JP2000326523A - Ink jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate an irregularity in discarding waste ink from a recording head at a recovery operation for the head and improve a recording quality, by setting an ink supply device with a means for measuring and controlling a flow rate of ink treasported to the recording head by a pump mechanism and, controlling the flow rate of ink according to the measured result. SOLUTION: A recording head 1, an air buffer tank 4, an ink tank 3 and an ink cartridge 5 are connected by tubes 35 to 39. An ink supply device is formed of measuring sensors 10, 11 and 12 for a flow rate of ink in the tank 3. Transportation of ink to each part is carried out by a pressure pump 20 and a recycle pump 30. The sensor 10 and the sensors 11, 12 respectively detect a full liquid level 13 and an empty liquid level 14 in the tank from whether or not the sensors are connected or insulated when a voltage is applied to the sensors. When the sensors are brought in an insulation state, an ink supply mode is set, a time for the liquid level to reach the sensor 10 is measured, a flow rate of ink is detected from an already measured value between the liquid levels 13 and 14, and an output of a driving motor for the pump is adjusted or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus for recording an image on a recording medium using an ink jet recording head for discharging ink from nozzles, and more particularly to an ink supply apparatus for such an ink jet recording apparatus. .

[0002]

2. Description of the Related Art At present, various recording methods have been developed as recording apparatuses. Among them, an ink jet recording method is excellent in quietness and high-speed recording because of non-contact with a recording medium. High density recording is possible,
They are widely used because they are easy to color and miniaturize.

A typical configuration and principle of a means for generating thermal energy as energy used for performing ink ejection are described in relation to a liquid path in which a liquid (ink) is held. There are electrothermal converters
Applying at least one drive signal corresponding to the recorded information and providing a rapid temperature rise exceeding nucleate boiling generates heat energy in the electrothermal transducer to cause film boiling on the heat acting surface of the recording head. As a result, bubbles can be formed in the liquid (ink) corresponding to the drive signal one-to-one, which is effective. By discharging the liquid (ink) through the discharge opening by the growth and contraction of the bubble, at least one droplet is formed.

FIG. 6 schematically shows an ink supply apparatus for forming an ink flow path of an ink supply system in a conventional ink jet recording apparatus to which such a basic principle is applied.

As shown in FIG. 6, an ink jet recording apparatus includes an ink jet recording head 101 (hereinafter, simply referred to as a recording head), a recovery tub 102, an ink tank 103, an air buffer tank 104, and an ink cartridge 105. , A pressurizing pump 110 and an ink supply device for forming an ink flow path generally constituted by a recycle pump 120. Such an ink supply device further includes a pressure valve 106 and an atmosphere release valve 107.
, A suction valve 108, a mechanical valve 130, one-way valves 131 and 132, and a filter 133.
The pressurizing pump 110 includes a rotating member 111 and a roller 1.
12, a pump tube 113, and a pump tube pressing member 114. The recycle pump 120 further includes a rotating member 121, a roller 122, a pump tube 123, and a pump tube pressing member 124.
It is composed of

The recording head 101 is connected to the air buffer tank 104 by a tube 140, is provided with a pressure valve 106 on the way, and further has a tube 141.
Connected to the ink tank 103, and a suction valve 108 is provided on the way. A tube 142 communicating with the atmosphere is connected to the top of the ink tank 103, and an atmosphere release valve 107 is provided on the way. Furthermore, the ink tank 103 is connected to the ink cartridge 105 by a tube 143, and a mechanical valve 130 is provided therebetween. The ink cartridge 105 is connected to the air buffer tank 104 by a tube 144, and is provided with a one-way valve 131 on the way.

In the illustrated ink supply device for forming such an ink flow path, recording is performed and the recording head 1 is used.
01 is required for the ink tank 103
The ink for this storage is supplied from a detachable ink cartridge 105.

On the ink tank 103 and the air buffer tank 104, a pressurizing valve 106, an air release valve 107, and a suction valve 108 are respectively provided in the ink flow path from the air buffer tank 104 to the recording head 101.
They are arranged in an air flow path communicating from the ink tank 103 to the outside air and in an ink flow path from the ink tank 103 to the recording head 101, respectively. These pressurizing valves 10
6. The suction valve 107 and the atmosphere release valve 108 can be simultaneously opened and closed by a drive means (not shown). Further, the mechanical valve 130 can be bidirectionally circulated only when the ink cartridge 105 is mounted.

The transport of ink to each part is performed by a pressurizing pump 110 and a recycle pump 1 forming a pump mechanism.
20 and two tube pumps. The operation method and the ink distribution route in each operation mode will be described below.

Ink supply mode: initial state of the printer,
Alternatively, when the ink stored in the ink tank 103 is consumed to the lower limit level 116 of the printable state for the printing operation or the recovery operation of the print head 101, the ink is supplied into the ink tank 103, or In this mode, a fixed amount of the ink in the tank 103 and the ink in the ink cartridge 105 are exchanged to average out component deterioration of the ink.

The operation sequence is as follows.
The pump tube pressing member 114 is raised by a driving unit (not shown), and the pump tube 113 is pressed by the rollers 112 arranged on the outer peripheral portion of the rotating member 111. The pressurizing valve 106, the air release valve 107, and the suction valve 108, which are arranged, are simultaneously closed by a driving means (not shown) so that ink and air cannot flow. In such a sealed state, the rotating member 1
11 is rotated counterclockwise to make the pressure pump 110 function as a tube pump.
Of the ink cartridge 105 to the one-way valve 131 to the air buffer tank 104 to the pump tube 11 of the pressure pump 110
3 to the ink tank 103, and further from the ink tank 103 via the tube 143 to the mechanical valve 130 to the ink cartridge 105, an ink circulation channel independent of the recording head 101 and isolated from the outside is formed. In this case, the ink is supplied into the ink tank 103, and when the ink level is equal to or higher than the upper limit level 115,
Circulates in the ink flow path.

During the operation of the ink supply mode, the positive pressure discharged from the ink tank 103 via the pump tube 123 of the recycle pump 120 is applied to the one-way valve 132.
Is held by

After the end of the ink supply mode, the pump tube pressing member 114 is lowered, and the roller 112 and the pump tube pressing member 114
3 is released and the pressure in the air buffer tank 104 is made uniform, and then the pressure valve 106 and the atmosphere release valve 10 are released.
7. The suction valve 108 is simultaneously switched to an open state in which ink and air can flow through the drive means (not shown).

Ink circulation mode: In an ink jet recording apparatus, the viscosity of the ink in the non-ejection nozzles generated by the shape of the recording image is increased at individual nozzles arranged on the nozzle surface 101a in the longitudinal direction of the recording head 101. In order to prevent ejection failure due to dust or clogging, etc., self-ejection or forced ejection of ink from the nozzle into the recovery tub 102 is performed by sequence control. However, in this mode, pressurization as a tube pump corresponding to the latter is performed. The ink is pressure-fed to the print head 101 by the pump 110, and the ink is forcibly discharged from the nozzles.
This is a mode for removing the stains in 1.

The operation sequence is as follows. First, the tube pressing members 114 and 124 are raised by driving means (not shown), and the pump tubes 113 and 12 are arranged by the respective rollers 112 and 122 arranged on the outer peripheral portions of the rotating members 111 and 121.
After pressing each of the pressure valves 3 on the ink tank 103 and the air buffer tank 104,
06, the air release valve 107 and the suction valve 108 are simultaneously opened by the valve driving means (not shown) so that the ink and the air can be circulated.

Next, when the rotating member 111 is rotated clockwise to make the pressure pump 110 function as a tube pump, the ink is sucked from the ink tank 103, and is passed through the air buffer tank 104 and the pressure valve 106. Is supplied to the recording head 101. In addition, the one-way valve 131 suppresses the ink that is pressure-fed to the air buffer tank 104 from flowing into the ink cartridge 105.

The ink supplied to the recording head 101 is
On the one hand, it is forcibly ejected from the nozzle of the recording head 101,
On the other hand, the ink passes through the suction valve 108 and is returned into the ink tank 103 again. By the way, the recording head 101
The ink forcibly discharged from the nozzle of the recycle pump 120 is received by the recovery tub 102,
21 is rotated clockwise to make the recycle pump 120 function as a tube pump, so that the one-way valve 13 is filtered by the filter 133.
2 and is returned into the ink tank 103 again.

Recycle mode: a mode for sucking ink accumulated in the recovery tub 102 by the recovery operation of the recording head 101 and returning the ink to the ink tank 103 again.

The operation sequence is as follows. First, the pump tube pressing member 124 is raised by a driving means (not shown) to make the pump tube 123 pressed by the rollers 122 arranged on the outer periphery of the rotating member 121, and then the ink tank 103 And a pressure valve 106, an air release valve 107, and a suction valve 10 disposed on the air buffer tank 104.
8 is simultaneously opened by a valve driving means (not shown) in which ink and air can flow.

Then, by rotating the rotating member 121 of the recycle pump 120 clockwise to make the recycle pump 120 function as a tube pump, the ink stored in the recovery tub 102 is filtered by the filter 133, After passing through the one-way valve 132, it is returned to the ink tank 103 again.

Recording mode: A mode in which actual recording is performed. The pump tube pressing members 114 and 124 are in the retracted state, respectively, the pressurizing valve 106, the atmosphere release valve 107, and the suction valve 108.
Is an open state through which ink and air can flow.

The ink consumed by the ejection of the ink is supplied to the ink tank 103, the pump tube 113, the air buffer tank 104,
The ink is automatically supplied to the recording head 101 by a bidirectional ink flow path from the pressure valve 106 to the recording head 101 and the ink tank 103 to the suction valve 108 to the recording head 101.

Standby mode: A mode in which a job such as turning off the power is not performed.
Reference numerals 4 and 124 denote a retracted state, respectively, and the air release valve 107 is in a closed state in which air cannot be circulated due to the need to prevent evaporation of water in the ink during standby. In this case, the recording head 101 is prevented from being affected by pressure changes due to expansion and contraction of air in the ink tank 103 and the air buffer tank 104.

Transport mode: basically the same as the standby mode, except that the mechanical valve 130 is in a closed state where ink cannot flow because the ink tank 103 is not mounted. In addition, the one-way valve 131 prevents the ink in the air buffer tank 104 from flowing out.

[0025]

However, when the ink is transported by driving the pump in each of the above-described operation modes, the ink transporting ability is deteriorated due to a difference in the external environment such as the outside air temperature and the aging of the pump function. Change.

For this reason, in particular, in the recovery operation of the recording head in the ink circulation mode, since the ink waste liquid from the recording head fluctuates with respect to a value determined by design, the recording head is caused to discharge poorly and the recording is induced. It greatly affects the quality.

Accordingly, the present invention has been made to solve the above-mentioned problems in the related art, and an object of the present invention is to eliminate a discharge failure by eliminating variations in ink waste liquid from a recording head in a recovery operation of the recording head. Another object of the present invention is to provide an ink jet recording apparatus capable of improving recording quality.

[0028]

In order to achieve the above object, an ink jet recording apparatus according to the present invention comprises: an ink tank for storing ink; a pump mechanism for supplying ink to a recording head; An ink supply device having an ink flow rate measuring means for measuring the ink flow rate transported by the pump mechanism and an ink flow rate controlling means for controlling the ink flow rate, wherein the ink flow rate is controlled based on the measurement result of the ink flow rate. Features.

The ink jet recording apparatus according to the present invention is characterized in that the ink flow rate measuring means is disposed in the ink tank.

Further, the ink jet recording apparatus of the present invention has a detachable ink cartridge for replenishing ink separately from the ink tank, and measures the ink flow by supplying ink from the ink cartridge into the ink tank. It is characterized in that it is performed at the time of the ink supply mode to be performed.

Further, the ink jet recording apparatus of the present invention is characterized in that the ink flow rate measuring means is provided in a tubular flow path pipe connecting between functional members such as the recording head and the ink tank.

The ink jet recording apparatus according to the present invention is characterized in that the ink flow rate measuring means is performed by measuring the number of revolutions of a pump driving motor, a reduction gear, and the like.

Further, in the ink jet recording apparatus of the present invention, the ink flow rate measuring means has a plurality of sensors.

Further, the ink jet recording apparatus according to the present invention is characterized in that the ink flow control means changes the rotation speed of a pump drive motor.

Still further, the ink jet recording apparatus of the present invention is characterized in that the ink flow control means is performed by changing the area of the ink flow path.

[0036] In the ink jet recording apparatus of the present invention, the ink supply device includes the recording head, the recovery tub, the ink cartridge, the ink tank, the air buffer tank, the pressure pump, and the recycle pump. It is characterized by having.

In the ink jet recording apparatus of the present invention, the pressurizing pump is connected between the ink tank and the air buffer tank, and the recycle pump is connected between the recovery tub and the ink tank. It is characterized by the following.

Further, the ink jet recording apparatus of the present invention is characterized in that the recording head has an electrothermal transducer for generating thermal energy used for discharging ink.

Further, the ink jet recording apparatus of the present invention is characterized in that the electrothermal transducer generates electric energy that causes film boiling of the ink.

In this specification, the term “record” (hereinafter also referred to as “record”) refers not only to the formation of significant information such as characters and figures, but also to significant or insignificant information. Regardless of whether or not the image is visualized so that a human can perceive it visually, the case where an image, a pattern, a pattern, or the like is widely formed on a recording medium or the medium is processed is also referred to.

Here, the "recording medium" is not limited to paper used in a general recording apparatus, but also broadly refers to a material that can accept ink, such as a cloth, a plastic film, and a metal plate.

Further, “ink” is to be interpreted broadly as in the definition of “recording” described above. When applied to a recording medium, it forms an image, a pattern, a pattern, or processes the recording medium. Liquid that can be provided to

In this specification, the term nozzle generally refers to a discharge port, a liquid path communicating with the discharge port, and an element that generates energy used for ink discharge, unless otherwise specified.

[0044]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the ink jet recording apparatus according to the present invention, the ink tank for storing the ink, a pump mechanism for supplying the ink to the recording head, and the transportation by the pump mechanism. An ink supply device having an ink flow rate measuring means for measuring an ink flow rate to be measured, and an ink flow rate controlling means for controlling the ink flow rate, and controlling the ink flow rate based on the measurement result of the ink flow rate, thereby enabling the recording head Variations in ink drainage from the recording head during the recovery operation can be eliminated, and ejection defects can be eliminated to improve recording quality.

Hereinafter, embodiments of the ink jet recording apparatus of the present invention will be described in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a schematic diagram showing the structure of an ink jet recording apparatus to which the present invention is applied.

As shown in the figure, an ink jet recording apparatus to which the present invention is applied includes a recording head 1 and a recovery tub 2.
, An ink tank 3, an air buffer tank 4,
It has an ink supply device that forms an ink flow path generally composed of an ink cartridge 5 and a pressure pump 20 and a recycle pump 30 as a pump mechanism.
Such an ink supply device further includes a pressure valve 6, an atmosphere release valve 7, a suction valve 8, a mechanical valve 25, one-way valves 26 and 27, and a filter 28. The pressurizing pump 20 includes a rotating member 21, a plurality of rollers 22, a pump tube 23, and a pump tube pressing member 24.
Comprises a rotating member 31, a plurality of rollers 32, a pump tube 33, and a pump tube pressing member.

The recording head 1 is connected to the air buffer tank 4 by a tube 35, is provided with a pressure valve 6 on the way, is further connected to the ink tank 3 by a tube 36, and is provided with a suction valve 8 on the way. ing. A tube 37 communicating with the atmosphere is connected to the top of the ink tank 3, and an atmosphere release valve 7 is provided on the way. The ink tank 3 is connected to the ink cartridge 5 by a tube 38, and a mechanical valve 25 is provided therebetween. The ink cartridge 5 is a tube 3
9 connects to the air buffer tank 4 and a one-way valve 26 is provided on the way. Further, as shown in FIG. 2, such an ink supply device includes sensors 10, 11,
12 are provided.

In the ink supply apparatus for forming the ink flow path of the ink jet recording apparatus of the present invention as shown in FIG. 1, the ink required for recording or for the recovery operation of the recording head 1 is stored in the ink tank 3. The ink to be stored is a detachable ink cartridge 5
Supplied from

On the ink tank 3 and the air buffer tank 4, a pressure valve 6, a suction valve 7, and an atmosphere release valve 8 are respectively provided in the ink flow path from the air buffer tank 4 to the recording head 1 and the ink tank. The ink tank 3 is disposed in the ink flow path from the ink tank 3 to the recording head 1 and in the air flow path communicating the ink tank 3 with the outside air. The pressurizing valve 6, the suction valve 8, and the atmosphere opening valve 7 are driven by driving means (not shown).
At the same time, switching between open and closed is possible. Further, the mechanical valve 25 can be circulated in both directions only when the ink cartridge 5 is mounted.

The ink is transported to each part by a pressurizing pump 20 and a recycle pump 30 which constitute a pump mechanism.
This is done by two tube pumps. In such an ink flow path, each tube is made of a suitable piping member such as a metal pipe or a plastic tube.

In the ink flow path of the ink jet recording apparatus of the present invention shown in FIG. 1, the ink flow rate measuring device as the ink flow rate measuring means is installed in the ink tank 3 as clearly shown in FIG. Sensors 10, 11, and 12 made of stainless steel. In these sensors 10, 11, 12, the sensor 10 detects the ink Full liquid level 13 of the ink in the ink tank 3, and the sensors 11, 12 detect the ink Empty level of the ink in the ink tank 3. 14 are arranged in the ink tank 3 so that the sensor terminals 14 detect them.

Accordingly, a voltage is applied between the sensor terminals of the sensors 10, 11, and 12 of such an ink flow rate measuring device, and the liquid level in the ink tank 3 fluctuates. In this case, the ink full liquid level 13 and the ink empty liquid level 14 can be detected by switching between conduction and insulation between the sensor terminals using the conductivity of the ink. I have. However, the sensors 10, 11,
Taking into account component tolerances such as 12, the sensors 10, 11, 1
The liquid level detection positions by the respective sensor terminals 2 are arranged at positions having a certain margin with respect to the accurate ink full liquid level 13 and the ink empty liquid level 14, respectively.

That is, on the one hand, the sensor 10
Ink Full liquid level 13 is arranged with a margin with respect to the upper limit level 15, and on the other hand, the ink Empty liquid level 14 with the sensors 11 and 12 is arranged with a margin with respect to the lower limit level 16. I have.

The ink Fu in the ink tank 3 is
It is preferable that the ink volume between the liquid level 13 and the ink empty level 14 is measured in advance.

For easy understanding, FIG. 1 shows a side view showing the installation positions of these sensors 10, 11, and 12, and FIG. 2 shows a front view thereof.

Next, the outline of the operation of this embodiment in the ink jet recording apparatus of the present invention will be described below with reference to the flowchart of FIG.

In the ink jet recording apparatus of the present invention configured as described above, as shown in the flowchart of FIG. 3, first, in step S1, recording by printing is performed on a recording medium, and the ink by this recording is printed. The fact that the ink liquid level in the ink tank 3 is sequentially lowered by the consumption of the ink tank 3 and the ink liquid level is lower than the tip of the sensor terminals of the sensors 11 and 12, and that the current between the sensors 11 and 12 is insulated by the step S2 When detected,
As a result, the ink Empty level 14 is recognized, and the print mode is interrupted or terminated. Therefore, after the print mode is interrupted or terminated, the mode is switched to the ink supply mode in step S3.

In the ink supply mode (S3), as described in the section of the prior art, ink is supplied from the ink cartridge 5 to the ink tank 3, and the ink level in the ink tank 3 rises again. Is started, but the ink liquid level touches the tip of the sensor terminal of the sensor 10 again to detect that the sensors 10, 11, and 12 are electrically connected.
At the time of detecting the conduction between the two (step S4) (ink F
The time until the liquid level 13) is measured. At this point, the ink full liquid level 13 is recognized, and the ink supply mode ends (S5).

The ink Fu from the ink Empty level 14
Since the ink capacity between the 11 liquid levels 13 is measured and recognized in advance, the ink flow rate at which the pump operates and is being sent at the present time can be calculated based on the measurement result of the ink supply time in the same section ( S6).

Next, the ink consumption flow rate obtained by the above-described means is compared with an appropriate pump delivery flow rate (S7). If there is a difference between these flow rates, the pump ink transport rate is determined. Is corrected (S8), and the process is terminated by setting an appropriate ink flow rate (S9).

As a means for correcting the pump capacity, for example, a circuit for controlling the output (rotation speed) of the motor is provided in the driver of the pump drive motor so that an appropriate flow rate can be obtained for the measured flow rate. Or a method of adjusting the flow rate by making the cross-sectional area of a part of the ink flow path variable.

In this embodiment, a sensor for detecting the ink Empty level and the ink Full level and a sensor for measuring the ink flow rate are shared.
Since these sensors provide an opportunity to correct the flow rate of the pump in this case, it is more preferable to separately provide a sensor only for detecting the flow rate so that the ink flow rate can be corrected. is there.

(Embodiment 2) FIG. 4 shows an example in which an arbitrary ink flow rate measuring means is provided in the ink jet recording apparatus of the present invention. In this embodiment, the principle of the Venturi tube is used as one of the ink flow rate measuring means,
A detailed cross-sectional view is shown in FIG.

As shown in FIG. 5, the ink now flows from the A section to the B section of the venturi tube 50, and a part of the ink flows between the A section and the B section with respect to the normal flow path cross-sectional area S1. The road cross section S2 is narrowed down, and the pressure sensors 5
1, 52 are provided. Ink flows at the normal flow velocity V1 in the flow path cross-sectional area S1 where the pressure sensor 51 is provided, but the flow velocity V2 in the flow path cross-sectional area S2 where the pressure sensor 52 is provided is equal to the flow velocity V2 in the flow path cross-sectional area S1. The flow velocity is higher and larger in accordance with the cross-sectional area ratio with the flow path cross-sectional area S1 portion than the flow velocity. As a result, a corresponding pressure difference is generated between the side constant pressures P1 and P2 at the pressure sensors 51 and 52, so that the flow path cross-sectional areas S1 and S2 and the pressures P1 and P2 measured by the pressure sensors 51 and 52 are measured.
The flow velocities V1 and V2 in the flow path cross-sectional areas S1 and S2 are obtained from the equation (1). Therefore, the flow rate per unit time in each flow path cross-sectional area can be known. The ink flow rate can be used as measurement data used for correction.

More specifically, by adding a Venturi coefficient to the flow rate obtained by applying the Bernoulli's theorem and the continuity theorem to the measurement data, a nearly accurate flow rate can be calculated.

As a result, the obtained measurement data was used in Example 1.
A suitable ink flow rate can be obtained by feeding back to the ink transport amount correction means described in the above section.

According to such an ink flow rate measuring means,
It can be installed at any location as long as it is tubular and where the flow rate of ink is generated by driving the pump.For example, if it is installed downstream of the print head, it is discharged from the nozzle of the print head. Since it is necessary to consider the amount of the ink, it is preferable to install the ink tank in a flow path such as a tube that passes from the ink tank through a pressure pump to a recording head.

According to the method described in the present embodiment, it is possible to obtain correction data every time ink flows in the ink flow rate measurement portion by driving the pump.

(Embodiment 3) In this embodiment, it is also possible to provide a rotation speed measuring means in a drive motor of a pump, a reduction gear, or the like, and to control the flow rate using a control table of rotation speed × flow rate.

In this embodiment, since the flow rate is estimated based on the number of rotations of the rotating member of the measuring portion without the direct ink flow rate measuring means, the accuracy of the measured value is slightly inferior.
The structure is simple, especially in the experiment using the tube pump, the above-mentioned control table of the number of rotations × flow rate shows a substantially proportional straight line, and there is almost no difference between the machines. It has been confirmed that there is no problem in using. Further, the flow rate can be corrected every time the pump is driven, regardless of the operation mode, as in the second embodiment.

(Others) The present invention includes a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for ejecting ink, particularly in an ink jet recording system. An excellent effect is obtained in a recording head and a recording apparatus of a type in which a change in the state of ink is caused by the thermal energy. This is because according to such a method, it is possible to achieve higher density and higher definition of recording.

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 740,796. 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 liquid path holding the liquid (ink). Applying at least one drive signal corresponding to the recording information and providing a rapid temperature rise exceeding nucleate boiling to the electrothermal transducer, thereby generating heat energy in the electrothermal transducer, and thereby forming a recording head. This is effective because a film in the liquid (ink) corresponding to the driving signal can be formed one by one by causing film boiling on the heat acting surface. By discharging the liquid (ink) through the discharge opening by the growth and contraction of the bubble, at least one droplet is formed.
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 liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. U.S. Pat. Nos. 4,463,359
No. 4,345,262 are suitable. In addition, US Pat. No. 4,313,12 of the invention relating to the temperature rise rate of the heat acting surface.
If the conditions described in the specification of JP-A No. 4 are adopted, more excellent recording can be performed.

As the configuration of the recording head, in addition to the combination of the discharge port, the liquid path, and the electrothermal converter (linear liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned respective specifications, The present invention also includes a configuration using U.S. Pat. No. 4,558,333 and U.S. Pat. No. 4,459,600 which disclose a configuration in which a heat acting portion is arranged in a bending region. It is. In addition, Japanese Unexamined Patent Publication No. Sho 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 opening for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration is based on JP-A-59-138461, which discloses a configuration corresponding to a discharge unit. That is, according to the present invention, recording can be reliably and efficiently performed regardless of the form of the recording head.

Further, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium on which a recording apparatus can record. Such a recording head may have a configuration that satisfies the length by a combination of a plurality of recording heads, or a configuration as one integrally formed recording head.

In addition, even in the case of the serial type as described above, a recording head fixed to the apparatus main body or an electric connection with the apparatus main body or ink from the apparatus main body is mounted by being mounted on the apparatus main body. The present invention is also effective when a replaceable chip-type recording head that can be supplied or a cartridge-type recording head in which an ink tank is provided integrally with the recording head itself is used.

Further, it is preferable to add ejection recovery means for the recording head, preliminary auxiliary means, and the like as the configuration of the recording apparatus of the present invention since the effects of the present invention can be further stabilized. If these are specifically mentioned, the recording head is heated using capping means, cleaning means, pressurizing or suction means, an electrothermal transducer, another heating element or a combination thereof. Pre-heating means for performing the pre-heating and pre-discharging means for performing the discharging other than the recording can be used.

The type and number of recording heads to be mounted are, for example, not only those provided for one color ink but also a plurality of inks having different recording colors and densities. A plurality may be provided. That is, for example, the printing mode of the printing apparatus is not limited to a printing mode of only a mainstream color such as black, but may be any of integrally forming a printing head or a combination of a plurality of printing heads. The present invention is also very effective for an apparatus provided with at least one of the recording modes of full color by color mixture.

In addition, in the embodiments of the present invention described above, the ink is described as a liquid. However, an ink which solidifies at room temperature or lower and which softens or liquefies at room temperature may be used. In general, the ink jet method generally controls the temperature of the ink itself within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range. Sometimes, the ink may be in a liquid state. In addition, in order to positively prevent temperature rise due to thermal energy by using it as energy for changing the state of the ink from a solid state to a liquid state, or to prevent evaporation of the ink, the ink is solidified in a standing state and heated. May be used. In any case, the ink liquefies by the application according to the recording signal of the heat energy,
The present invention is also applicable to a case in which an ink having a property of being liquefied for the first time by the application of thermal energy, such as an ink in which a liquid ink is ejected or an ink which starts solidifying when it reaches a recording medium, is used. In such a case, the ink is held in a state of being held as a liquid or solid substance in the concave portion or through hole of the porous sheet as described in JP-A-54-56847 or JP-A-60-71260. Alternatively, it may be configured to face the electrothermal converter. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

Further, the form of the ink jet recording apparatus of the present invention is not limited to those used as image output terminals of information processing equipment such as computers, copying apparatuses combined with readers and the like, and facsimile apparatuses having a transmission / reception function. It may take a form.

[0081]

According to the first aspect of the present invention having the above-described structure,
The ink jet recording apparatus described above includes an ink tank for storing ink, a pump mechanism for supplying ink to the recording head, an ink flow rate measuring unit for measuring an ink flow rate transported by the pump mechanism, and an ink flow rate. And an ink supply device having an ink flow rate control means for controlling the ink flow rate, and controlling the ink flow rate based on the measurement result of the ink flow rate. The printing quality can be improved by eliminating defects.

In the ink jet recording apparatus according to the second aspect of the present invention, since the ink flow rate measuring means is disposed in the ink tank, it is not necessary to provide a special installation place, and the ink jet recording apparatus can be downsized. Can be.

According to a third aspect of the present invention, there is provided an ink jet recording apparatus having a detachable ink cartridge for supplying ink separately from the ink tank, and measuring an ink flow rate from the ink cartridge to the inside of the ink tank. Since the ink supply is performed at the time of the ink supply mode in which the ink is supplied, the required ink flow rate can be reliably measured.

In the ink jet recording apparatus according to a fourth aspect of the present invention, the ink flow rate measuring means is preferably provided in a tubular flow path pipe connecting between functional members such as a recording head and an ink tank. And a predetermined flow rate measurement can be performed satisfactorily.

In the ink jet recording apparatus according to the fifth aspect of the present invention, since the ink flow rate measuring means is performed by measuring the number of revolutions of a pump driving motor, a reduction gear, and the like, necessary measurements can be performed by simple means. Can be done accurately.

In the ink jet recording apparatus according to the sixth aspect of the present invention, since the ink flow rate measuring means has a plurality of sensors, the ink flow rate can be accurately measured.

In the ink jet recording apparatus according to the present invention, since the ink flow control means changes the rotation speed of the pump drive motor, the ink flow can be reliably measured.

In the ink jet recording apparatus according to the eighth aspect of the present invention, since the ink flow rate control means changes the area of the ink flow path, the ink flow rate control means has a simple configuration and is easily configured. be able to.

According to a ninth aspect of the present invention, in the ink jet recording apparatus, the ink supply device comprises: the recording head;
Since it has a recovery tub, the ink cartridge, the ink tank and the air buffer tank, and the pump mechanism including a pressure pump and a recycle pump,
The ink flow path for the recording head can be made simple.

In the ink jet recording apparatus according to a tenth aspect of the present invention, the pressurizing pump is connected between the ink tank and the air buffer tank, and the recycle pump is connected between the recovery tub and the ink tank. Therefore, the ink supply device that forms the ink flow path can be simply configured.

The ink jet recording apparatus according to the eleventh aspect of the present invention has an electrothermal converter for generating thermal energy used for discharging the ink by the recording head. By discharging, high density and high definition of recording can be achieved, and clear recording can be obtained.

In the ink jet recording apparatus according to a twelfth aspect of the present invention, since the electrothermal transducer generates electric energy that causes ink to boil, the ink is discharged using the electric energy. Higher recording density and higher definition can be achieved, and clear recording can be obtained.

[Brief description of the drawings]

FIG. 1 is an ink flow path diagram showing a sensor terminal installation position which is an ink flow rate measuring unit in Embodiment 1 of an ink jet recording apparatus of the present invention.

FIG. 2 is a front sectional view of an ink tank showing a configuration of an ink flow rate measuring unit in Embodiment 1 of FIG. 1;

FIG. 3 is a flowchart illustrating an outline of an operation of the inkjet recording apparatus according to the first exemplary embodiment of the present invention.

FIG. 4 is an ink flow path diagram showing an installation position of an ink flow rate measuring unit in Embodiment 2 of the ink jet recording apparatus of the present invention.

FIG. 5 is a detailed sectional view showing a configuration of an ink flow rate measuring unit in Embodiment 2 in FIG.

FIG. 6 is an ink flow path diagram showing a conventional device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording head 2 Recovery tub 3 Ink tank 4 Air buffer tank 5 Ink cartridge 6 Pressure valve 7 Atmospheric release valve 8 Suction valve 10 Sensor 11 Sensor 12 Sensor 13 Ink full liquid level 14 Ink empty level 15 Upper limit level 16 Lower limit level 20 Addition Pressure pump 21 Rotating member 22 Roller 23 Pump tube 24 Pump tube pressing member 25 Mechanical valve 26 One-way valve 27 One-way valve 28 Filter 30 Recycle pump 31 Rotating member 32 Roller 33 Pump tube 34 Pump tube pressing member 35 Tube 36 Tube 37 Tube 38 tube 39 tube 40 tube 50 Venturi tube 51 pressure sensor 52 pressure sensor

Claims (12)

[Claims] 1. An ink tank for storing ink, a pump mechanism for supplying ink to a recording head, an ink flow rate measuring means for measuring an ink flow rate transported by the pump mechanism, and controlling the ink flow rate An ink jet recording apparatus, comprising: an ink supply device having an ink flow rate control means for controlling an ink flow rate based on a measurement result of the ink flow rate. 2. An ink jet recording apparatus according to claim 1, wherein said ink flow rate measuring means is arranged in said ink tank. And a detachable ink cartridge for replenishing the ink separately from the ink tank, and measuring the ink flow rate in accordance with an ink supply mode in which ink is supplied from the ink cartridge into the ink tank. The inkjet recording apparatus according to claim 1, wherein the recording is performed. 4. An ink jet recording apparatus according to claim 1, wherein said ink flow rate measuring means is provided in a tubular flow path pipe connecting functional members such as said recording head and ink tank. 5. The ink jet recording apparatus according to claim 1, wherein said ink flow rate measuring means is performed by measuring a rotation speed of a pump driving motor, a reduction gear, or the like. 6. An ink jet recording apparatus according to claim 1, wherein said ink flow rate measuring means has a plurality of sensors. 7. The ink jet recording apparatus according to claim 1, wherein said ink flow control means changes the rotation speed of a pump drive motor. 8. The ink jet recording apparatus according to claim 1, wherein said ink flow control means changes the area of an ink flow path. 9. The ink supply device includes the recording head, a recovery tub, the ink cartridge, the ink tank, an air buffer tank, and the pump mechanism including a pressure pump and a recycle pump. The ink jet recording apparatus according to claim 1, wherein: 10. The apparatus according to claim 9, wherein the pressure pump is connected between the ink tank and the air buffer tank, and the recycle pump is connected between the recovery tub and the ink tank. The inkjet recording apparatus according to any one of the preceding claims. 11. An ink jet recording apparatus according to claim 1, wherein said recording head has an electrothermal transducer for generating thermal energy used for discharging ink. 12. An ink jet recording apparatus according to claim 11, wherein said electrothermal converter generates electric energy for causing film boiling of the ink.