JP6973183B2 - Inkjet recording device and ink feeding method - Google Patents

Description

The present invention relates to an inkjet recording device and an ink liquid feeding method.

Conventionally, there is an inkjet recording device that records an image or the like by ejecting ink from a nozzle provided in an ink ejection unit onto a recording medium and landing it at a desired position. Some inkjet recording devices are provided with an ink storage section outside the ink ejection section, and ink is supplied from the ink storage section to the ink ejection section. In such an inkjet recording device, a stirring unit such as a screw for stirring the ink in the ink storage unit is provided, and the ink is stirred by the stirring unit so that the temperature and density of the ink become uniform and then supplied to the ink ejection unit. There is a technique (for example, Patent Document 1 to Patent Document 3).

Inks used in inkjet recording devices have been developed with various properties, and some of them are in a gel state at a predetermined phase change temperature (for example, about 40 ° C to 60 ° C) or less, and the phase change temperature is concerned. There is a phase change ink having the property of becoming a sol state when heated above. When this phase change ink is used, an ink heating unit is provided in the ink ejection unit, and the ink heated by the ink heating portion and in a sol state is ejected from the nozzle.

Further, when phase change ink is used in the above-mentioned inkjet recording apparatus having an ink reservoir, when the ink is left to stand in the ink reservoir and stored for a long time, the ink becomes a sol component and a gel component in the ink reservoir. In some cases, the gel components are separated and released in a non-uniform distribution. When the ink in this state is supplied to the ink ejection unit and an image is recorded, various image quality defects occur due to abnormalities in the ejected ink components, or the gel component is clogged in the ink flow path and the ink ejection failure occurs. Will occur. Therefore, it is necessary to supply the ink to the ink ejection portion after stirring the ink so that the gel component is uniformly distributed and in an appropriate state.

Japanese Unexamined Patent Publication No. 8-276599 Japanese Unexamined Patent Publication No. 2005-186399 Japanese Unexamined Patent Publication No. 2011-51170

However, under conditions where the ink storage temperature in the ink storage is extremely low, such as when the ink storage is placed in an environment close to the outside temperature in winter, the gel component strongly solidifies, so the ink is appropriate. It may take a long time to be agitated to a proper state, or even if the agitation is continued, it may not be possible to obtain an appropriate state. On the other hand, if a stirring unit having a higher stirring capacity is provided or a heater is provided in the ink storage unit in order to alleviate the solidification of the gel component, the cost of the inkjet recording device increases and the power consumption increases.
As described above, the above-mentioned conventional technique has a problem that it may not be easy to stir the ink in an appropriate state.

An object of the present invention is to provide an inkjet recording apparatus and an ink liquid feeding method capable of more easily stirring ink in an ink storage portion in an appropriate state.

In order to achieve the above object, the invention of the inkjet recording apparatus according to claim 1 is
An ink reservoir that stores ink that has the property of changing phase between the gel state and the sol state,
An ink heating unit that heats the ink supplied from the ink storage unit, and an ink heating unit.
An ink ejection unit having a nozzle and ejecting ink heated by the ink heating unit from the nozzle,
A first stirring unit that stirs the ink stored in the ink storage unit, and a first stirring unit.
A first temperature detection unit that detects the temperature of the ink stored in the ink storage unit, and
An ink receiving unit that receives and stores ink ejected from the nozzle of the ink ejection unit, and an ink receiving unit.
A discharge control means for controlling the discharge of ink from the nozzle of the ink discharge unit to the ink receiving unit, and a discharge control means.
A second temperature detecting unit that detects the temperature of the ink stored in the ink receiving unit, and
A reflux liquid feeding unit that performs a reflux liquid feeding operation to send the ink stored in the ink receiving unit to the ink storage unit, and a reflux liquid feeding unit.
A reflux liquid feed control means for causing the reflux liquid feed unit to perform the reflux liquid feed operation when the temperature detected by the second temperature detection unit is higher than the detection temperature by the first temperature detection unit.
To prepare for.

The invention according to claim 2 is the inkjet recording apparatus according to claim 1.
The reflux liquid feed control means causes the reflux liquid feed unit to perform the reflux liquid feed operation when a predetermined condition relating to the difficulty of stirring by the first stirring unit is satisfied.

The invention according to claim 3 is the inkjet recording apparatus according to claim 2.
The reflux liquid feed control means determines that the predetermined condition is satisfied when the temperature detected by the first temperature detection unit is lower than the predetermined reference temperature lower than the phase change temperature of the ink to the gel state. do.

The invention according to claim 4 is the inkjet recording apparatus according to any one of claims 1 to 3.
The discharge control means causes the reflux liquid supply unit to perform the reflux liquid feed operation when the first discharge control is started after the inkjet recording device is started.

The invention according to claim 5 is the inkjet recording apparatus according to any one of claims 1 to 4.
When the reflux liquid feeding operation is started by the reflux liquid feeding unit, the ink stored in the ink storage unit is used in the ink storage unit during a period including at least a part of the period during which the reflux liquid feeding operation is performed. A first stirring control means for stirring by the stirring unit of 1 is provided.

The invention according to claim 6 is the inkjet recording apparatus according to any one of claims 1 to 5.
A second stirring unit that stirs the ink stored in the ink receiving unit, and a second stirring unit.
When the reflux liquid feeding operation is started by the reflux liquid feeding unit, the ink stored in the ink receiving unit is used in the ink receiving unit during a period including at least a part of the period during which the reflux liquid feeding operation is performed. A second stirring control means for stirring by the stirring unit of 2 and
To prepare for.

The invention according to claim 7 is the inkjet recording apparatus according to any one of claims 1 to 6.
The reflux liquid feed control means stops the reflux liquid feed operation when the temperature detected by the first temperature detection unit becomes equal to or higher than a predetermined upper limit temperature.

The invention according to claim 8 is the inkjet recording apparatus according to any one of claims 1 to 7.
The discharge control means is such that the amount of ink ejected from the nozzle by the discharge control satisfies the relationship that the amount of ink ejected from the nozzle is monotonously non-decreasing with respect to the decrease in the detection temperature by the first temperature detection unit. Take control.

The invention according to claim 9 is the inkjet recording apparatus according to any one of claims 1 to 8.
The reflux liquid feed control means satisfies the relationship that the liquid feed amount per unit time in the reflux liquid feed operation is monotonously non-decreasing with respect to the decrease in the detection temperature by the first temperature detection unit. The recirculation liquid feeding operation is performed by the liquid feeding unit.

The invention according to claim 10 is the inkjet recording apparatus according to any one of claims 1 to 9.
An ink storage amount detecting unit for detecting the amount of ink stored in the ink storage unit is provided.
The discharge control means satisfies the relationship that the amount of ink ejected from the nozzle in the discharge control is monotonously non-decreasing with respect to an increase in the amount of ink stored detected by the ink storage amount detection unit. The discharge control is performed.

The invention according to claim 11 is the inkjet recording apparatus according to any one of claims 1 to 10.
An ink storage amount detecting unit for detecting the amount of ink stored in the ink storage unit is provided.
The reflux liquid feed control means satisfies the relationship that the liquid feed amount per unit time in the reflux liquid feed operation is monotonously non-decreasing with respect to the increase in the ink storage amount detected by the ink storage amount detection unit. As described above, the reflux liquid feeding unit is used to perform the reflux liquid feeding operation.

The invention according to claim 12 is the inkjet recording apparatus according to claim 8 or 10.
The ejection disposal control means controls the amount of ink by changing the number of times of ejection of ink from the nozzle in the ejection disposal control.

The invention according to claim 13 is the inkjet recording apparatus according to claim 8 or 10.
The ejection disposal control means controls the amount of ink by changing the amount of ink droplets ejected from the nozzle.

Further, in order to achieve the above object, the invention of the ink feeding method according to claim 14 is described.
An ink reservoir that stores ink that has the property of changing phase between the gel state and the sol state,
An ink heating unit that heats the ink supplied from the ink storage unit, and an ink heating unit.
An ink ejection unit having a nozzle and ejecting ink heated by the ink heating unit from the nozzle,
A first stirring unit that stirs the ink stored in the ink storage unit, and a first stirring unit.
A first temperature detection unit that detects the temperature of the ink stored in the ink storage unit, and
An ink receiving unit that receives and stores ink ejected from the nozzle of the ink ejection unit, and an ink receiving unit.
A second temperature detecting unit that detects the temperature of the ink stored in the ink receiving unit, and
A reflux liquid feeding unit that performs a reflux liquid feeding operation to send the ink stored in the ink receiving unit to the ink storage unit, and a reflux liquid feeding unit.
It is an ink liquid feeding method in an inkjet recording apparatus equipped with the above.
A discharge step of ejecting ink from the nozzle of the ink ejection portion to the ink receiving portion,
A reflux liquid feeding step of delivering the ink stored in the ink receiving unit to the ink storage unit when the temperature detected by the second temperature detecting unit is higher than the detection temperature by the first temperature detecting unit.
A stirring step of stirring the ink stored in the ink storage unit by the first stirring unit.
including.

According to the present invention, there is an effect that the ink in the ink storage portion can be agitated to an appropriate state more easily.

It is a figure which shows the schematic structure of the inkjet recording apparatus. It is a figure which shows the internal structure of a head unit. It is a schematic diagram which shows the structure of an ink supply mechanism. It is a block diagram which shows the main functional composition of an inkjet recording apparatus. It is a figure which shows the relationship between the temperature and viscosity of a phase change ink. It is a flowchart which shows the control procedure of the ink liquid feeding process.

Hereinafter, embodiments of the inkjet recording apparatus and ink feeding method of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of an inkjet recording device 1 according to an embodiment of the present invention.
The inkjet recording device 1 includes a transport unit 10, a head unit 20 (ink ejection unit), a fixing unit 30, a maintenance unit 50, and the like.

The transport unit 10 includes a transport belt 101, a transport roller 102, and the like. The transfer roller 102 rotates about a rotation axis by driving a transfer motor (not shown). The transport belt 101 is a ring-shaped belt whose inside is supported by a pair of transport rollers 102, and moves around as the transport rollers 102 rotate. In the inkjet recording device 1, with the recording medium M mounted on the transport belt 101, the transport belt 101 orbits at a speed corresponding to the rotation speed of the transport roller 102, whereby the recording medium M is moved around the transport belt 101. Performs a transport operation for transporting in the moving direction (transporting direction).

The recording medium M can be roll paper that is unwound (unrolled) from the roll (recording medium unwinding portion) on which the recording medium M is wound and supplied onto the transport belt 101. The recording medium M may be a sheet of paper cut to a certain size. The recording medium M is supplied onto the conveyor belt 101 by a paper feeding device (not shown), ink is ejected from the head unit 20, an image is recorded, and then the ink is ejected from the conveyor belt 101 to a predetermined paper ejection unit. As the recording medium M, in addition to paper such as plain paper and coated paper, various media such as cloth or sheet-shaped resin capable of fixing the ink landed on the surface can be used.

The head unit 20 ejects ink to the recording medium M conveyed by the conveying unit 10 at an appropriate timing based on the image data, and records the image. In the inkjet recording apparatus 1 of the present embodiment, four head units 20 corresponding to four colors of ink of yellow (Y), magenta (M), cyan (C), and black (K) are in the transport direction of the recording medium M. They are arranged so as to be arranged at predetermined intervals in the order of Y, M, C, and K colors from the upstream side. The number of head units 20 may be 3 or less or 5 or more.

FIG. 2 is a diagram showing an internal configuration of the head unit 20. FIG. 2A is a schematic view of the internal configuration of the head unit 20 when viewed from the front. FIG. 2B is a schematic view of the internal configuration of the head unit 20 when viewed from the conveyor belt 101 side. The case where the head unit 20 is viewed from the front means a case where the head unit 20 is viewed from a direction parallel to the transport direction of the recording medium M at a position facing the head unit 20 on the transport surface of the transport belt 101. ..

The head unit 20 has a plurality of recording heads 21 each provided with a plurality of recording elements for ejecting ink. The recording element communicates with a pressure chamber (channel) for storing ink, a piezoelectric element provided on the wall surface of the pressure chamber, an electrode for applying a voltage to the piezoelectric element to generate an electric field, and a pressure chamber. It has a nozzle 211 for ejecting ink in the pressure chamber. When a voltage signal with a drive waveform that deforms the piezoelectric element is applied to the electrodes of the recording element, the pressure chamber is deformed in response to this voltage signal and the pressure in the pressure chamber changes, and the pressure in the pressure chamber changes in response to the change in pressure. Ink is ejected from the nozzle 211 communicating with the pressure chamber. In the recording head 21, a plurality of nozzles 211 are arranged in two rows along the width direction to form two nozzle rows, and these two nozzle rows form two minutes of the arrangement interval of the nozzles 211 in the width direction. Only 1 is arranged so as to be offset from each other.

In the head unit 20, two recording heads 21 are combined to form a head module 21M (ink ejection unit), and the head modules 21M are arranged in a houndstooth pattern. In each head module 21M, the recording heads 21 are arranged in such a positional relationship that the nozzles 211 of the two recording heads 21 are arranged alternately in the width direction. The number of head modules 21M provided in the head unit 20 is not particularly limited, but is eight in the present embodiment. Due to such an arrangement of the recording head 21, the arrangement range of the nozzles 211 included in the head unit 20 in the width direction is the width in the width direction of the region of the recording medium M conveyed by the transfer belt 101 in which an image can be formed. It is designed to cover (recordable width). The head unit 20 is used with a fixed position when recording an image, and ink is sequentially ejected at predetermined intervals (transportation direction intervals) to positions in different transport directions according to the transport of the recording medium M. Record images using the single-pass method.

As shown in FIG. 2A, the recording head 21 includes an ink heating unit 212 that heats the ink supplied into the recording head 21, and an inlet 213 into which the ink supplied into the recording head 21 flows. It has an outlet 214 or the like from which the ink discharged from the recording head 21 flows out.

The ink ejected from the nozzle 211 of the recording head 21 is an ink that is cured by irradiating it with predetermined energy (ultraviolet rays in this embodiment), and in a state where it is not irradiated with ultraviolet rays, it is in a gel state depending on the temperature. Ink (phase change ink) having the property of changing phase with the sol state is used. Here, it is assumed that the gel state is contained in the solid and the sol state is contained in the liquid. This ink is uniformly liquefied (solified) by being heated to a predetermined phase change temperature (for example, about 40 ° C to 60 ° C) or higher, while it is kept at about normal room temperature (about 0 ° C to 30 ° C). Gelation occurs in the temperature range below the included phase change temperature.
More specifically, the gel state is a motility in which the solute is independent due to the interaction of lamellar structure, covalent or hydrogen-bonded polymer network, polymer network formed by physical aggregation, and aggregation structure of fine particles. It is a state in which it has an aggregated structure and is solidified or semi-solidified with a rapid increase in viscosity and a significant increase in elasticity.
A gelling agent is added to the ink of the present embodiment. Here, the gelling agent is a compound that can form a gel when added to another compound, and various known compounds can be used. The phase change temperature can be adjusted by the type and concentration of the gelling agent in the ink.
In the present embodiment, the ink is heated to a temperature at which the ink is in a sol state by the ink heating unit 212 provided in the recording head 21, and the ink in the sol state is ejected from the nozzle 211. The ink ejected from the nozzle 211 and landed on the recording medium M is cooled to room temperature and quickly becomes a gel state.

Further, each head unit 20 is provided so as to be movable in the width direction between a position facing the transport belt 101 and a position facing the maintenance unit 50. The head unit 20 is arranged at a position facing the transport belt 101 when performing an image recording operation of ejecting ink to the recording medium M, and is a maintenance unit 50 when performing maintenance by a discharge discharge operation or the like described later. It is moved to the position opposite to. The movement of the head unit 20 may be performed by a human hand, or may be performed by a driving operation of a head unit moving mechanism (not shown) under the control of the control unit 70 (FIG. 4).

The fixing portion 30 is provided on the downstream side in the transport direction of the four head units 20. The fixing portion 30 has a light emitting portion arranged over a recordable width in the width direction by the head unit 20, and energy rays such as ultraviolet rays are emitted from the light emitting portion with respect to the recording medium M mounted on the transport belt 101. Is irradiated to cure and fix the ink ejected on the recording medium M.

The maintenance unit 50 includes an ink receiving unit 51 that receives and stores ink ejected by the ink ejection operation (flushing) from the nozzle 211 of the head unit 20. Here, the ejection discarding operation is a maintenance operation of ejecting ink from the nozzle 211 to remove foreign matter and air bubbles that have entered the nozzle 211, and ink that has thickened in the nozzle. By this ejection failure operation, it is possible to prevent the occurrence of ink ejection failure from the nozzle 211, or to attempt to restore the nozzle to the normal state in which the ink ejection failure has already occurred. The spitting operation is performed when the inkjet recording device 1 is started (when the power is turned on), and is also periodically performed every predetermined time even during the operation of the inkjet recording device 1.

The ink receiving unit 51 has a saucer 511 that receives the ink ejected from the nozzle 211 of the head unit 20, and a collection tank 512 that stores the ink dropped downward from the funnel communicating with the saucer 511. The maintenance unit 50 is arranged at a position where the ink ejected from all the nozzles 211 can be received by the tray 511 when the head unit 20 moves in the width direction. The maintenance unit 50 is provided separately for each of the four head units 20.

Next, an ink supply mechanism for supplying ink to the recording head 21 in the inkjet recording apparatus 1 will be described.
FIG. 3 is a schematic diagram showing the configuration of the ink supply mechanism 60.
In FIG. 3, the ink supply mechanism 60 related to the head unit 20 of one of the inkjet recording devices 1 is extracted and shown, but in the other head units 20, the same ink supply mechanism 60 inks the recording head 21. Is supplied. Further, in FIG. 3, the ink feeding direction is indicated by an arrow.

In the ink supply mechanism 60, the ink of the main tank 41 (ink storage unit) that stores ink outside the head unit 20 is supplied to the first sub tank 611 provided in the head unit 20 by the supply pump 61. In the head unit 20, the first sub tank 611 passes through the first common flow path 602, the individual flow path 603, the second sub tank 612, the recording head 21 (head module 21M), and the second common flow path 604. An ink circulation path returning to 611 is provided, and ink can be circulated through this ink circulation path by the liquid feeding operation of the circulation pump 62.
As described above, the ink in the recording head 21 is heated by the ink heating unit 212 to form a sol. Further, the ink in each part of the ink supply mechanism 60 other than the recording head 21 is also heated by an ink heating part (not shown) provided in the head unit 20 and maintained in a sol shape.

The main tank 41 is provided outside the head unit 20 and stores ink of the color corresponding to the head unit 20. The capacity of the main tank 41 is not particularly limited, but a large capacity of, for example, about 30 liters is used.
Ink flows into the main tank 41 from the recovery tank 512 by the reflux liquid feeding operation described later. Therefore, it is used in a state where a free capacity corresponding to the amount of ink that can flow in by the reflux liquid feeding operation is left.

Further, the main tank 41 is provided with a first stirring unit 42 for stirring the ink stored in the main tank 41. The first stirring unit 42 has a first stirring screw 421 arranged in the main tank 41 and a first stirring driving unit 422 connected to the first stirring screw 421. The first stirring screw 421 rotates at a rotation speed corresponding to the operation of the motor provided in the first stirring drive unit 422 to agitate the ink.

Further, in the main tank 41, a first temperature detecting unit 43 for detecting the temperature of the ink stored in the main tank 41 is provided. The first temperature detection unit 43 has a temperature detection element such as a thermistor, and outputs data related to the ink temperature to the control unit 70 based on a control signal supplied from the control unit 70. The installation position of the first temperature detection unit 43 is not limited to the inside of the main tank 41, and it is possible to acquire the temperature corresponding to the ink temperature in the main tank 41, for example, the inside of the ink flow path 601 communicating with the main tank 41. It may be provided at any other position.

Further, in the main tank 41, an ink storage amount detecting unit 44 for detecting the amount of ink stored in the main tank 41 is provided. Specifically, the ink storage amount detection unit 44 detects the height of the ink surface based on the control signal supplied from the control unit 70, and outputs the data related to the detected height to the control unit 70.

The supply pump 61 performs a liquid feeding operation (supply liquid feeding operation) in which the ink stored in the main tank 41 is sent to the first sub tank 611 in the head unit 20. The supply pump 61 is not particularly limited, but for example, a volume transfer type pump such as a diaphragm pump, a tube pump in which a tube is squeezed by a roller to supply liquid, or the like can be used.

The first sub-tank 611 stores ink supplied from the main tank 41 and supplied to the recording head 21. The first sub-tank 611 communicates with the first common flow path 602 and the second common flow path 604. The first sub-tank 611 is a container open to the outside, and is maintained at substantially atmospheric pressure regardless of an increase or decrease in the amount of ink.

The circulation pump 62 is provided in the first common flow path 602, and is a liquid feeding operation for flowing ink in the liquid feeding direction from the first sub tank 611 toward the second sub tank 612 and the recording head 21 via the first common flow path 602. I do. The configuration of the circulation pump 62 is not particularly limited, but for example, a diaphragm pump or a tube pump can be used. The circulation pump 62 operates under the control of the control unit 70.

The first common flow path 602 is branched into a predetermined number of individual flow paths 603 on the downstream side of the circulation pump 62. Here, the predetermined number is the same as the number of the head modules 21M, and is 8 in this embodiment. In each individual flow path 603, the second sub tank 612 and the head module 21M communicate in series in this order. The second sub-tank 612 is a small ink chamber for temporarily storing the ink supplied to the recording head 21, and is sealed except for the connection points with the individual flow paths 603 and the ventilation passage 605. The ink that has entered the individual flow path 603 from the first common flow path 602 is temporarily stored in the second sub tank 612, and is supplied from the second sub tank 612 to the head module 21M by the liquid feeding operation by the circulation pump 62. More specifically, ink is supplied from each second sub-tank 612 in parallel to the inlets 213 of the two recording heads 21 constituting the head module 21M.

The plurality of second sub-tanks 612 are connected to the exhaust pump 63 via the ventilation passage 605 and the buffer tank 613. The exhaust pump 63 draws the ink in the recording head 21 toward the second sub tank 612 by exhausting the air in the buffer tank 613 to generate a negative pressure in the second sub tank 612. This prevents ink from leaking from the nozzle 211 of the recording head 21 when recording an image. Further, the ventilation passage 605 is provided with a valve 621 for switching between a communication state and a non-communication state between the second sub tank 612 and the buffer tank 613.

The outlet 214 of each head module 21M communicates with the second common flow path 604. Further, the second common flow path 604 is provided with a valve 622 that opens or closes the second common flow path 604.

Further, the ink supply mechanism 60 includes an ink receiving unit 51 of the maintenance unit 50 described above.
The collection tank 512 of the ink receiving unit 51 stores the ink discharged from the nozzle 211 of the head unit 20. As the recovery tank 512, a tank having a capacity smaller than that of the main tank 41, for example, a tank having a capacity of about 5 liters is used.

Further, the recovery tank 512 is provided with a second stirring unit 52 for stirring the ink stored in the recovery tank 512. The second stirring unit 52 has a second stirring screw 521 arranged in the recovery tank 512 and a second stirring driving unit 522 connected to the second stirring screw 521. The second stirring screw 521 rotates at a rotation speed corresponding to the operation of the motor provided in the second stirring drive unit 522 to agitate the ink.

Further, in the recovery tank 512, a second temperature detection unit 53 for detecting the temperature of the ink stored in the recovery tank 512 is provided. As the second temperature detection unit 53, the one having the same configuration as the first temperature detection unit 43 can be used. The installation position of the second temperature detection unit 53 is not limited to the inside of the recovery tank 512, and it is possible to acquire the temperature corresponding to the ink temperature in the recovery tank 512, for example, the inside of the ink flow path 606 communicating with the recovery tank 512. It may be provided at any other position.

The recovery tank 512 is communicated with the main tank 41 via the ink flow path 606. The ink flow path 606 is provided with a recirculation pump 64 (recirculation liquid feeding unit) that performs a liquid feeding operation (refluxing liquid feeding operation) to send the ink stored in the recovery tank 512 to the main tank 41. The recirculation pump 64 is not particularly limited, but for example, a pump having the same configuration as the supply pump 61 can be used.

In this way, in the ink supply mechanism 60, the ink discharged by the head unit 20 can be stored in the ink receiving unit 51 and returned to the main tank 41 via the ink flow path 606. The ink returned to the main tank 41 is supplied to the head unit 20 again and used for the ink ejection operation in the head unit 20.
Such a mechanism for returning the ejected ink to the main tank 41 is provided for the purpose of suppressing an increase in the cost related to ink consumption. That is, by providing the mechanism, it is possible to suppress the amount of expensive ink used (consumption) and the amount of waste, so that a large cost reduction effect can be obtained.

FIG. 4 is a block diagram showing a main functional configuration of the inkjet recording device 1.
The ink jet recording device 1 includes the above supply pump 61, circulation pump 62, exhaust pump 63, recirculation pump 64, valves 621, 622, first stirring drive unit 422, second stirring drive unit 522, and first temperature detection. In addition to the unit 43, the second temperature detection unit 53, the ink storage amount detection unit 44, and the ink heating unit 212, the control unit 70, the recording head control unit 215, the transfer drive unit 81, and the operation display unit 82 are included. It includes an output interface 83 and the like. Each of these parts of the inkjet recording device 1 is connected via a bus 84.

The control unit 70 includes a CPU 71 (Central Processing Unit) (discharge control means, reflux liquid feed control means, first stirring control means, second stirring control means), RAM 72 (Random Access Memory), ROM 73 (Read Only Memory). ) And a storage unit 74.

The CPU 71 reads out various control programs and setting data stored in the ROM 73 and stores them in the RAM 72, and executes the program to perform various arithmetic processes. Further, the CPU 71 comprehensively controls the overall operation of the inkjet recording device 1.

The RAM 72 provides a working memory space to the CPU 71 and stores temporary data. The RAM 72 may include a non-volatile memory.

The ROM 73 stores various control programs, setting data, and the like executed by the CPU 71. Instead of the ROM 73, a rewritable non-volatile memory such as an EEPROM (Electrically Erasable Programmable Read Only Memory) or a flash memory may be used.

The storage unit 74 stores a print job (image recording command) input from the external device 2 via the input / output interface 83, image data related to the print job, various setting data, and the like. The setting data includes data related to the setting of the discharge discharge operation, the setting of the reflux liquid feed operation, the reference temperature, the lower limit temperature TL, etc., which will be described later. As the storage unit 74, for example, an HDD (Hard Disk Drive) may be used, or a DRAM (Dynamic Random Access Memory) or the like may be used in combination.

The recording head control unit 215 outputs various control signals and image data to the head drive unit provided in the recording head 21 at an appropriate timing according to the control signal from the control unit 70. Here, the control signal includes a signal that specifies a drive waveform related to the drive signal supplied from the head drive unit to the recording element. The head drive unit supplies a drive waveform drive signal to the electrodes in the recording element of the recording head 21 according to the control signal and image data input from the recording head control unit 215, thereby supplying the drive waveform from the nozzle 211 of the recording element. Ink is ejected.

The transfer drive unit 81 supplies a drive signal to the transfer motor of the transfer roller 102 based on the control signal supplied from the control unit 70 to orbit the transfer belt 101 at a predetermined speed and timing.

The operation display unit 82 includes a display device such as a liquid crystal display or an organic EL display, and an input device such as an operation key and a touch panel arranged on the screen of the display device. The operation display unit 82 displays various information on the display device, converts the user's input operation to the input device into an operation signal, and outputs it to the control unit 70.

The input / output interface 83 mediates the transmission / reception of data between the external device 2 and the control unit 70. The input / output interface 83 is composed of, for example, various serial interfaces, various parallel interfaces, or a combination thereof.

The bus 84 is a path for transmitting and receiving signals between the control unit 70 and other configurations.

The external device 2 is, for example, a personal computer, and supplies print jobs, image data, and the like to the control unit 70 via the input / output interface 83.

Next, the ink feeding operation in the ink supply mechanism 60 of the inkjet recording device 1 will be described.

When the phase change ink used in the present embodiment is stored in the main tank 41 for a long time, the ink separates into a sol component and a gel component, and the gel component is released in a non-uniform distribution. There is. When the ink in this state is sent to the head unit 20 to record an image, various image quality defects occur due to abnormalities in the ejected ink components, or the gel component is clogged in the ink flow path and the ink ejection failure is poor. Will occur. Therefore, when the ink is stored in the main tank 41 for a long time, such as when the inkjet recording device 1 is started (when the power is turned on), the gel component is uniform by the first stirring unit 42. After stirring the ink so that the ink is distributed in an appropriate state, the liquid is started to be sent to the head unit 20.

However, when the storage temperature of the ink in the main tank 41 is extremely low (for example, less than 10 ° C.), the gel component is strongly solidified and the viscosity becomes high, and the gel component in the ink is agitated by the first stirring unit 42. The distribution cannot be made uniform in a short time (for example, a waiting time of about ten minutes to several tens of minutes, which is usually allowed as a waiting time until the start of the image recording operation).
FIG. 5 is a diagram showing the relationship between the temperature and the viscosity of the phase change ink. FIG. 5 is a semi-logarithmic graph with the ink viscosity on the vertical axis as a logarithmic scale. As shown in this figure, the viscosity of the ink increases as the temperature decreases. In FIG. 5, the range of the ink viscosity at which the ink can be stirred in an appropriate state in a short time is shown as the easy stirring range R. As shown, when the temperature of the ink is less than the predetermined lower limit temperature TL (about 10 ° C. in FIG. 5), the viscosity of the ink rapidly increases beyond the stirring easy range R.

The main parts such as the transport unit 10 and the head unit 20 of the inkjet recording device 1 are surrounded and protected by an exterior wall, and inside the exterior wall, the operating heat of each part and the heat of the ink heating unit 212 of the head unit 20 It is easy to keep the temperature due to such factors. However, since the main tank 41 is usually arranged on the outside of the exterior wall so that the operator can easily replenish the ink, the temperature outside the exterior wall is extremely low, such as in winter, which is less than 10 ° C. Under such an environment, the ink stored in the main tank 41 also drops to the temperature. Therefore, as described above, there may often be a situation in which the ink cannot be brought into a state where it can be sent in a short time by stirring by the first stirring unit 42.

Therefore, in the inkjet recording apparatus 1 of the present embodiment, in such a case, the head unit 20 performs an ink ejection operation, and the ink stored in the recovery tank 512 is returned to the main tank 41 by the ejection disposal operation. The reflux liquid feeding operation is performed. Specifically, when the ejection operation is started, the predetermined condition relating to the difficulty of stirring by the first stirring unit 42 is satisfied, and the temperature of the ink stored in the recovery tank 512 is the temperature of the ink in the main tank 41. If it is higher, the reflux liquid feeding operation is performed. In the present embodiment, when the temperature of the ink in the main tank 41 is lower than the predetermined reference temperature, it is determined that the predetermined condition relating to the difficulty of stirring is satisfied. Here, the reference temperature can be the above-mentioned lower limit temperature TL.

Since the ink ejected from the nozzle 211 by the ejection operation is heated to a temperature in which it becomes a sol state, the temperature of the ink stored in the recovery tank 512 is usually higher than the temperature of the ink in the main tank 41. ing. By refluxing the ink at such a temperature to the main tank 41, the temperature of the ink in the main tank 41 can be raised and the viscosity of the ink can be lowered. By raising the temperature of the ink to the lower limit temperature TL or more by the reflux liquid feeding operation, the viscosity of the ink can be lowered to the stirring easy range R, and the ink is brought into an appropriate state in a short time by the first stirring unit 42. You will be able to stir.
As described above, by using the ink recirculation mechanism provided for the purpose of suppressing the increase in the cost related to the ink, the ink temperature in the main tank 41 can be easily increased.

Further, when the reflux liquid feeding operation is started, the ink in the recovery tank 512 is stirred by the second stirring unit 52. The stirring by the second stirring unit 52 is performed during a period including at least a part of the period during which the reflux liquid feeding operation is performed. As a result, the gel component in the ink of the recovery tank 512 can be uniformly distributed and then sent to the main tank 41.
Further, when the reflux liquid feeding operation is started, the ink in the main tank 41 is stirred by the first stirring unit 42. The stirring by the first stirring unit 42 is performed during a period including at least a part of the period during which the reflux liquid feeding operation is performed. As a result, the high-temperature ink flowing from the recovery tank 512 can be quickly distributed in the main tank 41 to raise the temperature efficiently.

In the recirculation liquid feeding operation, the lower the temperature of the ink in the main tank 41, the more the amount of ink sent from the recovery tank 512 to the main tank 41 (at least one of the total amount of ink sent out and the amount of liquid sent per unit time). By increasing the number, it is possible to raise the temperature of the ink with an efficiency corresponding to the temperature of the ink in the main tank 41 so that it does not take a long time for the viscosity of the ink to drop to the stirring easy range R.

Therefore, in the ink ejection operation, the setting related to the ink ejection operation is made so that the lower the detection temperature by the first temperature detection unit 43, the larger the amount of ink ejected by the ejection disposal operation. Specifically, by changing the number of times the ink is ejected from the nozzles 211 in the ejection operation or changing the amount of ink droplets ejected from each nozzle 211, the ink ejected by the ejection operation is performed. The amount is controlled.
It should be noted that it is not always necessary that the relationship that the amount of ink discharged is monotonously increased with respect to the decrease in the detection temperature by the first temperature detection unit 43 is satisfied, and the ink concerned with respect to the decrease in the detection temperature. It suffices if the relationship that the amount is monotonically non-decreasing (broadly monotonically increasing) is satisfied. Therefore, the amount of ink may be controlled so that the amount of ink discharged is gradually changed for each predetermined detection temperature range.

Further, the operation of the recirculation pump 64 is controlled so that the lower the detection temperature by the first temperature detection unit 43, the larger the amount of liquid to be supplied per unit time in the operation of the recirculation pump 64.
Regarding this liquid feed amount, it is not always necessary that the relationship that the liquid feed amount per unit time increases monotonically with respect to the decrease in the detection temperature by the first temperature detection unit 43 is satisfied, and the detection temperature does not have to be satisfied. It suffices if the relationship that the amount of liquid sent per unit time is monotonically non-decreased (broadly monotonously increased) with respect to the decrease is satisfied. Therefore, the operation of the reflux pump 64 may be controlled so that the liquid feed amount per unit time changes stepwise for each predetermined detection temperature range.

Further, in the recirculation liquid feeding operation, the larger the amount of ink stored in the main tank 41, the more the amount of ink sent from the recovery tank 512 to the main tank 41 (at least the total amount of ink sent and the amount of liquid sent per unit time). On the other hand, by increasing the number (on the other hand), it is possible to more efficiently raise the temperature of the ink in the main tank 41 so that the time until the viscosity of the ink drops to the easy stirring range R does not become long.

Therefore, in the ink ejection operation, the ink ejection operation is related so that the larger the amount of ink in the main tank 41 detected by the ink storage amount detecting unit 44, the larger the amount of ink ejected by the ejection disposal operation. The settings are made.
Even in this case, it is not always necessary that the relationship that the amount of ink discharged is monotonously increased with respect to the increase in the amount of ink stored in the main tank 41 is satisfied, and the amount of ink stored is increased. It suffices if the relationship that the amount of ink discharged is monotonically non-decreasing (broadly monotonically increasing) is satisfied.

Further, the operation of the recirculation pump 64 is controlled so that the larger the amount of ink in the main tank 41 detected by the ink storage amount detection unit 44, the larger the amount of liquid sent per unit time in the liquid feeding operation by the recirculation pump 64. Will be done.
Even in this case, it is not always necessary that the relationship that the liquid feed amount per unit time increases monotonously with respect to the increase in the ink storage amount in the main tank 41 is not satisfied, and the ink storage amount increases. On the other hand, it suffices if the relationship that the amount of liquid sent per unit time is monotonically non-decreasing (broadly monotonically increasing) is satisfied.

Further, the reflux liquid feeding operation ends when the temperature of the ink in the main tank 41 becomes equal to or higher than a predetermined upper limit temperature. Here, the upper limit temperature can be a temperature higher than the lower limit temperature TL in which the viscosity of the ink is within the easy stirring range R.
Further, the reflux liquid feeding operation may be continued until all the ink in the recovery tank 512 is sent to the main tank 41.

Subsequently, a control procedure by the control unit 70 of the ink feeding process executed by the inkjet recording apparatus 1 will be described.

FIG. 6 is a flowchart showing a control procedure of the ink feeding process.
This ink feeding process is executed, for example, when the power of the inkjet recording apparatus 1 is turned on.

When the ink feeding process is started, the control unit 70 determines the ink temperature detection result of the main tank 41 by the first temperature detection unit 43 and the ink storage amount in the main tank 41 by the ink storage amount detection unit 44. Acquire the detection result (step S101).

Based on the detection result of the ink temperature of the main tank 41 and the detection result of the ink storage amount, the control unit 70 updates the setting of the discharge discharge operation and the setting of the recirculation liquid feeding operation by the recirculation pump 64 to the storage unit 74. Store it (step S102). Specifically, the control unit 70 is a unit in which the lower the ink temperature of the main tank 41 and the larger the amount of ink stored, the larger the amount of ink discharged by the discharge operation, and the more the ink is discharged by the reflux liquid feeding operation. Update the settings so that the amount of ink sent per hour increases. The set value in this case may be determined with reference to predetermined table data or the like stored in the storage unit 74, or may be calculated each time based on a predetermined calculation formula.

The control unit 70 starts the spitting control in which the head unit 20 performs the spitting operation (step S103: spitting step). That is, the control unit 70 moves the head unit 20 to a position facing the maintenance unit 50, and ejects ink of a droplet amount based on the setting updated in step S103 from each nozzle 211. Run as many times as based on.

The control unit 70 operates the first stirring unit 42 to start stirring the ink in the main tank 41, and operates the second stirring unit 52 to start stirring the ink in the recovery tank 512 (step S104). ).

The control unit 70 determines whether or not the temperature of the ink in the main tank 41 detected in step S101 is lower than the reference temperature (here, the lower limit temperature TL or less, that is, less than 10 ° C.) (step S105).

When it is determined that the temperature of the ink in the main tank 41 is lower than the reference temperature (“YES” in step S105), the control unit 70 is stored in the recovery tank 512 from the second temperature detection unit 53. The detection result of the ink temperature is acquired (step S106).

The control unit 70 collects the ink temperature of the main tank 41 based on the temperature detected by the first temperature detection unit 43 acquired in step S101 and the temperature detected by the second temperature detection unit 53 acquired in step S106. It is determined whether or not the temperature is lower than the ink temperature of 512 (step S107). When it is determined that the ink temperature of the main tank 41 is lower than the ink temperature of the recovery tank 512 (“YES” in step S107), the control unit 70 operates the recirculation pump 64 to start the recirculation liquid feeding operation. (Step S108: Refluxing liquid feeding step). That is, the control unit 70 sends the ink of the recovery tank 512 to the main tank 41 by the recirculation pump 64 with the liquid feed amount according to the setting updated in step S103.

The control unit 70 reacquires the detection result of the ink temperature of the main tank 41 by the first temperature detection unit 43, that the recovery tank 512 is empty, and that the ink temperature of the main tank 41 is equal to or higher than a predetermined upper limit temperature. It is determined whether or not any of the above conditions is satisfied (step S109), and if it is determined that any of the above conditions is satisfied (“YES” in step S109). , The recirculation pump 64 is stopped to end the recirculation liquid feeding operation (step S110). If it is determined that none of the above conditions is satisfied (“NO” in step S109), the control unit 70 executes the process of step S109 again.

When the processing of step S110 is completed, when it is determined in the processing of step S105 that the temperature of the ink in the main tank 41 is equal to or higher than the reference temperature (“NO” in step S105), or in the processing of step S107, the main tank 41 When it is determined that the ink temperature of the ink is equal to or higher than the ink temperature of the recovery tank 512 (“NO” in step S107), the control unit 70 satisfies the ink feeding start condition from the main tank 41 to the head unit 20. It is determined whether or not the ink is used (step S111). Here, the ink feeding start condition can be set so that the uneven distribution of the gel component in the ink of the main tank 41 is eliminated and the gel component is uniform. Whether or not the ink feeding start condition is satisfied can be determined by various known methods. The determination may be performed by the user and the result may be input to the operation display unit 82, or may be performed by the control unit 70 based on the detection result or the like by the sensor provided in the main tank 41. If it is determined that the ink feeding start condition is not satisfied (“NO” in step S111), the control unit 70 executes the process of step S111 again.

When it is determined that the ink feeding start condition is satisfied (“YES” in step S112), the control unit 70 operates the supply pump 61 to transfer the ink of the main tank 41 to the head unit 20. 1 The supply liquid feeding operation to be sent to the sub tank 611 is started (step S112).
When the process of step S112 is completed, the control unit 70 ends the ink feeding process.

As described above, the inkjet recording apparatus 1 of the present embodiment heats the main tank 41 for storing the ink having the characteristic of changing the phase between the gel state and the sol state, and the ink supplied from the main tank 41. A head unit 20 having an ink heating unit 212 and a nozzle 211 and ejecting the ink heated by the ink heating unit 212 from the nozzle 211, and a first stirring unit 42 for stirring the ink stored in the main tank 41. The first temperature detecting unit 43 for detecting the temperature of the ink stored in the main tank 41, the ink receiving unit 51 for receiving and storing the ink ejected from the nozzle 211 of the head unit 20, and the ink receiving unit 51. A second temperature detection unit 53 that detects the temperature of the ink stored in the recovery tank 512, a recirculation pump 64 that performs a recirculation liquid feeding operation to send the ink stored in the recovery tank 512 to the main tank 41, and a control unit. The control unit 70 controls the discharge of ink from the nozzle 211 of the head unit 20 to the ink receiving unit 51 (discharge control means), and the detection temperature by the second temperature detection unit 53 is measured. When the temperature is higher than the temperature detected by the first temperature detection unit 43, the recirculation pump 64 is used to perform the recirculation liquid feeding operation (recirculation liquid feeding control means).
In such a configuration, since the ink ejected from the nozzle 211 by the ejection disposal control is heated by the ink heating unit 212, the ink having a temperature higher than the environmental temperature can be collected and stored in the recovery tank 512. By refluxing the ink in the recovery tank 512 to the main tank 41 in which the ink having a lower temperature than the ink is stored, the temperature of the ink in the main tank 41 can be raised and the viscosity can be lowered. By such reflux of ink, the temperature of the ink in the main tank 41 can be raised to the above-mentioned lower limit temperature TL or more, whereby the viscosity of the ink can be lowered to the stirring easy range R. That is, the ink in the main tank 41 can be easily stirred in a short time.
Therefore, according to the inkjet recording apparatus 1 of the above embodiment, even when the storage temperature of the ink in the main tank 41 becomes extremely low in winter or the like and the gel component is strongly solidified, the ink has a simple configuration. The temperature of the main tank 41 can be raised, and the ink in the main tank 41 can be easily stirred in an appropriate state in a short time. Further, by using the ink recirculation mechanism provided for the purpose of suppressing the increase in the cost related to the ink, it is compared with the case where the main tank 41 is provided with a heater or a stirring portion having a higher stirring capacity. Therefore, the ink in the main tank 41 can be easily agitated to an appropriate state while suppressing an increase in cost and power consumption of the inkjet recording device 1.

Further, the control unit 70 causes the reflux pump 64 to perform a reflux liquid feed operation when the predetermined condition relating to the difficulty of stirring by the first stirring unit 42 is satisfied (reflux feed control means). As a result, when it is difficult to stir the ink in the main tank 41 to an appropriate state, the reflux liquid feeding operation can be selectively performed. Therefore, unnecessary reflux feeding operation can be omitted, and the power consumption of the inkjet recording apparatus 1 can be suppressed.

Further, the control unit 70 determines that the above-mentioned predetermined condition is satisfied when the temperature detected by the first temperature detection unit 43 is lower than the predetermined reference temperature lower than the phase change temperature of the ink to the gel state. (Recirculation liquid feed control means). As a result, when the ink in the main tank 41 becomes cold and it is difficult to stir to an appropriate state, the reflux liquid feeding operation can be selectively performed. Therefore, unnecessary reflux feeding operation can be omitted, and the power consumption of the inkjet recording apparatus 1 can be suppressed.

Further, the control unit 70 causes the reflux pump 64 to perform a reflux liquid feed operation when the first discharge control is started after the inkjet recording device 1 is started (reflux feed control means). When the operation of the inkjet recording device 1 is stopped and the ink in the main tank 41 is allowed to stand still, the gel component tends to be released non-uniformly in the ink. By performing the liquid operation, it is possible to easily eliminate the non-uniform release of the gel component described above.

Further, when the recirculation liquid feeding operation by the recirculation pump 64 is started, the control unit 70 collects the ink stored in the main tank 41 during a period including at least a part of the period during which the recirculation liquid feeding operation is performed. It is stirred by the first stirring unit 42 (first stirring control means). As a result, the high-temperature ink can be quickly distributed in the main tank 41 to raise the temperature efficiently.

Further, the inkjet recording device 1 includes a second stirring unit 52 that stirs the ink stored in the collection tank 512 of the ink receiving unit 51, and the control unit 70 starts the recirculation liquid feeding operation by the recirculation pump 64. In this case, the ink stored in the recovery tank 512 is stirred by the second stirring unit 52 during a period including at least a part of the period during which the reflux liquid feeding operation is performed (second stirring control means). As a result, the gel component in the ink of the recovery tank 512 can be uniformly distributed and then sent to the main tank 41.

Further, the control unit 70 stops the reflux liquid feed operation when the temperature detected by the first temperature detection unit 43 becomes equal to or higher than a predetermined upper limit temperature (reflux feed feed control means). As a result, the ink can be raised to a temperature at which it can be agitated to an appropriate state with the minimum necessary reflux feeding operation. Therefore, the power consumption of the inkjet recording device 1 can be suppressed.

Further, the control unit 70 controls the discharge so that the amount of ink ejected from the nozzle 211 by the discharge control satisfies the relationship that the amount of ink ejected from the nozzle 211 is monotonously non-decreasing with respect to the decrease in the detection temperature by the first temperature detection unit 43. Do (discard control means). As a result, the lower the temperature of the ink in the main tank 41, the more heat can be supplied to the ink by the reflux liquid feeding operation, so that the ink can be supplied in a short time regardless of the temperature of the ink in the main tank 41. The temperature can be raised to the desired temperature.

Further, the control unit 70 uses the recirculation pump 64 so as to satisfy the relationship that the amount of liquid to be fed per unit time in the reflux liquid feeding operation is monotonously non-decreasing with respect to the decrease in the detection temperature by the first temperature detecting unit 43. The reflux liquid feeding operation is performed (refluxing liquid feeding control means). As a result, the lower the temperature of the ink in the main tank 41, the more heat can be supplied to the ink by the reflux liquid feeding operation per unit time, so that the temperature is shorter regardless of the temperature of the ink in the main tank 41. The temperature of the ink can be raised to a desired temperature over time.

Further, the inkjet recording device 1 includes an ink storage amount detecting unit 44 that detects the amount of ink stored in the main tank 41, and the control unit 70 determines that the amount of ink ejected from the nozzle 211 in the ejection disposal control is the ink storage amount. Discharge control is performed so as to satisfy a non-monotonically decreasing relationship with respect to an increase in the amount of ink stored detected by the detection unit 44 (discarding control means). The larger the amount of ink stored in the main tank 41, the larger the heat capacity of the ink and the more difficult it is to warm up. Since a large amount of heat can be supplied, the temperature of the ink can be raised to a desired temperature in a short time regardless of the amount of ink stored in the main tank 41.

Further, the control unit 70 satisfies the relationship that the liquid feed amount per unit time in the recirculation liquid feed operation is monotonously non-decreasing with respect to the increase in the ink storage amount detected by the ink storage amount detection unit 44. The recirculation pump 64 is used to perform a recirculation liquid feeding operation (recirculation liquid feeding control means). According to this configuration, the larger the heat capacity of the ink in the main tank 41, the more heat can be supplied to the ink by the reflux liquid feeding operation per unit time, so that the amount of ink stored in the main tank 41 is stored. Regardless of this, the temperature of the ink can be raised to a desired temperature in a short time.

Further, the control unit 70 controls the amount of ink by changing the number of times of ink ejection from the nozzle 211 in the ejection discard control (discharge discard control means). This makes it possible to control the amount of ink with simple control.

Further, the control unit 70 controls the amount of ink by changing the amount of ink droplets to be ejected from the nozzle 211 (discharge control means). This makes it possible to control the amount of ink with simple control.

Further, in the ink liquid feeding method of the present embodiment using the inkjet recording device 1, the discharge step of ejecting ink from the nozzle 211 of the head unit 20 to the ink receiving unit 51, and the detection temperature by the second temperature detecting unit 53. Is higher than the temperature detected by the first temperature detection unit 43, the recirculation liquid feeding step of sending the ink stored in the recovery tank 512 of the ink receiving unit 51 to the main tank 41, and the ink stored in the main tank 41. A stirring step of stirring by the first stirring unit 42 is included. According to such a method, the ink in the main tank 41 can be easily agitated to an appropriate state in a short time while suppressing an increase in cost and power consumption of the inkjet recording device 1.

The present invention is not limited to the above embodiment and each modification, and various modifications can be made.
For example, in the above embodiment, both the amount of ink discharged by the discharge operation and the amount of liquid sent by the recirculation pump 64 per unit time are set according to the ink temperature and the ink storage amount of the main tank 41. Although described using the above, the present invention is not limited to this, and only one of the above may be adjusted.
Further, the amount of ink discharged by the discharge operation and the amount of liquid sent per unit time by the recirculation pump 64 may be set based on only one of the ink temperature and the ink storage amount of the main tank 41.
Further, regardless of the ink temperature and the ink storage amount of the main tank 41, the amount of ink discharged by the discharge operation and the amount of liquid sent by the recirculation pump 64 may be fixed.

Further, in the above embodiment, as a predetermined condition relating to the difficulty of stirring by the first stirring unit 42, the ink temperature of the main tank 41 is set as an example of being lower than the reference temperature, and the reference temperature is set to the lower limit temperature TL. Although it has been described in the aspect, the purpose is not limited to this.
For example, the reference temperature may be a temperature obtained by adding a predetermined value to the lower limit temperature TL. Specifically, in the example of FIG. 5, a margin of 5 ° C. may be taken with respect to the lower limit temperature TL of 10 ° C., and the reference temperature may be set to 15 ° C.
Further, the predetermined conditions may be determined by parameters other than the ink temperature of the main tank 41. For example, in the case of executing the reflux liquid feeding operation at the time of starting the inkjet recording device 1, when the length of the operation stop period until the inkjet recording device 1 is started is a predetermined time or more, a predetermined value relating to the difficulty of stirring. The conditions may be satisfied.
Further, it is not determined whether or not the above predetermined conditions are satisfied (step S105 in FIG. 6), and is based only on the determination result of whether or not the ink temperature of the recovery tank 512 is higher than the ink temperature of the main tank 41. The reflux liquid feeding operation may be started.

Further, in the above embodiment, the example of starting the supply liquid feeding operation from the main tank 41 to the head unit 20 after ending the reflux liquid feeding operation has been described, but the present invention is not limited to this, and the reflux liquid feeding operation is not limited thereto. You may perform the supply liquid feed operation while continuing.

Further, in the ink liquid feeding process, when the ink is replenished in the main tank 41 during the operation of the inkjet recording device 1 as well as when the power of the inkjet recording device 1 is turned on, the ink is supplied from the main tank 41 to the head unit 20. This may be performed when the operator gives an instruction to start the ink feeding process. In the ink feeding process in this case, it is determined whether or not the ink temperature of the main tank 41 is lower than the reference temperature (step S105 in FIG. 6) before the discharge operation is started, and the ink temperature of the main tank 41 is raised. When the temperature is lower than the reference temperature (that is, when it is necessary to heat the ink in the main tank 41 by the recirculation liquid feeding operation), the following various treatments may be performed.

Further, in the above embodiment, the example in which the recording medium M is transported by the transport unit 10 provided with the transport belt 101 has been described, but the purpose is not limited to this, and the transport unit 10 is, for example, the outer periphery of the rotating transport drum. The recording medium M may be held and conveyed on the surface.

Further, in the above embodiment, the single-pass type inkjet recording apparatus 1 has been described as an example, but the present invention may be applied to an inkjet recording apparatus that records an image while scanning a recording head.

Although some embodiments of the present invention have been described, the scope of the invention is not limited to the embodiments described above, but includes the scope of the invention described in the claims and the equivalent scope thereof. ..

1 Inkjet recording device 10 Transport unit 20 Head unit 21 Recording head 211 Nozzle 212 Ink heating unit 30 Fixing unit 41 Main tank 42 First stirring unit 421 First stirring screw 422 First stirring drive unit 43 First temperature detection Unit 44 Ink storage amount detection unit 50 Maintenance unit 51 Ink receiving unit 511 Reservoir 512 Recovery tank 52 Second stirring unit 521 Second stirring screw 522 Second stirring driving unit 53 Second temperature detection unit 60 Ink supply mechanism 61 Supply pump 62 Circulation pump 63 Exhaust pump 64 Recirculation pump 601 and 606 Ink flow path 602 1st common flow path 603 Individual flow path 604 2nd common flow path 605 Ventilation path 611 1st sub tank 612 2nd sub tank 613 Buffer tank 621, 622 Valve 70 Control unit M Recording medium

Claims (14)

An ink reservoir that stores ink that has the property of changing phase between the gel state and the sol state,
An ink heating unit that heats the ink supplied from the ink storage unit, and an ink heating unit.
An ink ejection unit having a nozzle and ejecting ink heated by the ink heating unit from the nozzle,
A first stirring unit that stirs the ink stored in the ink storage unit, and a first stirring unit.
A first temperature detection unit that detects the temperature of the ink stored in the ink storage unit, and
An ink receiving unit that receives and stores ink ejected from the nozzle of the ink ejection unit, and an ink receiving unit.
A discharge control means for controlling the discharge of ink from the nozzle of the ink discharge unit to the ink receiving unit, and a discharge control means.
A second temperature detecting unit that detects the temperature of the ink stored in the ink receiving unit, and
A reflux liquid feeding unit that performs a reflux liquid feeding operation to send the ink stored in the ink receiving unit to the ink storage unit, and a reflux liquid feeding unit.
A reflux liquid feed control means for causing the reflux liquid feed unit to perform the reflux liquid feed operation when the temperature detected by the second temperature detection unit is higher than the detection temperature by the first temperature detection unit.
Inkjet recording device equipped with. The first aspect of the present invention, wherein the reflux liquid feeding control means causes the reflux liquid feeding unit to perform the reflux liquid feeding operation when a predetermined condition relating to the difficulty of stirring by the first stirring unit is satisfied. Inkjet recording device. The reflux liquid feed control means determines that the predetermined condition is satisfied when the temperature detected by the first temperature detection unit is lower than the predetermined reference temperature lower than the phase change temperature of the ink to the gel state. The inkjet recording apparatus according to claim 2. The discharge control means is any one of claims 1 to 3 in which the reflux liquid feeding unit performs the reflux liquid feeding operation when the first discharge control is started after the inkjet recording device is started. The inkjet recording apparatus according to paragraph 1. When the reflux liquid feeding operation is started by the reflux liquid feeding unit, the ink stored in the ink storage unit is used in the ink storage unit during a period including at least a part of the period during which the reflux liquid feeding operation is performed. The inkjet recording apparatus according to any one of claims 1 to 4, further comprising a first stirring control means for stirring by the stirring unit of 1. A second stirring unit that stirs the ink stored in the ink receiving unit, and a second stirring unit.
When the reflux liquid feeding operation is started by the reflux liquid feeding unit, the ink stored in the ink receiving unit is used in the ink receiving unit during a period including at least a part of the period during which the reflux liquid feeding operation is performed. A second stirring control means for stirring by the stirring unit of 2 and
The inkjet recording apparatus according to any one of claims 1 to 5. The one according to any one of claims 1 to 6, wherein the reflux liquid feed control means stops the reflux liquid feed operation when the temperature detected by the first temperature detection unit becomes equal to or higher than a predetermined upper limit temperature. Inkjet recording device. The discharge control means is such that the amount of ink ejected from the nozzle by the discharge control satisfies the relationship that the amount of ink ejected from the nozzle is monotonously non-decreasing with respect to the decrease in the detection temperature by the first temperature detection unit. The inkjet recording apparatus according to any one of claims 1 to 7, wherein the inkjet recording apparatus is controlled. The reflux liquid feed control means satisfies the relationship that the liquid feed amount per unit time in the reflux liquid feed operation is monotonously non-decreasing with respect to the decrease in the detection temperature by the first temperature detection unit. The inkjet recording apparatus according to any one of claims 1 to 8, wherein the reflux liquid feeding operation is performed by the liquid feeding unit. An ink storage amount detecting unit for detecting the amount of ink stored in the ink storage unit is provided.
The discharge control means satisfies the relationship that the amount of ink ejected from the nozzle in the discharge control is monotonously non-decreasing with respect to an increase in the amount of ink stored detected by the ink storage amount detection unit. The inkjet recording apparatus according to any one of claims 1 to 9, wherein the discharge control is performed. An ink storage amount detecting unit for detecting the amount of ink stored in the ink storage unit is provided.
The reflux liquid feed control means satisfies the relationship that the liquid feed amount per unit time in the reflux liquid feed operation is monotonously non-decreasing with respect to the increase in the ink storage amount detected by the ink storage amount detection unit. The ink jet recording apparatus according to any one of claims 1 to 10, wherein the reflux liquid feeding operation is performed by the reflux liquid feeding unit. The inkjet recording apparatus according to claim 8 or 10, wherein the ejection control means controls the amount of ink by changing the number of times of ejection of ink from the nozzle in the ejection control. The inkjet recording apparatus according to claim 8 or 10, wherein the discharge control means controls the amount of ink by changing the amount of ink droplets discharged from the nozzle. An ink reservoir that stores ink that has the property of changing phase between the gel state and the sol state,
An ink heating unit that heats the ink supplied from the ink storage unit, and an ink heating unit.
An ink ejection unit having a nozzle and ejecting ink heated by the ink heating unit from the nozzle,
A first stirring unit that stirs the ink stored in the ink storage unit, and a first stirring unit.
A first temperature detection unit that detects the temperature of the ink stored in the ink storage unit, and
An ink receiving unit that receives and stores ink ejected from the nozzle of the ink ejection unit, and an ink receiving unit.
A second temperature detecting unit that detects the temperature of the ink stored in the ink receiving unit, and
A reflux liquid feeding unit that performs a reflux liquid feeding operation to send the ink stored in the ink receiving unit to the ink storage unit, and a reflux liquid feeding unit.
It is an ink liquid feeding method in an inkjet recording apparatus equipped with the above.
A discharge step of ejecting ink from the nozzle of the ink ejection portion to the ink receiving portion,
A reflux liquid feeding step of delivering the ink stored in the ink receiving unit to the ink storage unit when the temperature detected by the second temperature detecting unit is higher than the detection temperature by the first temperature detecting unit.
A stirring step of stirring the ink stored in the ink storage unit by the first stirring unit.
Ink feeding method including.

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