JP2018167437A - Ink jet recording device and ink jet recording method - Google Patents

Abstract

To provide an ink jet recording device and method capable of discharging the uniform amount of ink from each discharge part by applying a prescribed pressure to plural discharge parts discharging the inks different from each other in type.SOLUTION: An objective ink jet recording device comprises plural discharge parts 22 capable of discharging plural inks, respectively and the pressure applying means 44, 49 and 50 applying a prescribed pressure to plural discharge parts 22, respectively in order to remove the ink from plural discharge parts 22. Besides, the device further comprises a heating means 24 which carries out heating of respective discharge parts 22 in response to viscosity variation of the inks discharged from plural discharge parts 22 prior to the pressure application to the discharge parts 22 by the pressure applying means.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an ink jet recording apparatus and an ink jet recording method for performing recording by discharging different types of ink.

  In the ink jet recording apparatus, the quality of the ink ejection performance of the ejection port that ejects ink greatly affects the image quality. The ejection performance of the ejection port is degraded by the increase in the viscosity of the ink filled in the ejection port. Therefore, in a situation where recording is not performed, the ejection port is covered with a cap to reduce evaporation of the ink solvent from the ejection port. However, even if the discharge port is covered with a cap, it is difficult to completely block the discharge port from outside air. For this reason, when a recording operation is not performed for a long period of time, a solvent component such as moisture contained in the ink gradually evaporates from the cap to the outside air, the ink is thickened, and an ejection failure occurs at the ejection port. Sometimes.

  When a discharge failure occurs at the discharge port, a recovery process is performed to discharge the thickened ink and restore the discharge performance of the discharge port. As recovery processing, suction recovery is generally known in which thickened ink is sucked from the nozzle side through a cap and discharged. Japanese Patent Application Laid-Open No. 2004-228561 describes an apparatus that heats ink in a recording head by a heating unit provided in the recording head and performs suction recovery in a state where the viscosity of the ink is lowered.

JP 2007-313654 A

  As described above, Patent Document 1 discloses a technique for performing suction recovery by adjusting ink viscosity by heating. However, suction discharge due to a difference in thickening characteristics of a plurality of types of ink used in a recording apparatus is disclosed. There is no mention of variation in quantity. Since the ink has different formulations depending on the type, there is a difference in the thickening property due to evaporation of the solvent. For this reason, when a plurality of recording heads are simultaneously sucked and recovered by applying a certain negative pressure, ink with a low degree of thickening is sucked and discharged more from the recording head, whereas ink with a high degree of thickening is Variations in the discharge amount occur in that only a small amount is discharged from the recording head.

  The present invention relates to an ink jet recording apparatus and an ink jet recording capable of discharging a uniform amount of ink from each discharge portion by applying a predetermined pressure to a plurality of discharge portions that discharge different types of ink. The purpose is to provide a method.

In order to solve the above problems, the present invention has the following configuration.
According to one aspect of the present invention, a plurality of ejection units that can eject each of a plurality of inks, and a pressure application unit that applies a predetermined pressure to each of the plurality of ejection units to remove ink from the plurality of ejection units. And a heating unit that heats each of the plurality of ejection units according to variations in viscosity of the ink ejected by each of the plurality of ejection units prior to the application of pressure to the ejection unit by the pressure application unit. This is an ink jet recording apparatus.

According to another aspect of the present invention, there is provided a pressure applying step of applying a predetermined pressure to each of the plurality of ejection units in order to remove ink from the plurality of ejection units capable of ejecting a plurality of inks, and the pressure Prior to the application of pressure to the ejection unit in the application step, the heating step of heating the ejection unit according to variations in the viscosity of the ink ejected by each of the plurality of ejection units. Ink jet recording method.
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  According to the present invention, it is possible to discharge a uniform amount of ink from each ejection unit by applying a predetermined pressure to a plurality of ejection units that eject different types of ink.

It is a schematic block diagram of the inkjet recording device in this embodiment. FIG. 2 is a block diagram illustrating a schematic configuration of a control system of the ink jet recording apparatus of FIG. 1. It is a figure which shows typically the structure of an ink supply system and a recovery system. FIG. 4 is a cross-sectional view schematically illustrating a discharge portion of a discharge port of the recording head illustrated in FIG. 3. It is a figure which shows the relationship between the moisture evaporation rate of an ink, and the viscosity of an ink. It is a figure which shows the relationship between the temperature of an ink, and the viscosity of an ink. It is a figure which shows the relationship between the ink leaving period and the recovery temperature of ink viscosity. It is a flowchart which shows recovery operation control after being left.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the following embodiments are merely examples, and are not intended to limit the scope of the present invention.

  FIG. 1 is a front view schematically showing an ink jet recording apparatus (hereinafter simply referred to as a recording apparatus) in the present embodiment. The recording device 10 is connected to a host device 12 such as a personal computer that transmits image data, control commands, and the like. In the host device 12, four recording heads 22K, 22C, 22M, and 22Y serving as a plurality of ejection units capable of ejecting ink are conveyed in the conveyance direction (A direction) of a sheet P as a recording medium fed out from the roll sheet RP. ) Are arranged side by side. Black (K), cyan (C), magenta (M), and yellow (Y) inks are ejected from the four recording heads 22K, 22C, 22M, and 22Y, respectively. These four recording heads 22K, 22C, 22M, and 22Y are lines in which a plurality of ejection ports that eject ink are arranged along a direction orthogonal to the transport direction (direction orthogonal to the paper surface of FIG. 1 (C direction)). Head. The lengths in the C direction of these four recording heads 22K, 22C, 22M, and 22Y are slightly longer than the maximum width (length in the C direction) of the recording medium to be used. Further, these four recording heads 22K, 22C, 22M, and 22Y are held at fixed positions and do not move during image formation. As described above, the recording apparatus according to the present embodiment is a so-called full-line type recording apparatus that performs recording for each line by the recording heads 22K, 22C, 22M, and 22Y on the continuously conveyed sheet P. It has become.

  The recording apparatus 10 is suctioned as pressure application means for applying a predetermined pressure to each recording head 22 so that ink can be stably ejected from the four recording heads 22K, 22C, 22M, and 22Y. A recovery device 40 is incorporated. The suction recovery device 40 includes a capping mechanism, a pump 44 (see FIG. 2), a blade (not shown), and the like. The capping mechanism forcibly sucks and discharges ink from the ejection ports formed on the ejection port formation surfaces 22Ks, 22Cs, 22Ms, and 22Ys of the four recording heads 22K, 22C, 22M, and 22Y, and makes the recording head good in the initial stage. It restores the discharge performance. The capping mechanism includes four caps 50K, 50C, 50M, and 50Y (see FIG. 3) and a capping motor 122 (see FIG. 2) that closely contacts and separates the ejection port forming surfaces 22Ks, 22Cs, 22Ms, and 22Ys of the recording head 22. ). The blade described above is a member that performs a cleaning operation for wiping ink, dust, and the like adhering to the ejection port formation surfaces 22Ks, 22Cs, 22Ms, and 22Ys.

  The sheet P is supplied from the roll sheet RP held in the supply unit 25 and is conveyed in the A direction by the conveyance mechanism 26 incorporated in the recording apparatus 10. The transport mechanism 26 includes a transport belt 26a that moves while holding the sheet P, a transport motor 120 that circulates the transport belt 26a, a pair of pulleys 26c and a roller 26d that are stretched around the transport belt 26a under tension. Etc.

  An image is formed on the sheet P by ejecting ink from the recording heads 22K, 22C, 22M, and 22Y based on the recording data (image information) with respect to the sheet P that is continuously conveyed. Further, the recording apparatus 10 is provided with ink tanks 28Y, 28M, 28C, and 28K that store ink to be supplied to the recording heads 22K, 22C, 22M, and 22Y. Further, the recording apparatus 10 includes a single pump 44 (see FIG. 3 and the like) as negative pressure generating means for generating negative pressure for performing ink supply and recovery operations to the recording heads 22K, 22C, 22M, and 22Y. Is provided. In this embodiment, the pump 44 is connected to four caps 50K, 50C, 50M, and 50Y. By driving the pump 44 with the caps 50K, 50C, 50M, and 50Y being brought into close contact with the discharge port forming surfaces 22Ks, 22Cs, 22Ms, and 22Ys, four sealed spaces formed between the cap and the discharge port forming surface are formed. It becomes possible to apply the same negative pressure.

  As described above, in the present embodiment, the four recording heads 22K, 22C, 22M, and 22Y are used corresponding to the respective four colors (Y, M, C, and K). However, the four recording heads 22K, 22C, 22M, and 22Y all have substantially the same configuration except that the ink colors to be handled are different. For this reason, in the following description, the four recording heads and the ejection port forming surfaces may be collectively referred to as the recording head 22 and the ejection port forming surface 22s. Similarly, a cap and an ink tank provided for each ink color may also be referred to as a cap 50 and an ink tank 28.

  FIG. 2 is a block diagram illustrating a schematic configuration of a control system provided in the recording apparatus 10. The recording data and commands transmitted from the host device 12 are received by the CPU 100 via the interface controller 102. The CPU 100 receives the recording data of the recording apparatus 10 and controls functions as control means for executing various operations such as calculation, determination, analysis, and control.

  For example, after analyzing the received command, the CPU 100 develops a bitmap of the image data of each color component of the recording data in the image memory 106. Before the recording operation, the motor driving unit 116 connected to the CPU 100 is controlled via the output port 114 to drive the head up / down motor 118, and each recording head 22 is separated from the cap 50 of the capping mechanism, Move to the recording position. Subsequently, the CPU 100 drives the roll motor 125 and the conveyance motor 120 for feeding the sheet from the roll sheet RP via the output port 114 and the motor driving unit 116, and moves the sheet P to a position facing the recording head 22. Transport.

  In synchronism with the conveying operation of the sheet P, the CPU 100 sequentially reads the corresponding color recording data from the image memory 106, and the read data is transferred to the recording heads 22K, 22C, 22M, and 22Y. Transfer via the circuit 112.

  The processing executed by the CPU 100 as described above is executed based on the processing program stored in the program ROM 104. The program ROM 104 stores processing programs and tables corresponding to the control flow. The CPU 100 uses a work RAM 108 as a working memory.

  During the cleaning operation and the recovery operation of each recording head 22, the CPU 100 drives the pump motor 124 via the motor drive unit 116 and drives the pumps 42 and 44 to control the recovery operation such as ink suction and pressurization. Do.

  FIG. 3 is a diagram schematically showing an ink supply system from the ink tank 28 to the recording head 22 and a recovery system for discharging ink from the ejection port of the recording head 22 in the recording apparatus of the present embodiment. Since each recording head 22 has substantially the same configuration, in the following, description will be given by taking ink supply and recovery for the recording head 22K that discharges black ink as an example.

  The recording apparatus 10 includes a recording head 22K, a detachable main tank 28K, and an ink flow path 40 that connects the ink tank 28K and the recording head 22K. Further, one end of an air flow path 41 is connected to the upper part of the recording head 22K, and a pump 42 is connected to the other end of the air flow path 41. One end of the air flow path 41 communicates with the ink flow path 40 via the ink supply chamber 26 that is the internal space of the recording head 22K. The air supply system in the present embodiment is configured by the air flow path 41, the pump 42, and the ink tank 28 described above.

  In the ink supply system, the ink stored in the ink tank 28 is recorded via the ink flow path 40 by driving the pump 42 and reducing the pressure in the air flow path 41 and the ink supply chamber 26 of the recording head 22K. The ink is supplied to the ink supply chamber 26 of the head 22. Note that a supply filter 18 that removes dust, foreign matter, and the like contained in the ink is provided at one end of the ink flow path 40. The ink that has flowed into the ink supply chamber 26 is filled into the ejection port 23 (see FIG. 4) disposed in the lower part of the recording head. As a result, a meniscus suitable for discharging ink droplets is formed near the opening of the discharge port 23.

  A liquid level detection sensor 21 is attached to a part of the ink supply chamber 26, and ink supply from the ink tank 28K to the ink supply chamber 26 is controlled based on the measurement result. That is, when the liquid level detection sensor 21 determines that the liquid level in the ink supply chamber 26 is below a certain level, the pump 42 is driven and the ink in the ink tank 28 passes through the ink flow path 40 to the ink tank 28K. Is sucked into. When the liquid level of the ink in the ink tank 28 rises due to the ink sucked into the ink tank 28 and the liquid level detection sensor 21 detects that the liquid level is above a certain level, the driving of the pump 42 is stopped. Ink supply (suction) is then stopped. The drive control of the pump 42 by the liquid level sensor 21 is executed by the CPU 100.

  On the other hand, the pump 44 is used for the recovery operation for recovering the discharge performance of the discharge ports 23 (see FIG. 4) formed in each recording head 22. Here, the recovery operation is to remove the foreign matter such as fine bubbles and dust remaining in the discharge port 23 formed in the recording head 22 and the ink thickened by drying from the discharge port 23, This is an operation of filling the interior 23 with fresh ink. The recording apparatus 10 is provided with a cap 50K that can be closely spaced from the ejection port forming surface 22s of the recording head 22K, and the cap 50K and the pump 44 are connected by a recovery channel 49. In FIG. 3, only the cap 50K corresponding to the recording head 22K that discharges black ink is shown. However, in the present embodiment, caps 50M, 50C, and 50K corresponding to the recording heads 22C, 22M, and 22Y that discharge inks of other colors are also provided independently. These caps 50 are also connected to the recovery channel 49 and are connected to the inlet of the pump 44 through the recovery channel 49. The outlet of the pump 44 is connected to a waste liquid tank 46 for storing the waste liquid generated by the recovery operation. Further, the outlet of the pump 42 connected to the air flow path 41 is also connected to the upper part of the waste liquid tank 46.

  During the recovery operation, the cap 50K is brought into close contact with the ejection port forming surface 22Ks of the recording head 22K, and then the pump 44 is driven. Thereby, the sealed space and the recovery flow path 49 formed between the cap 50 and the discharge port forming surface 22Ks are decompressed. As a result, a small amount of thickened ink having increased viscosity is discharged from the ejection port 23 of the recording head 22, and along with this, bubbles in the ejection port 23, dust adhering to the vicinity of the ejection port 23, and the like are also covered with the cap 50 </ b> K. Sucked and discharged. At this time, also in the caps 50M, 50C, and 50K corresponding to the inks of other colors, the sealed space and the recovery flow path 49 formed between the ejection port forming surfaces 22Cs, 22Ms, and 22Ys are decompressed. Accordingly, ink and dust are also sucked and discharged into the caps 50M, 50C, and 50K for the recording heads 22C, 22M, and 22Y. The ink, bubbles, etc. discharged to each cap are guided to the waste liquid tank 46.

  FIG. 4 is an enlarged view schematically showing a cross section of a recording head used in the recording apparatus 10 in the present embodiment. The recording head 22 includes a discharge energy generating element (not shown) that generates energy for discharging the ink I supplied from the ink supply chamber 26 into the discharge port 23. As the discharge energy generating element, an electrothermal conversion element (heater), an electromechanical conversion element (piezo element), or the like can be used. When the electrothermal converter is used, the ink can be foamed by the heat generation, and the ink can be ejected from the ejection port 23 using the foaming energy. Further, an ink heater (heating means) 24 for heating the ink in the discharge port 23 is provided in the vicinity of the discharge port 23. Further, an ink temperature sensor (ink temperature detection means) 130 is provided in the vicinity of the ejection port 23, and the detected temperature data is input to the CPU 100. The CPU 100 controls driving of the ink heater 24 based on the detected temperature data.

  Next, recovery control of the recording head 22 will be described with reference to FIGS. FIG. 5 is a graph showing an increase in ink viscosity with respect to the evaporation rate of water in the ink. As described above, when the recording head 22 is left unused for a long period of time, solvent components such as moisture gradually evaporate to the outside air in the ink near the opening of the ejection port 23. Ink increases in viscosity (thickening).

  As shown in FIG. 5, when the leaving period exceeds 3 weeks, the evaporation rate of water in the ink exceeds 50%, and gradually black ink (Bk ink), cyan ink (C ink), magenta ink (M Ink) and yellow ink (Y ink) begin to differ in viscosity. The difference in the viscosity of each ink becomes more noticeable as the water in each ink evaporates.

  When the standing period exceeds 4 weeks, the water evaporation rate exceeds 65%. Further, when the water evaporation rate reaches 70%, the water in the ink near the discharge port 23 is completely evaporated, and the viscosity becomes maximum. The moisture evaporation rate in the ink varies depending on structural factors such as the adhesion between the recording head 22 and the cap 50 during the leaving period, factors such as the temperature and humidity environment where the ink is left, and ink prescription. The characteristics shown in FIG. 5 are merely examples.

  Next, the relationship between ink viscosity and temperature will be described. FIG. 6 is a graph showing viscosity characteristics with respect to the temperature of an ink having a water evaporation rate of 70%. Even ink that has increased in viscosity due to evaporation of moisture can be decreased in viscosity by increasing the temperature. For example, a Y ink that exhibits the highest viscosity at a room temperature of 25 ° C. can be lowered to a viscosity equivalent to that of an ink that has not been thickened by raising the temperature to 50 ° C.

  Such a viscosity characteristic with respect to the temperature of the ink differs depending on the evaporation rate of water in each ink. For example, an ink having a moisture evaporation rate of 60% has a lower viscosity at room temperature than an ink having a moisture evaporation rate of 70%, and therefore, the ink is reduced to a viscosity equal to that of an ink that has not been thickened at a temperature lower than 50 ° C. be able to.

  Further, the viscosity characteristic with respect to the temperature of the ink also changes depending on the formulation of each ink. FIG. 7 shows a heating temperature table representing the target heating temperature for the standing period, which is determined based on the ink viscosity characteristic with respect to moisture evaporation (FIG. 5) and the ink viscosity characteristic with respect to temperature (FIG. 6). According to FIG. 5, it can be seen that the water evaporation rate becomes 70% and the viscosity of each ink becomes maximum when the leaving period is 4 weeks or more. Further, according to FIG. 6, the thickening ink with 70% water evaporation is not thickened by heating up to 40 ° C. for Bk ink, up to 45 ° C. for C ink and M ink, and up to 50 ° C. for Y ink. It can be seen that the viscosity can be lowered to the same viscosity as the ink.

  Therefore, when there is a standing period T of 4 weeks (4W) or more (4W ≦ T), the Bk ink is heated to 40 ° C., the C ink and the M ink are heated to 45 ° C., and the Y ink is heated to 50 ° C. The heating temperature table is set so as to be performed. This makes the viscosity of all inks uniform by heating each ink to a temperature determined based on the viscosity characteristics with respect to the temperature of each ink, even if the degree of viscosity increase of each color ink due to moisture evaporation is different. can do.

  Similarly, in the case of a leaving period (3W ≦ T <4W) in which the water evaporation rate is 65% at the maximum and in the case of a leaving period (2W ≦ T <3W) in which the water evaporation rate is 55% at the maximum, each color The viscosity characteristics of each ink with respect to temperature are measured. And based on the measurement result in each case, the temperature required to make the viscosity of the four color inks uniform is set as a heating temperature table. Further, since the water evaporation rate does not exceed 50% and the viscosity hardly increases until the standing period is 2 weeks, it is not necessary to provide a heating temperature.

  Next, recovery control after being left will be described with reference to FIG. First, when the recording apparatus 10 is turned on and the recording apparatus is activated, or when returning from a sleep state in which the power is turned on but no operation related to recording is performed (step S1), the CPU 100 sets the idle period T. calculate. The neglected period T is calculated based on the difference between the “date and time when the last ejection operation was performed” recorded in the work RAM 108 and the “date and time when the system was activated or returned from the sleep state” (step S2). Thus, in the present embodiment, the CPU 100 has a function as an acquisition unit that acquires the idle period. However, the acquisition of the neglected period can be configured by a timer that is started in accordance with the discharge or discharge operation in addition to the CPU 100.

  Thereafter, the CPU 100 determines whether or not the leaving period T is less than 2 weeks (step S3). If the standing period T is less than 2 weeks, the water evaporation does not exceed 50% and the viscosity increase hardly occurs. Therefore, the ink suction from the ejection port 23 of the recording head 22 is unnecessary, and the viscosity increase is eliminated. The heating operation is not performed. On the other hand, when the leaving period is two weeks or more, the heating temperature table corresponding to each of the K, C, M, and Y ink leaving periods is referred to by referring to the heating temperature table shown in FIG. Is determined (step S4).

  When the heating temperature is determined, the determined temperature data is transferred from the CPU 100 to the recording head control circuit 112, and the heating operation by the ink heater 24 provided in each recording head 22 is started (step S5). When heating is started, the CPU 100 reads the temperature in the vicinity of the ejection port detected by the ink temperature detection sensor (temperature detection means) 130 provided in the recording head 22 at a constant cycle. Then, it is determined whether or not the read temperature has reached the heating temperature determined in step S4 (step S6). If the detected temperature does not reach the set temperature, the heating operation is continued. If the detected temperature reaches the set temperature, the heating operation is stopped (step S7), and the suction recovery operation is executed.

  As described above, in the recording apparatus of the present embodiment, prior to performing the suction recovery operation for forcibly sucking and discharging from the ejection port of the recording head, a plurality of types of inks having different viscosity characteristics are heated to perform all of the inks. The viscosity is uniformly made, and then a suction recovery operation is performed. For this reason, even when a uniform negative pressure is simultaneously applied to a plurality of caps by a single pump 44, it is possible to suck and discharge a substantially uniform amount of ink from each recording head, as in the conventional case. In addition, there is no variation in the amount of suction and discharge caused by the recording head. Therefore, it can be recovered uniformly and properly for all the recording heads.

(Other embodiments)
In the above embodiment, an example in which ink is forcibly recovered by suction from the ejection port of the recording head has been described. However, the present invention is not limited to this. As the recovery means for discharging the thickened ink or the like from the discharge port of the recording head, a so-called pressure recovery means that applies positive pressure in the recording head and forcibly discharges the ink from the discharge port is used. Is also possible. This pressure recovery can be performed by, for example, reversing the pump 42 and applying air from the pump 42 into the ink supply chamber 26 of the recording head 22 in the configuration shown in FIG. In this case as well, if the viscosity of various inks is made uniform by heating the ink in or near the ejection openings of multiple recording heads before performing the pressure recovery process, a uniform pressure is simultaneously applied to each recording head. By doing so, a uniform amount of ink can be discharged from all the recording heads.

  Furthermore, although the above description has been described taking as an example the case where inks having different viscosity characteristics are ejected from a plurality of separate recording heads, the present invention is not limited to this. In the recording head, a chip formed with a group of ejection ports composed of a plurality of ejection ports is arranged on a single support (supporting substrate) or the like, and a plurality of types of ink having different viscosity characteristics are ejected from each chip. There is also a composition. Even in a recording apparatus equipped with such a recording head, if an independent ink heating means is provided for each chip, and heating according to the viscosity characteristics of the ink is performed by each heating means, by suction or pressure recovery, A uniform amount of ink can be discharged from the ejection port group of the head chip.

  In the above-described embodiment, the configuration in which the heating time is selected from the table relating to the viscosity characteristic of the ink based on the standing time has been described, but the present invention is not limited to this. For example, even when a plurality of inks having the same viscosity characteristics are used, the viscosity of each ink may be made uniform by heating the ink based on the recording head leaving time. This also makes it possible to recover all the recording heads uniformly and appropriately.

DESCRIPTION OF SYMBOLS 10 Inkjet recording device 22 Discharge part 24 Ink heater (heating means)
50 Cap 42 Pump 44 Pump 100 CPU (Acquisition means, control means)
I ink

Claims (12)

A plurality of ejection sections capable of ejecting a plurality of inks;
Pressure application means for applying a predetermined pressure to each of the plurality of ejection units in order to remove ink from the plurality of ejection units;
Prior to the application of pressure to the ejection part by the pressure application means, heating means for heating the respective ejection parts according to variations in the viscosity of the ink ejected by each of the plurality of ejection parts;
An ink jet recording apparatus comprising:   The heating unit heats each of the plurality of ejection units based on at least one of ink viscosity characteristics and a leaving period in which ink is not ejected or removed from the plurality of ejection units. The ink jet recording apparatus according to claim 1.   The inkjet recording apparatus according to claim 1, wherein the heating unit heats the plurality of ejection units so as to make the viscosity of the ink in the plurality of ejection units uniform. And further comprising detection means for detecting the temperature of the ink in the plurality of ejection portions,
The heating unit heats the plurality of ejection units so that the temperature of the ink detected by the detection unit is equal to or higher than a target heating temperature determined according to the viscosity characteristic of the ink. 2. The ink jet recording apparatus according to 2 or 3.   The ink jet recording according to any one of claims 2 to 4, wherein the viscosity characteristics of the ink in the plurality of ejection portions is a characteristic representing a relationship between an evaporation rate of a solvent component of the ink and a viscosity. apparatus.   6. The ink jet recording apparatus according to claim 2, wherein the viscosity characteristics of the ink in the plurality of ejection portions are characteristics representing a relationship between a temperature and a viscosity of the ink.   The target heating temperature is a temperature at which the ink viscosity determined based on the relationship between the evaporation rate of the solvent component of the ink and the viscosity and the relationship between the ink temperature and the viscosity is reduced to a predetermined viscosity. The inkjet recording apparatus according to claim 4.   The ink jet recording apparatus according to claim 1, wherein the pressure applying unit applies a uniform negative pressure to the ink in the discharge ports of the plurality of discharge units.   The ink jet recording apparatus according to claim 1, wherein the pressure applying unit applies a uniform positive pressure to the ink in the plurality of ejection units.   The inkjet recording apparatus according to claim 8, wherein the pressure application unit includes a cap that seals the discharge port, and a negative pressure generation unit that applies a negative pressure to the cap.   The inkjet recording apparatus according to claim 1, wherein the pressure applying unit applies the predetermined pressure to each of the plurality of ejection units simultaneously. A pressure application step of applying a predetermined pressure to each of the plurality of ejection units in order to remove ink from the plurality of ejection units capable of ejecting a plurality of inks, respectively.
Prior to the application of pressure to the ejection unit by the pressure application step, a heating step of heating the respective ejection units according to variations in the viscosity of the ink ejected by each of the plurality of ejection units;
An ink jet recording method comprising:

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