Patent Description:
<CIT> discloses a configuration in which an ink can be supplied while gas-liquid exchange is performed between an ink supply container and an ink tank with a plurality of passages inserted into the tank through openings of the ink tank serving as an ink passage and an air passage. A user is thereby enabled to supply an ink to the ink tank without compressing the ink supply container.

In the configuration disclosed in <CIT>, however, there is a possibility of usability being decreased because ink injection may take time when the area of the aperture of the passage through which the ink flows is small.

The present invention has been developed in consideration of the aforementioned circumstance and provides an inkjet printing apparatus in which a time required for injecting an ink to an ink tank is reduced.

<CIT> discloses an inkjet printing apparatus, in particular an uninterrupted ink supply system, including a main cartridge connected to a printer, a connection device having an automatic airflow control structure and installed on said main cartridge, and a replenishment cartridge for connecting to the connection device. The replenishment cartridge is connected to the connection device, and is able to refill the ink into the main cartridge, and automatically stop refilling when the ink level reaching a specific height and start refilling again when ink level below a specific height. When the replenishment cartridge is removed for refilling when the ink is used up, the main cartridge still contains ink so that the printing will not be suspended.

<CIT> discloses an ink tank system for supplying ink to a print head of an ink jet printer from a replaceable ink tank by pressurizing inside of the ink tank with pressurized air. By disposing an air filter in an air supply channel of the ink tank, dust is prevented from entering the ink tank together with air, and the ink is prevented from adhering to the air filter, thereby keeping smooth ink force-feeding. At the time the ink tank is mounted, a seal releasing pin protruded on the side of a printer unit opens an auxiliary seal for sealing between the air filter in the air supply channel and an air chamber of the ink tank. After the ink tank is mounted, the pressurized air is passed through the air filter and fed into the ink tank. A replaceable ink tank used in the system is also provided.

<CIT> discloses a liquid container comprising: a hollow tubular member whose one end installed in the liquid container is connected to the supply port; liquid supply holes formed in the tubular member; and an air introducing port provided at a bottom of the tubular member to introduce air into the tubular member; wherein the liquid in the liquid container is introduced into the tubular member through the liquid supply holes and the liquid thus introduced is supplied from the supply port to another device. As air is introduced from the air introducing port into the tubular member and rises as a bubble in the tubular member, a convection is generated to agitate the liquid inside the tubular member. This agitating action alleviates concentration variations in the liquid in the tubular member.

<CIT> discloses an ink tank for an inkjet printer. The ink tank has a top end and a bottom end and includes an ink conduit connecting the inside of the tank to the outside and extending inside the tank from the top end by a first distance; an air conduit connecting the inside of the tank to the outside and extending inside the tank from the top end by a second distance, the second distance being less than the first distance; a vent connecting the inside of the tank to the outside, an inside opening of the vent being located at a third distance, less than the second distance, from the top end; and an ink outlet connecting the inside of the tank to the outside, an inside opening of the ink outlet being located at a fourth distance, greater than the second distance, from the top end.

<CIT> discloses a liquid discharge recording head formed by bonding a recording unit, having plural recording elements for discharging recording liquid, with a recording liquid supply supporting member used for supplying recording liquid to the recording unit. The recording liquid supply supporting member is provided with at least one first snap fitting extending substantially in the same direction as the bonding direction of the recording liquid supply supporting member and the recording unit, and at least one second snap fitting extending in a direction intersecting the extended direction of the first snap fitting. The recording unit is provided with at least one first receiving portion engaging with the first engaging portion formed for the first snap fitting, and at least one second receiving portion engaging with the second engaging portion formed for the second snap fitting.

<CIT> discloses an ink tank including a storage chamber formed of a front face wall, a back face wall, a first side wall, a second side wall, a top plate, and a bottom plate, an injection port, a partition wall connected to the first side wall and the second side wall, a first space surrounded by the back face wall, the first side wall, and the second side wall, and a second space surrounded by the front face wall, the first side wall, and the second side wall are formed by the partition wall, and wherein the injection port is arranged on a side of the first space, and a communication portion that communicates the first space and the second space is formed at a position between the partition wall and the bottom plate.

<CIT> discloses an inkjet recording apparatus including a recording head configured to eject ink to record an image, an ink tank including an filling port for injection of the ink and configured to contain the ink to be supplied to the recording head, a cap configured to close the filling port, and a connection portion configured to connect the cap to the ink tank or a main body of the apparatus. The inkjet recording apparatus includes a rib provided adjacently to the filling port, the connection portion biases the cap in a direction separating from the filling port, and the cap removed from the filling port releases the filling port while being in contact with the rib by biasing of the connection portion.

<CIT>, <CIT> and <CIT> disclose other inkjet printing apparatuses but at least do not disclose or suggest the characterizing features of appended claim <NUM>.

The present invention in its first aspect provides an inkjet printing apparatus as specified in claims <NUM> to <NUM>.

Each of the embodiments of the present invention described below can be implemented solely or as a combination of a plurality of the embodiments. Also, features from different embodiments can be combined where necessary or where the combination of elements or features from individual embodiments in a single embodiment is beneficial.

The following embodiment, however, does not intend to limit the present invention, and all of combinations of features described in the embodiment are not necessarily essential for solutions of the present invention. In addition, the relative position, the shape, and the like of each component described in the embodiment are merely presented as examples and do not intend to limit the scope of the present invention to them only.

<FIG> is an external perspective view of an inkjet printing apparatus (hereinafter referred to as the printing apparatus) <NUM> in the present embodiment. The printing apparatus <NUM> includes a housing <NUM>, a printing head <NUM> (refer to <FIG>) that performs printing operation with respect to a print medium, and an ink tank <NUM> as an ink containing container configured to contain an ink to be supplied to the printing head <NUM>. In the present embodiment, the ink tank <NUM> is disposed at the front of the housing <NUM> and fixed to the body of the apparatus. At the front of the housing <NUM>, an operation unit <NUM> that enables a user to perform operation, such as command input, for the printing apparatus <NUM> is also provided. The operation unit <NUM> of the present embodiment also includes a display panel capable of displaying, for example, an error of the printing apparatus <NUM>.

At the front of the housing <NUM>, a paper feeding cassette <NUM> insertable and extractable by a user with respect to the housing <NUM> is disposed. The paper feeding cassette <NUM> includes a window portion 6a to enable a user to visually recognize a print medium loaded inside the paper feeding cassette <NUM>. The window portion 6a can be constituted by a transparent member of, for example, glass or plastic.

At the upper portion of the housing <NUM>, a scanner unit <NUM> that performs operation of reading documents is disposed to be openable with respect to the housing <NUM>. <FIG> is an external perspective view of the printing apparatus <NUM> with the scanner unit <NUM> opened with respect to the housing <NUM>. When the scanner unit <NUM> is opened, a tank cover <NUM> capable of covering the upper surface of the ink tank <NUM> is exposed. In <FIG>, the tank cover <NUM> is closed. The detail of the tank cover <NUM> will be described later. Alternatively, a configuration in which a body cover on which the scanner unit <NUM> is not loaded is openable with respect to the housing <NUM> may be employed.

<FIG> is a perspective view illustrating an internal configuration of the printing apparatus <NUM>. The printing apparatus <NUM> feeds a print medium loaded on the paper feeding cassette <NUM> at the front of the housing <NUM> or a paper feed tray <NUM> at the back thereof by a feeder (not illustrated). The print medium fed by the feeder is conveyed onto a platen <NUM> at a position opposite the printing head <NUM> by a conveyance roller (conveying means) <NUM>. The platen <NUM> is a member for guiding and supporting a print medium onto which printing is performed by the printing head <NUM>. The print medium for which printing by the printing head <NUM> has been completed is discharged onto a discharge tray (discharge portion) <NUM> by a discharge roller (discharging unit) <NUM>. The discharge tray <NUM> is disposed above the paper feeding cassette <NUM>.

A direction (Y direction illustrated in <FIG>) in which a print medium is conveyed by the conveyance roller <NUM> is referred to as the conveyance direction. In other words, the upstream side in the conveyance direction corresponds to the back side of the housing <NUM>, and the downstream side in the conveyance direction corresponds to the front side of the housing <NUM>.

The printing head <NUM> is loaded on a carriage <NUM> that reciprocates in a main scanning direction (X direction illustrated in <FIG>) intersecting the conveyance direction. In the present embodiment, the conveyance direction and the main scanning direction are orthogonal to each other.

The printing head <NUM> prints (printing operation) an image of an amount of one band with respect to a print medium by ejecting ink droplets while moving together with the carriage <NUM> in the main scanning direction. When the image of the amount of one band is printed, the print medium is conveyed (intermittent conveyance operation) by a predetermined amount in the conveyance direction by the conveyance roller <NUM>. As a result of the printing operation of the amount of one band and the intermittent conveyance operation being repeated, the image is printed on the entirety of the print medium on the basis of image data.

The printing apparatus <NUM> includes a maintenance unit disposed within a scanning region of the carriage <NUM> and outside a printing region in which printing operation is performed by the printing head <NUM>. The maintenance unit is a unit that performs maintenance processing for maintaining the ejection performance of the printing head <NUM>. The maintenance unit is disposed at a position to face an ejection-port surface on which ejection ports for ink are arranged. The printing head <NUM> illustrated in <FIG> is positioned at a position (home position) that enables maintenance processing of the maintenance unit. The maintenance unit includes, for example, a cap capable of capping the ejection-port surface and a suction-based recovery mechanism that performs suction operation for removing residual bubbles and a thickened ink in the ejection ports by suctioning the ink forcibly while capping is performed.

In the present embodiment, an example of a serial head in which the printing head <NUM> is loaded on the carriage <NUM> is presented; however, the present invention is not limited thereto and is applicable to a line head in which a plurality of ejection ports are arranged in a region of a width corresponding to the width of a print medium.

The ink tank <NUM> is disposed in the printing apparatus <NUM> for each color of inks to be ejected by the printing head <NUM>. In the present embodiment, four ink tanks including an ink tank <NUM> for black, an ink tank 11C for cyan, an ink tank <NUM> for magenta, an ink tank 11Y for yellow are provided. These ink tanks are collectively referred to as the ink tank <NUM>. Cyan, magenta, and yellow are merely examples of ink colors, and ink colors are not limited thereto.

As illustrated in <FIG>, the ink tank <NUM> for black is disposed on the left side of the discharge tray <NUM> and the paper feeding cassette <NUM> when viewed from the front of the printing apparatus <NUM>. The ink tank 11C for cyan, the ink tank <NUM> for magenta, and the ink tank 11Y for yellow are disposed on the right side of the discharge tray <NUM> and the paper feeding cassette <NUM> when viewed from the front of the printing apparatus <NUM>. In other words, the discharge tray <NUM> and the paper feeding cassette <NUM> are disposed between the ink tank <NUM> for black and the ink tanks for color. Each ink tank <NUM> is connected to the printing head <NUM> by a flexible tube <NUM> that constitutes a supply passage for supplying an ink to the printing head <NUM>.

The printing apparatus <NUM> also includes a tank cover 12Bk for black and a tank cover 12Cl for color. The tank cover 12Bk for black covers the upper surface of the ink tank <NUM> for black. The tank cover 12CI for color integrally covers the upper surfaces of the ink tank 11C for cyan, the ink tank <NUM> for magenta, and the ink tank 11Y for yellow. Hereinafter, the tank cover 12Bk for black and the tank cover 12CI for color are collectively referred to as the tank cover <NUM>.

<FIG> are external perspective views of a tank unit <NUM> including the ink tank <NUM> and the peripheral configuration thereof. The basic configuration of the tank unit <NUM> is common among ink colors, and thus, a tank unit for black will be described as an example.

<FIG> illustrates a state in which the tank cover <NUM> is closed. <FIG> illustrates a state in which the tank cover <NUM> is opened. A user is enabled to access a tank cap <NUM> by opening the tank cover <NUM> in the S1 direction.

The upper surface of the ink tank <NUM> includes an injection port <NUM> for injecting an ink. The injection port <NUM> is sealable with the tank cap <NUM>. The tank cap <NUM> is constituted by a cap portion 13a for sealing the injection port <NUM> and a lever portion 13b that supports the cap portion 13a and that is operable by a user. The lever portion 13b is pivotably supported on the body of the printing apparatus <NUM> so as to be turnable. A user is enabled (refer to <FIG>) to inject ink by detaching the cap portion 13a from the injection port <NUM> while turning the lever portion 13b in the S2 direction illustrated in <FIG>. The lever portion 13b may be configured to be pivotably supported on the ink tank <NUM> or on the tank cover <NUM> so as to be turnable.

The cap portion 13a of the tank cap <NUM> is constituted by a member having rubber elasticity, and the lever portion 13b is constituted by plastic or the like. The lever portion 13b of the present embodiment is color-coded with a color corresponding to the color of an ink contained in the ink tank <NUM>. Specifically, the lever portion 13b for black is color-coded with black or grey, the lever portion 13b for cyan is color-coded with cyan, the lever portion 13b for magenta is color-coded with magenta, and the lever portion 13b for yellow is color-coded with yellow. Consequently, it is possible to suppress a user from injecting an ink of a wrong color when injecting an ink into the ink tank <NUM>. A form in which not only the lever portion 13b but also the cap portion 13a is color-coded may be employed.

<FIG> illustrates a state in which, with the tank cap <NUM> detached, an ink bottle <NUM>, which is an ink replenishment container, is inserted into the injection port <NUM> and an ink is injected. In the present embodiment, as a result of gas-liquid exchange being performed between the ink in the ink bottle <NUM> and the air in the ink tank <NUM>, the ink is injected into the ink tank <NUM>.

<FIG> is a perspective view of the ink tank <NUM>. The ink tank <NUM> includes an ink containing chamber <NUM> configured to contain an ink, an ink supply port <NUM> for supplying the ink in the ink containing chamber <NUM> to the printing head <NUM>, an air containing chamber <NUM> configured to contain air, and an air communication port <NUM> that causes the air containing chamber <NUM> to be in communication with the atmosphere. The ink containing chamber <NUM> is disposed in an upper portion of the ink tank <NUM> so as to open on a first side-surface side. <FIG> is a perspective view of the ink tank <NUM> viewed from the first side-surface side. The ink supply port <NUM> has one end connected to the ink containing chamber <NUM> and the other end connected to the tube <NUM> (refer to <FIG>). The ink containing chamber <NUM> is enabled to contain an ink as a result of the opening on the first side-surface side being closed by a flexible film (not illustrated).

The air containing chamber <NUM> is disposed below the ink containing chamber <NUM> so as to open on a second side-surface side opposite the first side-surface side. <FIG> is a perspective view of the ink tank <NUM> viewed from the second side-surface side. The second side-surface side of the air containing chamber <NUM> is divided into a plurality of rooms. The rooms are in communication with each other via a communication passage 18a disposed on the first side-surface side. The second side-surface side where the air containing chamber <NUM> opens is also closed by a flexible film (not illustrated). The rooms of the air containing chamber <NUM> are not in communication with each other on the second side-surface side and are in communication with each other via the communication passage 18a disposed on the first side-surface side.

The air containing chamber <NUM> and the ink containing chamber <NUM> are connected to each other by a connection passage <NUM> extending downward from the lower surface of the ink containing chamber <NUM>. The lower end portion of the connection passage <NUM> serves as a gas-liquid exchange portion where gas-liquid exchanged is performed between the ink and the air. The connection passage <NUM> is disposed on the first side-surface side of the ink tank <NUM>. The gas-liquid exchange portion of the connection passage <NUM> has a sectional area that enables a meniscus of ink to be maintained. The air communication port <NUM> in communication with the atmosphere is disposed in an upper portion of the air containing chamber <NUM>. The air communication port <NUM> and the connection passage <NUM> are disposed away from each other.

During normal use, an ink is supplied from the ink containing chamber <NUM> to the printing head <NUM> in response to ink ejection from the printing head <NUM>, and air of the same volume as that of the supplied ink is supplied from the air containing chamber <NUM> to the ink containing chamber <NUM> via the gas-liquid exchange portion. The ink in the ink containing chamber <NUM>, however, drops down into the air containing chamber <NUM> due to a hydraulic head difference when the meniscus of the gas-liquid exchange portion is broken as a result of the air in the ink containing chamber <NUM> expanding due to, for example, changes in atmospheric temperature or atmospheric pressure. The air containing chamber <NUM> thus has a capacity that can contain the ink contained in and filling up the ink containing chamber <NUM>. The air containing chamber <NUM> thus also functions as a buffer chamber that suppresses an ink from leaking through the air communication port <NUM> into the apparatus.

Even when the printing apparatus <NUM> is in an orientation that differs from the orientation during normal use in a state in which an ink is contained in the air containing chamber <NUM>, the ink is suppressed from leaking through the air communication port <NUM> due to the air communication port <NUM> and the connection passage <NUM> disposed away from each other. In addition, an effect of further suppressing leaking of ink is exerted because the air containing chamber <NUM> divided into the plurality of rooms is present between the connection passage <NUM> and the air communication port <NUM> and obstructs the flow of ink. Moreover, the side surface where the divided air containing chamber <NUM> opens and the side surface where the communication passage 18a is disposed differ from each other, which enables a configuration in which an ink does not easily move between adjacent rooms divided from each other. Thus, leaking of ink through the air communication port <NUM> is avoided.

The ink tank <NUM> further includes a needle <NUM> as an injection assistance member that assists ink injection. <FIG> is a schematic sectional view illustrating the detail of the needle <NUM> of the present embodiment. The needle <NUM> is constituted by a first passage 24a and a second passage 24b shorter than the first passage 24a and causes the inside and the outside of the ink tank <NUM> to be in communication with each other. In the present embodiment, the sectional area of the first passage 24a is larger than the sectional area of the second passage 24b.

The first passage 24a is defined by a first upper end portion 23a that is exposed by extending upward more than the upper end of the injection port <NUM> and that opens on the outside of the ink tank <NUM> and a first lower end portion 25a that opens on the inside of the ink tank <NUM> (ink containing chamber <NUM>). The second passage 24b is defined by a second upper end portion 23b that is exposed from the injection port <NUM> and that opens on the outside of the ink tank <NUM> and a second lower end portion 25b that opens on the inside of the ink tank <NUM> (ink containing chamber <NUM>).

The first upper end portion 23a of the first passage 24a is formed to be high in the gravitational direction so as to project upward more than the second upper end portion 23b of the second passage 24b. The first upper end portion 23a and the second upper end portion 23b each open obliquely in the direction in which the passages extend and each have an inclined surface that becomes higher toward the center portion at which the first upper end portion 23a and the second upper end portion 23b are in contact with each other. The first lower end portion 25a is formed to be low in the gravitational direction so as to project downward more than the second lower end portion 25b.

<FIG> are schematic views illustrating ink-injection operation utilizing gas-liquid exchange according to the present embodiment. <FIG> illustrates a state in which the ink tank <NUM> is empty. In the ink injection operation, one of the first passage 24a and the second passage 24b that form the needle <NUM> functions as an ink passage and the other functions as an air passage. The opening of the ink bottle <NUM> is closed by a sealing member (not illustrated) and configured such that the ink does not drip even when the opening is directed downward as illustrated in <FIG>.

When the ink bottle <NUM> is inserted into the ink tank <NUM> as illustrated in <FIG>, the needle <NUM> opens the sealing member of the ink bottle <NUM>. Consequently, the ink in the ink bottle <NUM> flows into the ink tank <NUM> through the first passage 24a, and the air in the ink tank <NUM> flows into the ink bottle <NUM> through the second passage 24b. In other words, the first passage 24a functions as an ink passage, and the second passage 24b functions as an air passage. The ink is thus injected into the ink tank <NUM> by utilizing gas-liquid exchange in which the ink and the air are exchanged between the ink tank <NUM> and the ink bottle <NUM>.

When an ink liquid surface L reaches the second lower end portion 25b of the second passage 24b that functions as the air passage, as illustrated in <FIG>, the gas-liquid exchange stops because the air is disabled to flow out from the second lower end portion 25b into the ink bottle <NUM>. In other words, ink injection from the ink bottle <NUM> into the ink tank <NUM> stops on the basis of the position of the second lower end portion 25b at the time when the ink bottle <NUM> is inserted into the ink tank <NUM>. The above is the principle of the ink injection operation utilizing gas-liquid exchange.

Next, features of the needle <NUM> of the present embodiment will be described in detail with reference to <FIG> are schematic sectional views when ink injection operation is started by a user. <FIG> illustrates a state immediately after the ink bottle <NUM> is inserted into the injection port <NUM>. In the insertion of the needle <NUM> into the ink bottle <NUM>, the first passage 24a first comes into contact with the ink contained in the ink bottle <NUM> because the first upper end portion 23a of the first passage 24a projects upward, compared with the second upper end portion 23b of the second passage 24b. Therefore, the needle <NUM> of the present embodiment has a configuration in which the first passage 24a is easily determined as an ink passage.

<FIG> illustrates a state after ink injection from the ink bottle <NUM> into the ink tank <NUM> (ink containing chamber <NUM>) is started. In the ink injection utilizing gas-liquid exchange, the ink flows from the ink bottle <NUM> into the ink tank <NUM> by an amount corresponding to the amount of air that has flowed from the ink tank <NUM> into the ink bottle <NUM>. Therefore, a configuration in which the air easily moves away from the needle <NUM> by becoming bubbles causes inflow of ink to be performed smoothly.

As described above, the first upper end portion 23a and the second upper end portion 23b have the inclined surfaces, and the inclined surfaces cause the air to easily move away from the needle <NUM>, which accelerates inflow of the air. Detail will be described with reference to <FIG> and <FIG>.

<FIG> illustrate a comparative example in which the first upper end portion 23a and the second upper end portion 23b have no inclined surfaces. <FIG> are schematic views of the first upper end portion 23a and the second upper end portion 23b having inclined surfaces as with the present embodiment. When air flows from the second upper end portion 23b into the ink in the ink bottle <NUM>, bubbles of the air are required to be formed and move away from the second upper end portion 23b, as illustrated in <FIG> and <FIG>.

At this time, when no inclined surfaces are formed, as with the comparative example illustrated in <FIG>, the bubbles are required to move away from the entirety of the opening surface of the second upper end portion 23b when transiting from the state in <FIG> to the state in <FIG>, which takes time. In other words, the bubbles are in surface contact with the second upper end portion 23b, and thus, the bubbles do not easily move away from the second upper end portion 23b because of the large contact area.

In contrast, when inclined surfaces are formed as with the present embodiment, the bubbles move away from a top portion 23bb of the second upper end portion 23b when transiting from the state in <FIG> to the state in <FIG>, and thus, bubbles are easily formed. In other words, the bubbles are in liner contact with the top portion 23bb, and thus, the bubbles easily move away from the top portion 23bb because the contact area is small compared with the case in <FIG>. Therefore, inflow of the air from the ink tank <NUM> into the ink bottle <NUM> is smoothly performed, and thus, the speed of inflow of the ink from the ink bottle <NUM> into the ink tank <NUM> is also increased. Moreover, the inclined surfaces are formed to become higher toward the portion at which the first upper end portion 23a and the second upper end portion 23b are in contact with each other. Consequently, the bubbles move upward while being in contact with the side surface of the first upper end portion 23a and thus more easily move away from the top portion 23bb (refer to <FIG>).

With reference to <FIG>, a configuration in which the first passage 24a easily functions as an ink passage has been described; however, there is actually a case in which the ink does not flow through the first passage 24a. In this case, the bubbles flow in from the first upper end portion 23a. Therefore, in the present embodiment, the first upper end portion 23a also has the inclined surface.

<FIG> illustrates a state in which the ink liquid surface L in the ink tank <NUM> has reached the first lower end portion 25a of the first passage 24a. A distance between the first lower end portion 25a and the bottom surface of the ink containing chamber <NUM> is smaller than a distance between the second lower end portion 25b and the bottom surface of the ink containing chamber <NUM>. When the ink liquid surface L reaches the first lower end portion 25a, the first lower end portion 25a is closed by the ink, which disables inflow of air from the first lower end portion 25a. Consequently, even if air flows in the first passage 24a and ink flows in the second passage 24b, the first passage 24a is determined to function as an ink passage and the second passage 24b is determined to function as an air passage. As a result of the distance between the first lower end portion 25a of the first passage 24a functioning as an ink passage and the bottom surface of the ink containing chamber <NUM> thus being set to be as small as possible, which one of the first passage 24a and the second passage 24b the ink flows through is quickly determined. Consequently, it is possible to reduce a time required for ink injection.

If the first lower end portion 25a has the same height as that of the second lower end portion 25b, the ink liquid surface L is slow to reach the first lower end portion 25a. Thus, it takes time to determine the first passage 24a as an ink passage. When pressure balance is generated before the determination of the passage due to the air and the ink mixed and present in the first passage 24a and the second passage 24b, inflow of the ink may stop before the ink is injected and fills up the ink containing chamber <NUM>. In contrast, by making the first lower end portion 25a extend to the vicinity of the bottom surface of the ink containing chamber <NUM>, as with the present embodiment to thereby quickly determine the passage, the ink can be injected to fill up the ink containing chamber <NUM>.

Here, the flow resistance of the ink is larger than the flow resistance of the air, and the sectional area of the first passage 24a is thus formed to be larger than the sectional area of the second passage 24b. Consequently, it is possible to increase the inflow amount of the ink per unit time. For example, the sectional area of the first passage 24a is <NUM><NUM>, and the sectional area of the second passage 24b is <NUM><NUM>.

As above, being constituted by the two passages including the upper end portions having different heights, the needle <NUM> of the present embodiment facilitates determination of the passage for the ink that flows out from the ink bottle <NUM>. Moreover, due to the upper end portions having the inclined surfaces, inflow of the air into the ink bottle <NUM> is smoothly performed. In addition, the small distance between the lower end portion of the first passage 24a and the bottom surface of the ink containing chamber <NUM> facilitates determination of the ink passage. Having the sectional area larger than the sectional area of the second passage 24b determined as the air passage, the first passage 24a determined as the ink passage increases the ink injection amount per unit time. These configurations reduce the time required for ink injection, which enables an improvement of usability of a user.

In the present embodiment, a form in which the ink tank <NUM> is fixed to the printing apparatus <NUM> and in which an ink is supplied through the tube <NUM> is presented; however, the present invention is not limited thereto and is also applicable to a form commonly known as on-carriage, in which the ink tank is loaded together with the printing head <NUM> on the carriage <NUM>. In other words, a form in which the ink tank loaded on the carriage <NUM> includes the injection port and the needle and in which the ink is injected from the ink bottle by a user may be employed.

Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. The basic configuration of the second embodiment is the same as that in the first embodiment, and thus, only configurations having features will be described below.

<FIG> are sectional views of the needle <NUM> in the second embodiment. <FIG> illustrates a state in which an ink is injected from the ink bottle <NUM> by using the needle <NUM> of the second embodiment. <FIG> illustrates a detailed configuration of the needle <NUM> of the second embodiment. Differently from the first embodiment, the needle <NUM> has a tapered shaped to make the sectional area of the first passage 24a be larger toward the first lower end portion 25a. The inside of the first passage 24a is constituted by a smooth surface without irregularity. Such a smooth passage shape having the sectional area that increases from the first upper end portion 23a toward the first lower end portion 25a makes it possible to increase the flow velocity of ink more than the first embodiment.

With reference to <FIG>, an effect of the tapered shape will be described. <FIG> is a schematic view illustrating a configuration of the first passage 24a of the second embodiment. <FIG> is a schematic view illustrating a comparative example in which the sectional area of a passage suddenly increases. In <FIG>, the ink flows in the S3 direction.

When the sectional area suddenly increases as illustrated in <FIG>, a vortex V is generated in a portion where the sectional area is increased, and a pressure loss is thereby generated. Consequently, the injection speed of the ink decreases. In contrast, when the sectional area slowly increases as illustrated in <FIG>, no pressure loss is generated, and thus, the flow velocity of the ink does not decrease. Configuring the first passage 24a to have the tapered shape the sectional area of which slowly increases makes it possible to increase the flow velocity of ink and reduce the ink injection time.

<FIG> is a schematic view of the needle <NUM> in a modification of the second embodiment. The ink flows in the first passage 24a in the S4 direction. Even when the first passage 24a is configured to have a trumpet shape the sectional area of which increases gradually as illustrated in <FIG>, an effect similar to that with the tapered shape can be obtained. Configuring the sectional area of the passage in which the ink flows to increase smoothly toward the first lower end portion 25a makes it possible to reduce the time required for ink injection.

In other words, according to the present invention, it is possible to provide an inkjet printing apparatus in which the time required for ink injection into the ink tank is reduced.

Claim 1:
An inkjet printing apparatus comprising:
an ink tank (<NUM>) configured to contain an ink to be supplied to a printing head (<NUM>) that ejects the ink, the ink being injected from an ink bottle (<NUM>);
a first passage (24a) defined by a first upper end portion (23a) and a first lower end portion (25a), the first upper end portion (23a), which opens obliquely, and to which the ink bottle (<NUM>) approaches for injection of the ink from the ink bottle (<NUM>) into the ink tank (<NUM>), the first lower end portion (25a) opening to an inside of the ink tank (<NUM>); and
a second passage (24b) defined by a second upper end portion (23b) and a second lower end portion (25b), the second upper end portion (23b), which opens obliquely, and to which the ink bottle (<NUM>) approaches for injection of the ink from the ink bottle (<NUM>) into the ink tank (<NUM>), the second lower end portion (25b) opening to an inside of the ink tank (<NUM>), the second passage (24b) being shorter than the first passage (24a) such that the second upper end portion (23b) and the second lower end portion (25b) are located between the first upper end portion (23a) and the first lower end portion (25a),
characterized in that
the first passage (24a) has a tapered shape, and a sectional area of the first lower end portion (25a) is larger than a sectional area of the first upper end portion (23a).