immediately follows because the piezo element did not generate heat after the end of image formation. It is thought that it was not possible.
As described above, the conventional ink jet recording apparatus cannot stabilize the temperature of the ink in the ink jet head during image formation. If image formation is continued while the temperature of the ink in the ink jet head exceeds the ink discharge temperature, ink discharge failure or image deterioration occurs. Further, when image formation is stopped until the temperature of the ink in the inkjet head is lowered to the ink discharge temperature, the time required for image formation increases.

  On the other hand, according to the inkjet recording apparatus 1 of the present invention, as shown in FIG. 9, the temperature of the ink in the inkjet head 241 is kept constant even during image formation, and the temperature of the ink is It is not higher or lower than the discharge temperature. For this reason, it is possible to perform image formation continuously without causing ink ejection failure or image deterioration, and it is not necessary to stop image formation, so that the time required for image formation can be shortened.

  As described above, the present invention is suitable for providing an ink jet recording apparatus and an ink temperature control method capable of stabilizing the temperature of ink in an ink jet head even during image formation.

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 40 Control part 241 Inkjet head 242 Storage part 243 Sub tank 300 Ink discharge mechanism 301 Supply path 303 Path 320 Ink supply system 2401 2nd heating part 2402 Temperature detection part 2421 1st heating part 2422 Temperature detection part 2431 3rd heating Unit 2432 temperature detection unit 3011 first heating unit 3012 temperature detection unit

Claims (5)

An ink jet recording apparatus that performs image formation by discharging an ink that is liquefied at a temperature equal to or higher than a liquefying temperature and gelled at a temperature equal to or lower than the gelation temperature lower than the liquefaction temperature,
An inkjet head that ejects ink;
An ink supply system for supplying ink to the inkjet head;
A first heating unit for heating the ink supply system;
A second heating unit for heating the inkjet head;
A temperature detector for detecting the temperature of ink in the ink supply system and the inkjet head, and
A control unit for controlling the first heating unit and the second heating unit,
The control unit heats the ink supply system and the inkjet head by the first heating unit and the second heating unit, and the temperature of the ink in the ink supply system detected by the temperature detection unit is equal to or higher than the liquefaction temperature. Then, the first heating unit is controlled such that the temperature of the ink in the ink supply system detected by the temperature detection unit is higher than the gelation temperature and lower than the liquefaction temperature. Inkjet recording device. A sub tank for storing ink supplied from an ink tank and supplying the stored ink to the ink supply system;
A third heating unit for heating the sub-tank,
The temperature detection unit further detects the temperature of the ink in the sub tank,
The control unit further controls the third heating unit, heats the sub tank by the third heating unit, and the temperature of the ink in the sub tank detected by the temperature detection unit becomes equal to or higher than the liquefaction temperature. The said 3rd heating part is controlled so that the temperature of the ink of the said subtank detected by the said temperature detection part may be higher than the said gelation temperature, and less than the said liquefaction temperature. Inkjet recording device.   The control unit heats the sub tank by the third heating unit when the temperature of the ink in the sub tank detected by the temperature detection unit becomes equal to or lower than the gelation temperature by supplying ink to the sub tank. Then, after the temperature of the ink in the sub tank detected by the temperature detection unit becomes equal to or higher than the liquefaction temperature, the temperature of the ink in the sub tank detected by the temperature detection unit is higher than the gelation temperature and the liquefaction. The inkjet recording apparatus according to claim 2, wherein the third heating unit is controlled so as to be lower than a temperature.   The said control part controls the said 2nd heating part so that the temperature of the ink of the said inkjet head detected by the said temperature detection part may become an ink discharge temperature higher than the said liquefaction temperature. 4. The ink jet recording apparatus according to any one of items 1 to 3. An ink temperature control method for an ink jet recording apparatus according to any one of claims 1 to 4,
Heating the ink supply system and the inkjet head by the first heating unit and the second heating unit, and setting the temperature of the ink in the ink supply system detected by the temperature detection unit to be equal to or higher than the liquefaction temperature;
And controlling the first heating unit such that the temperature of the ink in the ink supply system detected by the temperature detection unit is higher than the gelation temperature and lower than the liquefaction temperature. Ink temperature control method.

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