JPH11245428A - Ink-jet recorder and flushing control method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a highly reliable recorder in which occurrence of defective print is suppressed while shortening the waiting time after turn on power by an arrangement wherein an ink drop is ejected from a nozzle opening to a capping means in response to a flushing command signal. SOLUTION: A flushing pending timer 57 begins time measuring operation upon finishing a cleaning process and times up upon measuring a time elapsed before a bubble generated i the proximity of the nozzle opening of recording head 7, 8 extinguishes naturally in the cleaning process. When a user depresses a cleaning command switch 58 arranged on the control panel of a case, or the like, in order to eliminate clogging of a recording head, a CL command detecting means 53 is actuated to execute cleaning operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a recording head which moves in the width direction of a recording sheet, and prints an image on the recording sheet by discharging ink droplets toward the recording sheet based on print data. More particularly, the present invention relates to an improved technique of a control sequence of a flushing control unit for preventing clogging of a nozzle opening of a recording head.

[0002]

2. Description of the Related Art With the development of personal computers, graphic processing has become relatively easy to execute. Therefore, there is a demand for a recording apparatus capable of outputting a hard copy of, for example, a color image displayed on a display with high quality. In order to meet such a demand, a recording apparatus equipped with an ink jet recording head has been provided. This ink jet recording apparatus has relatively low noise at the time of printing and can form small dots at a high density. Therefore, these ink jet recording apparatuses are used in many printings including color printing in recent years.

[0003] Such an ink jet recording apparatus is
An ink jet recording head that receives supply of ink from an ink cartridge, and a paper feeding unit that relatively moves the recording paper with respect to the recording head, are provided with ink droplets on the recording paper while moving the recording head according to a print signal. Is ejected to form dots to perform recording. A common head holder is provided with a recording head capable of discharging black, yellow, cyan, and magenta inks.
By changing the ejection ratio of each ink, full-color printing is possible.

In such an ink jet type recording head, since the ink pressurized in the pressure generating chamber is ejected from a nozzle as an ink droplet to a recording sheet to perform printing, the ink viscosity caused by the evaporation of the solvent from the nozzle opening is printed. Rise,
There is a problem that clogging of the nozzle opening occurs due to solidification of ink, adhesion of dust, and mixing of air bubbles, resulting in poor printing.

[0005] For this purpose, the ink jet recording apparatus usually includes capping means for sealing the nozzle openings of the recording head during non-printing and a cleaning device for cleaning the nozzle plate as required. This capping means not only functions as a lid for preventing drying of the ink at the nozzle opening, but also seals the nozzle plate with a cap member when clogging occurs at the nozzle opening, so that the suction pump can It also has a function of sucking ink from the nozzle openings by negative pressure and eliminating clogging of the nozzle openings.

[0006] The forcible discharge process of ink for eliminating clogging of the recording head is usually called a cleaning operation.
This process is performed when the user presses a cleaning switch to eliminate clogging of the recording head, and involves a wiping operation using a cleaning member made of an elastic plate such as rubber after discharging ink droplets.

The recording head also has a function of applying a drive signal unrelated to printing to eject ink droplets. This function is usually called a flushing operation, and the nozzle opening of the head is performed by wiping or the like during a cleaning operation. This operation is performed at regular intervals for the purpose of recovering an irregular meniscus in the vicinity, or preventing clogging due to thickening of ink at a nozzle opening where ejection of ink droplets is small during printing.

[0008]

By the way, as described above, in the ink jet type recording apparatus, during non-printing or when the operation power to the recording apparatus is not turned on (power off state), the recording is performed by the capping means. The nozzle opening of the head is configured to be sealed. However, even if the nozzle opening is sealed by the capping means, the ink at the nozzle opening portion of the recording head thickens due to the evaporation of the solvent of the ink, causing a problem that the nozzle opening is clogged and printing failure occurs. Occurs.

Therefore, a conventional recording apparatus employs a sequence in which, when the operating power is turned on, a cleaning operation or a flushing operation is performed by judging an elapsed time after the previous cleaning operation was performed. Was. That is, the elapsed time in this case is set to a relatively short time, and after the elapsed time, the operation of always performing the cleaning operation sequence to recover the clogged nozzle opening has been performed.

However, in the cleaning operation, the head is sealed by the capping means, a main suction step of sucking a relatively large amount of ink is performed, and a valve communicating with the capping means is opened to suck the sucked ink into the drain ink tank. The process of discharging, the process of sucking a small amount of ink again so as not to bubble the bubbles that have entered from the nozzle of the head, the process of opening the valve and discharging the sucked ink to the waste ink tank, and the uneven meniscus in the head A series of cleaning sequences is completed after a small amount suction step for finishing to be recovered, an ink discharging step, and a waiting time for waiting for spontaneous disappearance of extremely small air bubbles entering from the nozzle.

Therefore, it takes at least one minute or more to execute these series of cleaning sequences, which causes the user to wait for a considerable waiting time after the power is turned on. Has the problem of giving mental trouble to the elderly. In addition, in the above-described cleaning sequence, the influence of the bubbling of the ink in the internal space in the capping device cannot be removed even though the small amount suction step and the weight step of the finish are performed, and printing defects such as missing dots are caused. In some cases, it is difficult to secure sufficient reliability.

Furthermore, since a relatively large amount of ink is sucked by the negative pressure, the consumption of ink is large, and there is a problem that the life of the ink cartridge is shortened and the running cost is increased. Furthermore, since a pump for applying a negative pressure to the capping device is driven, a relatively large operation sound is generated during a standby time when the power is turned on,
There were also problems such as giving users anxiety.

In view of such a problem, the present inventors have paid attention to the fact that the degree of thickening in the same elapsed time differs between, for example, black ink and color ink among a plurality of types of inks. A means for effectively eliminating the occurrence of printing failure due to the thickened ink by a flushing operation in which dot missing or the like is unlikely to occur, whereby the standby time after turning on the power can be reduced. It is another object of the present invention to provide a highly reliable recording apparatus capable of suppressing the occurrence of printing defects. Another object of the present invention is to provide a recording apparatus of high commercial value that can suppress unnecessary consumption of ink due to a cleaning operation and can suppress generation of noise due to driving of a suction pump when power is turned on. Is what you do.

[0014]

According to the present invention, there is provided a flushing control method for an ink jet recording apparatus, comprising: a plurality of ink jet recording heads for ejecting ink droplets from nozzle openings; A plurality of capping units corresponding to the respective recording heads for sealing the nozzle openings of the respective recording heads, and configured to discharge ink droplets from the nozzle openings to the capping units by a flushing command signal. A flushing control method for an ink jet recording apparatus, comprising: a recording head that handles a printing ink other than a printing ink that is most easily thickened in response to a flushing command signal, from a nozzle opening of at least one recording head. Capping for recording heads that handle printing inks that tend to thicken The ejected ink to stage 1
A flushing step, a capping step of closing a nozzle opening of a recording head that handles printing ink that easily increases in viscosity by a capping unit that receives the ejected ink in the first flushing step, and a recording that handles the printing ink that easily increases in viscosity. A standby step of waiting with the nozzle opening of the head sealed by the capping means, and a printing head that handles printing ink other than the printing ink ejected in the first flushing step. The second to discharge
The flushing step is sequentially performed.

In this case, the printing ink is black,
In the flushing control method for an ink jet recording apparatus using yellow, magenta, and cyan, all of yellow, magenta, and cyan are used as printing inks other than the printing ink that is most easily thickened in response to the flushing command signal. Ink or two or one of them are controlled to be ejected from the nozzle openings to capping means corresponding to the black print recording head.

Further, the flushing control method in the ink jet type recording apparatus according to the present invention comprises a plurality of ink jet type recording heads for ejecting ink droplets from nozzle openings, and respective recordings for sealing the nozzle openings of the respective recording heads. A flushing control method for an ink jet recording apparatus, comprising: a plurality of capping means corresponding to a head, wherein the flushing command signal is used to discharge ink droplets from the nozzle openings to the capping means. A first flushing step of ejecting the ink from a nozzle opening of the recording head that handles the printing ink that is most difficult to thicken in response to the signal to a capping unit corresponding to the recording head that handles the printing ink that is most easily thickened; , Which handles printing inks that are most likely to thicken A capping step in which the nozzle opening of the head is sealed by a capping unit that has received the ejected ink in the first flushing step; A standby step of waiting and a second flushing step of discharging printing ink to the capping means from a recording head that handles printing ink other than the printing ink discharged in the first flushing step are sequentially executed. Done.

In this case, the printing ink is black,
In the flushing control method for an ink jet recording apparatus using yellow, magenta, and cyan, any one of yellow, magenta, and cyan is used as a printing ink that hardly thickens in response to the flushing command signal.
The ink is controlled to be ejected from the nozzle openings to the capping means corresponding to the recording head for black printing.

In any of the above-mentioned methods, in the first flushing step, the position of the nozzle opening of the recording head of the printing ink which is hardly thickened with respect to the capping means for receiving the ink ejection is sealed in the capping step. Control is performed so that the nozzle openings of the recording head of the printing ink, which tends to increase the viscosity in the stopped state, are located at opposing positions.

The flushing control method in the ink jet recording apparatus according to the present invention includes a recording head for discharging ink droplets from a plurality of rows of nozzle openings for handling a plurality of types of printing inks, and a method for sealing the nozzle openings of the recording head. A flushing control method for an ink jet recording apparatus, comprising: a capping unit for stopping the ink jetting unit; and ejecting an ink droplet from the nozzle opening to the capping unit by a flushing command signal. A first flushing step of discharging a printing ink other than the printing ink which is most easily thickened from the nozzle opening to the capping means from among the printing inks of the type, and capping the nozzle opening of the recording head by the capping means. Before the capping step to seal A standby step of waiting while the nozzle openings of the recording head are sealed with capping means, and a second flushing step of discharging printing ink other than the printing ink discharged in the first flushing step to the capping means. Are sequentially executed.

In this case, the printing ink is black,
In the flushing control method for an ink jet recording apparatus using yellow, magenta, and cyan, all of yellow, magenta, and cyan are used as printing inks other than the printing ink that is most easily thickened in response to the flushing command signal. The ink or two of them or one of them is controlled to be ejected to the capping means.

Further, the flushing control method in the ink jet recording apparatus according to the present invention includes a recording head for discharging ink droplets from a plurality of rows of nozzle openings for handling a plurality of types of printing ink, and a method for sealing the nozzle openings of the recording head. A flushing control method for an ink jet recording apparatus, comprising: a capping unit for stopping the ink jetting unit; and ejecting an ink droplet from the nozzle opening to the capping unit by a flushing command signal. A first flushing step of ejecting ink from the nozzle openings to the capping means with only the printing inks which are least likely to increase in viscosity among the printing inks of the type; and capping for sealing the nozzle openings of the recording head by the capping means. Steps and the recording head A waiting step for waiting for the nozzle openings while sealed by capping means, said first
And a second flushing step of discharging printing ink other than the printing ink discharged in the flushing step to the capping means.

In this case, the printing ink is black,
In the flushing control method for an ink jet recording apparatus using yellow, magenta, and cyan, in response to the flushing command signal, any one of yellow, magenta, and cyan is used as a printing ink that hardly thickens. Control is performed so that ink is ejected to the capping unit.

In this case, in the first flushing step, the position of the nozzle opening of the printing ink which is not easily thickened with respect to the capping means is changed to the position of the nozzle opening of the printing ink which is easily thickened in the sealed state in the capping step. Are controlled so as to face each other.

Further, in the ink jet recording apparatus controlled as described above, preferably, the capacity of the ink cartridge corresponding to the printing ink ejected in the first flushing step is larger than that of the other printing ink ink cartridge. Is also configured to be large.

The ink jet recording apparatus according to the present invention is provided with an ink jet recording head for discharging ink droplets from nozzle openings, and capping means for sealing the nozzle openings of the recording head. An ink jet recording apparatus configured to discharge ink droplets from a nozzle opening to a capping unit, wherein the ink jet recording device receives the flushing command signal and supplies a flushing-only ink other than a printing ink to the capping unit from the nozzle opening. In some cases, the apparatus may be provided with a control means for causing the liquid to be ejected.

In this case, a preferable flushing control method includes a plurality of ink jet recording heads for discharging ink droplets from the nozzle openings, and a plurality of ink jet recording heads corresponding to the respective recording heads for sealing the nozzle openings of the respective recording heads. It is equipped with a capping unit, and is configured to discharge an ink droplet from the nozzle opening to the capping unit by a flushing command signal, and receives a flushing command signal and handles a flushing-only ink other than the printing ink from a nozzle opening of a recording head. A first flushing step of discharging ink to a capping means corresponding to a recording head which handles printing ink which is most easily thickened, and a nozzle opening of a recording head which handles printing ink which is most easily thickened. The cap that has received the ejected ink in the flushing step A capping step of sealing with a ping unit, a standby step of waiting with a nozzle opening of a recording head that handles the printing ink that is liable to increase in viscosity sealed by the capping unit, and flushing discharged in the first flushing step And a second flushing step of ejecting the printing ink to the capping means from a recording head that handles the printing ink other than the dedicated ink.

In another preferred flushing control method in this case, a printing head for discharging ink droplets from a plurality of rows of nozzle openings for handling a plurality of types of ink, and capping means for sealing the nozzle openings of the printing head are provided. The flushing command signal is provided so that ink droplets are ejected from the nozzle opening to the capping means by the flushing command signal. A first flushing step of discharging ink to the capping unit, a capping step of sealing the nozzle opening of the recording head by the capping unit, and a standby step of waiting while the nozzle opening of the recording head is sealed by the capping unit. And the said And a second flushing step of ejecting printing ink other than the flushing-only ink ejected in one flushing step to the capping means.

In the first flushing step according to the flushing control method described above, the position of the nozzle opening of the flushing-only ink with respect to the capping means for receiving the ink ejection is set in a state where the viscosity is increased in the sealed state in the capping step. Control is performed so that the nozzle openings of the ink are located at opposing positions.

In the above-described apparatus and control method, preferably, glycerin diluted with pure water is used as the flushing-only ink. Further, it is preferable that each of the above-described control methods is configured to sequentially execute the above-described steps when the operation power of the recording apparatus is turned on or before printing is started.

In any of the above-described control methods, as a preferred embodiment, an ink jet recording head for discharging ink droplets from a nozzle opening, and a capping means for sealing the nozzle opening of the recording head are provided. A suction pump that supplies a negative pressure to the capping unit; a cleaning control unit that suctions ink from a nozzle opening of the recording head through the capping unit by the suction pump; and cleaning by the cleaning control unit. Flushing control means for an ink jet recording apparatus, comprising: a post-cleaning elapsed time detecting means for detecting a time elapsed after the cleaning; and a cumulative opening time detecting means for detecting an accumulated time during which the recording head is released from the capping means. Is used,
The number of ink droplets ejected in the first flushing step is controlled to a number corresponding to the time length detected by the post-cleaning elapsed time detecting means and the time length detected by the cumulative opening time detecting means.

Further, in the case of adopting any of the control methods described above, another preferred embodiment is as follows.
An ink jet recording head that ejects ink droplets from a nozzle opening, a capping unit that seals the nozzle opening of the recording head, a suction pump that supplies a negative pressure to the capping unit, and the recording head via the capping unit Cleaning control means for sucking ink from the nozzle opening by the suction pump, elapsed cleaning time detecting means for detecting a time after cleaning is performed by the cleaning control means, and the recording head being opened from the capping means. Flushing control means of an ink jet recording apparatus having a cumulative open time detecting means for detecting the accumulation of the time being performed is used, and the waiting time in the waiting step is the time detected by the post-cleaning elapsed time detecting means. Length and cumulative release It is controlled to a time corresponding to the time length detected by between detection means.

According to the ink jet recording apparatus and the flushing control method configured as described above, the ink other than the ink which is most easily thickened or the thickest among the plurality of types of printing inks in response to the flushing command signal. Only the difficult ink is discharged from the nozzle opening to the capping device. Further, when a flushing command signal is received, a flushing-specific ink other than the printing ink is discharged from the nozzle opening to the capping means.

Thus, the capping device is made wet by the ink which is not easily thickened or the ink dedicated to flushing, and in a subsequent step, the recording head which handles the ink which is easily thickened by the capping means is capped and waits for a predetermined time. This makes it possible to soften or dissolve the thickened ink that has adhered to the nozzle surface of the recording head. Therefore, a discharge signal (flushing command) is sent to the print head that subsequently discharges the ink that tends to thicken.
By adding the ink, the ink in the thickened state is released from the nozzle opening and the nozzle surface, and can be restored to the normal printable state.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an ink jet recording apparatus employing a flushing control method according to the present invention will be described with reference to the embodiment shown in the drawings. FIG. 1 is a perspective view showing the whole of an ink jet recording apparatus to which the present invention is applied. In the drawing, reference numeral 1 denotes a carriage, which is guided by a timing belt 2 which reciprocates by driving a carriage motor 3. It is configured to be guided by the member 4 and reciprocated in the axial direction of the platen 5.

A black recording head 7 and a color recording head 8 are mounted on the side of the carriage 1 facing the recording paper 6, and a black ink cartridge for supplying ink to each recording head is mounted above the black recording head 7 and the color recording head 8. 9 and a color ink cartridge 10 are detachably mounted.

In the drawing, reference numeral 11 denotes a capping device as capping means disposed outside the non-printing area, on which a cap unit 37 for a black head and a cap unit 38 for a color head are mounted. A suction pump 12 for applying a negative pressure to the capping device 11 is disposed below the capping device 11.

The cap units 37 and 38 function as cap means for preventing drying of the nozzle openings during the idle period of the recording apparatus, function as ink receivers during a flushing operation, and operate under a negative pressure from the suction pump 12. Is applied to the recording heads 7 and 8 to also function as a means for sucking ink.

FIG. 2 shows an example of an actuator unit in the above-described color recording head 8, in which three piezoelectric vibrators 13 are arranged on a nozzle plate 14, which is not shown in FIG. Independent ink supply passages for each nozzle opening row are provided between each piezoelectric vibrator 13 and the nozzle plate 14 so that ink of a different color can be ejected from a nozzle opening row described later formed on the lower surface thereof. 20a to 20f are provided.

With this configuration, a print control signal is applied to each piezoelectric vibrator 13 so that the ink supply flow path 2
The yellow, cyan, and magenta inks supplied to 0a to 20f are respectively ejected from the nozzle opening rows, and color printing is performed on the recording paper 6. Although not shown, the black recording head 7 has substantially the same configuration as the color recording head 8 described above.

FIGS. 3A and 3B show the entire configuration of the capping device 11, FIG. 3A is a perspective view of the capping device 11 viewed from one direction, and FIG. It is the perspective view seen from the back side of a). In the figure, reference numeral 22 denotes a slider, which is an arm 23 that freely rotates.
When the carriage 1 moves to the non-printing area side and comes into contact with the flag piece 25, the carriage 1 follows the movement of the carriage 1. A valve unit 28 is fixed to the slider 22, and the valve unit 28
A valve 29 for opening and closing the valve is fixed via a compression spring 30.

The flag piece 25 has a convex piece 26 at the lower end, and is configured to abut on the inclined guide surface 24 formed on the base 21 and slide on the surface thereof. Also,
A guide surface 32 is also provided on the side on the printing area side,
A protrusion 33 projecting horizontally from the slider 22 is configured to slide on the surface thereof. By the operation of these two guide surfaces 24 and 32, the slider 22 can move up and down while maintaining a substantially horizontal posture.

That is, when the carriage 1 moves to the non-printing area side, the slider 22 moves obliquely upward in conjunction with the movement of the carriage 1 so that a cap member described later and the nozzle plate surface of the recording head come into close contact with each other. The capping operation is performed.

Cap unit mounting portion 3 of slider 22
6 is connected to the slider 22 by a spring 34 and a projection 35, and can rotate slightly about the projection 35. The cap units 37 and 38 are fixed to the slider 22 via compression springs 39, respectively.
Therefore, at the time of the capping operation, the adhesion between the cap and the nozzle plate is always kept good.

In each of the cap units 37 and 38, an ink suction port 18 is formed at the lower bottom thereof, and is connected to the suction pump 12 shown in FIG. 1 through a tube (not shown) having excellent ink resistance. ing. Each of the cap units 37 and 38 has an air opening 19 on one side thereof.
The other end of the tube 27 whose one end is connected to the valve unit 28.

With the above arrangement, when the carriage 1 moves to the non-printing area side, the carriage 1 comes into contact with the flag piece 25 as described above, whereby the slider 22 moves diagonally upward and the cap units 37, 38 Is in a capping state in which the nozzle plate surface of the recording head is closed. When the slider 22 is positioned on the non-printing area side (home position), the valve unit 28 comes into contact with the valve 29, and the air opening 19 is closed. By supplying a negative pressure from the suction pump 12 to the inside of the cap in this state, ink can be sucked from the nozzle openings of the recording head.

FIG. 4 is a sectional view showing a state in which the above-mentioned color recording head 8 is capped by a color head cap unit 38, and FIG. 5 is also a state in which the cap unit 38 is viewed from above. Is shown. FIG. 4 is a sectional view taken along line AA in FIG.

The color recording head 8 is located above the capping device during the cleaning operation and the flushing operation, and the nozzle plate 14 is capped by the capping device. Nozzle openings 15 are arranged in the nozzle plate 14, and each of the yellow, magenta, and cyan inks is ejected by the action of the piezoelectric element 13 arranged corresponding to each nozzle opening 15. .

The cap unit 38 is formed of a rectangular cap case 40 having an open upper surface and a flexible material having ink resistance, particularly an elastic member such as rubber, housed in the cap case 40. It comprises a cup-shaped cap member 16. The cap member 16 is formed so that its upper edge slightly protrudes from the cap case 40. Also, the cap member 16
An ink absorbing member 17 made of a porous material having excellent ink resistance and ink absorbing properties is inserted into the inner bottom portion so as to substantially cover the bottom surface.

An air opening 19 for opening the inside of the cap member 16 to the atmosphere is provided substantially at the center of one side surface of the cap member 16 so as to pass through the thick portion of the cap member 16. The through hole is formed with an inclination so as to gradually decrease toward the ink absorbing material 17, and the opening on the inner surface side of the cap member 16 is positioned above the surface of the ink absorbing material 17. Is formed. The air opening 19 is connected to the valve unit 28 via the tube 27 as described above.

Further, as shown in FIG. 5, an ink suction port 18 is formed substantially at the lower center of the cap member 16 and is connected to the suction pump 12 via a tube (not shown) as described above. .

Next, FIG. 6 shows an example of a control circuit mounted on the recording apparatus having the above-described configuration. Note that the recording heads 7 and 8, the ink cartridges 9 and 10, and the valve unit 28 (two valve units are shown as 28A and 28B in FIG. 6) which have already been described with reference to FIG. Therefore, the description is omitted.

In FIG. 6, reference numeral 50 denotes print control means, which generates bitmap data based on print data from a host computer of the recording apparatus, and generates a drive signal by a head drive means 51 based on the data. Thus, ink is ejected from the recording heads 7 and 8. The head driving unit 51 is configured to receive a flushing command signal and output a drive signal for a flushing operation to the recording heads 7 and 8 in addition to a drive signal based on print data.

Reference numeral 52 denotes cleaning control means.
Cleaning (hereinafter also referred to as CL) command detecting means 53,
The pump driving means 55 is controlled by signals from the post-CL elapsed time detecting means 54 and the cumulative opening time detecting means 59 to control each of the suction pumps 12A and 12B.

Here, the post-CL elapsed time detecting means 54
Immediately after the cleaning is performed by the cleaning control unit 52, a cleaning end signal is sent from the cleaning control unit 52, and the elapsed time after the cleaning is counted. The cumulative opening time detecting means 59 counts the accumulation of time during which the recording head has been released from the capping means for printing by the printing control means 50. When the recording head is released from the capping means, it counts the time. Start, stop printing when printing is completed and the recording head is capped. The cumulative opening time detecting means is reset by the cleaning control means 52 when cleaning is performed, or when a flushing command is issued from the print control means 50 after a long printing operation.

Reference numeral 56 denotes a flushing control unit, which is used immediately before the printing operation is started, or when a flushing command is output from the printing control unit 50 after the printing operation is continued for a certain period of time, or When a suction end signal is output and a time-up signal is output from a flushing suspension timer 57, which will be described later, or when the operation power of the printing apparatus is turned on, the print control unit 50 causes the print head 7 to print. , 8 are moved to a flushing position, that is, a capping position, and a predetermined number of ink droplets are ejected from nozzle openings of the recording head 7 or 8 in accordance with a sequence described later to prevent clogging and to eliminate clogging. It is.

The flushing hold timer 57 starts a timing operation at the end of the cleaning process, and measures the time corresponding to the time when the bubbles generated near the nozzle openings of the recording heads 7 and 8 in the cleaning process disappear naturally. At the stage when it is done, the time is up.

Reference numeral 58 in FIG. 6 indicates a cleaning command switch provided on a control panel or the like of the case, and is used by a user to eliminate clogging of the recording head.
By pushing on this, the CL command detecting means 53 is operated to execute the cleaning operation.

Next, the operation of the flushing operation in the printing apparatus configured as described above will be described based on each control flow shown in FIGS. First, FIG. 7 shows a control sequence applied to a printing apparatus having independent cap units 37 and 38 corresponding to the above-described black print head 7 and color print head 8, respectively.

Prior to the description of the control sequence, a description will be given of how the viscosity of the printing ink increases with time. As described above, as the printing ink, black ink and three color inks of yellow, magenta, and cyan are generally used. In recent years, in order to improve the print quality in color printing, particularly the color resolution, those in which light magenta and light cyan are added in addition to the three colors of normal color inks have been commercialized.

Here, in general, the degree of viscosity increase between the black ink and the color ink in the same elapsed time is larger for the black ink and smaller for the color ink. Therefore, the following description is based on the assumption that a printing ink having such characteristics is used.

As shown in FIG. 7, when the operation power is turned on (PW / ON) for the recording apparatus (in the figure, it is indicated as a printer and the same applies hereinafter), or while the operation power is turned on. Even if the printing operation is to be started by the printing control means 50, the color recording head 8 is moved to the position of the black head cap unit 37 in step S11.

This is achieved by the operation of the host motor mounted on the recording apparatus, whereby the carriage motor 3 is driven and the carriage 1 is moved via the timing belt 2.

In step S12, the color ink is flushed from the color recording head 8 into the black head cap unit 37 (first flushing step). This is achieved by receiving a timing signal from the host computer and applying a flushing command signal from the flushing control means 56 to the head drive means 51 as shown in FIG.

In this case, it is desirable that the discharge position of the color ink is a position where the nozzle openings face each other in a state where the black recording head is capped by the black cap in step S14 described later. Thus, the inside of the black head cap unit 37 is made wet by the color ink that is hardly thickened.

The head driving means 51, which has received the flushing command signal from the flushing control means 56, may control so as to simultaneously discharge all of the three color inks described above, or only one of the three color inks may be controlled. May be ejected. Further, in some cases, each time the control sequence shown in FIG. 7 is repeated, control may be performed such that yellow, magenta, and cyan are sequentially discharged. That is, these three color inks are
This is because there is no great difference in the degree of thickening in reality. If there is a difference in the degree of thickening between the three color inks, it is desirable to flush only the ink that is hardest to thicken.

In step S13, the black recording head 9 is moved to the black head cap unit 3.
Move to position 7. In this case, the color recording head 8 also moves to the position of the color head cap unit 38 at the same time. In this operation, the carriage motor 3 is driven by the operation of the host computer in the same manner as described above.
This is achieved by moving the carriage 1 via the timing belt 2.

Then, in step S14, cap units 37, 38 are attached to heads 7, 8, respectively.
(Capping step). As described in FIG. 3, when the carriage 1 moves to the non-printing area side, the slider 22 moves diagonally upward in conjunction with the movement of the carriage 1,
The cap member and the nozzle plate surface of the recording head come into close contact with each other, and a capping operation is performed.

After capping has been performed in this way, a standby state is set in step S15 (Wai).
t = wait step). During this time, it acts to soften or melt the thickened black ink adhering to the nozzle surface of the black ink recording head 7 and the like.

After the ink adhering to the nozzle surface of the black ink recording head 7 is softened or melted from the thickened state in this way, the black ink is ejected from the black ink recording head 7 in step S16. Flashing is performed (second flushing step). By the second flushing step, the recording head 7 for black ink is restored to perform a normal recording operation. At this time, flushing for discharging the color ink from the color ink recording head 8 may be performed at the same time.

At this time, the flushing operation also receives the timing signal from the host computer as described above,
Is applied by applying a flushing command signal.

Through the above control sequence, the flushing step at the time of turning on the operation power to the recording apparatus or before starting the printing operation is completed. In this case, the rise time from when the operation power supply is turned on to a state in which printing is possible is about 10 to 30 seconds, so that the printing operation can be performed in a much shorter time than when the cleaning operation is performed.

Next, the sequence shown in FIG. 8 shows an example in which the present invention is applied to a recording apparatus having a recording head having a black nozzle row and a color nozzle row, and one common cap unit corresponding to these nozzle rows.

In FIG. 8, when the printing power is to be started by the printing control means when the operation power is turned on to the recording apparatus, or even while the operation power is turned on, in step S21, the ink other than the ink which is most likely to thicken is used. 1 ink
Flushing into two common cap units (first
Flushing step). This is, for example, in a recording apparatus using black, yellow, magenta, and cyan as printing inks, all inks of yellow, magenta, and cyan or two or one of them are used as inks other than the ink that is most easily thickened. From the nozzle opening to the capping means.

In this case, it is desirable that the discharge position of the color ink is a position where the black nozzle opening faces in a state where the black nozzle is capped in step S22 described later. As a result, the common cap unit is made wet by color inks other than the ink that is most likely to thicken. In this case, it is preferable that the capacity of the ink cartridge corresponding to the printing ink ejected in the first flushing step is made larger than the ink cartridges of the other printing inks.

Then, in step S22, the recording head is capped by the cap unit (capping step). This capping action is the same as in step S14 in FIG.

Subsequently, a standby state is set in step S23 (standby step). This step S23 is also the same as step S15 described in FIG. 7, and during this time, acts to soften or melt the thickened black ink that has adhered to the nozzle surface of the black ink recording head.

Then, in step S24, ink other than the ink ejected in the first flushing step is flushed (second flushing step). The operation that occurs in this case is the same as that in step S16 described with reference to FIG. 7, and the second flushing step recovers the black ink recording head so as to perform a normal recording operation. At this time, flushing for discharging the color ink from the color ink recording head may be performed at the same time.

Next, the sequence shown in FIG. 9 was applied to a printing apparatus having a printing head having a black nozzle row and a color nozzle row, and one common cap unit corresponding to these nozzle rows, as described above. Here is another example. In the sequence shown in FIG. 9, step S31 is different from the sequence shown in FIG. 8, and the steps after step S32 are the same as the steps after step S22 described in FIG.

That is, in step S31, only the ink that hardly thickens is flushed in one common cap unit (first flushing step).
Any one of magenta and cyan inks is flushed into the capping unit from the nozzle openings. In this case, it is desirable that the ink ejection position where the viscosity is most difficult to increase is a position where the nozzle opening of the ink which is most easily thickened in the capped state in step S32 is opposed. Further, it is desirable that the ink cartridge capacity of the printing ink to be flushed in the first step is set to be larger than that of the other printing inks.

Subsequently, in step S34, the first
The ink other than the ink ejected in the flushing step is flushed (second flushing step). Therefore, by going through the sequence shown in FIG. 9, similarly to the case going through the sequence shown in FIG. 8, for example, the print head for black ink recovers to perform a normal printing operation.

Next, the sequence shown in FIG. 10 is applied to a recording apparatus in which capping devices for a black recording head and a color recording head are independently provided, and when a flushing-specific ink other than the printing ink is used. Is shown. As the flushing-dedicated ink, for example, glycerin diluted with pure water can be used. Then, a flushing-only head different from the recording head may be prepared for flushing the flushing-only ink, or, for example, one of two nozzle rows of the black head is used for flushing of the dedicated ink. You may do it.

In step S41 shown in FIG.
The head from which the flushing-only ink is ejected (the flushing-only head) is moved to the black cap unit position. Then, in step S42, the flushing-only ink is flushed into the black cap unit from the head from which the flushing-only ink is ejected. In this case, the ejection position of the flushing-only ink with respect to the cap unit is determined in step S4 described later.
In the state of being capped in 4, it is desirable that the position be opposed to the nozzle opening of the recording head that ejects the printing ink that is most likely to thicken, ie, the black ink.

Thus, the inside of the cap unit is made wet by the flushing-only ink. Subsequently, in step S43, the black ink head is moved to the cap unit position of the black ink head. Then, step S44 and the following step S4
In 5, the ink acts to soften or dissolve the thickened ink adhering to the black ink head. After the ink attached to the black ink recording head is softened or dissolved from the thickened state in this way, the printing ink is discharged from each recording head in step S46 (second flushing step). As a result, the recording head for black ink and the recording head for color ink are restored to perform a normal recording operation.

Next, the sequence shown in FIG. 11 includes a recording head having a black nozzle row and a color nozzle row,
An example is shown in which the present invention is applied to a printing apparatus configured with one common cap unit corresponding to these nozzle arrays, and uses flushing-specific ink in the same manner as described above.

The flushing-only ink used in this case is the same as that described in the sequence shown in FIG. To flush the dedicated ink, a flushing dedicated head different from the recording head may be prepared in the same manner as described above, or, for example, one of the two nozzle rows of the black head may be provided with the dedicated ink. May be used for flushing.

In step S51 shown in FIG.
The above-mentioned flushing-only ink is flushed in the cap unit (first flushing step).
In this case, the ejection position of the flushing-only ink (or the dissolving liquid) with respect to the cap unit is the nozzle opening of the printing ink which is most easily thickened in the state of being capped in step S52 described later, that is, the nozzle of the black ink. Desirably, the position is opposite to the opening.

As a result, the inside of the cap unit is made wet by the flushing-only ink, and step S
In step 52 and subsequent step S53, the ink acts to soften or melt the thickened ink adhering to the color nozzle row including the black nozzle row. After the ink attached to each nozzle row is softened or melted from the thickened state in this way, the printing ink is ejected from each nozzle row in step S54 (second flushing step), whereby the black ink is discharged. The nozzle row for printing and the nozzle row for color ink are restored to perform a normal printing operation.

The above description is based on the assumption that the degree of thickening in the same elapsed time is large for the black ink and small for the color ink. If the size is large for the ink, it goes without saying that the above description is reversed.

FIG. 12 shows the relationship between the desired number of inks to be ejected in the first flushing step executed in the printing apparatus of the present invention and the desired standby time in the standby step.

That is, the horizontal axis shown in FIG. 12 indicates the elapsed time (unit: time) after the cleaning, regardless of whether the power supply to the recording apparatus is on or off. The elapsed time is shown. The elapsed time after the cleaning is measured by the post-CL elapsed time detecting means 54 shown in FIG.

In the figure, T2 indicates the cumulative print time, which is the cumulative time (unit: time) during which the recording head has been released from the capping device for printing, which is the cumulative time shown in FIG. The time is measured by the open time detecting means 59.

The left vertical axis in FIG. 12 shows the ideal number of ejections (shots / nozzle) from the head in the first flushing step when the cumulative printing time T2 is used as a parameter. I have. The vertical axis on the right in FIG. 12 also indicates a case where the accumulated printing time T2 is also used as a parameter.
An ideal standby time (unit: second) in the standby step described above is shown.

Therefore, for example, when the elapsed time after CL is 40 hours and the accumulated printing time T2 is between 30 minutes and 1 hour, the relationship indicated by the long dashed line drawn substantially at the center of the figure is read. The number of ink ejections required in the first flushing step at this time is the number corresponding to the left vertical axis (for example, about 10000 shots / 1 nozzle). The standby time required in the standby step at this time is a time corresponding to the right vertical axis (for example, about 9 seconds).

In the above control, the flushing control means 56 takes in the time measured by the elapsed time after CL detecting means 54 and the cumulative opening time detecting means 59 in FIG. 6 and is stored in the flushing control means 56 as shown in FIG. The control can be performed by calculating the number of discharges and the standby time with reference to the relation table.

In the above description, a recording apparatus using black ink and three color inks is taken as an example. However, the same applies to a recording apparatus to which light magenta and light cyan are added. Needless to say, an operational effect can be obtained.

[0096]

As is apparent from the above description, in the ink jet recording apparatus and the flushing control method according to the present invention, the ink which is most likely to increase in viscosity among a plurality of types of printing inks in response to the flushing command signal. Is controlled so that only the ink other than the ink, or the ink that is hardly thickened, or the flushing-only ink other than the printing ink is discharged from the nozzle opening to the capping device, so that the inside of the capping device is in a wet state. be able to. Therefore, during the subsequent capping and predetermined standby time, it is possible to soften or dissolve the thickened ink adhering to the nozzle surface of the recording head that handles ink that tends to thicken, enabling normal printing by the flushing action It can be restored to a state.

Therefore, by executing this flushing operation when the power of the apparatus is turned on, the standby time after the power is turned on can be extremely reduced, and the occurrence of printing defects can be suppressed. A recording device can be provided. In addition, it is possible to provide a printing apparatus with high commercial value that can suppress unnecessary consumption of ink and suppress generation of noise due to driving of the suction pump when the power is turned on.

[Brief description of the drawings]

FIG. 1 is a perspective view of an ink jet recording apparatus to which the present invention is applied.

FIG. 2 is a perspective view showing an example of an actuator unit in a print head mounted on the printing apparatus shown in FIG.

FIG. 3 is a perspective view showing an example of a capping device mounted on the recording device shown in FIG.

4 is a cross-sectional view of the cap unit mounted on the recording apparatus of the present invention, taken along line AA in FIG.

5 is a top view of the cap unit shown in FIG.

FIG. 6 is a block diagram showing an example of a control circuit provided in the recording apparatus of the present invention.

FIG. 7 is a flowchart illustrating an example of a first control sequence of a flushing operation performed in the recording apparatus of the present invention.

FIG. 8 is a flowchart illustrating an example of a second control sequence of a flushing operation performed in the recording apparatus of the present invention.

FIG. 9 is a flowchart illustrating an example of a third control sequence of a flushing operation performed in the recording apparatus of the present invention.

FIG. 10 is a flowchart illustrating an example of a fourth control sequence of a flushing operation performed in the recording apparatus of the present invention.

FIG. 11 is a flowchart illustrating an example of a fifth control sequence of a flushing operation performed in the recording apparatus of the present invention.

FIG. 12 is a diagram illustrating a relationship between an ideal number of ink ejections during flushing and an ideal standby time in a standby step performed in the printing apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Carriage 2 Timing belt 3 Carriage motor 6 Recording paper 7 Black recording head 8 Color recording head 9 Black ink cartridge 10 Color ink cartridge 11 Capping device 12 Suction pump 13 Piezoelectric vibrator 14 Nozzle plate 15 Nozzle opening 16 Cap member 37 Cap unit for black head 38 Cap unit for color head 50 Printing control unit 51 Head driving unit 52 Cleaning control unit 53 CL command detection unit 54 Elapsed time after CL detection unit 55 Pump driving unit 56 Flushing control unit 57 Flash retention timer 58 Cleaning Command switch 59 Cumulative open time detection means

Claims (19)

[Claims] 1. A flushing system comprising: a plurality of ink jet recording heads for discharging ink droplets from nozzle openings; and a plurality of capping means corresponding to the respective recording heads for sealing the nozzle openings of the respective recording heads. A flushing control method for an ink jet recording apparatus configured to discharge an ink droplet from a nozzle opening to a capping means by a command signal, the method comprising the steps of: receiving a flushing command signal; A first flushing step of ejecting ink from a nozzle opening of at least one of the recording heads handling printing ink to capping means corresponding to the recording head handling printing ink which is easily thickened; The nozzle opening of the print head that handles printing ink A capping step of sealing with a capping unit that has received the ejected ink by a capping step; a standby step of waiting with a nozzle opening of a recording head that handles the printing ink that easily increases in viscosity sealed by the capping unit; A second flushing step of sequentially discharging the printing ink to the capping means from a recording head that handles printing ink other than the printing ink discharged in one flushing step, is sequentially executed. A flushing control method in a recording apparatus. 2. A flushing control method for an ink jet recording apparatus using black, yellow, magenta, and cyan as printing inks, the method comprising the steps of: All inks of yellow, magenta, and cyan or two of them or one of them
2. The flushing control method according to claim 1, wherein the ink is discharged from the nozzle opening to a capping unit corresponding to a recording head for black printing. 3. A flushing system comprising: a plurality of ink jet recording heads for ejecting ink droplets from nozzle openings; and a plurality of capping means corresponding to the respective recording heads sealing the nozzle openings of the respective recording heads. What is claimed is: 1. A flushing control method for an ink jet recording apparatus configured to discharge an ink droplet from a nozzle opening to a capping unit by a command signal. A first flushing step of ejecting ink from a nozzle opening of the recording head to a capping unit corresponding to the recording head that handles the printing ink that is most easily thickened; The nozzle opening receives the ink ejected by the first flushing step A capping step of sealing with a capping unit, a standby step of waiting with a nozzle opening of a recording head that handles the printing ink that is likely to increase in viscosity sealed by the capping unit, and a printing discharged in the first flushing step. And a second flushing step of ejecting the printing ink to the capping means from a recording head which handles the printing ink other than the printing ink. 4. A flushing control method for an ink jet recording apparatus using black, yellow, magenta, and cyan as printing inks, wherein yellow, magenta, and magenta printing inks which hardly increase in viscosity in response to the flushing command signal. 4. A flushing control method according to claim 3, wherein any one of cyan, cyan and cyan is ejected from said nozzle opening to a capping unit corresponding to a recording head for black printing. 5. In the first flushing step, the position of the nozzle opening of the recording head of the printing ink which is hardly thickened with respect to the capping unit receiving the ink ejection is printed in a state where the viscosity is easily increased in a sealed state in the capping step. The flushing control method according to any one of claims 1 to 4, wherein the control is performed such that nozzle openings of the recording head of the ink for use are opposed to each other. 6. A printing head for discharging ink droplets from a plurality of rows of nozzle openings for handling a plurality of types of printing inks, and capping means for sealing the nozzle openings of the printing head, wherein the nozzles are provided by a flushing command signal. What is claimed is: 1. A flushing control method for an ink jet recording apparatus configured to discharge ink droplets from an opening to a capping unit, wherein the printing method is configured to receive a flushing command signal, and to facilitate printing of a plurality of types of printing ink. A first flushing step of discharging ink for printing from the nozzle openings to the capping means other than the printing ink, a capping step of sealing the nozzle openings of the recording head by capping means, Waiting to wait while sealing with capping means And a second flushing step of ejecting printing ink other than the printing ink ejected in the first flushing step to the capping means in the first flushing step. Flushing control method. 7. A flushing control method for an ink jet recording apparatus using black, yellow, magenta, and cyan as printing inks, the printing method comprising: All inks of yellow, magenta, and cyan or two of them or one of them
7. The flushing control method in an ink jet recording apparatus according to claim 6, wherein different types of ink are ejected to the capping unit. 8. A printing head for ejecting ink droplets from a plurality of rows of nozzle openings for handling a plurality of types of printing inks, and capping means for sealing the nozzle openings of the printing head, wherein the nozzle is provided by a flushing command signal. A flushing control method for an ink jet recording apparatus configured to discharge ink droplets from an opening to a capping means, the printing method comprising: receiving a flushing command signal; The first method is to discharge ink only from the nozzle opening to the capping means through the nozzle opening.
A flushing step; a capping step of sealing a nozzle opening of the recording head with a capping unit; a waiting step of waiting while the nozzle opening of the recording head is sealed with a capping unit; and a discharge step in the first flushing step. A flushing control method in the ink jet recording apparatus, wherein a second flushing step of discharging a printing ink other than the printing ink to the capping means is sequentially performed. 9. A flushing control method for an ink jet recording apparatus using black, yellow, magenta, and cyan as printing inks, wherein the printing ink which hardly thickens in response to the flushing command signal is yellow, magenta, or magenta. 9. The flushing control method according to claim 8, wherein any one of cyan and cyan is ejected to the capping unit. 10. In the first flushing step, the position of the nozzle opening of the printing ink which is not easily thickened with respect to the capping unit is opposed to the nozzle opening of the printing ink which is easily thickened in the sealed state in the capping step. The flushing control method in the ink jet recording apparatus according to claim 6, wherein the flushing control method is performed so that the position of the flushing is controlled. 11. The ink cartridge according to claim 1, wherein the capacity of the ink cartridge corresponding to the printing ink ejected in the first flushing step is made larger than the ink cartridges of the other printing inks.
An ink jet recording apparatus according to any one of claims 6 to 9. 12. An ink jet recording head for discharging ink droplets from a nozzle opening, and a capping unit for sealing the nozzle opening of the recording head, wherein the flushing command signal causes the ink droplet to be discharged from the nozzle opening to the capping unit. An ink jet recording apparatus configured to eject the flushing-only ink other than the printing ink in response to the flushing command signal from the nozzle opening to the capping unit. An ink jet recording apparatus characterized by the above-mentioned. 13. A flushing device comprising a plurality of ink jet recording heads for discharging ink droplets from nozzle openings, and a plurality of capping means corresponding to each recording head for sealing the nozzle openings of each recording head. What is claimed is: 1. A flushing control method for an ink jet recording apparatus configured to discharge an ink droplet from a nozzle opening to a capping means by a command signal, the method comprising: receiving a flushing command signal and using a flushing-only ink other than a printing ink. A first flushing step of ejecting ink from a nozzle opening of the head to a capping means corresponding to a recording head which handles printing ink which is most easily thickened; and a nozzle of a printing head which handles printing ink which is most easily thickened. Discharge opening by first flushing step A capping step of sealing with a capping unit that has received ink, a standby step of waiting with the nozzle opening of a recording head that handles the printing ink that is susceptible to thickening sealed with the capping unit, and the first flushing step. 13. The flushing step according to claim 12, wherein a second flushing step of ejecting the printing ink to the capping means from a recording head that handles the printing ink other than the ejected flushing ink is sequentially executed. A flushing control method in an ink jet recording apparatus. 14. A printing head for ejecting ink droplets from a plurality of rows of nozzle openings for handling a plurality of types of ink, and capping means for sealing the nozzle openings of the printing head. A flushing control method for an ink jet recording apparatus configured to discharge ink droplets to a capping means, comprising: receiving a flushing command signal and using a flushing-only ink other than a printing ink among a plurality of types of ink. A first flushing step of discharging ink from the opening to the capping unit, a capping step of sealing the nozzle opening of the recording head by the capping unit, and waiting while the nozzle opening of the recording head is sealed by the capping unit. A waiting step; 13. The ink jet type apparatus according to claim 12, wherein a second flushing step of ejecting a printing ink other than the flushing-only ink ejected in the first flushing step to the capping means is sequentially executed. A flushing control method in a recording apparatus. 15. In the first flushing step, the position of the nozzle opening of the flushing-only ink with respect to the capping means for receiving the ink discharge is opposed to the nozzle opening of the printing ink which is likely to thicken in the sealed state in the capping step. The flushing control method in the ink jet type recording apparatus according to claim 13, wherein the control is performed so as to be performed at a predetermined position. 16. The ink-jet recording apparatus or ink-jet recording according to claim 12, wherein the composition component of the flushing-only ink is obtained by diluting glycerin with pure water. Flushing control method in the apparatus. 17. The flushing method according to claim 1, wherein the steps are sequentially executed when the operation power of the recording apparatus is turned on or before printing is started. Control method. 18. An ink jet recording head for discharging ink droplets from a nozzle opening, a capping unit for sealing the nozzle opening of the recording head, a suction pump for supplying a negative pressure to the capping unit, and the capping unit. Cleaning control means for suctioning ink from the nozzle openings of the recording head by the suction pump, cleaning-time elapsed time detecting means for detecting a time period after the cleaning is performed by the cleaning control means, A flushing control means for an ink jet recording apparatus, comprising: a cumulative opening time detecting means for detecting a cumulative time of opening from the capping means, wherein the number of ejected ink droplets in the first flushing step is determined by the cleaning Detected by the elapsed time detection means. 18. The flushing control of the ink jet recording apparatus according to claim 1, wherein the number is a number corresponding to the time length obtained and the time length detected by the cumulative open time detection means. Method. 19. An ink jet recording head for discharging ink droplets from a nozzle opening, a capping unit for sealing the nozzle opening of the recording head, a suction pump for supplying a negative pressure to the capping unit, and the capping unit. Cleaning control means for suctioning ink from the nozzle openings of the recording head by the suction pump, cleaning-time elapsed time detecting means for detecting a time period after the cleaning is performed by the cleaning control means, A flushing control unit of an ink jet recording apparatus comprising: a cumulative opening time detecting unit that detects an accumulation of a time that is released from the capping unit, wherein the standby time in the standby step is the post-cleaning elapsed time detecting unit. The time length detected by Flushing control method for an ink jet recording apparatus according to any one of claims 1 to 18, characterized in that a time corresponding to the time length detected by the accumulated open time detection means.