JPH1191121A - Method and apparatus for detecting residual quantity of liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform printing work smoothly by grasping the residual quantity of ink in an ink tank and the timing for replacing an ink cartridge accurately during printing work. SOLUTION: The residual liquid quantity detector in a liquid jet unit comprises a liquid tank 14 for storing liquid being supplied to a liquid jet head 11, a liquid cartridge 17 to be coupled removably with the liquid tank 14, and a pump 19 for supplying ink from the liquid cartridge 17 to the liquid tank 14. The residual liquid quantity detector further comprises a liquid level sensor 27 for making a decision that the quantity of liquid in the liquid tank 14 is lower than a specified value by detecting noncontact state of the liquid level of liquid in the liquid tank 14, and means for separating the liquid level of liquid in the liquid tank 14 by a specified interval from the liquid level sensor 27 when a decision is made the quantity of liquid in the liquid tank 14 is lower than a specified value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for detecting a remaining amount of liquid in a liquid ejecting apparatus having a replaceable liquid cartridge and a liquid tank for storing liquid to be supplied to a print head.

[0002]

2. Description of the Related Art Conventionally, in an ink jet printing apparatus provided with an exchangeable ink cartridge and an ink tank for storing ink to be supplied to a print head, the ink remaining in the ink tank during a printing operation on a print medium is performed. The ink level is monitored at any time using a liquid level sensor.If the remaining amount of ink in the ink tank is less than a predetermined amount, it is determined that the remaining amount of ink in the ink tank is small, that is, the ink tank is empty. Then, the printing operation is temporarily interrupted, ink is supplied from the ink cartridge into the ink tank, and the printing operation is resumed.

FIG. 5 shows a procedure of a conventional ink supply process for an ink tank during such a printing operation. That is, it is determined whether or not the amount of the ink stored in the ink tank in the step S1 is equal to or less than a predetermined amount, and the ink is stored in a larger amount than the predetermined amount, that is, the ink is sufficiently stored in the ink tank. If it is determined that the operation has been performed, the step of S1 is repeated every predetermined control cycle.

If it is determined in step S1 that the amount of ink stored in the ink tank is equal to or less than a predetermined amount, that is, it is determined that the ink tank is empty, the process proceeds to step S2 to perform a printing operation. Is temporarily interrupted and S
In step 3, a process of replenishing the ink in the ink cartridge to the ink tank is performed.

In step S4, it is determined again whether or not the amount of ink stored in the ink tank is equal to or less than a predetermined amount. Usually, after the ink is refilled in the ink tank in step S3. Since the ink has been sufficiently stored in the ink tank, the process proceeds to step S5 to resume the printing operation, and returns to step S1 to return to the state where the ink stored in the ink tank is stored. It is determined whether it is below the fixed amount.

In step S4, the amount of ink stored in the ink tank is equal to or less than a predetermined amount, that is, it is determined that the ink tank is empty even after replenishing the ink in the ink tank in step S3. In this case, since there is no ink in the ink cartridge, the process proceeds to step S6 to issue a warning for replacing the ink cartridge, for example, turning on a warning lamp or sounding a buzzer to prompt replacement of the ink cartridge. In step S7, it is determined whether or not the ink cartridge has been replaced.

If it is determined in step S7 that the ink cartridge has not been replaced yet, the process returns to step S6 to issue a warning for replacing the ink cartridge, but the ink cartridge has been replaced. If it is determined that the ink cartridge is present, the warning process for exchanging the ink cartridge is stopped as necessary, and the process returns to step S3 to perform a process of replenishing the ink tank with the ink in the ink cartridge.

[0008]

In the case of the conventional ink supply processing method for the ink tank during the printing operation as shown in FIG. 5, the ink stored in the ink tank in the step S1 is less than a predetermined amount. The positional relationship between the ink level in the ink tank and the detection terminal of the liquid level sensor in the state where it is determined that there is, is as shown in FIG. They are separated by a minute distance d _O.

In this state, when the printing operation is temporarily interrupted and the supply of ink from the ink cartridge to the ink tank is performed, the ink cartridge which is open to the atmosphere is temporarily sealed. After the process of replenishing ink from the ink tank into the ink tank, the inside of the ink tank is opened to the atmosphere again. For this reason, even if there is no ink in the ink cartridge, after the above-described ink supply process, the pressure in the ink tank is reduced due to the release to the atmosphere, so that the ink in the ink supply pipe connected to the ink tank is Is drawn back into the ink tank, and the liquid surface F of the ink 12 in the ink tank comes into contact with the detection terminal 28 of the liquid level sensor by capillary action from the state shown in FIG. It may be determined that the ink 12 is stored in the tank in an amount larger than a predetermined amount.

In other words, even if the ink cartridge has run out of ink, in the determination step of S4 after the ink replenishment process of step S3, it is considered that more ink is stored in the ink tank than the predetermined amount. Therefore, the presence or absence of the ink in the ink cartridge cannot be accurately grasped, and it is difficult to accurately inform the operator of the time of replacement. Moreover, following the step of S4, S5
The printing operation is resumed in the step S. Immediately after the resuming of the printing operation, it is determined in the step S1 that the amount of ink stored in the ink tank is less than a predetermined amount. It has been repeated,
Smooth printing cannot be performed.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to accurately grasp the amount of ink remaining in an ink tank during a printing operation so that a smooth printing operation can be performed, and it is possible to accurately notify an operator of a time to replace an ink cartridge. It is an object of the present invention to provide a liquid remaining amount detection method and a device therefor.

[0012]

According to a first aspect of the present invention, there is provided a method for detecting a remaining amount of liquid in a liquid discharging apparatus for replenishing a liquid tank storing liquid supplied to a liquid discharging head with liquid from a liquid cartridge. A step of determining that the liquid level in the liquid tank has become equal to or less than a predetermined amount by the liquid level position of the liquid level in the liquid tank and the liquid level sensor being in a non-contact state; A step of separating the liquid level position of the liquid in the liquid tank and the liquid level sensor by a predetermined amount when it is determined that the liquid level is equal to or less than the predetermined amount. is there.

According to a second aspect of the present invention, there is provided a liquid tank for storing a liquid supplied to a liquid discharge head, a liquid cartridge detachably connected to the liquid tank, and a liquid cartridge in the liquid cartridge. A liquid remaining amount detection device for a liquid ejection device having a liquid supply pump for supplying ink to a liquid tank, wherein the liquid remaining amount detection device is in a non-contact state with respect to a liquid level position of the liquid in the liquid tank. A liquid level sensor for determining that the liquid in the liquid tank is equal to or less than a predetermined amount; and a liquid surface level position of the liquid in the liquid tank when determining that the liquid in the liquid tank is equal to or less than a predetermined amount. A liquid remaining amount detecting device, comprising: means for separating a distance from the surface level sensor by a predetermined amount.

According to the present invention, when the liquid level of the liquid in the liquid tank and the liquid level sensor are brought into a non-contact state, it is determined that the liquid in the liquid tank is equal to or less than a predetermined amount, and The distance between the liquid level position and the liquid level sensor is separated by a predetermined amount.

Then, an operation of replenishing the liquid from the liquid cartridge to the liquid tank is performed, and thereafter, it is determined whether or not the liquid in the liquid tank is equal to or less than a predetermined amount by using a liquid level sensor. Here, when there is no liquid to be replenished in the liquid cartridge, the liquid is not replenished in the liquid tank, but the liquid level slightly rises due to pressure fluctuations in the liquid tank. However, since the distance between the liquid level position of the liquid in the liquid tank and the liquid level sensor is separated by a predetermined amount, it is determined that the liquid in the liquid tank is less than the predetermined amount, and it is necessary to replace the liquid cartridge. Sex is grasped.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In a liquid remaining amount detecting method according to a first embodiment of the present invention, a distance between a liquid surface position of a liquid in a liquid tank and a liquid surface level sensor is separated by a predetermined amount, and then the liquid cartridge is removed from the liquid cartridge. Refilling the liquid tank with a predetermined amount of liquid; and, after refilling the liquid tank with the liquid from the liquid cartridge, determining again whether the liquid in the liquid tank is equal to or less than the predetermined amount. Is also good.

The step of separating the distance between the liquid level position of the liquid in the liquid tank and the liquid level sensor by a predetermined amount may be discharging of a predetermined amount of liquid from the liquid discharging head. The ejection of a predetermined amount of liquid from the head
It may be associated with print processing on a print medium.

In the liquid remaining amount detecting device according to the second embodiment of the present invention, the means for separating the liquid level position of the liquid in the liquid tank from the liquid level sensor by a predetermined amount is a predetermined amount from the liquid discharge head. The operation for discharging the liquid may be performed, and in this case, the operation for discharging the predetermined amount of the liquid from the liquid discharge head may be performed along with the printing process on the print medium.

In the present invention according to the first and second embodiments described above, the liquid discharge head may have a discharge energy generating section for discharging liquid. In this case, the discharge energy generating section is It may have an electrothermal converter that generates thermal energy that causes film boiling in the liquid.

The liquid may be a processing liquid for adjusting the printability of the ink and / or the ink discharged onto the print medium.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment in which a liquid remaining amount detecting device according to the present invention is applied to an ink jet printing apparatus will be described with reference to FIGS.
Although described in detail with reference to FIG. 4, the present invention is not limited to such an embodiment, and can be applied to techniques in other fields that include similar problems.

As shown in FIG. 2 showing the concept of the ink supply system in this embodiment and FIG. 3 showing the structure in the sub-tank, the ink-jet printing apparatus of this embodiment And a communication port opening / closing valve 1 for temporarily storing and storing the air communication port 13 of the present invention.
5, an ink supply pipe 16 connected to the inkjet head 11 and the sub-tank 14, a supply pipe 18 connected to the sub-tank 14 and an ink cartridge 17 for storing the ink 12, and an ink provided in the middle of the supply pipe 18. An ink supply pump 19 for supplying the ink 12 in the cartridge 17 to the sub-tank 14;
An ink return pipe 20 connected to the ink cartridge 17 at both ends thereof for returning a predetermined amount or more of ink 12 in the sub-tank 14 to the ink cartridge 17, and an ink return pipe 20 connected at both ends to the inkjet head 11 and the sub-tank 14. Circulating pipe 21 for circulating ink 12 in ink jet head 11
The ink 12 in the sub-tank 14 provided in the ink circulation pipe 21 is discharged from a discharge port (not shown) of the inkjet head 11 or the ink supply pipe 1
Ink 1 supplied to inkjet head 11 from 6
2 through the ink circulation pipe 21 to the sub tank 14 again.
And an ink circulation pump 22 that can be returned to the inside.

A capping member 23 that covers a discharge port surface (not shown) where the discharge port of the inkjet head 11 opens.
And the ink cartridge 17, the waste ink collecting pipe 24
The waste ink collecting pipe 24 is provided with a waste ink collecting pump 25 for pumping the waste ink received by the capping member 23 to the ink cartridge 17.

The above-described pumps 19, 22, and 25 are tube pumps, respectively, and the operation and idle rotation of the ink supply pump 19 and the ink circulation pump 22 can be switched via a pressure release cam 26.

In the sub-tank 14, a pair of detection terminals 28 of an ink level sensor 27 are protruded downward, and a detection signal of the ink level sensor 27 is output to a control device (not shown).

During a printing operation on a print medium (not shown), the control device detects that the ink 12 is stored in the sub-tank 14 in an amount equal to or less than a predetermined amount, based on a detection signal from the ink level sensor 27 of the sub-tank 14, that is, detects no ink. Then, the printing operation is temporarily interrupted to shift to the ink replenishing process, the communication port opening / closing valve 15 is energized to close the air communication port 13, and the pressure release cam 26 is operated to operate the ink replenishment pump 19 for the suction operation. Thus, the ink 12 is supplied from the ink cartridge 11 into the sub tank 14. After the ink replenishment process, the position of the liquid level F of the ink 12 in the sub-tank 14 is detected again by the ink level sensor 27, and it is determined whether or not the amount of ink stored in the sub-tank 14 is equal to or less than a predetermined amount.

When the liquid level F of the ink 12 is located below the lower end of the detection terminal 28 as shown by the two-dot chain line in FIG. The apparatus determines that only a predetermined amount or less of ink 12 is stored in the sub-tank 14, that is, determines that there is no ink, switches the pressure release cam 26, and causes the ink supply pump 19 to move the ink 12 in the ink cartridge 17 into the sub-tank 14. Replenished. As a result, the ink 12 in the sub tank 14
Liquid level F rises to a connection portion with the ink return pipe 20.

The control device includes an ink level sensor 27
Upon receiving the detection signal from, the processing as shown in FIG. 1 is executed. That is, during the printing operation on the print medium (not shown), first, in step S11, the sub tank 1 is set based on the detection signal from the ink level sensor 27.
It is determined whether or not the ink 12 stored in the ink tank 4 is equal to or less than a predetermined amount, and it is determined that the ink 12 is stored in an amount larger than the predetermined amount, that is, the ink 12 is sufficiently stored in the sub tank 14. In this case, the step of S11 is repeated every predetermined control cycle.

In step S11, the sub tank 14
If it is determined that the ink 12 stored in the sub tank 14 is equal to or less than the predetermined amount, that is, it is determined that there is no ink 12 in the sub tank 14, the printing operation is continued as it is, and the process proceeds to step S12, where the ink 12 is stored in the sub tank 14. After determining that there is no print job, it is determined whether or not a printing operation has been performed on a predetermined number of print media.

If it is determined in step S12 that there is no ink 12 in the sub-tank 14, and it is determined that the printing operation on a predetermined number of print media has not been completed, this step S12 is repeated. here,
The printing operation for a predetermined number of print media is completed, that is, the liquid level of the ink 12 in the sub tank 14 and the ink level sensor 27 detected in step S11.
The distance d _{O from} the lower end of the detection terminal 28 is separated by a predetermined amount d _R, and from the position of the liquid level F indicated by the two-dot chain line in FIG. 4 detected in the step of S11 to the liquid level F ′ indicated by the solid line If it is determined that the ink 12 has been further consumed, the process proceeds to step S13 to temporarily stop the printing operation, and the ink supply process is performed at step S14.

After the ink replenishment process, in step S15, it is again determined based on the detection signal from the ink level sensor 27 whether or not the amount of the ink 12 stored in the sub tank 14 is less than a predetermined amount. If it is determined that the ink 12 is stored more than the predetermined amount, that is, if the ink 12 is sufficiently stored in the sub tank 14, the process proceeds to S1.
The process proceeds to step 6 to resume the printing operation.

In step S15, the sub tank 1
If it is determined that the ink 12 stored in the ink cartridge 4 is equal to or less than the predetermined amount, that is, it is determined that the ink 12 is not present in the ink cartridge 17, the process proceeds to step S17 and the operator is prompted to replace the ink cartridge 17. Give some warnings. Then, it is determined in step S18 whether or not the replacement of the ink cartridge 17 has been completed, and the above-described warning is continuously output until the replacement of the ink cartridge 17 is completed.

If it is determined in step S18 that the replacement of the ink cartridge 17 has been completed, the process returns to step S14 to perform the ink supply process again.

As described above, when the necessity of ink replenishment is recognized by the ink level sensor 27, the printing operation is further continued from this state, and a predetermined amount of the ink 12 in the sub-tank 14 is used. 1
2 is lowered from the liquid level F to the liquid level F ', it is possible to prevent erroneous detection due to the liquid level rise as shown in FIG. Can be planned.

If the ink supply in the ink cartridge 17 is small and the printing operation is resumed after the ink replenishment process, the determination that there is no ink 12 in the sub tank 14 is immediately output. Therefore, if the above-described step of S12 is performed as it is, there is a possibility that a problem such as a printing failure may occur.
In order to prevent such inconvenience, it is determined in step S19 whether or not a print operation has been performed on a predetermined number of print media after the restart of the print operation. If it is determined that the printing work for the
In step 0, it is determined whether or not the amount of the ink 12 stored in the sub tank 14 is equal to or less than a predetermined amount based on the detection signal from the ink level sensor 27.

The amount of the ink 12 stored in the sub-tank 14 is larger than a predetermined amount.
If it is determined that there is enough ink 12 in S19, S19
It is determined whether or not the printing operation on a predetermined number of print media has been performed after the printing operation is resumed by returning to the step. However, if it is determined that the amount of the ink 12 stored in the sub-tank 14 is equal to or less than the predetermined amount, that is, if there is almost no remaining ink in the ink cartridge 17 by the ink replenishment process in step S14, the process proceeds to S1.
The process proceeds to step 7, and a warning is issued to urge replacement of the ink cartridge 17.

On the other hand, in the step S19, it was determined that the printing operation for a predetermined number of print media could be performed after the printing operation was restarted, that is, it was determined that the ink 12 to be supplied to the sub tank 14 was sufficient in the ink cartridge 17. In this case, the flow returns to step S11 to determine again whether or not the amount of ink 12 stored in the sub-tank 14 is equal to or less than a predetermined amount based on the detection signal from the ink level sensor 27. Of remaining ink 12 and ink cartridge 1
Know exactly when to replace 7.

It should be noted that the present invention includes a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for discharging a liquid, particularly in an ink jet system. This provides an excellent effect in a printing apparatus of a type in which a change in the state of a liquid is caused by thermal energy. According to such a method, it is possible to achieve higher density and higher definition of the print.

The typical configuration and principle are described in, for example, US Pat. No. 4,723,129 and US Pat.
It is preferable to use the basic principle disclosed in Japanese Patent Application No. 0796. This method can be applied to both the so-called on-demand type and the continuous type. In particular, in the case of the on-demand type, it is arranged corresponding to the sheet or the flow path holding the liquid. By applying to the electrothermal transducer at least one drive signal corresponding to print information and providing a rapid temperature rise exceeding nucleate boiling, heat energy is generated in the electrothermal transducer and a liquid ejection head, In this case, film boiling occurs on the heat-acting surface of the ink jet head, and as a result, bubbles in the liquid corresponding to this drive signal on a one-to-one basis are effective. By the growth and shrinkage of the bubble, the liquid is discharged through the discharge port to form at least one droplet. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of the liquid having particularly excellent responsiveness can be achieved, which is more preferable. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in U.S. Pat. No. 4,313,124 relating to the rate of temperature rise of the heat acting surface are adopted, more excellent printing can be performed.

The structure of the ink jet head is a combination of a discharge port, a flow path, and an electrothermal converter (a linear liquid flow path or a right-angled liquid flow path) as disclosed in the above-mentioned specifications. In addition, the present invention includes a configuration using U.S. Pat. No. 4,558,333 or U.S. Pat. No. 4,459,600, which discloses a configuration in which a heat acting portion is arranged in a bent region. In addition, JP-A-59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters, and an aperture for absorbing a pressure wave of thermal energy is provided. JP-A-59-138461 which discloses a configuration corresponding to a discharge section
The effects of the present invention are effective even if the configuration is based on the above publication. That is, according to the present invention, printing can be performed reliably and efficiently regardless of the form of the inkjet head.

Further, the present invention can be effectively applied to a full line type ink jet head having a length corresponding to the maximum width of a print medium that can be printed by a printing apparatus. Such an ink-jet head may have a configuration that satisfies its length by a combination of a plurality of ink-jet heads, or a configuration as one integrally formed ink-jet head. Conversely, even for a serial type, the ink jet head is fixed to the main body of the apparatus, or is exchangeable when it is attached to the main body of the apparatus so that it can be electrically connected to the main body of the apparatus or supplied with liquid from the main body of the apparatus. The present invention is also effective when a chip type ink jet head is used.

Further, it is preferable to add a discharge recovery means of the ink jet head, a preliminary auxiliary means, and the like as the constitution of the liquid discharge apparatus of the present invention since the effect of the present invention can be further stabilized. Specific examples include capping means for the ink jet head, cleaning means, pressurizing or sucking means, an auxiliary heating element using an electrothermal transducer, another heating element, or a combination thereof. Examples of the heating unit include a preliminary ejection unit that performs ejection different from printing.

The type and number of ink jet heads to be mounted are, for example, not only one provided for a single color ink but also a plurality of inks having different print colors and densities. A plurality may be provided. That is, for example, the print mode of the printing apparatus is not limited to the print mode of only the mainstream color such as black, and may be either an integrated ink jet head or a combination of a plurality of ink jet heads. The present invention is also very effective for an apparatus provided with at least one of the full-color print modes using mixed colors. In this case, a processing liquid for adjusting the printability of the ink according to the print medium, for example, a printability improving liquid for preventing ink bleeding or improving water resistance, etc., is ejected from the inkjet head to the print medium. It is also effective.

In addition, in the embodiment of the present invention described above, a material which solidifies at room temperature or lower and softens or liquefies at room temperature may be used, or the liquid itself may be heated to 30 ° C. or higher in an ink jet system. In general, the temperature is controlled within the range of not more than ° C. and the temperature is controlled so that the viscosity of the liquid is in a stable ejection range. In addition, in order to positively prevent the temperature rise due to thermal energy by using it as the energy of the state change from the solid state to the liquid state, or to prevent the evaporation of the liquid,
What solidifies in a standing state and liquefies by heating may be used. In any case, the liquid is liquefied by the application of the thermal energy according to the print signal, and is liquefied only by the application of the thermal energy, such as the one from which the liquid is ejected and the one which already starts to solidify when reaching the print medium. The present invention can be applied to the case of using a material having a property. The liquid in such a case is disclosed in JP-A-54-56847.
JP-A No. 60-71260 or Japanese Patent Application Laid-Open No. Sho 60-71260, in a state in which the porous sheet is held as a liquid or solid substance in a concave portion or a through hole and faces the electrothermal converter. Is also good. In the present invention,
The most effective one for each of the above-mentioned liquids is to execute the above-mentioned film boiling method.

In addition, the form of the liquid ejection apparatus according to the present invention is not only used as an image output terminal of an information processing apparatus such as a computer, but also a copying apparatus combined with a reader or the like, and further, a facsimile having a transmission / reception function. An apparatus or a textile printing apparatus may be used.

[0046]

According to the present invention, when the liquid level in the liquid tank and the liquid level sensor are brought into a non-contact state, it is determined that the liquid in the liquid tank has fallen below a predetermined amount. The distance between the liquid level position of the liquid in the liquid tank and the liquid level sensor is set to a predetermined distance, so that erroneous detection by the liquid level sensor due to a slight rise in the liquid level position is prevented and smooth. Printing work can be performed.

After the distance between the liquid level position of the liquid in the liquid tank and the liquid level sensor is separated by a predetermined amount, a predetermined amount of liquid is supplied from the liquid cartridge to the liquid tank, and then the liquid in the liquid tank is refilled. When it is determined again whether or not is less than the predetermined amount, it can also be accurately grasped whether or not the liquid to be supplied to the liquid tank is in the liquid cartridge.

In this case, a predetermined amount of liquid is ejected from the liquid ejection head for the printing process on the print medium, thereby separating the liquid level of the liquid in the liquid tank from the liquid level sensor by a predetermined amount. If you do so, you can minimize the interruption of printing work,
Printing can be performed more smoothly.

[Brief description of the drawings]

FIG. 1 is a flowchart of an embodiment in which a liquid remaining amount detection method according to the present invention is applied to an ink jet printing apparatus.

FIG. 2 is a perspective view illustrating an appearance of an ink supply system in the embodiment illustrated in FIG.

FIG. 3 is a cross-sectional view schematically illustrating an internal structure of an ink tank in FIG.

FIG. 4 is an enlarged view of an arrow IV portion in FIG. 3 showing the case where the amount of ink in the ink tank is equal to or less than a predetermined amount.

FIG. 5 is a flowchart illustrating an example of a conventional liquid remaining amount detection method.

FIG. 6 is a diagram showing a positional relationship between a liquid level and a liquid level sensor when the liquid in the liquid tank is equal to or less than a predetermined amount.
It is a similar enlarged view.

FIG. 7 is an enlarged view similar to FIG. 6, showing a state in which the liquid level sensor performs erroneous detection.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 Ink jet head 12 Ink 13 Atmospheric communication port 14 Subtank 15 Communication port opening and closing valve 16 Ink supply pipe 17 Ink cartridge 18 Supply pipe 19 Ink supply pump 20 Ink return pipe 21 Ink circulation pipe 22 Ink circulation pump 23 Capping member 24 Waste ink collection Tube 25 Waste ink recovery pump 26 Pressure release cam 27 Ink level sensor 28 Detection terminal F, F 'Ink liquid level d _O , d _R Distance between the lower end of ink level sensor detection terminal and ink liquid level

Claims (13)

[Claims] 1. A method for detecting a remaining amount of liquid in a liquid ejection apparatus for replenishing a liquid tank storing liquid to be supplied to a liquid ejection head with liquid from a liquid cartridge, the liquid level and the liquid level of the liquid in the liquid tank. A step of determining that the liquid in the liquid tank is equal to or less than a predetermined amount by a non-contact state with the level sensor; and determining that the liquid in the liquid tank is equal to or less than a predetermined amount. A step of separating a distance between the liquid level position of the liquid inside the liquid level sensor and the liquid level sensor by a predetermined amount. 2. A method for replenishing the liquid tank with a predetermined amount of liquid from the liquid cartridge after a predetermined amount of space between the liquid level position of the liquid in the liquid tank and the liquid level sensor. 2. The method according to claim 1, further comprising, after refilling the liquid tank with the liquid from the liquid cartridge, determining again whether the liquid in the liquid tank is equal to or less than a predetermined amount. Amount detection method. 3. The method according to claim 2, wherein the step of separating the liquid level in the liquid tank from the liquid level position by a predetermined amount is discharging a predetermined amount of liquid from the liquid discharge head. The liquid remaining amount detection method according to claim 1 or 2, wherein 4. The liquid remaining amount detecting method according to claim 3, wherein the discharge of the predetermined amount of liquid from the liquid discharge head is accompanied by a printing process on a print medium. 5. The liquid remaining amount detecting method according to claim 1, wherein the liquid discharge head includes the discharge energy generating unit for discharging a liquid. 6. The liquid remaining amount detecting method according to claim 5, wherein the discharge energy generating section has an electrothermal converter for generating thermal energy for causing film boiling of the liquid. 7. The liquid according to claim 1, wherein the liquid is a processing liquid for adjusting printability of ink and / or ink ejected on a print medium. Remaining amount detection method. 8. A liquid tank for storing a liquid supplied to a liquid discharge head, a liquid cartridge detachably connected to the liquid tank, and a refill for supplying ink in the liquid cartridge to the liquid tank. A liquid remaining amount detection device for a liquid ejection device having a liquid supply pump, wherein the liquid in the liquid tank is equal to or less than a predetermined amount by being in a non-contact state with respect to a liquid level position of the liquid in the liquid tank. A liquid level sensor for determining that the liquid level in the liquid tank is equal to or less than a predetermined amount, and determining the distance between the liquid level position of the liquid in the liquid tank and the liquid level sensor by a predetermined amount. And a means for separating the remaining amount of liquid. 9. A means for separating a liquid level position of the liquid in the liquid tank from the liquid level sensor by a predetermined amount,
The liquid remaining amount detecting device according to claim 8, wherein an operation of discharging a predetermined amount of liquid from the liquid discharging head is performed. 10. The liquid remaining amount detecting device according to claim 9, wherein the operation of discharging a predetermined amount of liquid from the liquid discharging head is accompanied by a printing process on a print medium. 11. The liquid remaining amount detecting device according to claim 8, wherein the liquid discharge head includes the discharge energy generating section for discharging a liquid. 12. The liquid remaining amount detecting device according to claim 11, wherein the discharge energy generating section has an electrothermal converter for generating thermal energy for causing film boiling of the liquid. 13. The liquid processing apparatus according to claim 8, wherein the liquid is a processing liquid for adjusting printability of ink and / or ink ejected to a print medium.
3. The liquid remaining amount detection device according to any one of 2.