JP2002321390A - Ink jet recording device, and device and method for feeding ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording device, and a device and a method for feeding ink, which can constantly and stably supply the ink by maintaining negative pressure in the ink tank. SOLUTION: The ink of a quantity required for generation of the prescribed negative pressure in the ink tank 54 is discharged out of a recording head 10 while an inflow of air into the ink tank 54 is limited by an air inflow adjusting part 62.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ink jet recording apparatus, an ink supply apparatus, and an ink supply method capable of stably supplying ink to a recording head.

[0002]

2. Description of the Related Art In an ink jet recording apparatus, it is necessary to stably supply ink from an ink tank to an ink jet recording head so as not to cause deterioration of recording performance due to ink leakage from a recording head or excessive supply of ink.

Conventionally, as a method for realizing a stable supply of ink, there has been proposed a method of adjusting the pressure in an ink tank by a pressure adjusting means so as to prevent a water head pressure of the ink from being applied to a recording head. I have. As such a pressure adjusting means, for example, those having a valve structure as described in Japanese Utility Model Publication No. 56-53012 and Japanese Utility Model Application Laid-Open No. 55-61665 can be adopted.

[0004]

However, when the pressure inside the ink tank is adjusted to a predetermined negative pressure by the pressure adjusting means provided in the ink tank, particularly when the recording apparatus is stopped for a long period of time, the pressure adjustment is performed. The negative pressure in the ink tank may gradually escape to the outside from any part of the means or the ink tank, and the negative pressure in the ink tank may not be properly maintained. In this manner, when the pressure in the ink tank rises to near the atmospheric pressure, the head pressure of the ink is applied to the print head, and the ink leaks from the print head and the printing performance deteriorates due to an excessive supply of ink. There is a risk.

An object of the present invention is to provide an ink jet recording apparatus, an ink supply apparatus, and an ink supply method that can always supply ink stably while maintaining a negative pressure in an ink tank.

[0006]

According to the present invention, there is provided an ink jet recording apparatus comprising: a recording head capable of discharging ink; and an ink tank for supplying the ink contained therein to the recording head with the inflow of air. In an ink jet recording apparatus that performs recording using, a restricting unit that restricts the flow of air into the ink tank, and from the recording head,
And an ink discharging means for discharging an amount of ink required to generate a predetermined negative pressure in the ink tank.

An ink supply apparatus according to the present invention supplies an ink contained in an ink tank to a recording head capable of discharging the ink with the inflow of air. The ink jet recording apparatus further includes a restricting unit that restricts the inflow, and an ink discharging unit that discharges an amount of ink required to generate a predetermined negative pressure into the ink tank from the recording head.

According to the ink supply method of the present invention, there is provided an ink supply method for supplying ink contained in an ink tank to a recording head capable of ejecting ink with the inflow of air. The method is characterized in that an amount of ink required to generate a predetermined negative pressure in the ink tank is discharged from the recording head while restricting the inflow.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 5 is a perspective view for explaining a schematic configuration of a recording apparatus to which the present invention can be applied. The printing apparatus 50 of this embodiment is a printing apparatus of a serial scan system, and a carriage 53 is guided by guide shafts 51 and 52 so as to be movable in a main scanning direction indicated by an arrow A. Carriage 53
Is reciprocated in the main scanning direction by a driving force transmission mechanism such as a carriage motor and a belt for transmitting the driving force. The recording head 10 (not shown in FIG. 5) and an ink tank 54 for supplying ink to the recording head 10 are mounted on the carriage 53. The recording head 10 and the ink tank 54 may constitute an ink jet cartridge. The recording head 10 can discharge the ink supplied from the ink tank 54 from the discharge port based on the drive signal, and various methods can be adopted as the method of discharging the ink. For example, a method in which bubbles are generated in ink by thermal energy generated by an electrothermal transducer (heater) and the ink is ejected using the foaming energy can be adopted. In addition, a recording head 10 of an arbitrary ejection method such as a method of ejecting ink using a piezo element can be adopted. A sheet P as a recording medium is inserted into an insertion port 5 provided at the front end of the apparatus.
After being inserted from 5, the transport direction is reversed,
The sheet is conveyed by the feed roller 56 in the sub-scanning direction indicated by the arrow B. The recording apparatus performs a recording operation in which the recording head 10 is moved in the main scanning direction and ink is ejected toward the print area of the paper P on the platen 57, and the paper P is moved in the sub-scanning direction by a distance corresponding to the recording width. The image is sequentially recorded on the paper P by repeating the transport operation for transporting the image to the paper P.

The recording head 1 mounted on the carriage 53 is located at the left end in FIG.
A recovery system unit (recovery processing means) 58 facing the formation surface of the discharge port 0 is provided. The recovery system unit 58 is provided with a cap capable of capping the ejection port of the recording head 10, a suction pump capable of introducing a negative pressure into the cap, and the like. , A recovery process (also referred to as a “suction recovery process”) is performed so that the ink is sucked and discharged from the discharge ports, and a good ink discharge state of the recording head 10 is maintained.
In addition, by discharging ink that does not contribute to the image from the discharge port toward the inside of the cap, the recording head 10 is discharged.
A recovery process (also referred to as an “ejection recovery process”) can be performed to maintain a good ink ejection state. The upper position of the recovery system unit 58 is set with the recording head 10 as a home position. When the recording head 10 is waiting at the home position, the cap of the recovery system unit 58 caps the ejection port, thereby protecting the ejection port and preventing evaporation of ink from the ejection port. You. When the recording apparatus uses a plurality of colors of ink, it is preferable that the recording apparatus be configured so that the recovery processing can be performed for each ink color.

FIG. 6 is a schematic block diagram of a control system of a printing apparatus to which the present invention can be applied. In FIG.
U100 executes control processing of the operation of the recording apparatus, data processing, and the like. The ROM 101 stores programs for the processing procedures and the like, and the RAM 102 is used as a work area or the like for executing the processing. The ejection of ink from the recording head 10 is performed via a head driver 10A. For example, the recording head 10
In the case where a method of ejecting ink using the heat generated by the electrothermal transducer is adopted, the CPU 1
00 represents the drive data (image data) and the drive control signal (heat pulse signal) of the heating element 19 as the head driver 1.
0A will be supplied. The CPU 100 controls a carriage motor 103 for driving the carriage 53 in the main scanning direction via a motor driver 103A. F motor 10
4 is controlled via the motor driver 104A. Also,
The CPU 100 controls the recovery system unit 58 to perform the above-described recovery process of the recording head 10 and also controls the recovery system unit 58 to perform a negative pressure generation process in the ink tank 54 described later.

FIG. 1 is a schematic structural view of an ink tank 54, and supplies ink I contained in the ink tank 54 to a recording head 10 from a supply pipe 61. On the lower surface of the recording head 10,
An ejection port for ejecting ink downward is formed. The ink tank 54 is provided with an air inflow / outflow adjustment section (restriction means) 62 for adjusting the inflow / outflow of air between the inside and the outside of the ink tank 54. This adjustment unit 62
Are provided at the air inlet / outlet formed in the ink tank 54 to limit the amount of air flowing from the outside into the ink tank 54 and the amount of air flowing from the inside of the ink tank 54 to the outside. As this adjusting means, for example, a filter structure having a resistance against inflow of air from the outside into the ink tank 54 and a resistance against air outflow from inside the ink tank 54 to the outside can be adopted. The adjusting unit 62 of this example limits the inflow / outflow speed V1 of the air based on the relationship with the ink consumption speed V2, as described later.

As described above, the adjusting section 62 restricts the flow of air from the outside into the ink tank 54, so that a predetermined amount of ink is discharged from the discharge port of the recording head 10 by a negative pressure generation process described later. And the ink tank 54
Negative pressure is generated in the inside. That is, when the liquid level of the ink I in the ink tank 54 drops by the amount of ink discharged by the negative pressure generation processing, the adjusting unit 62 limits the inflow of air flowing into the ink tank 54 from outside. Then, a negative pressure is generated in the ink tank 54. The ink tank 54 is used while keeping the inside thereof at a negative pressure, and supplies ink to the recording head 10 through the supply pipe 61 in accordance with the amount of ink consumed by the recording head 10, that is, the amount of ink discharged from the discharge port. . The adjusting unit 62 of the present example controls the air outflow / inflow speed V1 (μcc / μm) so that the negative pressure in the ink tank 54 is maintained even by such ink consumption.
sec) is limited to the ink consumption speed V2 (μcc / sec) or less, that is, V1 ≦ V2.

Ink consumption speed V2 (μcc / sec)
Is derived by the following equation (1). In the following formula (1), A (ng) is the amount of ink ejected per nozzle, N is the number of nozzles in the recording head 10, H (Hz) is the driving frequency of the recording head 10, and D is the average recording duty per unit area. It is. The average recording duty D differs depending on the use condition of the recording apparatus, and can be set to, for example, about 2%, that is, about (0.02). V2 = A × N × H × D × 10 ^-3 (1) The adjusting unit 62 restricts the flow rate V1 of the air to be equal to or less than the ink consumption amount V2 of the above equation (1), and thereby controls the inside of the ink tank 54. Negative pressure can be maintained. Further, the adjusting unit 62 determines the ink consumption V2 of the above equation (1) with respect to at least the flow rate of air from the outside into the ink tank 54.
The outflow of air from the inside of the ink tank 54 to the outside is not particularly limited.

Next, the negative pressure generation processing will be described. The negative pressure generation process is a process of discharging a predetermined amount of ink from the ejection openings of the print head 10 before the start of the printing operation. This negative pressure generation processing may be performed, for example, when the power of the printing apparatus is turned on, before the printing operation is started after the printing apparatus has been stopped for a predetermined time or more, or when the negative pressure in the ink tank 54 has become equal to or lower than a predetermined value. Is detected. The sensor for detecting the negative pressure in the ink tank 54 is
An ink tank 54 can be provided. In addition, the discharge of a predetermined amount of ink from the discharge port in the negative pressure generation processing can be performed in the same manner as the above-described suction recovery processing or discharge recovery processing. That is, similarly to the suction recovery process described above, by introducing a negative pressure into the cap of the recovery system unit 58 covering the discharge port, a predetermined amount of ink can be suctioned and discharged from the discharge port. Alternatively, similarly to the above-described ejection recovery processing, a predetermined amount of ink that does not contribute to an image can be ejected from the ejection port toward the inside of the cap of the recovery system unit 58. When the recording apparatus uses a plurality of colors of ink, it is preferable to perform such negative pressure generation processing independently for each ink color.

The discharge amount C1 (mm ³ ) of the ink in the negative pressure generation process is set to be equal to or more than the discharge amount C2 (mm ³ ) derived by the following equation (2), that is, C1 ≧ C2. In the following equation (2), S (mm ² ) is the cross-sectional area of the bottom surface of the ink tank 54, and the amount of air in the ink tank 54 is S (H1−h) mm ³ . Also,
One atmosphere is 10340 mmAq. C2 = {S. (H1-h). (H + H2)} / (10340 + H1-h) (2) In the above equation (2), (h + H2) is the recording head 10
"0", which is the head of the ink I applied to the ejection port
The amount of discharged ink required to generate a negative pressure (hereinafter, referred to as “required negative pressure”) required in the ink tank 54 is C2. That is, when the ink of the discharge amount C2 is discharged from the ink tank 54, [10340 · C2 / {S (H1-h)}] is stored in the ink tank 54.
When a negative pressure of (mmAq) is generated and the negative pressure is set as a required negative pressure, the following equation (2a) is obtained. 10340 · C2 / {S (H1-h)} = h + H2- (C / S) (2a) In the above equation (2a), the required negative pressure is {h + H2- (C
/ S)｝ is the decrease in water head due to ink discharge (-
C / S). This decrease (-C / S) may be ignored. By rearranging the above equation (2a), the above equation (2) is obtained. In the above equation (2), the denominator (H1
-H) may be neglected as in the following equation (2) 'since its influence is about 0.5% of 1 atm. C2 = {S (H1−h) (h + H2)} / 10340 (2) ′ As described above, the discharge amount C1 (mm ³ ) of the ink in the negative pressure generation processing is calculated by the above equation (2) or (2). 'Is set to the discharge amount C2 (mm ³ ) or more. By performing the negative pressure generation process, a negative pressure is generated in the ink tank 54 such that the water head pressure of the ink is not applied to the ejection openings of the recording head 10. When calculating the emission amount C2,
The unknown value h can be directly detected using a level sensor that detects the liquid level of the ink I in the ink tank 54. Alternatively, it is also possible to calculate the ink consumption of the print head 10 from print data, the number of times of recovery processing, and the like, and then indirectly obtain the value h based on the calculated value.

In the above equation (2) ', the discharge amount C2
Is differentiated by h and set to “0”, h when the discharge amount C2 becomes maximum is expressed by the following equation (3). That is, when the liquid level of the ink I in the ink tank 54 is positioned at half the height of the total head difference (H1 + H2), the discharge amount C2 becomes the largest. h = (H1 + H2) / 2 (3) By setting h = H1 in the above equation (2), the discharge amount C2 when the ink in the ink tank 54 is filled with the ink is expressed by the following equation (4). Is represented by The discharge amount C2 in the following equation (4) is the discharge amount C2 when a new ink tank 54 that is full is used. C2 = S (H1 + H2) / 10340 (4) As described above, before starting the first printing operation using the new ink tank 54 that is full, the negative pressure is waited after the power of the printing apparatus is turned on, for example. Perform generation processing and calculate the above equation (4).
By discharging the ink by the discharge amount C1 equal to or larger than the discharge amount C2, a negative pressure can be generated in the ink tank 54 such that the water head pressure of the ink is not applied to the discharge port of the recording head 10. Thereafter, by executing the printing operation, ink is supplied from the ink tank 54 to the printing head 10 with the consumption of ink by the printing head 10. At this time, the negative pressure in the ink tank 54 is maintained by restricting the inflow speed of the air to the ink consumption amount V2 of the above equation (1) by the adjustment unit 62.

Before starting the recording operation after the recording apparatus has been suspended for a predetermined time or more, for example, the power supply of the recording apparatus is turned on, a negative pressure generation process is performed, and the above equation (2) or (2) 'is performed.
By discharging the ink by the discharge amount C1 equal to or larger than the discharge amount C2, a negative pressure can be generated in the ink tank 54 such that the water head pressure of the ink is not applied to the discharge port of the recording head 10. At this time, by discharging the ink by the discharge amount C1 equal to or larger than the discharge amount C2 of the above equation (4), it is possible to more reliably generate a negative pressure that does not apply the water head pressure of the ink to the discharge port of the recording head 10. Can be. Thereafter, by executing the printing operation, ink is supplied from the ink tank 54 to the printing head 10 with the consumption of ink by the printing head 10. At this time, the negative pressure in the ink tank 54 is maintained by restricting the inflow speed of the air to the ink consumption amount V2 of the above equation (1) by the adjustment unit 62.

If it is detected before the start of the recording operation that the negative pressure in the ink tank 54 is equal to or less than a predetermined value, a negative pressure generating process is performed, and the above equation (2) or (2) is performed. By discharging the ink by the discharge amount C1 which is equal to or more than the discharge amount C2, a negative pressure can be generated in the ink tank 54 such that the water head pressure of the ink is not applied to the discharge port of the recording head 10. At this time, by discharging the ink by the discharge amount C1 equal to or larger than the discharge amount C2 of the above equation (4), it is possible to more reliably generate a negative pressure that does not apply the water head pressure of the ink to the discharge port of the recording head 10. Can be. Thereafter, by executing the printing operation, ink is supplied from the ink tank 54 to the printing head 10 with the consumption of ink by the printing head 10. At that time, the adjusting unit 6
2, the air inflow rate is limited to the ink consumption V2 of the above equation (1) or less, so that the ink tank 54
The negative pressure in is maintained.

Also, during the recording operation, when it is detected that the negative pressure in the ink tank 54 has become smaller than a predetermined value, or the negative pressure in the ink tank 54 may be smaller than the predetermined value. When it is determined that the recording operation is interrupted, the negative pressure in the ink tank 54 can be recovered by performing the negative pressure generation process.

(Other Embodiments) FIG.
FIG. 4 is an explanatory diagram of a recycling mechanism capable of recycling ink discharged from the printer.

In FIG. 2, 58A is a cap provided in the recovery system unit 85, which can cap the ejection port of the recording head 10 located at the home position, as described above. P1 and P2 are first and second suction pumps, and 59B is a temporary ink storage unit. The first suction pump P1 introduces a negative pressure into the cap 58A covering the discharge port of the recording head 10 during the above-described suction recovery process, and temporarily stores the ink sucked and discharged from the discharge port.
Discharge to B. Further, the first suction pump P1 discharges the ink received by the cap 58A to the temporary storage section 58B at the time of the above-described ejection recovery. Similarly, the second suction pump P1 operates the recording head 10 during the negative pressure generation processing described above.
The ink sucked or discharged or discharged into the cap 58A from the discharge port is discharged to the temporary storage section 58B.

On the other hand, when the recording head 10 is at the home position, the second suction pump P2 supplies the ink temporarily stored in the temporary storage portion 58B to the ink tank 54.
Will be returned within. The ink return path between the temporary storage section 58B and the ink tank 54 includes, for example, a pipe connected to the temporary storage section 58B via the suction pump P2, and an ink introduction port formed in the ink tank 54. It is formed by connecting with a joint (not shown). When the ink is returned from the temporary storage section 58B to the ink tank 54, the ejection opening of the recording head 10 is capped by the cap 58A. If the pressure inside the ink tank 54 rises above a predetermined pressure when the ink is returned, the pressure inside the ink tank 54 can be released to the outside by the adjusting unit 62.

As described above, by recycling the ink discharged from the recording head 10, the running cost of the recording apparatus can be reduced by eliminating waste of the ink. In addition, such an ink recycling mechanism can be configured to recycle at least only the ink discharged at the time of the negative pressure generation processing. When the recording apparatus uses a plurality of color inks, an independent recycling mechanism is configured for each color ink.

FIGS. 3 and 4 are explanatory views of different construction examples in which an opening 54A of the ink tank 54 provided with the adjusting section 62 is provided with an opening / closing mechanism 200 for opening and closing the opening 54A.

The opening / closing mechanism 200 shown in FIG.
The configuration is such that an elastic valve body 201 is provided on the four sides. When the ink tank 54 is separated from the home position together with the recording head 10, the valve element 201 is separated from the operation unit 202 provided on the recording apparatus side to open the opening 54A, as indicated by the solid line in FIG. When the ink tank 54 is located at the home position together with the recording head 10, the valve body 201 is elastically deformed by hitting the operation unit 202 on the recording apparatus side, and the opening 54A as shown by a two-dot chain line in FIG.
Close. As described above, when the recording head 10 is at the home position, the valve body 201 automatically opens the opening 5.
Seal 4A. Therefore, the power of the recording device is turned off.
When the recording head 10 is at the home position, such as when the recording head is in a standby state for recording operation, the opening 54A is closed to maintain the negative pressure in the ink tank 54, and the negative pressure is maintained. The drop can be prevented. A spring may be provided to bias the valve 201 in the opening direction of the opening 54A.

The opening / closing mechanism 200 shown in FIG. 4 has a configuration in which a valve body 211 is provided on the recording apparatus side. Ink tank 54
When the ink cartridge 54 is located at the home position together with the recording head 10, the valve body 211 is moved by the actuator 212 on the recording apparatus side as shown by the two-dot chain line in FIG.
To close the opening 54A. Therefore, similarly to the case of FIG. 3, when the recording head 10 is at the home position, it is possible to seal the opening 54A to maintain the negative pressure in the ink tank 54 and prevent the negative pressure from lowering. it can.

As described above, the opening / closing mechanism 200 may be provided on either the ink tank 54 side or the recording apparatus side.
Further, the opening / closing mechanism 200 can be configured to automatically open when the pressure in the ink tank 54 exceeds a predetermined range. For example, when the pressure in the ink tank 54 exceeds a predetermined value due to the expansion of air in the ink tank 54 due to a change in environment, the opening / closing mechanism 200 is opened to open the Can be suppressed. As a result, it is possible to prevent the pressure in the ink tank 54 from increasing more than the capillary force at which the ejection ports of the recording head 10 hold the ink, and to prevent ink leakage from the ejection ports of the recording head 10. . Also,
The negative pressure in the ink tank 54 is a predetermined value (for example, -300
When the pressure becomes equal to or less than (mmAq), the opening / closing mechanism 200 is opened, whereby the occurrence of insufficient ink supply to the recording head 10 can be prevented. As a result, the recording head 1
It is possible to prevent the occurrence of blurring of the recorded image due to the insufficient ink supply to zero.

The opening / closing mechanism 20 is provided in the ink tank 54.
A mechanism for opening and closing 0 may be provided. When an ink jet cartridge is constituted by the ink tank 54 and the recording head 10, the ink jet cartridge may be provided with a mechanism for opening and closing the opening / closing mechanism 200. Further, the opening / closing mechanism 200 performs the ink tank 5
When a negative pressure is introduced into 4, the opening 54A can be closed to maintain the negative pressure.

The present invention is widely applied to a full-line type recording apparatus having a recording head extending over the entire width of a recording area of a recording medium, in addition to a serial scan recording apparatus. be able to.

[0032]

As described above, the present invention restricts the inflow of air into an ink tank and supplies an amount of ink necessary for generating a predetermined negative pressure in the ink tank from the recording head. By discharging the ink, the negative pressure in the ink tank is maintained, and the ink can always be stably supplied to the recording head.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view illustrating an ink tank and a recording head according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a recycling mechanism for recycling ink discharged from a recording head of FIG. 1;

3 is a cross-sectional view of a main part for describing an example of an opening and closing mechanism that can open and close an opening of the ink tank of FIG. 1;

FIG. 4 is a cross-sectional view of a main part for describing another example of an opening / closing mechanism that can open and close an opening of the ink tank of FIG. 1;

FIG. 5 is a perspective view of a recording apparatus to which the present invention can be applied.

FIG. 6 is a schematic block diagram of a control system of the printing apparatus of FIG. 5;

[Explanation of symbols]

 Reference Signs List 10 recording head 50 recording device 51, 52 guide shaft 53 carriage 54 ink tank 55 insertion port 54A opening 56 feed roller 57 platen 58 recovery system unit 58A cap 58B temporary storage unit 61 supply pipe 62 air inflow amount adjustment unit (restriction means) Reference Signs List 200 opening / closing mechanism (opening / closing means) 201 valve body 202 operating unit 211 valve body 212 actuator

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C056 EA26 EB20 EB34 EC02 EC19 EC24 EC32 EC54 EC57 FA03 FA10 KB05 KB08 KB11 KB16 KC16 KC27

Claims (15)

[Claims] 1. An ink jet recording apparatus that performs recording using a recording head capable of discharging ink and an ink tank that supplies ink contained therein to the recording head while inflow of air does not occur. Limiting means for restricting the inflow of air into the tank; and ink discharging means for discharging an amount of ink required to generate a predetermined negative pressure from the recording head into the ink tank. Characteristic inkjet recording device. 2. The ink jet recording apparatus according to claim 1, wherein the restricting means applies a predetermined inflow resistance to air flowing into the ink tank from outside. 3. The ink jet recording apparatus according to claim 1, wherein the ink discharging unit discharges ink from the recording head before starting a recording operation. 4. The ink discharging device according to claim 1, wherein at least when the power of the inkjet recording apparatus is turned on, after the inkjet recording apparatus has been stopped for a predetermined time or more, or when the pressure in the ink tank has become a predetermined value or more. 4. The ink jet recording apparatus according to claim 1, wherein the ink is ejected from the recording head at any time. 5. The ink jet recording apparatus according to claim 1, wherein said ink discharging means suctions and discharges ink from an ink discharge port of said recording head. 6. An ink jet recording apparatus according to claim 1, wherein said ink discharge means discharges ink not contributing to image recording from ink discharge ports of said recording head. 7. The ink discharging device according to claim 1, wherein the ink discharging unit discharges an amount of ink necessary for generating a negative pressure in the ink tank for reducing a head pressure of the ink applied to the recording head from the recording head. The ink jet recording apparatus according to any one of claims 1 to 6, wherein: 8. The height from the bottom surface to the top surface inside the ink tank is H1 (mm), and the height from the ink ejection port of the recording head to the bottom surface inside the ink tank is H.
2 (mm), the height from the bottom surface inside the ink tank to the liquid surface of the ink is h (mm), S (mm ² ) is the cross-sectional area of the bottom surface of the ink tank, 1 atm = 10340 mmA
When q, the ink discharging means calculates the ink amount C2 (mm ³ ) of the following formula:
The ink jet recording apparatus according to claim 7, wherein the ink is discharged from the recording head. C2 = {S. (H1-h). (H + H2)} / (103
40 + H1-h) 9. An ink jet recording apparatus according to claim 1, wherein said restricting means restricts a flow rate of air into said ink tank to be equal to or less than an ink consumption rate of said recording head. apparatus. 10. The number of ink ejection ports in the recording head is N, the amount of ink ejection per ink ejection port is A (ng), and the driving frequency of the recording head is H (H
z) When the average recording duty is D, the limiting means limits the inflow speed of air into the ink tank to an ink consumption speed V2 (μcc / sec) or less according to the following formula. An ink jet recording apparatus according to claim 9. V2 = A × N × H × D × 10 ^-3 11. The ink jet printer according to claim 1, wherein the limiting unit is configured to reduce the ink consumption amount to V2 or less when the average recording duty D is 2%.
11. The air inlet speed is limited.
3. The ink jet recording apparatus according to claim 1. 12. The ink jet recording apparatus according to claim 1, wherein the recording head has an electrothermal converter that generates thermal energy as energy for discharging ink. 13. A recycle mechanism for collecting ink discharged from the recording head by the discharge means and returning the ink to the ink tank.
13. The inkjet recording apparatus according to any one of items 1 to 12. 14. An ink supply device for supplying ink contained in an ink tank to a recording head capable of ejecting ink while causing air to flow in, wherein the restricting means restricts the flow of air into the ink tank. And an ink discharging means for discharging an amount of ink required to generate a predetermined negative pressure in the ink tank from the recording head. 15. An ink supply method for supplying ink contained in an ink tank to a recording head capable of ejecting ink while causing air to flow in the ink supply method. An ink supply method, characterized in that an amount of ink required to generate a predetermined negative pressure in the ink tank is discharged from the recording head.