JP7003602B2 - Liquid discharge device and liquid discharge method - Google Patents

Description

The present invention relates to a liquid discharge device and a liquid discharge method.

In the liquid discharge device, when the member to which the liquid is applied is heated and dried, dew condensation occurs on the nozzle surface due to the temperature difference from the head, a lump of liquid (condensation liquid) is formed, and the dew condensation liquid comes into contact with the periphery of the nozzle. This may lead to ejection failure.

Therefore, conventionally, when cleaning the nozzle surface of the liquid discharge head, a cleaning means for cleaning the nozzle surface, a dew condensation amount determining means for detecting or predicting the amount of dew condensation generated on the nozzle surface, and a cleaning means for cleaning the nozzle surface, the liquid overflows from the nozzle. It is known to have an overflow control means for controlling the amount of dew condensation, and to control the amount of overflow to be relatively smaller when the amount of dew condensation is large than when the amount of dew condensation is small (for example, patent). See Document 1).

An object of the present invention is to provide a liquid discharge device capable of removing dew condensation while suppressing a decrease in productivity.

The liquid discharge device of the present invention as a means for solving the above problems has a liquid discharge head having a nozzle for discharging liquid, a wiping means for wiping the nozzle surface, and heating for heating a member to which the liquid is applied. When the amount of dew condensation determined by the means, the dew condensation amount determining means for predicting or detecting the dew condensation amount on the nozzle surface, and the dew condensation amount determining means exceeds the threshold value, the liquid is not overflowed from the nozzle and the wiping is performed. It is provided with a means for controlling the wiping operation by the means.

According to the present invention, it is possible to provide a liquid discharge device capable of removing dew condensation while suppressing a decrease in productivity.

FIG. 1 is an external perspective explanatory view showing an example of a liquid discharge device according to the present invention. FIG. 2 is a side explanatory view showing an example of the mechanical part of the liquid discharge device according to the present invention. FIG. 3 is a plan explanatory view showing an example of the mechanical part of the liquid discharge device according to the present invention. FIG. 4 is a plan explanatory view showing an example of the head. FIG. 5 is a block explanatory view for explaining an example of the control unit of the liquid discharge device according to the present invention. FIG. 6 is a plan explanatory view for explaining the contents of an example of the dew condensation wiping operation in the embodiment of the present invention. FIG. 7 is a plan explanatory view for explaining the contents showing an example of the dew condensation wiping operation in the comparative example. FIG. 8 is an explanatory diagram showing an example of a temperature coefficient table used for explaining the first example of the condition for carrying out the dew condensation wiping operation during printing. FIG. 9 is a flow chart for explaining an example of control of the dew condensation wiping operation in the first example of the condition for performing the dew condensation wiping operation during printing. FIG. 10 is an explanatory diagram for explaining an example of the timing of the dew condensation wiping operation during printing. FIG. 11 is an explanatory diagram showing an example of a scan number coefficient table used for explaining the second example of the condition for performing the dew condensation wiping operation during printing. FIG. 12 is a schematic view showing an example of a cleaning device in the droplet ejection device of the present invention.

(Liquid discharge device and liquid discharge method)
The liquid discharge device of the present invention has a liquid discharge head having a nozzle for discharging liquid, a wiping means for wiping the nozzle surface, a heating means for heating a member to which the liquid is applied, and a dew condensation amount on the nozzle surface. Control is performed by the dew condensation amount determining means for predicting or detecting and the wiping operation by the wiping means without overflowing the liquid from the nozzle when the dew condensation amount determined by the dew condensation amount determining means exceeds the threshold value. Provide means and, if necessary, other means.
The liquid ejection method of the present invention comprises a liquid ejection head having a nozzle for ejecting a liquid, a wiping means for wiping the nozzle surface, a heating means for heating a member to which the liquid is applied, and a dew condensation amount on the nozzle surface. Control is performed by the dew condensation amount determining means for predicting or detecting and the wiping operation by the wiping means without overflowing the liquid from the nozzle when the dew condensation amount determined by the dew condensation amount determining means exceeds the threshold value. A liquid discharge method using a liquid discharge device comprising means, wherein the liquid contains water, an organic solvent, and a coloring material, and the organic solvent has a vapor pressure of 0.2 mmHg or less at 20 ° C. An ink containing a certain compound is used, and if necessary, other steps are included.

The liquid discharge device and the liquid discharge method of the present invention have a problem that in the conventional device and method, the productivity is lowered if the cleaning is performed so that the liquid overflows from the nozzle every time the amount of dew condensation exceeds the threshold value. It is based on the finding that there is.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, an example of the liquid discharge device according to the present invention will be described with reference to FIGS. 1 to 4. FIG. 1 is an external perspective explanatory view of the liquid discharge device 100 according to the present invention, FIG. 2 is a side view of the mechanism portion of the device, FIG. 3 is a plan view of the mechanism portion of the device, and FIG. 4 is a plan view of the head. It is a plan view of an example.

The liquid discharge device 100 is a serial type device, and uses a roll body 1 in which a print medium 2 is wound in a roll shape. In addition, a configuration using cut paper may be used.

Heating heaters 3A and 3B, which are heating means divided into a plurality of parts along the transport direction of the print medium 2,
3C is arranged. Here, the heating heater 3A is arranged in the pre-printing portion, the heating heater 3B is arranged in the printing region portion, and the heating heater 3C is arranged in the post-printing portion. Although the heating means may be arranged without being divided into a plurality of parts, the heating can be finely controlled by dividing the heating means into a plurality of parts. Further, the heating heater 3B also serves as a guiding means for the print medium 2 which is conveyed facing the liquid discharge head 6.

By arranging the drying fan heater 4 facing the heating heater 3C in the post-printing portion and applying warm air, the printed matter can be reliably dried.

A carriage 5 equipped with a liquid discharge head (hereinafter, simply referred to as “head”) 6 for discharging liquid is arranged in the print area portion so as to be reciprocating in the main scanning direction in FIG. Here, the carriage 5 is equipped with two heads 6a and 6b.

As shown in FIG. 3, the carriage 5 is reciprocally supported by a guide member 11 arranged in the main scanning direction, and is bridged between the drive pulley 16 and the driven pulley 17 by the main scanning motor 15. It is reciprocated via the timing belt 18.

As shown in FIG. 4, for example, the head 6 has two nozzle rows Na and Nb in which a plurality of nozzles 6n are arranged on the nozzle surface 61, respectively. One nozzle row Na of the head 6a discharges a black (K) liquid, and the other nozzle row Nb discharges a cyan (C) liquid. One nozzle row Na of the head 6b discharges a magenta (M) liquid, and the other nozzle row Nb discharges a yellow (Y) liquid.

The heads 6a and 6b are integrally provided with sub tanks 7a and 7b, respectively. The sub-tanks 7a and 7b are supplied with the required liquid from the liquid cartridges 50 of each color interchangeably mounted on the cartridge holder 51 by the liquid pump of the liquid pump unit 52 via the supply tube 56.

Further, as shown in FIG. 3, outside the print area (conveyed area of the print medium 2), a maintenance / recovery mechanism 20 for maintaining and recovering the state of the head 6 is arranged on one end side in the main scanning direction.

The maintenance / recovery mechanism 20 is a wiping means for wiping and cleaning the caps 21 and 22 that cap the nozzle surface 61 of each head 6, the empty discharge receiver 24 that receives the liquid that does not contribute to printing, and the nozzle surface 61. It includes a member 23 and the like. The moving direction (wiping direction) of the wiping member 23 is the arrow direction (direction along the nozzle arrangement direction of the head 6).

Next, the outline of the control unit of this apparatus will be described with reference to the block explanatory diagram of FIG.

The control unit 500 includes a CPU 501 that controls the entire device that also serves as a dew condensation amount determining means in the present invention, a program including a program for causing the CPU 501 to execute the control according to the present invention, and a ROM 502 that stores other fixed data. A main control unit 500A including a RAM 503 for temporarily storing print data and the like is provided.

The control unit 500 includes a non-volatile memory (NVRAM) 504 for holding data even while the power of the device is cut off. Further, the control unit 500 includes an ASIC 505 that processes an image process that performs various signal processes on the image data and other input / output signals for controlling the entire device.

The control unit 500 includes an I / F 506 for transmitting and receiving data and signals used when receiving print data from an external host device 600.

The control unit 500 includes an I / O 507 for capturing detection signals of various sensors. The I / O 507 includes, for example, a heater temperature sensor 572 that detects the temperature of the heater 3B, a head temperature sensor 573 that detects the temperature of the head 6, a temperature sensor that detects the temperatures of the other heaters 3A and 3C, and the temperature inside the device. The detection signal from the environmental temperature sensor for detecting the above and various other sensors (sensor group 570) is input.

The control unit 500 includes a head drive control unit 508 that drives and controls the head 6. The control unit 500 reads and analyzes the print data in the receive buffer included in the I / F 506, performs image processing, data rearrangement processing, and the like necessary for the ASIC 505, and heads this data from the head drive control unit 508. Transfer to driver 509.

The control unit 500 moves one or more of the main scanning motor 15 that moves the carriage 5 in the main scanning direction, the feed motor 71 that feeds the print medium 2, the caps 21 and 22 of the maintenance / recovery mechanism 20, and the wiping member 23. The motor drive unit 510 for driving the maintenance / recovery motor 72 is provided.

The control unit 500 includes a supply system drive unit 511 that drives the liquid feed pump 54.

The control unit 500 includes a heater drive unit 512 that drives the heaters 3A to 3C.

An operation panel 514 for inputting and displaying information necessary for this device is connected to the control unit 500.

The head drive control unit 508 transfers the above-mentioned data as serial data, and outputs a transfer clock, a latch signal, a control signal, etc. necessary for transferring the data and confirming the transfer to the head driver 509.

The head drive control unit 508 includes a drive signal generation unit including a D / A converter for D / A conversion of drive pulse pattern data stored in the ROM 502, a voltage amplifier, a current amplifier, and the like. Then, a drive waveform composed of one drive pulse or a plurality of drive pulses is generated and output to the head driver 509.

The head driver 509 selects a drive pulse constituting a drive waveform given from the head drive control unit 508 based on data corresponding to one line of the head 6 serially input to the pressure generating means of the head 6. Give. This drives the head 6. At this time, by selecting a part or all of the pulse constituting the drive waveform or all or part of the waveform element forming the pulse, dots having different sizes such as a large drop, a medium drop, and a small drop are selected. Can be separated.

Next, the dew condensation wiping operation in the present embodiment will be described with reference to FIG. FIG. 6 is a plan explanatory view for explaining the contents of the dew condensation wiping operation.

First, the water content of the liquid discharged to the printing medium 2 evaporates due to heating by the heating heater 3B, and the steam adheres to the nozzle surface 61 of the head 6, causing dew condensation. For example, as shown in FIG. 6A, dew condensation 401 is formed on the nozzle surface 61. The dew condensation 401 is shown in the same size for the sake of clarity, but the actual size is not constant and the places where it adheres are random.

When the amount of dew condensation 401 is generated and increased, the discharge failure due to the dew condensation 401 occurs. Therefore, it is necessary to periodically remove the dew condensation 401 during printing.

Therefore, as shown in FIG. 6B, the nozzle surface 61 is wiped with the wiping member 23 to remove the dew condensation 401. After that, as shown in FIG. 6 (c), the meniscus of the nozzle 6n is formed by performing empty ejection.

Next, the dew condensation wiping operation in the comparative example will be described with reference to FIG. 7. FIG. 7 is a plan explanatory view for explaining the contents of the dew condensation wiping operation.

In this comparative example, as shown in FIG. 7B, for example, by performing nozzle suction in which the nozzle surface 61 is capped and sucked by the cap 21, the liquid 400 is overflowed from the nozzle 6n to the nozzle surface 61, and then the liquid 400 is overflowed. As shown in FIG. 7 (c), the nozzle surface 61 is wiped with the wiping member 23 to remove the dew condensation 401.

If the nozzle suction is performed so that the liquid overflows to the nozzle surface 61 every time the dew condensation is wiped off as in this comparative example, the dew condensation wiping operation takes time, the productivity is lowered, and the wasteful liquid consumption is also increased. Will be done.

Therefore, as in the present embodiment, by wiping without performing an operation such as nozzle suction to overflow the liquid from the nozzle 6n to the nozzle surface 61, the time required for wiping and removing the dew condensation can be shortened, and the productivity can be improved. Can be improved.

Next, a first example of the condition for carrying out the dew condensation wiping operation during printing will be described with reference to FIG. FIG. 8 is an explanatory diagram of a temperature coefficient table used for explaining the same conditions.

In the present embodiment, since the head suction for discharging the liquid from the nozzle is not performed in the dew condensation wiping operation, it is not possible to recover the nozzle in which the discharge failure has occurred. Therefore, it is necessary to predict the amount of dew condensation adhering to the nozzle surface as accurately as possible, and to carry out the dew condensation wiping operation at a timing that does not cause ejection failure.

The amount of dew condensation adhering to the nozzle surface 61 increases as the ejection time (printing time) increases, and dew condensation is more likely to occur as the temperature difference increases. Therefore, the larger the difference between the heater temperature and the head temperature, the greater the amount of dew condensation. It will increase.

Therefore, in the first example, the time when the caps 21 and 22 do not cap the nozzle surface 61 is defined as the decap time (seconds), and can be obtained by "count (seconds) = Σ (temperature coefficient x decap time (seconds))". When the count value exceeds the threshold value, the dew condensation wiping operation is started.

That is, a temperature coefficient is obtained using the heater temperature and the head temperature, and the count is calculated as a predicted value of the amount of dew condensation by multiplying this by the decap time. When the count exceeds the threshold value, the nozzle by the wiping member 23 The dew condensation wiping operation of the surface 61 is performed.

Here, the temperature coefficient is predetermined by the heater temperature and the head temperature as shown in the temperature coefficient table of FIG. 8, and the temperature coefficient is set so that the larger the temperature difference between the heater 3B and the head 6, the larger the temperature coefficient. ing. The larger the temperature coefficient, the faster the count reaches the threshold value. Therefore, the larger the difference between the heater temperature and the head temperature, the more frequently the dew condensation wiping operation is performed.

In the example of FIG. 8, when the heater temperature is 40 ° C. and the head temperature is 20 ° C. (= temperature difference 20 ° C.) and when the heater temperature is 60 ° C. and the head temperature is 40 ° C. (= temperature difference 20 ° C.), the temperature difference is the same. Since there are, the same temperature coefficient is used.

However, even if the temperature difference is the same, the higher the heater temperature, the larger the amount of evaporation, and as a result, the amount of dew condensation is expected to increase. That is, as described above, the same temperature difference is obtained when the heater temperature is 40 ° C. and the head temperature is 20 ° C. (= temperature difference 20 ° C.) and when the heater temperature is 60 ° C. and the head temperature is 40 ° C. (= temperature difference 20 ° C.). However, the latter, which has a higher heater temperature, has a larger amount of dew condensation adhering to the nozzle surface, and it is necessary to wipe the nozzle more frequently.

Therefore, by multiplying not only the heater temperature and the head temperature but also the coefficient by the heater temperature, the dew condensation wiping operation can be performed at a more accurate timing.

Next, the control of the dew condensation wiping operation in the first example will be described with reference to the flow chart of FIG.

Here, when printing is started, the heater temperature sensor 572 detects the temperature of the heater 3B (heater temperature), and the head temperature sensor 573 detects the temperature of the head 6 (head temperature) (temperature detection).

Then, using the temperature coefficient table described above, the temperature coefficient corresponding to the detected heater temperature and head temperature is determined.

Next, the caps 21 and 22 start counting the time (decap time) when the nozzle surface 61 of the head 6 is not capped.

After that, the calculation of "count (seconds) = Σ (temperature coefficient x decap time (seconds))" is performed to determine whether or not the count exceeds the threshold value.

At this time, if the count is not equal to or greater than the threshold value, it is determined whether or not printing is completed, and if printing is not completed, the process returns to the above determination process.

On the other hand, when the count exceeds the threshold value, the wiping member 23 wipes the nozzle surface 61 without overflowing the liquid from the nozzle, resets the count, restarts printing, and adjusts the temperature. Return to the detection process.

When printing is completed, the process ends.

In this way, in the wiping operation during the printing operation, the liquid does not overflow from the nozzle, that is, the operation of sucking the liquid from the nozzle or the operation of pressurizing the inside of the head to discharge the liquid from the nozzle is performed. , Wipe the nozzle surface. As a result, the time required for the operation of wiping the dew condensation can be shortened, the productivity can be improved, and the wasteful liquid consumption can be suppressed.

Next, a specific example of the timing of the dew condensation wiping operation during printing will be described with reference to FIG. 10. FIG. 10 is an explanatory diagram provided for the same explanation.

When the temperature coefficient is determined to be A in FIG. 8 based on the result of the temperature detection at the start of printing, the temperature coefficient becomes a large value, so that the start timing of the dew condensation wiping operation comes earlier (T1 to T3). Since the timing of temperature detection is the timing of restarting printing, if the temperature coefficient changes to B while printing is continued (for example, if the head temperature rises during printing), the coefficient B is used in T4. It consists of wiping. In the dew condensation wiping operation of T3, since the temperature coefficient is A at the end of the wiping operation of T2, A is used as the coefficient. Similarly, the temperature coefficient C is used from the wiping of T7. In this way, when each temperature changes during printing, the start timing of the dew condensation wiping operation is controlled under the optimum conditions at that time.

Next, a second example of the condition for performing the dew condensation wiping operation during printing will be described with reference to FIG. 11. FIG. 11 is an explanatory diagram of a scan number coefficient table used for explaining the same conditions.

Since the cause of dew condensation is liquid vapor, the higher the printing rate (the amount discharged from the head 6, the number of scans of the head 6 and the like), the easier it is for the amount of dew condensation to increase.

Therefore, in the second example, in addition to the first example, the printing condition (here, the number of scans) is taken into consideration, and "count (seconds) = Σ (temperature coefficient x number of scans coefficient x decap time (seconds))". When the obtained count value exceeds the threshold value, the dew condensation wiping operation is started.

Here, the scan number coefficient is a coefficient that changes according to the number of scans of the head 6 (carriage 5) corresponding to the number of print passes (pass number) as shown in FIG. In this case, the larger the number of scans, the larger the coefficient of the number of scans, so that the timing of the dew condensation wiping operation becomes earlier, and the smaller the number of scans, the later the timing of the dew condensation wiping operation.

Basically, the number of scans does not change during printing, so the timing for determining the number of scans coefficient is sufficient only at the start of printing or between pages.

Next, the wiping means will be described.

In the present embodiment, since the wiping means is used for wiping without performing the head suction operation of overflowing the liquid on the nozzle surface, the damage to the nozzle surface is larger than that of the normal cleaning operation of wiping with the nozzle surface wet. There is a risk of becoming.

Therefore, it is preferable to use a web (strip-shaped wiping member) as the wiping means. If the nozzle surface is wiped with a web, damage to the nozzle surface can be reduced even if the nozzle surface is not wet with liquid.
Further, in order to suppress damage to the nozzle surface and effectively wipe the nozzle surface, the wiping means may have a cleaning liquid.

（ただし、前記一般式（１）中、Ｒ^１は、炭素数１以上４以下のアルキル基を表す。） <Cleaning liquid>
The cleaning liquid used in the liquid discharge device and the liquid discharge method of the present invention can be used without particular limitation.
In particular, a cleaning solution containing water, a glycol ether compound, and a surfactant and having a content of the glycol ether compound of 1% by mass or more and 30% by mass or less is excellent in detergency. High detergency can be obtained even if the pressure when rubbing the nozzle surface with the wiping means is lowered. As a result, not only the nozzle surface can be satisfactorily wiped off, but also damage to the nozzle surface can be reduced.
Further, when the cleaning liquid further contains the compound of the following general formula (1), the above effect is further improved.

(However, in the general formula (1), R ¹ represents an alkyl group having 1 or more carbon atoms and 4 or less carbon atoms.)

<Surfactant>
The surfactant is not particularly limited, but by containing the surfactant, the friction with the nozzle surface at the time of wiping can be reduced, so that the damage to the nozzle surface can be reduced. Further, since the cleaning liquid is promoted to enter the interface of the ink adhering to the nozzle surface, the effect of reducing damage is further improved. Further, since the liquid condensed on the nozzle surface is promoted to permeate into the wiping member, more efficient wiping becomes possible.

<Glycol ether compound>
The glycol ether compound is not particularly limited and may be appropriately selected depending on the intended purpose.
For example, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dibutyl ether, diethylene glycol methyl ethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene. Examples thereof include glycol ethers such as glycol monobutyl ether, propylene glycol-n-propyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether and tripropylene glycol monomethyl ether. These may be used alone or in combination of two or more.
Among these, it is particularly preferable to contain a dialkyl glycol ether compound. Examples of the dialkyl glycol ether compound include diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, tetraethylene glycol dimethyl ether, and tetraethylene glycol diethyl ether.
The glycol ether compound has a strong action on the ink adhered to the nozzle surface and has improved detergency, and the dialkyl glycol ether compound tends to soften the adhered substance due to the solvent, thereby improving the detergency. At the same time, damage to the nozzle surface can be mitigated.
The glycol ether compound is preferably 1% by weight or more and 30% by weight or less.

（ただし、前記一般式（１）中、Ｒ^１は、炭素数１以上４以下のアルキル基を表す。） <Amide compound>
Further, by containing the compound of the following general formula (1) in the cleaning liquid, the softening effect can be further enhanced, the cleaning property can be improved, and the damage to the nozzle surface can be suppressed.

(However, in the general formula (1), R ¹ represents an alkyl group having 1 or more carbon atoms and 4 or less carbon atoms.)

The amount of the cleaning liquid applied to the wiping means may be changed depending on the type of ink and cleaning liquid used. Further, it may be selected from a plurality of set amounts such as a normal amount and a large amount, or a small amount and a normal amount.
The amount of the cleaning solution to be applied is preferably 0.05 mL / cm ² or more and less than 1 mL / cm ² as a small amount, preferably 1 mL / cm ² or more and less than 0.3 mL / cm ² as a normal amount, and 0.3 mL / cm as a large amount. Cm ² or more is preferable.

When the cleaning liquid is applied, pressure is applied to the cleaning liquid application nozzle, and the amount of the cleaning liquid applied can be adjusted to a desired amount by changing the pressure (selection of pressure). In addition, the amount of cleaning liquid applied can be adjusted by changing the number of nozzles applied by a plurality of cleaning liquid application nozzles (selection of the number of nozzles), and the number of times the cleaning liquid is applied from the cleaning liquid application nozzle is changed (number of times the cleaning liquid is applied). By selecting), the amount of grant can be adjusted (selection of the number of grants).
Next, the nozzle surface is wiped using the wiping member to which the cleaning liquid is applied.
In this way, the nozzle surface on the ink ejection side of the nozzle plate of the ink ejection head can be wiped (cleaned).

Here, FIG. 12 is a schematic view showing an example of a cleaning device in the droplet ejection device of the present invention. The cleaning device 300 of FIG. 12 is a device that cleans the nozzle surface 301a on the ink ejection side of the nozzle plate 301 of the ink ejection head.
The cleaning device 300 includes a non-woven fabric 303 as a wiping member, a cleaning liquid applying nozzle 302 as a cleaning liquid applying means, a pressing roller 305 as a pressing member, and a winding roller 304 for winding the non-woven fabric after the wiping process. There is.
The cleaning liquid is supplied from the cleaning liquid tank via a cleaning liquid supply tube (not shown). By driving a pump provided in the middle of the cleaning liquid supply tube, cleaning liquid is applied to the non-woven fabric 303 as a wiping member from the cleaning liquid application nozzle 302 in an amount of cleaning liquid applied according to the recording time. The nonwoven fabric 303 is wound in a roll shape.
Then, as shown in FIG. 12, the non-woven fabric 303 to which the cleaning liquid is applied abuts on the nozzle surface 301a of the ink ejection head 301 by the pressing roller 305 as a pressing member and is pressed to clean the nozzle surface 301a. After the wiping process is completed, the nonwoven fabric 303 is wound by the winding roller 304.
A plurality of cleaning liquid application nozzles 302 as cleaning liquid application means can be provided, and pressure can be applied based on the control of the control means (not shown), and the amount of cleaning liquid applied can be adjusted by appropriately changing the pressure. Can be adjusted. Further, based on the control of the control means (not shown), the amount of the cleaning liquid applied can be adjusted by changing the number of nozzles to which the cleaning liquid is applied. Further, the amount of the cleaning liquid applied can be adjusted by changing the number of times the cleaning liquid is applied based on the control of the control means (not shown).

Next, a means for predicting or detecting the amount of dew condensation adhering to the nozzle surface during printing will be described.

Since the dew condensation 401 adhering to the nozzle surface 61 is generated by the vapor of the liquid, time and temperature / humidity have a great influence. Therefore, a counting means for measuring the time is provided, and the amount of dew condensation can be predicted according to the counted time, or the amount of dew condensation can be predicted by using the temperature detecting means and the humidity detecting means.

Regarding the temperature, specifically, as described above, there are the heater temperature, the head temperature, and the temperature inside the device. In particular, the heater temperature and the head temperature have high sensitivity, and the higher the heater temperature and the lower the head temperature, the more dew condensation occurs. The amount will increase.

Further, the higher the printing rate, the larger the amount of liquid vapor, so that the amount of dew condensation can be predicted from the amount of liquid discharged and the number of scans of the carriage.

Further, there are a method of predicting by considering the type of the print medium (member to which the liquid is applied) selected by the user, and a method of predicting from the distance detected by the gap detecting means for detecting the distance between the head and the print medium. be.

Further, as a method of directly measuring the amount of dew condensation, there are a method of directly observing the nozzle surface using an imaging means and a method of irradiating the nozzle surface with light and measuring the reflected light to measure the amount of dew condensation. ..

In the present invention, the "liquid" to be discharged may have a viscosity and surface tension that can be discharged from the head, and is not particularly limited, but has a viscosity of 30 mPa · s at room temperature, under normal pressure, or by heating or cooling. It is preferable that it is as follows. More specifically, solvents such as water and organic solvents, colorants such as dyes and pigments, functionalizing materials such as polymerizable compounds, resins and surfactants, biocompatible materials such as DNA, amino acids and proteins, and calcium. , Solvents, suspensions, emulsions and the like containing edible materials such as natural dyes, etc., which can be used, for example, in inks for inkjets, surface treatment liquids and the like.

The liquid used in the liquid discharge device and the liquid discharge method of the present invention can be used without particular limitation, but contains water, an organic solvent, and a coloring material, and the vapor pressure at 20 ° C. as the organic solvent is 0.2 mmHg. When an ink containing the following compounds is used, it is possible to suppress ejection defects due to drying of the ink on the nozzle surface.
On the other hand, when the ink is used, since it contains a solvent having a low vapor pressure, dew condensation is likely to occur due to the influence of the heater temperature and the head temperature difference, but the present invention can remove the dew condensation without impairing the productivity.
Here, the dew condensation includes a lump of a liquid such as an organic solvent or water. For example, it includes those in which liquid components such as organic solvent and water contained in the ink are vaporized and then aggregated on the nozzle surface, and those in which droplets generated by printing by an inkjet method adhere to the nozzle surface as a mass of liquid. ..
Further, the compound having a vapor pressure at 20 ° C. of 0.2 mmHg or less preferably has a vapor pressure of 0.01 mmHg or more and 0.2 mmHg or less at 20 ° C.
As a result, the dryness of the printed image can be improved, blocking can be suppressed, and an image with good fixing property can be obtained.
Further, the content of the compound having a vapor pressure of 0.2 mmHg or less at 20 ° C. is preferably 5% by mass or more, more preferably 5% by mass or more and 40% by mass or less, based on the total amount of ink. ..
As a result, it is possible to suppress ejection defects due to the drying of the ink, suppress blocking, and obtain an image having good fixability.

<Organic solvent>
The organic solvent used in the present invention is not particularly limited, and a water-soluble organic solvent can be used.
Examples of the organic solvent include ethers such as polyhydric alcohols, polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines and sulfur-containing compounds.
Specific examples of the water-soluble organic solvent include, for example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butane. Diol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol , 2,4-Pentanediol, 1,5-Pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, Glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl- Polyhydric alcohols such as 1,3-pentanediol and petriol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl Polyhydric alcohol alkyl ethers such as ethers, polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone. , 1,3-Dimethyl-2-imidazolidinone, ε-caprolactam, γ-butyrolactone and other nitrogen-containing heterocyclic compounds, formamide, N-methylformamide, N, N-dimethylformamide, 3-methoxy-N, N- Amidos such as dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide, amines such as monoethanolamine, diethanolamine and triethylamine, sulfur-containing compounds such as dimethylsulfoxide, sulfolane and thiodiethanol, propylene carbonate and ethylene carbonate. And so on.

Polyol compounds having 8 or more carbon atoms and glycol ether compounds are also preferably used. Specific examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol.
Specific examples of the glycol ether compound include polyhydric alcohol alkyls such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Ethers; Examples thereof include polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

A polyol compound having 8 or more carbon atoms and a glycol ether compound can improve the permeability of ink when paper is used as a recording medium.

As the organic solvent, it is preferable to use at least one compound having a vapor pressure of 0.2 mmHg or less at 20 ° C.

Two or more kinds of the above compounds may be used in combination.

Examples of the compound having a steam pressure of 0.2 mmHg or less at 20 ° C. include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,2-butanediol, 2,3-butanediol, and 1,3-propanediol. , 1,3-Butanediol, 1,5-Propanediol, 2-ethyl-1,3-hexanediol, glycerin, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, 2-pyrrolidone, formamide, etc. Be done.

The compound having a vapor pressure at 20 ° C. of 0.2 mmHg or less is more preferably having a vapor pressure of 0.01 mmHg or more and 0.2 mmHg or less at 20 ° C.

The vapor pressure can be measured by, for example, the DSC method.
Further, in addition to the compound having a vapor pressure of 0.2 mmHg or less at 20 ° C., another organic solvent may be used in combination, if necessary.
The total content of the organic solvent in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 5% by mass or more and 60% by mass or less from the viewpoint of ink drying property and ejection reliability. , 20% by mass or more and 60% by mass or less are more preferable.

<Water>
The content of water in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but from the viewpoint of ink drying property and ejection reliability, it is preferably 10% by mass or more and 90% by mass or less, and 20% by mass. % To 60% by mass is more preferable.

<Color material>
The coloring material is not particularly limited, and pigments and dyes can be used.
As the pigment, an inorganic pigment or an organic pigment can be used. These may be used alone or in combination of two or more. Further, a mixed crystal may be used.
As the pigment, for example, a black pigment, a yellow pigment, a magenta pigment, a cyan pigment, a white pigment, a green pigment, an orange pigment, a glossy color pigment such as gold or silver, a metallic pigment, or the like can be used.
As inorganic pigments, carbon black produced by known methods such as contact method, furnace method, thermal method, in addition to titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow. Can be used.
Examples of organic pigments include azo pigments and polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinofuralone pigments, etc.). , Dye chelate (for example, basic dye type chelate, acid dye type chelate, etc.), nitro pigment, nitroso pigment, aniline black and the like can be used. Among these pigments, those having a good affinity with a solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used.
As a specific example of the pigment, for black, carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, or copper, iron (CI pigment black 11) , Metals such as titanium oxide, and organic pigments such as aniline black (CI pigment black 1).
Further, for color, C.I. I. Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104 , 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213, C.I. I. Pigment Orange 5, 13, 16, 17, 36, 43, 51, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48: 2, 48: 2 (Permanent Red 2B (Ca)), 48: 3, 48: 4, 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmin 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81, 83, 88, 101 (Mengara), 104, 105, 106, 108 ( Cadmium Red), 112, 114, 122 (Quinacridone Magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, 264, C.I. I. Pigment Violet 1 (Rhodamine Lake), 3, 5: 1, 16, 19, 23, 38, C.I. I. Pigment Blue 1, 2, 15 (phthalocyanine blue), 15: 1, 15: 2, 15: 3, 15: 4 (phthalocyanine blue), 16, 17: 1, 56, 60, 63, C.I. I. Pigment Greens 1, 4, 7, 8, 10, 17, 18, 36, etc.
The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used, and one type may be used alone or two or more types may be used in combination.
As the dye, for example, C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. I. Acid Red 52,80,82,249,254,289, C.I. I. Acid Blue 9,45,249, C.I. I. Acid Black 1,2,24,94, C.I. I. Food Black 1, 2, C.I. I. Direct Yellow 1,12,24,33,50,55,58,86,132,142,144,173, C.I. I. Direct Red 1,4,9,80,81,225,227, C.I. I. Direct Blue 1,2,15,71,86,87,98,165,199,202, C.I. I. Dilekdo Black 19,38,51,71,154,168,171,195, C.I. I. Reactive Red 14, 32, 55, 79, 249, C.I. I. Reactive Black 3, 4, 35 can be mentioned.
The content of the coloring material in the ink is preferably 0.1% by mass or more and 15% by mass or less, more preferably 1% by mass or more and 10% by mass, from the viewpoint of improving the image density, good fixing property and ejection stability. It is as follows.
To disperse the pigment in the ink, a method of introducing a hydrophilic functional group into the pigment to obtain a self-dispersing pigment, a method of coating the surface of the pigment with a resin and dispersing it, a method of dispersing using a dispersant, And so on.
As a method of introducing a hydrophilic functional group into a pigment to obtain a self-dispersing pigment, for example, a self-dispersing pigment in which a functional group such as a sulfone group or a carboxyl group is added to a pigment (for example, carbon) so that it can be dispersed in water, etc. Can be used.
As a method of coating the surface of the pigment with a resin and dispersing it, a method in which the pigment is encapsulated in microcapsules and can be dispersed in water can be used. This can be rephrased as a resin-coated pigment. In this case, it is not necessary that all the pigments blended in the ink are coated with the resin, and the uncoated pigments and the partially coated pigments are dispersed in the ink as long as the effect of the present invention is not impaired. May be.
Examples of the method of dispersing using a dispersant include a method of dispersing using a known low-molecular-weight dispersant and high-molecular-weight dispersant represented by a surfactant.
As the dispersant, for example, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant and the like can be used depending on the pigment.
The dispersant may be used alone or in combination of two or more.

<Pigment dispersion>
It is possible to obtain ink by mixing a material such as water or an organic solvent with a coloring material. It is also possible to produce an ink by mixing a material such as water or an organic solvent with a pigment dispersion obtained by mixing a pigment and other water or a dispersant.
The pigment dispersion is obtained by dispersing water, a pigment, a pigment dispersant, and other components as necessary, and adjusting the particle size. It is good to use a disperser for dispersion.
The particle size of the pigment in the pigment dispersion is not particularly limited, but the maximum frequency is 20 nm or more in terms of the maximum number because the dispersion stability of the pigment is good and the image quality such as ejection stability and image density is also high. It is preferably 500 nm or less, and more preferably 20 nm or more and 150 nm or less. The particle size of the pigment can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrac Bell Co., Ltd.).
The content of the pigment in the pigment dispersion is not particularly limited and may be appropriately selected depending on the intended purpose. However, good ejection stability can be obtained and the image density is increased by 0.1 mass. % Or more and 50% by mass or less are preferable, and 0.1% by mass or more and 30% by mass or less are more preferable.
It is preferable that the pigment dispersion is degassed by filtering coarse particles with a filter, a centrifuge, or the like, if necessary.

<Resin>
The type of resin contained in the ink is not particularly limited and may be appropriately selected depending on the intended purpose. For example, urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, etc. Examples thereof include resins, styrene-butadiene resins, vinyl chloride resins, acrylic styrene resins, and acrylic silicone resins.
Resin particles made of these resins may be used. It is possible to obtain ink by mixing resin particles with a material such as a coloring material or an organic solvent in the state of a resin emulsion in which water is used as a dispersion medium. As the resin particles, those synthesized as appropriate may be used, or commercially available products may be used. Further, these may be used alone or in combination of two or more kinds of resin particles.
The volume average particle size of the resin particles is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of obtaining good fixability and high image hardness, 10 nm or more and 1,000 nm or less are preferable. More than 200 nm is more preferable, and 10 nm or more and 100 nm or less is particularly preferable.
The volume average particle size can be measured using, for example, a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrac Bell Co., Ltd.).

The content of the resin is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of fixability and storage stability of the ink, 1% by mass or more and 30% by mass or less with respect to the total amount of the ink. Is preferable, and 5% by mass or more and 20% by mass or less is more preferable.

The particle size of the solid content in the ink is not particularly limited and can be appropriately selected according to the purpose, but from the viewpoint of improving image quality such as ejection stability and image density, the maximum frequency in terms of the maximum number of inks. Is preferably 20 nm or more and 1000 nm or less, and more preferably 20 nm or more and 150 nm or less. The solid content includes resin particles, pigment particles, and the like. The particle size can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrac Bell Co., Ltd.).

<Additives>
If necessary, a surfactant, an antifoaming agent, an antiseptic / antifungal agent, a rust preventive agent, a pH adjuster and the like may be added to the ink.

<Surfactant>
As the surfactant, any of a silicone-based surfactant, a fluorine-based surfactant, an amphoteric surfactant, a nonionic surfactant, and an anionic surfactant can be used.
The silicone-based surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. Among them, those that do not decompose even at high pH are preferable, and examples thereof include side chain modified polydimethylsiloxane, double-ended modified polydimethylsiloxane, single-ended modified polydimethylsiloxane, side chain double-ended modified polydimethylsiloxane, and the like. Those having an oxyethylene group and a polyoxyethylene polyoxypropylene group are particularly preferable because they exhibit good properties as an aqueous surfactant. Further, as the silicone-based surfactant, a polyether-modified silicone-based surfactant can also be used, and examples thereof include compounds in which a polyalkylene oxide structure is introduced into the Si portion side chain of dimethylsiloxane.
Examples of the fluorine-based surfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphate ester compound, a perfluoroalkyl ethylene oxide adduct, and a perfluoroalkyl ether group in the side chain. Polyoxyalkylene ether polymer compounds are particularly preferred because they have low foaming properties. Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid and perfluoroalkyl sulfonic acid salt. Examples of the perfluoroalkylcarboxylic acid compound include perfluoroalkylcarboxylic acid and perfluoroalkylcarboxylic acid salt. The polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain includes a sulfate ester salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain and a perfluoroalkyl ether group in the side chain. Examples thereof include salts of polyoxyalkylene ether polymers. The counter ions of the salts in these fluorine-based surfactants include Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , and NH (CH ₂ CH ₂ OH). ₃ etc. can be mentioned.
Examples of the amphoteric tenside include laurylaminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine.
Examples of the nonionic surfactant include polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkyl amine, polyoxyethylene alkyl amide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, and polyoxyethylene sorbitan. Examples thereof include a fatty acid ester and an ethylene oxide adduct of acetylene alcohol.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, lauryl salt, polyoxyethylene alkyl ether sulfate salt and the like.
These may be used alone or in combination of two or more.

一般式（Ｓ－１）
（但し、一般式（Ｓ-1）式中、ｍ、ｎ、ａ、及びｂは整数を表わす。 Ｒ及びＲ’はアルキル基、アルキレン基を表わす。）
上記のポリエーテル変性シリコーン系界面活性剤としては、市販品を用いることができ、例えば、ＫＦ－６１８、ＫＦ－６４２、ＫＦ－６４３（信越化学工業株式会社）、ＥＭＡＬＥＸ－ＳＳ－５６０２、ＳＳ－１９０６ＥＸ（日本エマルジョン株式会社）、ＦＺ－２１０５、ＦＺ－２１１８、ＦＺ－２１５４、ＦＺ－２１６１、ＦＺ－２１６２、ＦＺ－２１６３、ＦＺ－２１６４（東レ・ダウコーニング・シリコーン株式会社）、ＢＹＫ－３３、ＢＹＫ－３８７（ビックケミー株式会社）、ＴＳＦ４４４０、ＴＳＦ４４５２、ＴＳＦ４４５３（東芝シリコン株式会社）、ＴＥＧＯ Ｗｅｔ ＫＬ２４５、ＴＥＧＯ Ｗｅｔ ２５０、ＴＥＧＯ Ｗｅｔ ２６０、ＴＥＧＯ Ｗｅｔ ２６５、ＴＥＧＯ Ｗｅｔ ２７０、ＴＥＧＯ Ｗｅｔ ２８０（エボニック社製）などが挙げられる。
前記フッ素系界面活性剤としては、フッ素置換した炭素数が２～１６の化合物が好ましく、フッ素置換した炭素数が４～１６である化合物がより好ましい。
フッ素系界面活性剤としては、パーフルオロアルキルリン酸エステル化合物、パーフルオロアルキルエチレンオキサイド付加物、及びパーフルオロアルキルエーテル基を側鎖に有するポリオキシアルキレンエーテルポリマー化合物などが挙げられる。 これらの中でも、パーフルオロアルキルエーテル基を側鎖に有するポリオキシアルキレンエーテルポリマー化合物は起泡性が少ないため好ましく、特に一般式（Ｆ-１）及び一般式（Ｆ-２）で表わされるフッ素系界面活性剤が好ましい。

一般式（Ｆ-１）
上記一般式（Ｆ-１）で表される化合物において、水溶性を付与するためにｍは０～１０の整数が好ましく、ｎは０～４０の整数が好ましい。
一般式（Ｆ-２）
Ｃ_ｎＦ_2ｎ+1－ＣＨ₂ＣＨ（ＯＨ）ＣＨ₂－Ｏ－（ＣＨ₂ＣＨ₂Ｏ）_ａ－Ｙ
上記一般式（Ｆ-２）で表される化合物において、ＹはＨ、又はＣｎＦ_２ｎ＋１でｎは1～6の整数、又はＣＨ_２ＣＨ（ＯＨ）ＣＨ_２－ＣｎＦ_２ｎ＋１でｎは4～６の整数、又はＣｐＨ_２ｐ＋１でｐは１～１９の整数である。ａは４～１４の整数である。
上記のフッ素系界面活性剤としては市販品を使用してもよい。 この市販品としては、例えば、サーフロンＳ－１１１、Ｓ－１１２、Ｓ－１１３、Ｓ－１２１、Ｓ－１３１、Ｓ－１３２、Ｓ－１４１、Ｓ－１４５（いずれも、旭硝子株式会社製）；フルラードＦＣ－９３、ＦＣ－９５、ＦＣ－９８、ＦＣ－１２９、ＦＣ－１３５、ＦＣ－１７０Ｃ、ＦＣ－４３０、ＦＣ－４３１（いずれも、住友スリーエム株式会社製）；メガファックＦ－４７０、Ｆ－１４０５、Ｆ－４７４（いずれも、大日本インキ化学工業株式会社製）；ゾニール（Ｚｏｎｙｌ）ＴＢＳ、ＦＳＰ、ＦＳＡ、ＦＳＮ－１００、ＦＳＮ、ＦＳＯ－１００、ＦＳＯ、ＦＳ－３００、ＵＲ（いずれも、ＤｕＰｏｎｔ社製）；ＦＴ－１１０、ＦＴ－２５０、ＦＴ－２５１、ＦＴ－４００Ｓ、ＦＴ－１５０、ＦＴ－４００ＳＷ（いずれも、株式会社ネオス社製）、ポリフォックスＰＦ－１３６Ａ，ＰＦ－１５６Ａ、ＰＦ－１５１Ｎ、ＰＦ－１５４、ＰＦ－１５９（オムノバ社製）、ユニダインＤＳＮ-４０３Ｎ（ダイキン工業株式会社製）などが挙げられ、これらの中でも、良好な印字品質、特に発色性、紙に対する浸透性、濡れ性、均染性が著しく向上する点から、Ｄｕ Ｐｏｎｔ社製のＦＳ－３００、株式会社ネオス製のＦＴ－１１０、ＦＴ－２５０、ＦＴ－２５１、ＦＴ－４００Ｓ、ＦＴ－１５０、ＦＴ－４００ＳＷ、オムノバ社製のポリフォックスＰＦ－１５１Ｎ及びダイキン工業株式会社製のユニダインＤＳＮ-４０３Ｎが特に好ましい。
インク中における界面活性剤の含有量としては、特に制限はなく、目的に応じて適宜選択することができるが、濡れ性、吐出安定性に優れ、画像品質が向上する点から、０．００１質量％以上５質量％以下が好ましく、０．０５質量％以上5質量％以下がより好ましい。 The silicone-based surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, side chain-modified polydimethylsiloxane, double-ended modified polydimethylsiloxane, one-ended modified polydimethylsiloxane, side. Examples thereof include polydimethylsiloxane modified at both ends of the chain, and a polyether-modified silicone-based surfactant having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as a modifying group exhibits good properties as an aqueous surfactant, and is particularly effective. preferable.
As such a surfactant, an appropriately synthesized one may be used, or a commercially available product may be used. As commercially available products, for example, they can be obtained from Big Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Toray Dow Corning Silicone Co., Ltd., Nippon Emulsion Co., Ltd., Kyoeisha Chemical Co., Ltd., and the like.
The above-mentioned polyether-modified silicone-based surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a polyalkylene oxide structure represented by the general formula (S-1) may be dimethylpoly. Examples thereof include those introduced into the Si part side chain of siloxane.

General formula (S-1)
(However, in the general formula (S-1), m, n, a, and b represent integers. R and R'represent an alkyl group and an alkylene group.)
Commercially available products can be used as the above-mentioned polyether-modified silicone-based surfactant, for example, KF-618, KF-642, KF-643 (Shinetsu Chemical Industry Co., Ltd.), EMALEX-SS-5602, SS- 1906EX (Nippon Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (Toray Dow Corning Silicone Co., Ltd.), BYK-33, BYK-387 (Big Chemie Co., Ltd.), TSF4440, TSF4452, TSF4453 (Toshiba Silicon Co., Ltd.), TEGO Wet KL245, TEGO Wet 250, TEGO Wet 260, TEGO Wet 265, TEGO Wet 270, TEGO Wet 280 (Evonic) Can be mentioned.
As the fluorine-based surfactant, a compound having 2 to 16 carbon atoms substituted with fluorine is preferable, and a compound having 4 to 16 carbon atoms substituted with fluorine is more preferable.
Examples of the fluorine-based surfactant include a perfluoroalkyl phosphate ester compound, a perfluoroalkylethylene oxide adduct, and a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain. Among these, the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain is preferable because it has less foaming property, and is particularly a fluorine-based compound represented by the general formula (F-1) and the general formula (F-2). Surfactants are preferred.

General formula (F-1)
In the compound represented by the general formula (F-1), m is preferably an integer of 0 to 10 and n is preferably an integer of 0 to 40 in order to impart water solubility.
General formula (F-2)
C _n F _{2n + 1-} CH ₂ CH (OH) CH ₂ -O- (CH ₂ CH ₂ O) _a -Y
In the compound represented by the above general formula (F-2), Y is H or CnF _{2n + 1} and n is an integer of 1 to 6, or CH ₂ CH (OH) CH ₂ -CnF _{2n + 1} and n is 4 to 6. It is an integer, or CpH _{2p + 1} and p is an integer of 1 to 19. a is an integer of 4 to 14.
Commercially available products may be used as the above-mentioned fluorine-based surfactant. Examples of this commercially available product include Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, and S-145 (all manufactured by Asahi Glass Co., Ltd.); Full Lard FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M Co., Ltd.); Megafuck F-470, F -1405, F-474 (all manufactured by Dainippon Ink and Chemicals Co., Ltd.); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR (all) FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW (all manufactured by Neos Co., Ltd.), Polyfox PF-136A, PF-156A, PF-151N, PF-154, PF-159 (manufactured by Omniova), Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.), etc. Among these, good print quality, especially color development and permeability to paper. FS-300 manufactured by Du Pont, FT-110, FT-250, FT-251, FT-400S, FT-150, FT- of Neos Co., Ltd. from the viewpoint of remarkably improving wettability and leveling property. 400SW, Polyfox PF-151N manufactured by Omniova, and Unidyne DSN-403N manufactured by Daikin Industries, Ltd. are particularly preferable.
The content of the surfactant in the ink is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of excellent wettability and ejection stability and improvement in image quality, 0.001 mass is used. % Or more and 5% by mass or less are preferable, and 0.05% by mass or more and 5% by mass or less are more preferable.

<Defoamer>
The defoaming agent is not particularly limited, and examples thereof include a silicone-based defoaming agent, a polyether-based defoaming agent, and a fatty acid ester-based defoaming agent. These may be used alone or in combination of two or more. Among these, a silicone-based defoaming agent is preferable because it has an excellent defoaming effect.

<Preservatives and fungicides>
The antiseptic and antifungal agent is not particularly limited, and examples thereof include 1,2-benzisothiazolin-3-one and the like.

<Rust inhibitor>
The rust preventive is not particularly limited, and examples thereof include acidic sulfites and sodium thiosulfate.

<pH adjuster>
The pH adjusting agent is not particularly limited as long as the pH can be adjusted to 7 or more, and examples thereof include amines such as diethanolamine and triethanolamine.
The physical characteristics of the ink are not particularly limited and may be appropriately selected depending on the intended purpose. For example, the viscosity, surface tension, pH and the like are preferably in the following ranges.

The viscosity of the ink at 25 ° C. is preferably 5 mPa · s or more and 30 mPa · s or less, preferably 5 mPa · s or more and 25 mPa · s or less, from the viewpoint of improving the print density and character quality and obtaining good ejection properties. More preferred. Here, for the viscosity, for example, a rotary viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.) can be used. As the measurement conditions, it is possible to measure at 25 ° C. with a standard cone rotor (1 ° 34'× R24), a sample liquid volume of 1.2 mL, a rotation speed of 50 rpm, and 3 minutes.

The surface tension of the ink is preferably 35 mN / m or less, and more preferably 32 mN / m or less at 25 ° C. from the viewpoint that the ink is preferably leveled on the recording medium and the drying time of the ink is shortened.

The pH of the ink is preferably 7 to 12, and more preferably 8 to 11 from the viewpoint of preventing corrosion of the metal member that comes into contact with the liquid.

The "liquid discharge head" includes a piezoelectric actuator (laminated piezoelectric element and thin film type piezoelectric element), a thermal actuator using an electric heat conversion element such as a heat generating resistor, a vibrating plate and a counter electrode as an energy generation source for discharging liquid. Includes those that use electrostatic actuators and the like.

The "liquid discharge device" includes a device that drives a liquid discharge head to discharge a liquid. This "liquid discharge device" can also include means related to feeding, transporting, and discharging paper to which a liquid can adhere, as well as a pretreatment device, a posttreatment device, and the like.

For example, as a "liquid ejection device", there is an image forming apparatus which is an apparatus for ejecting ink to form an image on paper.

Further, the "liquid discharge device" is not limited to a device in which a significant image such as characters and figures is visualized by the discharged liquid. For example, those that form patterns that have no meaning in themselves are also included.

Further, the "liquid discharge device" includes, but is not limited to, a device in which the liquid discharge head and the device to which the liquid can adhere move relatively. Specific examples include a serial type device that moves the liquid discharge head, a line type device that does not move the liquid discharge head, and the like.

In the present invention, image formation, recording, printing, printing, printing, etc. are all synonymous.

Hereinafter, examples of the present invention will be described, but the present invention is not limited to these examples.

(Preparation Example 1)
<Preparation of black pigment dispersion>
After premixing the mixture described below, it was circulated and dispersed for 7 hours in a disc type bead mill (KDL type of Simmal Enterprises, media: zirconia ball having a diameter of 0.3 mm) to obtain a black pigment dispersion.
-Carbon black pigment (trade name: Monarch800, manufactured by Cabot): 15 parts by mass-Anionic surfactant (Pionin A-51-B, manufactured by Takemoto Oil & Fat Co., Ltd.): 2 parts by mass-Ion-exchanged water: 83 parts by mass

(Preparation Example 2)
<Preparation of cyan pigment dispersion>
In Preparation Example 1, the cyan pigment dispersion was prepared in the same manner as in Preparation Example 1 except that the carbon black pigment was changed to Pigment Blue 15: 3 (trade name: LIONOL BLUE FG-7351, manufactured by Toyo Ink Co., Ltd.). Obtained.

(Preparation Example 3)
<Preparation of magenta pigment dispersion>
A magenta pigment dispersion was obtained in the same manner as in Preparation Example 1 except that the carbon black pigment was changed to Pigment Red 122 (trade name: Toner Magenta EO02, manufactured by Clariant Japan Co., Ltd.).

(Preparation Example 4)
<Preparation of yellow pigment dispersion>
A yellow pigment dispersion was obtained in the same manner as in Preparation Example 1 except that the carbon black pigment was changed to Pigment Yellow 74 (trade name: First Yellow 531; manufactured by Dainichiseika Kogyo Co., Ltd.). ..

(Preparation Example 5)
-Preparation of ink 1-
Ink 1 was prepared by mixing and stirring the compounds described below and filtering through a polypropylene filter having an average pore size of 0.2 μm.
-Black pigment dispersion prepared in Preparation Example 1: 20 parts by mass-Polyurethane resin (product name: Superflex 150, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 8 parts by mass-1,2-propanediol: 15 parts by mass-3 -Methoxy-N, N-dimethylpropionamide: 9 parts by mass, 3-methoxy-3-methylbutanol: 3 parts by mass, 2-ethyl-1,3-hexanediol: 3 parts by mass, surfactant (product name: SAG-002, manufactured by Nisshin Kagaku Kogyo Co., Ltd.): 3 parts by mass, antiseptic and antifungal agent (product name: Proxel LV, manufactured by Abyssia): 0.05 parts by mass, rustproofing agent (product name: BT-120, Johoku Chemical Industry Co., Ltd.): 0.05 parts by mass, defoaming agent (product name: AD01, manufactured by Nissin Chemical Industry Co., Ltd.): 0.1 parts by mass, high pure water: remaining amount

(Preparation Examples 6-9)
-Preparation of inks 2-5-
Ink 2 to 5 were prepared in the same manner as ink 1 except that the composition was changed as shown in Table 1 in Preparation Example 1.

(Preparation Example 10)
-Preparation of cleaning solution 1-
The compounds described below were mixed to prepare a cleaning solution 1.
-Diethylene glycol dibutyl ether: 10 parts by mass-Emargen LS110 (manufactured by Kao Corporation): 1 part by mass-High pure water: 89 parts by mass

(Preparation Example 11)
-Preparation of cleaning solution 2-
In Preparation Example 10, the cleaning liquid 2 was prepared in the same manner as the cleaning liquid 1 except that the composition was changed as shown in Table 2 below.
As the compound of the general formula (1) added to the cleaning liquid 2, Equamid M-100 manufactured by KJ Chemicals Co., Ltd., in which ^R1 is a methyl group, was used.

(Examples 1 to 8)
The effects of the prepared inks 1 to 5 and the cleaning liquids 1 and 2 on the ejection stability of the liquid ejection device were evaluated as follows.

<Discharge stability evaluation>
The dew condensation wiping operation is performed using the conditions for performing the dew condensation wiping operation during printing (see FIG. 8) and the inkjet printer shown in FIGS. 1 to 3 in which the prepared inks 1 to 5 are controlled according to the flow chart shown in FIG. Continuous printing was carried out while doing so. The dew condensation wiping conditions and the dew condensation wiping means related to the dew condensation wiping operation are shown below.
[Conditions for wiping dew condensation]
Dew condensation wiping condition 1: Do not apply the cleaning liquid to the wiping means Dew condensation wiping condition 2: Apply the cleaning liquid 1 to the wiping means Dew condensation wiping condition 3: Apply the cleaning liquid 2 to the wiping means [Condensation wiping means]
Dew condensation wiping means 1: Use the wiping means shown in FIG. 23 23 Dew condensation wiping means 2: Using the wiping means shown in FIG. 12 Dew condensation wiping using the dew condensation wiping means shown in FIG. 12 was performed by the following procedure.
Using the ink ejection head cleaning device 300 shown in FIG. 12, the cleaning liquid 1 or 2 is applied to a non-woven fabric 303 (trade name: Inkjet) as a wiping member at 0.05 mL / cm ² , and the cleaning liquid is applied by the pressing member. The nozzle surface was cleaned by pressing the member against the nozzle surface 301a of the ink ejection head 301 of the inkjet printer. Butyl rubber was used for the pressing roller 305 as the pressing member in the cleaning device for the ink ejection head shown in FIG. 12.
Next, using an inkjet printer after cleaning the nozzle surface, output the nozzle check pattern, check the number of nozzles with missing nozzles (total number of nozzles: 192), and eject based on the following criteria. Stability was evaluated. The results are shown in Table 3.
[Evaluation criteria]
⊚: No nozzle omission ○: Nozzle omission occurred 2 or less △: Nozzle omission occurred 3 or more and 5 or less ×: Nozzle omission occurred 6 or more

1 Roll body 2 Printing medium 5 Carriage 6 Liquid discharge head 23 Wiping member 3A, 3B, 3C Heater 500 Control unit

JP-A-2015-131419A

Claims (11)

A liquid discharge head with a nozzle that discharges liquid,
A cap that caps the nozzle surface of the liquid discharge head,
A wiping means for wiping the nozzle surface and
A heating means for heating the member to which the liquid is applied, and
A dew condensation amount determining means for predicting or detecting the dew condensation amount on the nozzle surface,
A means for controlling the wiping operation by the wiping means without overflowing the liquid from the nozzle when the amount of dew condensation determined by the dew condensation amount determining means exceeds the threshold value is provided .
A liquid discharge device characterized in that at least the temperature of the heating means, the temperature of the liquid discharge head, and the decap time in which the cap does not cap the nozzle surface are used for predicting the amount of dew condensation . The liquid discharge head can be reciprocated and can be reciprocated.
The liquid discharge device according to claim 1, wherein the number of scans of the liquid discharge head is used for predicting the amount of dew condensation. The liquid discharge device according to claim 1 or 2, wherein the discharge amount from the liquid discharge head is used for predicting the amount of dew condensation. The liquid discharge device according to claim 1, wherein the nozzle surface is imaged to detect the amount of dew condensation. The liquid ejection device according to claim 1, wherein the liquid ejection device receives the reflected light when the nozzle surface is irradiated with light and detects the amount of dew condensation. The liquid is an ink, which contains water, an organic solvent, and a coloring material.
The liquid discharge device according to any one of claims 1 to 5, wherein the organic solvent contains a compound having a vapor pressure of 0.2 mmHg or less at 20 ° C. The liquid ejection device according to claim 6, wherein the content of the compound having a vapor pressure of 0.2 mmHg or less at 20 ° C. is 5% by mass or more with respect to the total amount of ink. The wiping means contains a cleaning liquid and
The cleaning solution contains water, a glycol ether compound, and a surfactant.
The liquid discharge device according to any one of claims 1 to 7, wherein the content of the glycol ether compound is 1% by mass or more and 30% by mass or less with respect to the total amount of the cleaning liquid. The liquid discharge device according to claim 8, wherein the cleaning liquid further contains a compound represented by the following general formula (1).

(However, in the general formula (1), R ¹ Represents an alkyl group having 1 or more and 4 or less carbon atoms. ) A liquid discharge head with a nozzle that discharges liquid,
A cap that caps the nozzle surface of the liquid discharge head,
A wiping means for wiping the nozzle surface and
A heating means for heating the member to which the liquid is applied, and
A dew condensation amount determining means for predicting or detecting the dew condensation amount on the nozzle surface,
A means for controlling the wiping operation by the wiping means without overflowing the liquid from the nozzle when the amount of dew condensation determined by the dew condensation amount determining means exceeds the threshold value is provided.
A liquid discharge method using a liquid discharge device, which uses at least the temperature of the heating means, the temperature of the liquid discharge head, and the decap time during which the cap does not cap the nozzle surface for predicting the amount of dew condensation. There,
The liquid contains water, an organic solvent, and a coloring material.
A liquid ejection method, wherein the organic solvent uses an ink containing a compound having a vapor pressure of 0.2 mmHg or less at 20 ° C. The wiping means contains a cleaning liquid and
The cleaning solution contains water, a glycol ether compound, and a surfactant.
The liquid discharge method according to claim 10, wherein the content of the glycol ether compound is 1% by mass or more and 30% by mass or less with respect to the total amount of the cleaning liquid.

Images