Liquid ejecting apparatus

A liquid ejecting apparatus includes a first liquid containing unit containing a liquid therein and a second detachable liquid containing unit containing a liquid therein and having a liquid containing volume smaller than that of the first liquid containing unit. A communication passage communicates the first liquid containing unit with the second liquid containing unit. The first and second liquid containing units are reciprocally replenished with the liquid by a liquid replenishing unit through the communication passage. When the liquid is replenished from the first or second liquid containing units to the other, a control unit controls the liquid replenishing unit to replenish the liquid from the one liquid containing unit to the other liquid containing unit, until the liquid contained in the one liquid containing unit reaches a predetermined amount smaller than the liquid containing volume of the second liquid containing unit.

BACKGROUND

1. Technical Field

The present invention relates to a liquid ejecting apparatus having a function of agitating a liquid.

2. Related Art

As ink to be used in a liquid ejecting apparatus, for example, a printer device, there is known ink using a color component which is not dissolved by a solvent or is nearly insoluble in the solvent. For example, pigment-based ink contains fine particles of pigment which are a color component and are dispersed in a solvent such as water or petroleum solvent, and the pigment is likely to be settled down. For example, specific gravity of white pigment is approximately 4 and specific gravity of metallic pigment is approximately 2 to 3, but specific gravity of the solvent is less than 1. Because of a difference in the specific gravity between the pigment and the solvent, the pigment is easily separated from the solvent and is precipitated. Also, in the case of the ink using insoluble or hardly-soluble dye as a color component, the dye is likely to be precipitated. If the color component is precipitated, shading occurs in the ink, so that ink of uniform concentration is not fed to the head. There is a problem that a dense portion of the ink does not fall in drops from a nozzle of the head, so that the nozzle is likely clogged, or brightness of a dot is changed.

It is known that the ink is moved and agitated to prevent sedimentation of the color component. For example, a technique of providing a first ink containing unit (i.e., an ink tank) and a second ink containing unit and reciprocating the ink between two ink containing units is known (e.g., JP-A-9-327929, WO95/31335, and JP-A-9-234886).

In the above-mentioned publications, however, the ink is moved between two ink containing units due to difference in height, that is, a water head difference, between a liquid level of the ink filled in the first ink containing unit and a liquid level of the ink filled in the second ink containing unit. In other words, only a portion of the ink reciprocates between two ink containing units, and thus only the portion is agitated. For this reason, the ink remaining in the ink containing units is insufficiently agitated, and thus it does not prevent sedimentation of the color component of the ink in the ink containing units.

SUMMARY

An advantage of some aspects of the invention is to provide a liquid ejecting apparatus capable of preventing precipitate or adhesion of a liquid and sedimentation of a color component of the liquid and also preventing idle striking operation of the liquid in a head, without installing an agitating unit in a liquid containing unit.

An aspect of the invention is to provide a liquid ejecting apparatus including: a first liquid containing unit containing a liquid therein; a second detachable liquid containing unit containing a liquid therein and having a liquid containing a volume smaller than that of the first liquid containing unit; a communication passage that communicates the first liquid containing unit with the second liquid containing unit, in which the first liquid containing unit and the second liquid containing unit are reciprocally replenished with the liquid via the communication passage; a liquid replenishing unit that replenishes the liquid between the first liquid containing unit and the second liquid containing unit via the communication passage; and a control unit that, when the liquid is replenished from any one of the first and second liquid containing units to the other, controls the liquid replenishing unit so as to replenish the liquid from the one liquid containing unit to the other liquid containing unit, until the liquid contained in the one liquid containing unit reaches a predetermined amount smaller than the liquid containing volume of the second liquid containing unit. By supplying the liquid from the one liquid containing unit to the other liquid containing unit via the communication passage, the liquid filled in both liquid containing units and the communication passage is agitated. Therefore, it is possible to prevent precipitate or adhesion of the liquid or sedimentation of the color component of the liquid, in the case where the agitating unit is not installed in the liquid containing units. Also, the first liquid containing unit has a liquid containing volume larger than that of the second liquid containing unit. Therefore, for example, even after the second liquid containing unit is left for a long time in the state a remainder of the ink is large, it is possible to be sure of agitating the liquid contained in the second liquid containing unit by replenishing the first liquid containing unit with the total amount of the liquid contained in the second liquid containing unit.

Whenever the liquid replenishing unit replenishes the liquid between the respective liquid containing units, the control unit judges whether or not the liquid filled in the one liquid containing unit is the predetermined amount, and controls the liquid replenishing unit based on the judged result. Since the agitating effect of the liquid is obtained whenever the liquid is supplied between both liquid containing units, it is possible to be sure of preventing sedimentation or adhesion of the liquid, and sedimentation of the color component of the liquid.

In the case where the liquid replenishing unit replenishes the liquid between the respective liquid containing units, whenever the number of replenishments reaches a predetermined number or reciprocal replenishments reaches a predetermined time, the control unit judges whether or not the liquid filled in the one liquid containing unit is the predetermined amount, and controls the liquid replenishing unit based on the judged result. Since the agitating operation is sufficiently carried out with respect to the liquid while changing the replenishing operation of the liquid which is carried out between both liquid containing units, it is possible to be sure of preventing sedimentation or adhesion of the liquid, and sedimentation of the color component of the liquid.

When liquid replenishing unit replenishes the liquid between the respective liquid containing units, the control unit controls the liquid replenishing unit in such a way that a desired amount after the number of replenishments reaches a predetermined number is less than the desired amount before the number of the replenishments reaches the predetermined number, thereby changing the replenishing operation of the liquid which is carried out between both liquid containing units. More specifically, before the number of replenishments of the liquid reaches the predetermined number, the predetermined amount is set high as compared to the predetermined amount after the number of replenishments of the liquid reaches the predetermined number, so that it is possible to increase the number of replenishing operations of the liquid carried out between both liquid containing units. Meanwhile, after the second liquid containing unit is exchanged and before the number of replenishments of the liquid reaches the predetermined number, it is assumed that the total amount of the liquid contained in both liquid containing units and the communication passage is relatively increased. With the above configuration, it is possible to suppress deterioration of the number of replenishing operations of the liquid which is carried out between both liquid containing units, even in the above instance.

The control unit controls the liquid replenishing unit in such a way that the predetermined amount is gradually decreased in accordance with consumption of the liquid. Therefore, immediately after the second liquid containing unit is exchanged, it is possible to stop the number of replenishing operations of the liquid which is carried out between both liquid containing units from decreasing, even though the total amount of the liquid contained in both liquid containing units and the communication passage is relatively large. Also, if the total amount of the liquid contained in both liquid containing units and the communication passage is decreased with the consumption of the liquid, the predetermined amount is set to be gradually decreased. Thus, a ratio of the liquid supplied to the other liquid containing unit to the liquid contained in the one liquid containing unit is gradually increased. Therefore, the agitating operation of the liquid can be surely carried out by the replenishing operation of the liquid between both liquid containing units.

The control unit controls the liquid replenishing unit in such a way that the predetermined amount in the case where the first liquid containing unit replenishes the second liquid containing unit with the liquid differs from the predetermined amount in the case where the second liquid containing unit replenishes the first liquid containing unit with the liquid. For example, the total amount of the liquid contained in the one liquid containing unit is supplied to the other liquid containing unit, and only a part of the liquid contained in the other liquid containing unit is supplied to the one liquid containing unit. In this instance, the liquid contained in the one liquid containing unit is agitated more surely than the liquid contained in the other liquid containing unit. In other words, with the above configuration, it is possible to agitate intensively the liquid contained in any one of the first liquid containing unit and the second liquid containing unit, by properly setting the predetermined amount.

Another aspect of the invention is to provide a liquid ejecting apparatus including: a first liquid containing unit containing a liquid therein; a second detachable liquid containing unit containing a liquid therein and having a liquid containing volume smaller than that of the first liquid containing unit; a communication passage that communicates the first liquid containing unit with the second liquid containing unit, in which the first liquid containing unit and the second liquid containing unit are reciprocally replenished with the liquid via the communication passage; a liquid replenishing unit that replenishes the liquid between the first liquid containing unit and the second liquid containing unit via the communication passage; a control unit that, when the liquid is supplied from any one of the first and second liquid containing units to the other, controls the liquid replenishing unit to replenish the liquid from the one liquid containing unit to the other liquid containing unit, until the liquid contained in the one liquid containing unit reaches a predetermined amount smaller than the liquid containing volume of the second liquid containing unit; a detecting unit that detects an amount of the liquid contained in the liquid containing unit of any one of the first liquid containing unit and the second liquid containing unit, or an amount of the liquid flowing through the communication passage; and a judging unit that judges the total amount of the liquid filled in the respective liquid containing units based on an output of the detecting unit, wherein the control unit performs stop control of the operation of reciprocal replenishment based on a judged result of the judging unit, and in the stop control, the operation is stopped in a state where the liquid remains in any one of liquid containing unit of the first liquid containing unit and the second liquid containing unit. Therefore, the liquid ejecting apparatus includes an ink agitating function, so that the pigment and solvent are sufficiently agitated to prevent discoloration. Also, when the total amount of the liquid reaches a predetermined remaining amount, the reciprocal replenishment stops or an end display is performed. A predetermined remaining amount of the liquid can remain in any one of the first and second liquid containing units as the total amount of the liquid. Since the remaining amount of the ink is consumed by the head even after the operation of reciprocal replenishment stops, it is possible to prevent the idle striking operation in the head. Further, it is possible to prevent precipitate or adhesion of the ink and the sedimentation of the ink by the agitation resulting from the reciprocal replenishment. Also, a predetermined remaining amount of the liquid can remain in any one of the first liquid containing unit and the second liquid containing unit. Thus, the remaining amount of the liquid can be consumed by the head, and it is possible to be sure of preventing the idle striking operation of the liquid in the head.

The control unit transfers the liquid contained in the second liquid containing unit to the first liquid containing unit immediately after the operation of reciprocal replenishment stops or when the operation of reciprocal replenishment stops, so that the liquid contained in the second liquid containing unit becomes an empty state or a near empty state. Therefore, since the liquid does not remain in the second liquid containing unit to be exchanged, it is possible to prevent the liquid remained in the second liquid containing unit from wastefully throw away, when the second liquid containing unit is wasted at the exchange.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIGS. 1 to 5show the first embodiment of the invention.FIG. 1is a view showing the configuration of a printer device as one example of a liquid ejecting apparatus according to the invention.FIG. 2is a view showing a fluctuation of an amount IT of ink contained in a tank, a fluctuation of an amount IC of ink contained in a cartridge, a fluctuation of the total amount IK of the ink, and generation timing of a pulse P.FIG. 3is a flowchart showing the operation of reciprocal replenishing control.FIG. 4is a perspective view of an ink tank and an ink cartridge.FIG. 5is a cross-sectional view showing the ink tank, the ink cartridge and a head.

As shown inFIG. 1, the liquid ejecting apparatus, for example, a printer device1, includes a first liquid containing unit, that is, an ink tank2(hereinafter referred to as a tank), for containing ink as a liquid therein, a second liquid containing unit, that is, an ink cartridge3(hereinafter referred to as a cartridge) which serves as a storage tank, for containing ink as a liquid therein, a head4, a communication passage5for communicating the tank2and the cartridge3via the head4, a pump P1of the tank2side, an open-close valve V1of the tank2side, a pump P2of the cartridge3side, an open-close valve V2of the cartridge3side, a flow sensor Q serving as a detection unit, and a control unit11.

The tank2communicates with the cartridge3via the communication passage5extending through the head4, so that a liquid (i.e., ink) is reciprocally (alternatively) supplied to the tank2and the cartridge3via the communication passage5. The pump P1of the tank2side serves as a liquid replenishing unit for replenishing the ink to the cartridge3from the tank2via the communication passage5. The pump P2of the cartridge3side serves as a liquid replenishing unit for replenishing the ink to the tank2from the cartridge3via the communication passage5. In the case where the ink is supplied from any one of the tank2and the cartridge3to the other via the communication passage5, the control unit11controls in such a way that the ink replenishing side replenishes the ink until the ink filled in the ink replenishing side reaches a specified amount, for example, an empty state or a near empty state, which will be described below.

The tank2is fixed or detachably attached to the carriage (head attaching part) IK which is a movable part of the printer device1. The tank2is not replaced with a new one by consumption of the ink in this embodiment, but the tank2may be replaced with a new one. As shown inFIGS. 1,4and5, the tank2has a containing unit15forming a pressure chamber13, and a storage bag body16provided in the pressure chamber13and serving as an ink (liquid) containing unit. The containing unit15is made of a nonporous hard material such as hard plastic, and is provided with a containing unit-side ink flow port17having a bag-side ink flow port20which is described below, an air inlet port18for communicating an inside of the pressure chamber13with the exterior, and an air outlet port19for communicating the inside of the pressure chamber13with the exterior. The storage bag body16is formed of a thin-type bag containing the ink therein and having a variable volume, the bag made of a flexible material having gas permeability substantially equal to or higher than that of the material forming the containing unit15, such as butyl rubber, polysulfide rubber, epichlorohydrin rubber, high nitrile rubber, or fluorine-contained rubber. The storage bag body is provided with the bag-side ink flow port20. The bag-side ink flow port20is fixed to the containing unit15in such a way as to face the exterior of the containing unit15through the containing unit-side ink flow port17, and an opened end of an ink passage21of the tank2is connected to the bag-side ink flow port20of the storage bag body16in order to communicate the ink between the ink passage21of the tank2side and the storage bag body16. Also, in order to supply the air into the pressure chamber13, the other opened end of an air supply passage23is connected to the air inlet port18, and the one opened end of the air supply passage23is connected to the outlet port26of the pump P1of the tank2side. The intake port22of the pump P1of the tank2side is opened to the atmosphere. Also, in order to open the inside of the pressure chamber13to the atmosphere or interrupt the inside thereof from the atmosphere, the other opened end of an air discharge passage27is connected to the air outlet port19, and the one opened end of the air discharge passage27is connected to the open-close valve V1of the tank2side.

The cartridge3is detachably attached to the body of the printer device1, so that the cartridge is replaced with new one by consumption of the ink in the embodiment. As shown inFIGS. 1,4and5, the cartridge3has a containing unit35forming a pressure chamber33therein, and a storage bag body36provided in the pressure chamber33and serving as an ink (liquid) containing unit. The containing unit35is made of a nonporous hard material such as hard plastic, and is provided with a containing unit-side ink flow port37having a bag-side ink flow port40which is described below, an air inlet port38for communicating an inside of the pressure chamber33with the exterior, and an air outlet port39for communicating the inside of the pressure chamber33with the exterior. The storage bag body36is formed of a thin-type bag containing the ink therein and having a variable volume, the bag made of a flexible material having gas permeability substantially equal to or higher than that of the material forming the containing unit35, such as butyl rubber, polysulfide rubber, epichlorohydrin rubber, high nitrile rubber, or fluorine-contained rubber. The storage bag body36is provided with the bag-side ink flow port40. The bag-side ink flow port40is fixed to the containing unit35in such a way to face the exterior of the containing unit35through the containing unit-side ink flow port37, and an opened end of an ink passage41of the cartridge3side is connected to the bag-side ink flow port40of the storage bag body36in order to communicate the ink between the ink passage41of the cartridge3side and the storage bag body36. Also, in order to supply the air into the pressure chamber33, the other opened end of an air supply passage43is connected to the air inlet port38, and the one opened end of the air supply passage43is connected to the outlet port46of the pump P2of the cartridge3side. The intake port42of the pump P2of the cartridge3side is opened to the atmosphere. Also, in order to open the inside of the pressure chamber33to the atmosphere or interrupt the inside thereof from the atmosphere, the other opened end of an air discharge passage47is connected to the air outlet port39, and the one opened end of the air discharge passage47is connected to the open-close valve V2of the cartridge3side.

In this embodiment, the tank2and the cartridge3have a similar configuration, except for the replaceable structure. When the cartridge3is not in use, the bag-side ink flow port40is sealed by a sealing film (not shown). The one opened end of the ink passage41of the cartridge3side is provided with an ink supply needle (not shown). In the configuration as described above, in the case where the cartridge3is attached to the printer device1, the ink supply needle breaks the sealing film, so that the ink contained in the storage bag body36of the cartridge3is supplied to the head4via a hollow passage of the ink supply needle and the ink passage41of the cartridge3side. The ink passage41of the cartridge3side is provided with an open-close valve (not shown) at a position close to the ink supply needle, so that the open-close valve is closed by the control unit11when the cartridge3is exchanged. The cartridge3may be installed in the carriage IK. If a new cartridge3is mounted, a switch (not shown) is pushed to initiate the operation of liquid reciprocal replenishment which is described below.

As shown inFIG. 5, the head4has an ink chamber24, a pressure chamber25, a nozzle28and an actuator30. One opened end of the ink chamber24is connected to the other opened end of the ink passage21of the tank2side in a communication manner, and the other opened end of the ink chamber24is connected to the other opened end of the ink passage41of the cartridge3side in a communication manner. In other words, the communication passage5for communicating the tank2with the cartridge3via the head4is constituted by the ink passage21of the tank2side for communicating the tank2with the ink chamber24, the ink passage41of the cartridge3side for communicating the cartridge3with the ink chamber24, and the ink chamber24serving as an ink passage for communicating the ink passage21of the tank2side with the ink passage41of the cartridge3side. One opened end of the pressure chamber25communicates with the ink chamber24, and the other opened end of the pressure chamber25communicates with the nozzle28. The actuator30is formed by, for example, a piezoelectric device or heater device which is provided on a wall of the pressure chamber25.

In the head4, the ink supplied from the ink chamber24to the pressure chamber25forms a recessed surface (meniscus) of the ink at an exit of the nozzle28, and the ink is pushed out from the nozzle28by operation of the actuator30to form a drop. The drop is adhered to an object to be printed on to carry out the printing with respect to the object to be printed on, such as paper.

The flow sensor Q is provided in the ink passage21of the tank2as the communication passage5, and detects that an amount of the ink flowing through the ink passage21of the tank2side becomes zero. The flow sensor Q outputs a pulse P which is described below, and supplies the pulse to the control unit11. Accordingly, the flow sensor Q constitutes a detecting unit for detecting an empty state of the ink filled in the tank2and the cartridge3. The amount IT of ink filled in the tank2or the amount IC of ink filled in the cartridge3is reciprocally varied, as shown inFIG. 2, to become an empty state. Then, if the ink remains in the communication passage5(ink passage) of a forward path route A or a return path route B, and the head4, the flow of ink stops. For this reason, the flow sensor Q detects an amount of the ink flowing through the ink passage21of the tank2side as zero, and outputs the pulse P (pulse Pa and pulse Pb) indicating that the ink supplied to the tank2or the cartridge3becomes an empty state, to the control unit11. In the case where the cartridge3replenishes the tank2with the ink at the forward path route A, the pulse Pa is output from the flow sensor Q at the time where the amount IC of the ink filled in the cartridge3becomes an empty state and the tank is not replenished with the ink. Meanwhile, in the case where the tank2replenishes the cartridge3with the ink at the return path route B, the pulse Pb is output from the flow sensor Q at the time where the amount IT of the ink filled in the tank2becomes an empty state and the cartridge is not replenished with the ink. The flow sensor Q is constituted by a bidirectional flow detector, and has a pulse circuit for outputting the pulse P (i.e., the pulse Pa and the pulse Pb) if the amount IT of the ink filled in the tank2or the amount IC of the ink filled in the cartridge3becomes an empty state. As shown inFIG. 2, if a remaining amount X of the ink becomes zero at the time tm, the pulse P is not output.

The control unit11has a pulse detecting unit54for reciprocally detecting the pulse P (i.e., the pulse Pa and the pulse Pb) output from the flow sensor Q, and reciprocally drives a forward path replenishment control unit51and a return path replenishment control unit52based on the output from the pulse detecting unit54to reciprocally set the replenishment route to the forward path route A or the return path route B. The control unit11outputs the control signal to a driver50for the pumps P1and P2or a driver58for the open-close valves V1and V2via an input/output interface45. Each of the drivers50and58controls the pumps P1and P2and the open-close valves V1and V2based on the control signal output from the control unit to form the forward path route A and the return path route B.

As shown inFIGS. 1 and 2, if the pulse P (i.e., pulse Pb) is output from the flow sensor Q, the forward path replenishment control unit51is driven by the reciprocal replenishment control unit53, so that the return path route B is converted into the forward path route A. Then, the cartridge3replenishes the tank2with the ink by transferring the ink from the cartridge3to the tank2via the communication path5based on the forward path route A. After that, the pulse P (i.e., the pulse Pa) is output from the flow sensor Q at the time when the amount IC of the ink is in the empty state at the forward path route A. Then, the return path replenishment control unit52is driven by the reciprocal replenishment control unit53, so that the forward path route A is converted into the return path route B. Then, the tank2replenishes the cartridge3with the ink by transferring the ink from the tank2to the cartridge3via the communication passage5based on the return path route B. In other words, the control unit11reciprocally receives the pulses Pa and Pb to enable the reciprocal replenishment control unit53to control reciprocally the reciprocal replenishment between the forward path replenishment control unit51and the return path replenishment control unit52. Therefore, the forward path route A and the return path route B are reciprocally formed, and the ink is reciprocated more than once between the cartridge3and the tank2, so that the ink is agitated to prevent precipitate or adhesion of the ink. Further, the concentration of the ink can be properly maintained to prevent sedimentation of the color component of the ink.

The operation of the control unit11will now be described in detail. As shown inFIG. 2, whenever the amounts IT and IC of the ink filled in the tank2and the cartridge3become zero, that is, an empty state, the pulse P (i.e., the pulse Pa and the pulse Pb) is reciprocally output from the flow sensor Q to the control unit. More specifically, when the ink flows from the cartridge3to the tank2via the forward path route A, if the amount IC of the ink becomes zero, the flow amount of the ink is zero, and the pulse Pa is output from the flow sensor Q. On the contrary, when the ink flows from the tank2to the cartridge3via the return path route B, if the amount IT of the ink becomes zero, the flow amount of the ink is zero, and the pulse Pb is output from the flow sensor Q. If the pulse detecting unit54of the control unit11input the pulse Pa, the control of the forward path replenishment control unit51is converted into the control of the return path replenishment control unit52to form the return path route B. Meanwhile, if the pulse detecting unit54input the pulse Pb, the control of the return path replenishment control unit52is converted into the control of the forward path replenishment control unit51to form the forward path route A. Therefore, the control of reciprocal replenishment is performed to repeat reciprocally the control of the forward path replenishment by the forward path route A and the control of the return path replenishment by the return path route B. Whenever the control unit11input the pulse Pa from the flow sensor Q, the control unit11determines that the amount IC of the ink filled in the cartridge3becomes an empty state, and starts to control the return path replenishment by the return path route B, in which the tank2replenishes the cartridge3with the ink. Further, whenever the control unit11input the pulse Pb from the flow sensor Q, the control unit11determines that the amount of the ink filled in the tank2becomes an empty state, and starts to control the forward path replenishment by the forward path route A, in which the cartridge3replenishes the tank2with the ink. Since the control unit11reciprocally transfers the ink from the cartridge3to the tank2or from the tank2to the cartridge3by the control of replenishment, reciprocal flowage lead to an agitation effect, thereby preventing precipitate or adhesion of the ink and thus properly maintaining the concentration of the ink.

The control operation of reciprocal replenishment will be described with reference to a flowchart shown inFIG. 3. The printer device1has the tank2of a near empty state in the state of a new product (i.e., an initial use state). The cartridge3filled with the ink is mounted in the printer device to form the forward path route A, so that the tank2is replenished with the ink via the forward path route A. After that, the control of reciprocal replenishment is initiated according to the flowchart shown inFIG. 3. The control of reciprocal replenishment is performed at the same time as the control of printing operation after the control unit11input a printing command.

First of all, at step S1, in the state where the pump P1of the tank2side and the pump P2of the cartridge3side stop, the open-close valve V1of the tank2side is opened to open the pressure chamber13of the tank2side to the atmosphere. At the same time, the open-close valve V2of the cartridge3side is closed to interrupt the pressure chamber33of the cartridge3side from the atmosphere, so that the pressure chamber33of the cartridge3side is maintained in a closed state. At step S2, the pump P2of the cartridge3side is driven to pressurize the inside of the pressure chamber33of the cartridge3side. Therefore, the forward path route A is formed, and the storage bag body36of the cartridge3is pressurized by the pressure in the inside of the pressure chamber33of the cartridge3side, so that the ink filled in the storage bag body36of the cartridge3is fed to the communication passage5and then is moved to the head4and the storage bag body16of the tank2. In other words, the control is performed by the forward path replenishment control unit51for feeding the ink through the above-described forward path route A. In the replenishment control of the forward path route A, at step S3, in the case where a amount of the ink flowing through the ink passage21of the tank2side is detected (Yes at step S3), the control unit11judges that the amount of the ink in the storage bag body36of the cartridge3(referred to as an amount IC of ink in the cartridge) is not an empty state, and continuously drives the pump P2of the cartridge3side. The control of the forward path replenishment in the forward path route A is continued by continuously pressurizing the inside of the pressure chamber33of the cartridge3side (step S2). At step S3, if the amount IC of the ink filled in the cartridge becomes an empty state and the flow amount of the ink is zero, the pulse Pa is output from the flow sensor Q. In the case where the pulse detecting unit54detects the pulse Pa (No at step S3), the control unit11judges that the amount IC of the ink filled in the cartridge has been an empty state as a predetermined amount (that is, the pulse Pa is generated), and stops the pump P2of the cartridge3side. At the same time, the control unit11opens the open-close valve V2of the cartridge3side to open the pressure chamber33of the cartridge3side to the atmosphere. At the same time, the control unit11closes the open-close valve V1of the tank2side to interrupt the pressure chamber13of the tank2side from the atmosphere, so that the pressure chamber13of the tank2side is maintained in a closed state (Step S4) to complete the control of the forward path replenishment in the forward path route A. At step S5, the return path route B is formed by the pulse Pa, and the pump P1of the tank2side is driven to pressurize the inside of the pressure chamber13of the tank2side. In other words, the control of the return path replenishment in the return path route B starts. At step S6, in the case where a flow amount of the ink flowing through the ink passage21of the tank2side is detected, that is, in the case where the pulse Pb is not input from the flow sensor Q (Yes at step S6), the control unit11judges that the amount of the ink in the storage bag body36of the tank2(referred to as an amount IT of ink in the tank) is not an empty state, and continuously drives the pump P1of the tank2side. The control of the return path replenishment is continued by continuously pressurizing the inside of the pressure chamber13of the tank2side (step S5). At step S6, if the amount IT of the ink filled in the tank becomes an empty state and the flow amount of the ink is zero, the flow sensor Q outputs the pulse Pb. In the case where the pulse detecting unit54detects the pulse Pb (No at step S6), the control unit11judges that the amount IT of the ink filled in the tank becomes an empty state, and stops the pump P1of the tank2side at step S7. At the same time, the control unit11opens the open-close valve V1of the tank2side to open the pressure chamber13of the tank side to the atmosphere. Also, the control unit11closes the open-close valve V2of the cartridge3side to interrupt the pressure chamber33of the cartridge3side from the atmosphere. Therefore, the pressure chamber33is maintained in a closed state, and the control of the return path replenishment in the return path route B is completed. As a result, the control of the forward path replenishment in the forward path route A and the control of the return path replenishment in the return path route B are reciprocally performed based on the pulse P (i.e., the pulse Pa and the pulse Pb) output from the flow sensor Q. If the ink is supplied to the ink chamber24of the head4and then is consumed for printing while the control of the reciprocal replenishment is performed, a time interval T during the empty state is shortened, so that the judgment1(No at step S3) and the judgment2(No at step S6) become gradually faster. As a result, the number of the pulses P (i.e., the pulse Pa and the pulse Pb) generated every unit time F is increased, and the total amount IK of the amount IC of the ink filled in the cartridge and the amount IT of the ink filled in the tank shown inFIG. 2is decreased to the extent requiring exchange of the cartridge3in accordance with the number of generated pulse. For this reason, at step S8, it is judged whether or not the judgment1and the judgment2are repeated by the predetermined number N within a certain (unit) time F, that is, whether or not the input number of the pulse Pa and the pulse Pb reaches the predetermined number set in advance within the unit time F. At step S8, in the case where the pulse P reaches the predetermined number N within the unit time (predetermined number) within the unit time, an ink end indicator57performs an ink end display (step S9), and instructs the exchange of ink. After the lapse of time tm, if there is no remaining amount X of the ink, the control of the reciprocal replenishment by the control unit11stops because the pulse P is not output from the flow sensor Q.

As described above, since the control of the reciprocal replenishment and the control of the printing operation are simultaneously performed, and a part of the ink is fed to the ink chamber24of the head4via the communication passage5and is consumed for the printing, as the control of the reciprocal replenishment proceeds, as shown inFIG. 2, the total amount IK of the amount IC of the ink filled in the cartridge and the amount IT of the ink filled in the tank (the amount of ink exists in the communication passage and the head, but is neglected herein for the sake of convenience) is decreased. The remaining amount X of the ink (i.e., the total amount IK of the ink) is judged at step S8, and since the ink end display has been previously performed before the ink runs down, the necessity for the exchange of the cartridge3is urged.

In this instance, it is set in such a way that if there is no remaining amount X of the ink at the time tm, the pulse P is not output from the flow sensor Q, and the operation of the printer device1is stopped.

According to the first embodiment, since the ink reciprocates between the ink containing unit (i.e., the tank2) and the ink containing unit (i.e., the cartridge3), it is possible to prevent sedimentation or adhesion of the ink and thus properly maintain the concentration of the ink. Also, since the ink contained in the ink containing unit at the side of replenishing the ink is fully squeezed to the empty state, the agitation effect of the ink is increased, and it is possible to prevent effectively sedimentation of the color component of the ink. Also, since the bidirectional flow sensor Q is utilized, it is possible to judge accurately whether or not the ink contained in the ink containing unit at the side of replenishing the ink becomes the empty state, based on the output of one flow sensor Q. Further, since the tank2and the cartridge3have the pressure chambers13and33for feeding the ink from the ink containing units to the communication passage5at the air pressure output from the pumps P1and P2, the operation of reciprocal replenishment can be surely performed. Also, since the tank2and the cartridge3have the ink containing unit possessing flexibility, the operation of reciprocal replenishment can be surely performed. Meanwhile, if the judgment at step S8can be quickly performed, step S7may be omitted.

In the second embodiment, the idle striking of the ink is prevented by instructing the exchange of the cartridge3at the end of the ink replenishment, in the state where the ink remains in the tank2at the remaining amount X of the ink. Also, it is possible to prevent the ink from being wastefully thrown away when the cartridge3is exchanged.

The ink containable volume of the storage bag body36of the cartridge3is smaller than that of the storage bag body16of the tank2. Therefore, even though the cartridge3replenishes the tank2with the total amount of the ink when the cartridge3is mounted, it prevents the ink from overflowing the tank2, and the ink contained in the cartridge3is agitated surely. Even though the whole amount of the ink is transferred from the cartridge3to the tank2after the cartridge3is exchanged in the state where the ink remains in the tank2, there is no overflow of the ink from the tank2.

The control of the reciprocal replenishment and the control of the cartridge exchange according to the second embodiment will now be described with reference toFIG. 6. Since the control of reciprocal replenishment at steps S11to S17is similar to the control of reciprocal replenishment at steps S1to S7according to the first embodiment, the description thereof will be omitted. At step S18, it is judged whether or not the judgment1(No at step S13) and the judgment2(No at step S16) are repeated by the determined number N every unit time F (hereinafter referred to as exchange judgment). If the judged result at step S18is Yes, the reciprocal replenishment stops. This corresponds to when the control of the reciprocal replenishment stops when the number of the pulses P (i.e., Pa and Pb) generated every unit time F reaches the predetermined number, and the ink end display may be performed at step S23in the state where the remaining amount X of the ink remains at a required amount. As the predetermined number N is set high, the remaining amount X of the ink is decreased. Also, as the predetermined number N is set low, the remaining amount X of the ink is increased. Accordingly, in order to increase the remaining amount X of the ink existing in the cartridge3when the cartridge3is exchanged, the predetermined number N every unit time F may be set low. Also, in order to decrease the remaining amount X of the ink existing in the cartridge3when the cartridge3is exchanged, the predetermined number N every unit time F may be highly set. In other words, the constant time (unit time) F and the predetermined number N, that is, an exchange judgment value, are determined in accordance with the remaining amount X of the ink existing in the cartridge3when the cartridge3is exchanged. Also, the exchange judgment value is compensated in accordance with viscosity of the used ink and surrounding temperature. The control unit11includes a compensation table to relate the exchange judgment value to the viscosity of the ink, and a compensation table to relate the exchange judgment value to the surrounding temperature. Further, the control unit11sets the exchange judgment value by comparing the input viscosity of the ink and the input surrounding temperature with the compensation table. The viscosity of the ink and the surrounding temperature are values input to the control unit11via a setting device (not shown) by a user, or values measured by a viscometer (not shown) and a thermometer (not shown) provided in the communication passage5and input to the control unit11.

If the judged result at step S18is Yes, the control unit11judges that the total amount IK of ink has reach the predetermined remaining amount X of the ink set in advance, and stops the operation of the reciprocal replenishment. It proceeds to step S19. At step S19, the control unit11stops the driving of the respective pumps P1and P2, and opens the open-close valve V1of the tank2side to open the pressure chamber13of the tank2side to the atmosphere. At the same time, the control unit11closes the open-close valve V2of the cartridge3side. Next, at step S20, the control unit11forms the forward path route A, and drives the pump P2of the cartridge3side to pressurize the inside of the pressure chamber33of the cartridge3side, so that the whole amount of the ink existing in the cartridge3is transferred to the tank2. In the case where the flow amount of the ink flowing through the ink passage21of the tank2side is detected at step S21, that is, while the flow sensor Q inputs a certain number other than zero (Yes at step S21), the control unit11judges that the amount of the ink filled in the cartridge3is not an empty state. The pump P2of the cartridge3side is continuously driven to pressurize continuously the inside of the pressure chamber33of the cartridge3side (step S20). And then, if the flow amount of the ink flowing through the ink passage21of the tank2side is zero at the step S21, the control unit11cause the flow sensor Q to detect the flow rate of zero (No at step S21). The control unit11judges that the amount of the ink filled in the cartridge3is an empty state (No at step S21), and stops the driving of the respective pumps P1and P2and closes the respective open-close valves V1and V2(step S22). Therefore, in the state where all predetermined remaining amounts X of the ink accurately exist in the tank2, the ink end indicator57provided in the body of the printer device1performs the ink end display (step S23). The control unit11closes an open-close valve (not shown) provided at a position close to the ink supply needle of the ink passage21of the cartridge3side. After that, the user verifies the ink end display performed by the ink end indicator57to operate the exchange of the cartridge3.

In the second embodiment, the cartridge3can be exchanged in the state where the predetermined remaining amount X of the ink accurately exists in the tank2. Therefore, although the printing operation is carried out, without exchanging the cartridge3, after the ink end display is performed, the remaining amount of the ink is spent by the head4until the predetermined remaining amount Y of the ink is exhausted. As a result, it is possible to prevent the idle striking of the ink in the head4. Also, since the cartridge3is exchanged in the empty state, it is possible to prevent the ink from being wastefully thrown away.

As shown inFIG. 7, the air supply passages23and43may be provided with air exhaust passages27and47, respectively, in such a way that the air supply passages23and43communicate with the air exhaust passages27and47, and open-close valves V1and V2may be installed in the air exhaust passages27and47.

In the case where the ink is one employing a petroleum solvent, as shown inFIG. 8, the ink containing units of the tank2and the cartridge3for containing the ink may be formed of a vessel60made of a hard material and having a constant ink containing volume. In this instance, as shown inFIG. 8, the control of reciprocal replenishment may be performed by pressing the ink filled in the containing unit60using the pressurized air of the press pumps P1and P2, similar to the configuration according to the first embodiment shown inFIG. 1. In this instance, the ink comes in contact with the air, but the ink can be used if the ink which is not deteriorated by the air is available. Instead of the configuration shown inFIG. 8, similar to the case shown inFIG. 7, the air supply passages23and43may be provided with air exhaust passages27and47, respectively, in such a way that the air supply passages23and43communicate with the air exhaust passages27and47, and open-close valves V1and V2may be installed in the air exhaust passages27and47, which is not shown in the drawings. As shown inFIG. 9, the communication passage5may be provided with suction pumps62and63, and a suction direction of the suction pumps62and63may be controlled by the control unit11via drivers62aand63ato perform the control of reciprocal replenishment.

As shown inFIG. 10, the ink containing unit may be constituted by a bag made of a flexible material having gas impermeability and a variable ink containing volume, and utilize the tank2and the cartridge3which have no pressure chambers13and33. In this instance, the communication passage5is provided with the suction pumps62and63, and a suction direction of the suction pumps62and63is controlled by the control unit11via drivers62aand63ato perform the control of reciprocal replenishment.

As shown inFIG. 11, a level sensor may be provided in the ink containing unit of the tank2and the ink containing unit of the cartridge3, respectively, as a detecting unit, to output an analog signal in accordance with a liquid volume of the ink contained in the respective ink containing units. For example, a level sensor Sx for detecting and outputting a liquid level ITa of the ink filled in the ink containing unit of the tank2and a level sensor Sy for detecting and outputting a liquid level ICa of the ink filled in the ink containing unit of the cartridge may output analog signals ITb and ICb indicative of the liquid levels, and predetermined values (predetermined amounts) M1and M2of adjustable size stored in a memory (not shown) of the control unit11may be compared with the analog signals ITb and ICb to control the reciprocal replenishment, as shown inFIG. 12. In other words, whenever the signals ITb and ICb reach the predetermined values (predetermined amounts) M1and M2, it is possible to control the switching timing of reciprocal replenishment between the forward path route A and the return path route B. It is possible to control the replenishment until the ink filled in the tank2and the cartridge3reaches a predetermined amount. More specifically, if reference values M1and M2are set to zero, the control of the reciprocal replenishment is carried out until both ink filled in the tank2and the cartridge3becomes an empty state as described in the first embodiment. Also, if the reference values M1and M2are set to a certain number other than zero, it is possible to switch the control of forward path replenishment and the control of return path replenishment in the state where the ink remains in any one of the tank2and the cartridge3.

As shown inFIG. 12, in the case where the cartridge3replenishes the tank2with the ink via the forward path route A, the replenishment can be controlled until the ink filled in the ink containing unit of the cartridge3remains in a predetermined amount Z. In the case where the tank2replenishes the cartridge3with the ink via the return path route B, the replenishment control can be switched into the control of forward path replenishment until the ink filled in the ink containing unit of the tank2becomes an empty state. With the above configuration, when the ink is replenished between the tank2and the cartridge3, the ink to be contained in the tank2is agitated more surely than the ink to be contained in the cartridge3. In other words, it is possible to select an ink containing unit which intensively agitates the ink contained in the tank2and the cartridge3, by properly setting the reference value M1and the reference value M2.

As shown inFIG. 13, the configuration below may be employed as the control of reciprocal replenishment performed by the control unit11. In other words, until the number of the control of reciprocal replenishments reaches predetermined numbers N3and N4, the replenishment control is performed in such a way that amounts of the ink filled in both ink containing units of the tank2and the cartridge3remain in the predetermined amount Z. Meanwhile, at the time that the number of the control of reciprocal replenishments reaches predetermined numbers N3and N4, the ink is supplied until the amount of the ink filled in both ink containing units of the tank2and the cartridge3becomes an empty state. In this instance, it is possible to change the replenishing operation of the ink which is carried out between the tank2and the cartridge3. More specifically, before the number of the control of reciprocal replenishments reaches the predetermined numbers N3and N4, the amount of the ink remaining in the tank2or the cartridge3is set high when the replenishment of the ink is operated, rather than the time when the number of the control of reciprocal replenishments reaches the predetermined numbers N3and N4. Therefore, it is possible to increase the number of the replenishing operations of the ink carried out between the tank2and the cartridge3. Immediately after the cartridge3is exchanged and before the number of the control of reciprocal replenishments reaches the predetermined numbers N3and N4, it is assumed that the total amount of the ink contained in the tank2and the cartridge3is relatively increased. With the above configuration, it is possible to suppress reduction in the number of the replenishing operation of the ink which is carried out between the tank2and the cartridge3, even in the above instance.

Alternatively, the configuration below may be employed as the control of reciprocal replenishment carried out by the control unit11. In other words, until time from the start of the control of reciprocal replenishments reaches predetermined times t1and t2set in a timer (not shown), the control of replenishment is stopped, with the amount of the ink filled in the ink containing unit supplying the ink being left only by a predetermined amount Z. If it reaches the predetermined times t1and t2, the ink is replenished until the amount of the ink filled in the ink containing unit supplying the ink becomes an empty state in the control of replenishment at that time. In this instance, the control unit11reciprocally replenishes the ink containing units with the ink, and whenever the number of replenishments reaches a predetermined number or the reciprocal replenishments reaches a predetermined time, the replenishment is carried out until the amount of the ink filled in the ink containing unit supplying the ink becomes an empty state. With the above configuration, it is possible to prevent effectively the precipitate or adhesion of the ink, or the sedimentation of the color component of the ink, since the operation of the reciprocal replenishment is varied. Further, since the control of reciprocal replenishment is quickly switched and the head4is early supplied with the ink, the invention is effective against the case where the ink consumption of the head4is high. Since the level sensors Sx and Sy for outputting analog signals in accordance with the amount of the ink filled in the ink containing unit are used as a detecting unit, the judgment whether or not the ink filled in the ink containing unit supplying the ink is a predetermined amount can be accurately performed by the output of the level sensors.

Although there is described above the flow sensor Q for outputting the pulse Pa (at the route A) or the pulse Pb (at the route B) at the time in which the amount of the ink supplied in the tank2and the cartridge3becomes an empty state and thus the flow amount of the ink is zero; nevertheless a bidirectional flow sensor, which outputs an analog signal to the control unit11without pulse-processing the analog signal corresponding to the flow amount of the ink, may be utilized as the flow sensor Q. In the latter instance, the control unit11is adapted to compare the analog signal with a predetermined value (a comparative level) and reciprocally control the forward path replenishment control unit51and the return path replenishment control unit52based on the compared results.

Therefore, if the predetermined value is set to zero, it is possible to switch the forward path route A and the return path route B when the flow amount is zero. Also, by setting the predetermined value to a variable value and setting the ink to a near empty state, it is possible to reciprocally replenish the ink, with a little ink remaining.

Alternatively, by setting the predetermined value of any one of the tank2and the cartridge3to zero, it is possible to control just one of the tank2and the cartridge3in an empty state, as shown inFIG. 12.

As shown inFIG. 14, after the flow sensor Q outputs the pulse P, the control unit11may be adapted to carry out the replenishing operation during a certain time Tx previously set in a separate timer (not shown), and then control the reciprocal replenishment. In other words, as shown inFIG. 1, in the case where the control unit11has such a configuration that only one flow sensor Q is provided in the ink flow passage, at the time the flow sensor Q outputs the pulse P (i.e., the pulse Pa and the pulse Pb) to the control unit11, the ink with respect to the ink containing unit supplying the ink may not become an empty state. In the eighth embodiment, even after the flow sensor Q outputs the pulse Pa or the pulse Pb to the control unit11as the amount of the ink in the forward path route A or the return path route B becomes zero, the control unit11receives the pulse Pa or the pulse Pb from the flow sensor Q, and carries out the squeezing operation of the ink with respect to the ink containing unit during a certain time Tx to perform the control of the reciprocal replenishment. With this configuration, since it is possible to improve the squeezing effect of the ink with respect to the ink containing units of the tank2and the cartridge3, so that the ink existing in the ink containing unit of the tank2or the cartridge3is more surely extruded and agitated to improve the agitating effect of the ink. Also, with the configuration capable of maintaining the empty state of the ink in the ink containing units of the tank2and the cartridge3during the predetermined time Tx, the ink can be empty-squeezed during the predetermined time Tx, and, as a result, the precipitate of the ink is driven out, and thus the squeezing effect can be expected.

In the case where a bag made of a flexible material having gas permeability substantially equal to or higher than that of the material forming the containing unit15and having a variable ink containing volume is used as the ink containing unit, as shown inFIGS. 15 and 16, a sensor65for detecting contact-point contact may be used as the detecting unit for detecting that the ink filled in the ink containing unit supplying the ink becomes an empty state. That is, arms66and66are respectively attached to outer surfaces of the opposite inner surfaces of the storage bag bodies16and36, and the respective arms66and66are provided at the front end thereof with the sensors65and65for detecting contact-point contact. If the opposite inner surfaces come in contact with each other and thus the sensors65and65for detecting the contact-point contact come in contact with each other, the control unit11receives the pulse indicating that the amount of the ink filled in the ink containing unit supplying the ink is a predetermined value. In other words, since the detecting unit is constituted by a sensor for detecting a size variation of the flexible ink containing unit provided in the tank and the cartridge, it can accurately judge whether the ink filled in the ink containing unit supplying the ink becomes an empty state, based on the output of the sensor.

In the case where a bag made of a flexible material having gas impermeability and a variable ink containing volume is used as the ink containing unit, mechanical scissor unit70A and70B may be used as a unit for pressurizing the ink containing unit and pushing the ink into the communication passage5, as shown inFIG. 17. The mechanical scissor unit70A and70B include two rods71and71which can pivot on a rotation shaft72in an opposite direction to vary an angle of intersection. Two rods71and71are connected to each other by a spring73, with the ink containing units of the tank2and the cartridge3being interposed between a free end71aand a free end71bopposite to the free end71a. Also, the two rods71and71include a solenoid74provided at the other end71cof one of the two rods facing each other, and a magnet75provided at the other end71dof the of the two rods. Therefore, the control unit11turns on and off the solenoid74of the mechanical scissor unit70A provided in the tank2and the solenoid74of the mechanical scissor unit70B provided in the cartridge3to control the reciprocal replenishment using the forward path route A and the return path route B.

As shown inFIG. 18, the head4may be provided with an ink supply passage68and an ink reciprocating passage69respectively. The ink supply passage68is provided with an open-close valve77. In this instance, the control of printing and the control of reciprocal replenishment are separately performed. More specifically, the open-close valve77is closed, and the forward path route A and the return path route B are formed between the tank2and the cartridge3via the ink reciprocating passage69to agitate the ink through the control of reciprocal replenishment. After that, the open-close valve77is opened, and the pump P1is driven to feed the air to the pressure chamber13of the tank2to supply the ink from the ink containing unit to the head4. In this embodiment, the head4can be supplied with the ink, having little condensation unevenness, which is agitated by the ink flowing through the forward path route A and the return path route B to carry out the printing. Also, the distance of the ink reciprocating passage69between the tank2and the cartridge3can be shortened to reciprocate the ink in a short time and improve the agitating effect of the ink.

As shown inFIG. 19, the head4may include a sub-tank80communicating with ink passages21and41, an ink chamber24communicating with the sub-tank80, a pressure chamber25communicating with the ink chamber24, a nozzle28communicating with the pressure chamber25, and an actuator30. In other words, the communication passage5is constituted by the ink passage21of the tank2side for communicating the tank2with the sub-tank80, the ink passage41of the cartridge3side for communicating the cartridge3with the sub-tank80, and the sub-tank80serving as the ink passage for communicating the ink passage21of the tank2side with the ink passage41of the cartridge3side, so that the communication passage5and the ink chamber24are disposed in parallel with each other. With the configuration, since the printer device includes the sub-tank80, a storage amount of the ink in the head4can be increased, and continuous printing time can be extended.

In the control explained inFIG. 12(the sixth embodiment), the reference values M1and M2may be set in such a way that the values are gradually decreased with the lapse of time of the ink usage, as shown inFIG. 20. Therefore, a reciprocal switching number of the forward path route A and the return path route B can be increased, and the agitation effect of the ink can be improved in the initial time period of the ink ejection. In other words, like immediately after the cartridge3is exchanged, it is possible to suppress reduction in the number of the replenishing operations of the ink which is carried out between the tank2and the cartridge3, even though the total amount of the ink contained in the tank2and the cartridge3is relatively large. Also, if the total amount of the ink contained in the tank2and the cartridge3is decreased with the consumption of the ink, the amount of the ink remaining in the tank2or the cartridge3is set to be gradually decreased upon the replenishing operation of the ink. Therefore, the agitating operation of the ink can be surely carried out by the reciprocating operation of the ink between the tank2and the cartridge3.

The tank2may be adapted to be detachably (exchangeably) attached to the body of the printer device1.

The flow sensor Q may be installed to any one of the ink passage21of the tank2side and the ink passage41of the cartridge3side, or to both the ink passage21of the tank2side and the ink passage41of the cartridge3side.

Also, the empty state of the tank2and the cartridge3means that the ink is not replenished by pressurizing the pumps P1and P2. Therefore, even though a few droplets of the ink remain in the tank2and the cartridge3, it may be regarded as the empty state. Accordingly, it contains the empty state and the near empty state.

The weight of the ink may be measured by a weight sensor detecting an amount of the ink (liquid amount) filled in the tank2and the cartridge3and outputting an analog signal.

The control of reciprocal replenishment may be carried out by using any one of the pulses Pa and Pb or any one of the analog signals ITa and ICa.

In the above-described embodiments, although the printer device of an inkjet type is exemplified, the invention may be embodied as a liquid ejecting apparatus that ejects or discharges a liquid other than ink, and a liquid vessel filled with the liquid. The invention can be utilized in various liquid ejecting apparatuses including a liquid ejecting head for ejecting very small quantity of droplets. The droplet unit a state of the liquid to be ejected from the liquid ejecting apparatus, and includes a granular type, a tear-drop type, and a filamentary type with a trail. The liquid mentioned herein may be a material which can be ejected by the liquid ejecting apparatus. For example, it is appropriate that the substance is a fluid state, and it includes a fluid state of high or low viscosity, sol, gel water, other inorganic solvent, organic solvent, solution, liquid resin, a flowage state such as liquid metal (metal melt), not only a liquid having one state of substance, but also a liquid having solid particles, such as dye or metal particle, which are dissolved, dispersed or mixed with a solvent. Also, as described in the above embodiments, a typical example of the liquid is the ink or liquid crystal. The ink includes various liquid compositions, such as aqueous ink, oil-based ink, gel ink, hot melt ink or the like. For example, the liquid ejecting apparatus may be a liquid ejecting apparatus that ejects a liquid in which a material such as an electrode material or a color material, which is used for manufacturing a liquid crystal display, an EL (electroluminescent) display, a surface emitting display or a color filter, is dispersed or dissolved, a liquid ejecting apparatus for ejecting a biological organic substance which can be used to fabricate a biochip, a liquid ejecting apparatus that is used as a precision pipette to discharge a liquid to be used to test materials, a printing apparatus, a micro dispenser, and so forth. Furthermore, the liquid ejecting apparatus may be a liquid ejecting apparatus that ejects a lubricant at pinpoints of precision machines, such as a watch or a camera, a liquid ejecting apparatus that ejects a transparent resin liquid, such as an ultraviolet curing resin on the substrate, for forming a microscopic semi-spherical lens (optical lens) used for an optical communication element, a liquid ejecting apparatus that sprays an acid or alkaline etching solution to etch substrates or the like, and so forth. The invention may be applied to a type of the ejecting apparatus described above.