Patent Description:
<CIT> discloses an ink cartridge comprising a container having a body unit and a cover unit to form an internal space therebetween and an ink bag containing ink therein. A periphery of the ink bag is held by the cover unit of the container.

<FIG> is a schematic illustration of a bag <NUM> according to an example. The bag <NUM> comprises an outer edge or perimeter <NUM>, which in the example shown has a rectangular shape, but which may have other shapes in other examples. The perimeter <NUM> of the bag <NUM> extends in a first direction x and in a second direction y, which in <FIG> are mutually perpendicular and coincide with the plane of the drawing.

In the example shown, the bag <NUM> extends in the first direction x for a first length, and the bag <NUM> extends in the second direction y for a second. The first length may be e.g. <NUM> to <NUM>, or of <NUM> to <NUM>, and the second length may be e.g. <NUM> to <NUM>, or of <NUM> to <NUM>. However, any other shapes and sizes of the bag <NUM> are also possible.

The bag <NUM> of <FIG> may be formed by two sheets of bag material, which may be substantially identical to each other. The two sheets of bag material may be arranged parallel to each other and mutually joined and sealed, for example thermally welded to each other, at an outer edge of each of the sheets of bag material, thereby forming the perimeter <NUM> of the bag <NUM>, such that an interior space of the bag <NUM> is formed between the two sheets of bag material and surrounded, in the plane defined by the first and second directions x and y, by the perimeter <NUM>. In some examples, a perimeter region of the bag <NUM>, which extends around the perimeter <NUM> of the bag <NUM>, in which the two sheets of bag material are joined together, may have a width P from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>.

<FIG> further shows a zoomed-in view of the material composition of the bag <NUM> or of each of the sheets of bag material that may form the bag <NUM> according to some examples. The bag <NUM> may be made of a multilayer bag material comprising a sealing layer <NUM> to seal a fluid within the bag <NUM>, a barrier layer <NUM>, arranged on the sealing layer <NUM>, which may be impermeable to at least one of water and oxygen, and a protective layer <NUM>, defining an exterior surface of the bag <NUM>. The sealing layer <NUM> may form an internal layer arranged in contact with the interior of the bag <NUM>. The barrier layer <NUM> may be an intermediate layer arranged between the sealing layer <NUM> and the protective layer <NUM>, and the protective layer <NUM> may be an outermost layer of the bag <NUM>.

The sealing layer <NUM> may comprise or consist of one or more of polyethylene, ethylene-vinyl acetate (EVA), and an ionomer. The barrier layer <NUM> may comprise or consist of one or more of metallized PET, aluminum foil, polyvinylidene chloride (PVDC), ethylene vinyl alcohol (EVOH), polyvinyl alcohol (PVOH), polyacrylonitrile (PAN), polyamide MXD6 (PAMXD6), and an inorganic oxide coating, for example alumina or silica. The protective layer <NUM> may protect the structural integrity of the bag <NUM>, for example by providing protection against abrasion, scratching and piercing. The protective layer <NUM> may comprise or consist of one or more of polyamide (nylon), oriented polyamide and biaxially oriented polyamide.

The bag <NUM> further comprises a fluid opening <NUM> to allow a fluid to flow therethrough, i.e. from an exterior of the bag <NUM> into an interior of the bag <NUM> and/or vice versa. The bag <NUM> may comprise a fluid valve <NUM> arranged at the fluid opening <NUM> to control the flow of fluid through the fluid opening. In other examples, the bag <NUM> may comprise more than one fluid opening, possibly equipped with respective valves, for example a first fluid opening to allow or control a fluid to flow into the bag <NUM> and a second fluid opening to allow or control the fluid to flow out of the bag <NUM>. In some examples, the aforesaid fluid may be a printing fluid, for example ink. In other examples, the aforesaid fluid may however be or comprise any fluid, for example blood.

If the bag <NUM> comprises more than one fluid opening and more than one associated valve, the more than one fluid openings and respective valves may be arranged at different positions of the perimeter <NUM> of the bag <NUM>. For example, a first fluid opening, with a corresponding first fluid valve, may be arranged on one side of the rectangular perimeter <NUM> represented in <FIG>, and a second fluid opening, with a corresponding second fluid valve, may be arranged on the same side or on another side of the rectangular perimeter <NUM>.

The bag <NUM> may be made of non-elastic materials. Non-elastic materials may allow achieving better impermeability to oxygen and water as compared to elastic materials. The bag <NUM> may have a form variable as a function of a balance of pressures between the interior and the exterior of the bag <NUM>. Such balance of pressures may for example occur when an external pressure is applied upon the exterior surface of the bag <NUM> by a compression fluid, such as air or a pressure gas, or when internal pressure is applied to the interior walls of the bag <NUM> by a fluid received within the bag <NUM>, such as ink. The bag hence may expand and be compressed depending on internal and external pressure, substantially without elastic deformation of the bag walls. The bag <NUM> may e.g. increase its volume to receive a fluid in its interior and may decrease its volume to expel a fluid from its interior.

<FIG> schematically shows an example of a variation in the form of the bag <NUM> depending on a balance of pressures between the interior and the exterior thereof. The bag <NUM> shown in <FIG> comprises a first sheet of bag material <NUM> and a second sheet of bag material <NUM>. The first sheet of bag material <NUM> and the second sheet of bag material <NUM> are mutually joined at their peripheral edges forming the perimeter <NUM> of the bag <NUM>, for example thermally welded. <FIG> schematically represents a bag <NUM> according to an example as seen from a direction perpendicular to the directions x and y represented in <FIG>, as seen in the plane defined by the first direction x and by a third direction z perpendicular to each of the first direction x and the second direction y.

<FIG>, on the left hand side at a), a schematically represents a situation in which the bag <NUM> is affected by a balance of pressures and the bag <NUM> is empty, for instance after a fluid has been completely drained from an interior of the bag <NUM> as a result of a balance of pressures between the interior and the exterior of the bag <NUM>. For example, the fluid may be drained from the bag by an external positive, i.e. compressing, pressure applied to the exterior walls of the bag <NUM> or by an internal negative, i.e. suctioning, pressure applied to the interior of the bag <NUM>. In this situation, the bag <NUM> has a substantially planar or flat form extending in the first and second directions x and y represented in <FIG>, and the first sheet of bag material <NUM> and the second sheet of bag material <NUM> extend substantially planar and parallel to each other.

<FIG>, on the right hand side at b), schematically represents a situation in which the bag <NUM> is completely or partly filled with a fluid. In this situation, the bag <NUM> deforms relative to the planar configuration shown in <FIG>), whereby the exterior walls of the bag <NUM>, which may be formed by the first sheet of bag material <NUM> and the second sheet of bag material <NUM>, separate from each other such that an interior volume of the bag <NUM> enclosed by the exterior walls of the bag <NUM> increases. The bag <NUM> may deform without substantially stretching due to the pressure applied by the fluid.

In the situation in <FIG>), the bag <NUM> no longer has a substantially planar form extending in no more than the first direction x and the second direction y, but further has a non-negligible dimensional component in the third direction z. In the example shown in <FIG>), the bag <NUM> has an approximately oval form or lemon-shape in the plane defined by the first direction x and the third direction z. In different examples, the bag <NUM> may have a capacity of <NUM><NUM> to <NUM><NUM>, or of <NUM><NUM> to <NUM><NUM>, or of <NUM><NUM> to <NUM><NUM>.

<FIG> schematically illustrates a rigid container <NUM> according to an example. The rigid container <NUM> may be of a rigid molded plastic or metal material. In the example shown, the rigid container <NUM> comprises a first container element <NUM> and a second container element <NUM>. <FIG>, on the top left, at a) and on the top right at b) show, respectively, two opposite exterior sides of the rigid container <NUM>, respectively corresponding to the first and second container elements <NUM> and <NUM>. <FIG>, on the bottom left, at c) and on the bottom right at d) show, respectively, interior views of the rigid container <NUM>, respectively corresponding to the first and second container elements <NUM> and <NUM>. The first and second rigid container elements <NUM> and <NUM> are mutually attachable to form the rigid container <NUM>. Thus, the exterior side of the first container element <NUM> shown in <FIG>) and the exterior side of the second container element <NUM> shown in <FIG>) form an exterior of the rigid container <NUM>. An interior cross-section of the rigid container <NUM> at the junction of the first and second rigid container elements <NUM> and <NUM> corresponds to the interior of the first container element <NUM> shown in <FIG> and to the interior of the second container element <NUM> shown in <FIG>. The rigid container <NUM> shown in <FIG> extends in the first direction x and in the second direction y.

The opposite exterior side of the rigid container shown in <FIG> and the interior cross-section of the rigid container <NUM> shown in <FIG> correspond, respectively, to two opposite sides of the first rigid container element <NUM>. The opposite exterior side of the rigid container shown in <FIG> and the interior cross-section of the rigid container <NUM> shown in <FIG> correspond, respectively, to two opposite sides of the second rigid container element <NUM>.

The first container element <NUM> and the second container element <NUM> are attachable to each other, for example removably attachable by a clamping mechanism, thereby defining an interior cavity of the container <NUM> between the first container element <NUM> and a second container element <NUM>. In some examples, the first container element <NUM> and a second container element <NUM> may be welded together.

In some examples, the rigid container <NUM> may comprise a pressure fluid opening <NUM> to allow a pressure fluid, such as a pressurized gas or air or a pressurized liquid, like water, to flow into and/or out of the interior of the rigid container <NUM>. In the example shown, the rigid container <NUM> further comprises a pressure fluid valve <NUM> arranged at the pressure fluid opening <NUM> to control the flow of pressure fluid through the pressure fluid opening <NUM>. In other examples, the rigid container may be a sealed rigid container <NUM> and may comprise a pressurized fluid sealed in its interior.

The interior cavity of the rigid container <NUM> may be formed by a first interior recess <NUM> formed at an inner surface of the first container element <NUM> and a second interior recess <NUM> formed at an inner surface of the second container element <NUM>. The position and shape of the second interior recess <NUM> may correspond to the position and shape of the first interior recess <NUM>, such that the second interior recess <NUM> may overlap the first interior recess <NUM> and both the first and second interior recesses <NUM> and <NUM> may have equal shapes and dimensions. The first interior recess <NUM> and the second interior recess <NUM> may be dimensioned such as to receive and accommodate a bag <NUM> like the bag <NUM> described with respect to <FIG>. For example, as shown in <FIG>, the first interior recess <NUM> and the second interior recess <NUM> may have a substantially rectangular form, as seen in the plane defined by the first direction x and the second direction y.

The first rigid container element <NUM> may comprise a first internal rim <NUM> arranged around a boundary of the first interior recess <NUM>, i.e. surrounding the first interior recess <NUM>, wherein the first internal rim <NUM> protrudes in the first direction z, that is perpendicularly to the first direction x and to the second direction y, with respect to the plane of the first interior recess <NUM>. Likewise, the second rigid container element <NUM> may comprise a second internal rim <NUM> arranged around a boundary of the second interior recess <NUM>, i.e. surrounding the second interior recess <NUM>, wherein the second internal rim <NUM> protrudes in the first direction z with respect to the plane of the second interior recess <NUM>. The shape and dimensions of the second internal rim <NUM> may correspond to the shape and dimensions of the first internal rim <NUM>.

In the example shown in <FIG>, the first and second internal rims <NUM> and <NUM> extend around the entire boundary of the first and second interior recesses <NUM> and <NUM>, respectively. However, in other examples, the first and second internal rims <NUM> and <NUM> may partly extend around the boundary of the first and second interior recesses <NUM> and <NUM>, respectively. For example, each of the first and second internal rims <NUM> and <NUM> may discontinuously extend around the boundary of the first and second interior recesses <NUM> and <NUM>, respectively. In other examples, each of the first and second internal rims <NUM> and <NUM> may extend over some sides of the boundary of the first and second interior recesses <NUM> and <NUM>, respectively, for example over two opposite sides in the case of rectangular-shaped interior recesses <NUM> and <NUM>, as shown in <FIG>.

The rigid container <NUM> may further comprise reinforcement ribs <NUM>, <NUM> formed on an outer surface of the rigid container <NUM>. One or more reinforcement ribs <NUM> may be formed on the first container element <NUM> and may extend in the first direction x. One or more reinforcement ribs <NUM> may be formed on the second container element <NUM> and may extend in the first direction x or in the second direction y. Reinforcement ribs extending in other directions and having different shapes, such as a reticular shape (e.g. extending both in the first direction x and in the second direction y) and a honey-comb lattice shape are also possible. The reinforcement ribs <NUM> and <NUM> strengthen the rigidity and mechanical stability of the rigid container <NUM>, thereby preventing deformations. Further, the reinforcement ribs <NUM> and <NUM> may provide improved stackability of different rigid containers by allowing interlocking the reinforcement ribs <NUM> of a first rigid container <NUM> and the reinforcement ribs <NUM> of a second rigid container <NUM>' arranged on the first rigid container, as shown in <FIG>.

<FIG> schematically illustrates a cross section of the rigid container <NUM> of <FIG> in a plane defined by the first direction x and the third direction z (i.e. the same plane as in <FIG>). In the example shown in <FIG>, the first container element <NUM> and the second container element <NUM> are joined and sealed together at a sealing joint <NUM>, thereby forming the interior cavity <NUM> that is enclosed between the first container element <NUM> and the second container element <NUM>.

The first interior recess <NUM> and the second interior recess <NUM> may have a substantially semi-oval or semi-lemon-shaped cross-section in the plane defined by the first direction x and the third direction z, such that the interior cavity <NUM> may have, in in said plane, a substantially oval-shaped or lemon-shaped cross-section. However, other forms of the first interior recess <NUM>, the second interior recess <NUM> and the interior cavity <NUM> are possible.

The rigid container <NUM> may comprise a gap <NUM> that surrounds the interior cavity <NUM> and which, in the example shown in <FIG>, is formed between the first container element <NUM> and the second container element <NUM>. The gap <NUM> may correspond to a region of minimal width of the interior cavity <NUM> in the third direction z or, to a region of minimal distance between the first container element <NUM> and the second container element <NUM> (other than at the sealing joint <NUM>). The gap <NUM> may be formed as an interstice between the first internal rim <NUM> of the first rigid container element <NUM> and the second internal rim <NUM> of the second rigid container element <NUM>.

Also shown in <FIG> are reinforcement ribs <NUM> formed on the first container element <NUM>, which extend in the first direction x, and reinforcement ribs <NUM> formed on the second container element <NUM>, which extend in the second direction y (i.e. perpendicular to the first and second directions x and z).

In some examples, a width of the gap <NUM> in the third direction z may be from <NUM> to <NUM> or from <NUM> to <NUM>. An length of the gap <NUM> in the first direction x or in the second direction y, which may correspond to a length of the first internal rim <NUM> or second internal rim <NUM>, respectively, and in different examples, may be from <NUM> to <NUM>, or from <NUM> to <NUM> or, from <NUM> to <NUM>.

<FIG> schematically shows a cross-section of a fluid tank <NUM> in the x-z plane, according to an example, which comprises a rigid container <NUM> and a bag <NUM> according to the previously discussed examples, wherein the bag <NUM> is arranged within the rigid container <NUM>. In the example shown, the rigid container <NUM> comprises a first container element <NUM> and a second container element <NUM>, wherein the first and second container elements <NUM>, <NUM> may be attached to each other at a sealing junction <NUM>, for example removably attached by a clamping mechanism <NUM> or other means.

The bag <NUM> is arranged within the interior cavity <NUM> formed between the first container element <NUM> and the second container element <NUM>. A form or cross-section of the interior cavity <NUM> in the plane defined by the first direction x and the second direction y may correspond to the form or cross-section of a bag <NUM> in said plane. Thus, the dimensions and shape of the interior cavity <NUM> in the x-y plane may be approximately equal to the dimensions and shape of the bag <NUM> in the x-y plane (cf.

The bag <NUM> is received within the rigid container <NUM> such that it extends in the first direction x and in the second direction y and is supported within the rigid container <NUM> such that the perimeter <NUM> of the bag <NUM> is movable in no more than the first direction x and the second direction y, i.e. in at least one or both of the first and second directions x and y. In <FIG>, the vertical and horizontal directions of the drawing plane correspond, respectively, to the third direction z and the first direction x, whereas the second direction y is perpendicular to the first and third directions x, z, i.e. perpendicular to the drawing plane.

<FIG>, on the bottom at a), schematically illustrates a situation in which the bag <NUM> arranged within the rigid container <NUM> is empty, corresponding to the situation illustrated in <FIG>). In this situation, the bag <NUM> has a substantially planar shape extending in the first direction x and in the second direction y, with almost no significant separation between the sidewalls of the bag <NUM>, e.g. between a first sheet of bag material <NUM> and the second sheet of bag material <NUM> in the third direction z.

The bag <NUM> is received within the rigid container <NUM> such that the perimeter <NUM> of the bag <NUM> is supported by interior walls of the rigid container <NUM> in such a manner that a mobility of the perimeter <NUM> of the bag <NUM> is restricted in the third direction z by the rigid container <NUM>, while the perimeter <NUM> of the bag <NUM> can move within the rigid container <NUM> in the first direction x and/or in the second direction y. In the example shown, the perimeter <NUM> of the bag <NUM> is supported in the gap <NUM> between the first container element <NUM> and the second container element <NUM>.

An width of the gap <NUM> in the third direction z, perpendicular to the first and second directions x and y, in which the perimeter <NUM> of the bag <NUM> extends, may be slightly bigger than a thickness of the perimeter <NUM> of the bag <NUM> in the third direction z, such that at the rigid container <NUM>, for example by means of the gap <NUM>, restricts the freedom of movement of the perimeter <NUM> of the bag <NUM> in the third direction z but without restricting its movement in the first direction x and in the second direction y, for example without rigidly holding or pressing the perimeter <NUM>. The bag hence, to a certain degree, may slide into and out of the gap <NUM> in one or both of the first direction x and the second direction y.

In different examples, a dimension of the gap <NUM> in the third direction z, i.e. a width of the gap <NUM>, may be <NUM> to <NUM> times, or <NUM> to <NUM> times or <NUM> to <NUM> times the thickness of the bag <NUM> in the third direction z. The bag <NUM> may for instance have a thickness of <NUM> and the gap <NUM> may have a thickness of <NUM>.

The gap <NUM> formed between the first container element <NUM> and the second container element <NUM> may have a depth in the first direction x or in the second direction y greater than a width P of the perimeter <NUM> of the bag <NUM> (cf. <FIG>) in a corresponding section of the perimeter <NUM> extending in the second direction y or in the first direction x, respectively.

In particular, an depth of the gap <NUM> in the first direction x and/or in the second direction y, respectively, may be <NUM> to <NUM> times or <NUM> to <NUM> times the width P of the perimeter <NUM> of the bag <NUM>, such that the perimeter <NUM> may move or slide within the gap <NUM> and still be supported by the gap <NUM>. For example, the perimeter <NUM> of the bag <NUM> may have a width P of <NUM> and the gap <NUM> may extend in the first direction x and in the second direction y (having, for example, the aforesaid gap thickness of <NUM>) for <NUM>, respectively.

When the bag <NUM> arranged within the rigid container <NUM> is filled with fluid, for example a printing fluid, such as ink, the bag <NUM> may change its shape and volume without stretching. However, unlike in the situation depicted in <FIG>, in which the bag <NUM> could expand freely, when arranged within the rigid container <NUM>, the bag <NUM> may expand to the extent that the rigid container <NUM> allows. <FIG> schematically illustrates a situation in which the bag <NUM> arranged within the rigid container <NUM> is partially or totally filled with fluid. The fluid may enter the interior of the bag <NUM> through the fluid opening <NUM> shown in <FIG>.

As compared to the situation in <FIG>, in which the bag <NUM> is substantially planar and extends in the first direction x and the second direction y, the bag <NUM> in <FIG> further extends in the third direction z, such that the exterior walls of the bag <NUM> enclose an interior volume of the bag <NUM>, in which the fluid is received. Thus, the first sheet of bag material <NUM> and the second sheet of bag material <NUM> may extend conforming to the interior walls of the rigid container <NUM>.

When the bag <NUM> is filled with fluid, the pressure generated by the fluid entering the interior of the bag <NUM> may make the bag <NUM> change its external contour as seen in the plane defined by the first and third directions x, z, for example transitioning from the substantially planar shape shown in <FIG> and <FIG> to the approximately oval or lemon shape shown in <FIG> and <FIG>. Meanwhile, the position of the perimeter <NUM> of the bag <NUM>, at which the sidewalls of the bag <NUM> are joined together, may remain unchanged in the third direction z.

When transitioning from the situation shown in <FIG> to the situation shown in <FIG>, for example due to pressure exercised by fluid entering the bag <NUM>, the overall surface covered by the exterior walls of the bag <NUM> may remain substantially unchanged, while, its orientation or contour may change. For example, if the bag <NUM> comprises the first and second sheets of bag material <NUM> and <NUM>, an overall length of each of the first and second sheets of bag material <NUM> and <NUM> measured along the surface of the bag <NUM> may remain substantially unchanged. However, since the exterior walls of the bag <NUM> now have a component in the third direction z, an overall length covered by the exterior walls (or by each of the first and second sheets of bag material <NUM> and <NUM>) in the first direction x, i.e. a projection of the exterior walls of the bag <NUM> on the first direction x, may change with respect to the situation in <FIG>.

For example, when the bag <NUM> is empty and substantially planar, as shown in <FIG>, the bag <NUM>, in the first direction x, may extend across a first length L<NUM>, whereas, when the bag <NUM> is partially or totally filled with fluid such that the bag <NUM> conforms to the walls of the interior cavity <NUM> of the rigid container <NUM>, the bag <NUM>, in the first direction x, may extend across a second length L<NUM> smaller than the first length L<NUM>, as shown in <FIG>. The second length L<NUM> corresponds to a projection of the bag <NUM> upon the first direction x. An analogous situation may apply to corresponding lengths covered by the bag <NUM> in the second direction y.

As a consequence of the change in the shape of the bag <NUM>, the perimeter <NUM> of the bag <NUM> may move or slide in the first direction x and in the second direction y within the rigid container <NUM>, for example within the gap <NUM>, in order to accommodate the increase in the volume of the bag <NUM> without stretching. The perimeter <NUM> of the bag <NUM> may move freely in the first direction x and in the second direction y but movement is restricted by the rigid container <NUM> in the third direction z.

As shown in <FIG>, the rigid container <NUM> may limit the expansion of the bag <NUM>, such that the perimeter <NUM> of the bag <NUM> is movable in no more than the first direction x and the second direction y by a distance Δ, which may correspond to a difference between the aforesaid first length L<NUM> and the aforesaid second length L<NUM> (i.e. L<NUM>-L<NUM>= Δ). Thus, when the bag <NUM> is filled with fluid, an outer edge of the bag <NUM> may be displaced within the rigid container in the first and second directions x and y, for example within the gap <NUM>, as compared to the situation shown in <FIG>, by the distance Δ. The distance Δ may be smaller than a depth of the gap <NUM> in the first and second directions x and y, and may further be smaller than the perimeter width P (cf. In some examples, the distance Δ may be at least <NUM>, at least <NUM>, or at least <NUM>.

The rigid container <NUM> may be dimensioned such that, in the situation shown in <FIG>, i.e. when the bag <NUM> is filled with fluid, the bag <NUM> may completely occupy the interior of the rigid container <NUM> and may conform thereto. Thus, the rigid container <NUM> may limit the deformation of the bag <NUM> and may define the form, size and volume that the bag <NUM> may have within the rigid container <NUM> when the bag <NUM> is filled with fluid. For example, when the bag <NUM> is completely filled with fluid, the bag <NUM> may completely occupy the interior cavity <NUM> of the rigid container <NUM>.

Thus, the volume of the interior of the rigid container <NUM>, e.g. the volume of the interior cavity <NUM>, controls a maximal capacity of the bag <NUM> when the bag <NUM> is arranged within the rigid container <NUM>.

The transition from the situation shown in <FIG> to the situation shown in <FIG> may be reversed by pressurizing the interior of the rigid container <NUM>, for example by letting a pressure fluid, such as air, flow into the interior cavity <NUM> through the pressure fluid valve represented in <FIG>. In some examples, water may be used as a pressure fluid, for example water at a predefined temperature to regulate a temperature of the fluid in the bag <NUM>. In examples in which the rigid container <NUM> comprises a pressurized fluid sealed in its interior, the interior of the rigid container may be pressurized as a consequence of fluid entering the bag <NUM>. In some examples, fluid may be drained from the interior of the bag <NUM> by a suctioning pressure, provided for example by a suction pump.

As a result, the fluid contained within the bag <NUM> may be expelled, for example through the fluid opening <NUM> shown in <FIG> or through another opening of the bag <NUM>, to the exterior of the bag <NUM>, such that the perimeter <NUM> of the bag <NUM> moves back within the gap <NUM> towards the position and form it had, as shown in <FIG>, when the bag <NUM> was empty (e.g. by the distance Δ).

The fluid tank <NUM> allows storing fluid and controlling a flow of fluid into the bag <NUM> and out of the bag <NUM>. The rigid container <NUM> limits the deformation of the bag <NUM>, such that the bag <NUM> does not substantially shrink, stretch, or fold during use, for example when being compressed to eject fluid or when being filled or refilled with new fluid. The rigid container <NUM> allows the perimeter <NUM> of the bag <NUM> to move in the first and/or second direction x, y to react to changes of form and volume of the bag <NUM> due to fluid entering or exiting the bag <NUM> without having to shrink, stretch or bend abruptly, thereby reducing material fatigue of the bag. As a result, the bag <NUM> may be suitable for withstanding a large number, for example up to <NUM>, empty-and-refill cycles without puncturing or tearing, and hence without requiring replacement.

<FIG> shows a schematic representation of a fluid tank <NUM>' according to an example comprising a first rigid container element 30a, a second rigid container element 30b and a third rigid container element 30c. The first rigid container element 30a is arranged on the second rigid container element 30b, and the second rigid container element 30b is arranged on the third rigid container element 30c. The first, second and third rigid container elements 30a, 30b and 30c are modular elements having the same or similar geometry and can be attached, for example removably attached, to each other in a stacked configuration, as shown in <FIG>.

The fluid tank <NUM>' further comprises a first bag <NUM> arranged between the first rigid container element 30a and the second rigid container element 30b and a second bag <NUM> arranged between the second rigid container element 30b and the third rigid container element 30c. Although three rigid container elements and two bags are represented in <FIG>, this is a non-limiting example and a fluid tank may comprise any number of rigid container elements and any number of bags.

The first bag <NUM> and the second bag <NUM> may correspond to a bag according to any of the previously discussed examples, including the bag <NUM> discussed with respect to <FIG>. Each of the first and second bags <NUM> and <NUM> has a perimeter that extends in a first direction x, indicated in <FIG> as coincident with the horizontal direction of the drawing plane, and in a second direction y perpendicular to the first direction x, which in <FIG> is perpendicular to the drawing plane (analogous to the previously discussed first and second directions x and y).

In the configuration shown in <FIG>, the first rigid container element 30a and the second rigid container element 30b in combination, and the second rigid container element 30b and the third rigid container element 30c in combination act, respectively, as a printed fluid tank according to any of the previously discussed examples.

The perimeter of the first bag <NUM> is supported within a gap between the first rigid container element 30a and the second rigid container element 30b, such that the perimeter of the first bag <NUM> is movable in no more than the first direction x and the second direction y. Like in the previously discussed examples, the gap formed between the first rigid container element 30a and the second rigid container element 30b may limit the mobility of the perimeter of the first bag <NUM> in the third direction z, thereby avoiding that the first bag may fold abruptly, stretch or shrink when it is filled with fluid or emptied of fluid.

Likewise, the second bag <NUM> is supported within a gap between the second rigid container element 30b and the third rigid container element 30c, such that the perimeter of the second bag <NUM> is movable in no more than the first direction x and the second direction y.

The first rigid container element 30a may be attached, for example removably attached by means of an interlocking mechanism or a clamping mechanism, to the second rigid container element 30b, such that a first cavity <NUM> is formed between the first rigid container element 30a and the second rigid container element 30b. Likewise, the second rigid container element 30b may be attached or removably attached to the third rigid container element 30c, such that a second cavity <NUM> is formed between the second rigid container element 30b and the third rigid container element 30c.

The first bag <NUM> is arranged within the first cavity <NUM> and the second bag <NUM> is arranged within the second cavity <NUM>. The first and second cavities <NUM> and <NUM> may be dimensioned such that, when the first and second bags <NUM> and <NUM> are filled with fluid, the first and second bag <NUM> and <NUM> completely fills and occupies, respectively, the first cavity <NUM> or the second cavity <NUM>.

When the first and second bags <NUM> and <NUM> are filled with fluid, an exterior surface of the first bag <NUM> may conform to the interior walls of the first rigid container element 30a and the second rigid container element 30b that form the first cavity <NUM> and an exterior surface of the second bag <NUM> may conform to the interior walls of the second rigid container element 30b and the third rigid container element 30c that form the first cavity <NUM>.

Each of the first, second and third rigid container elements 30a, 30b and 30c may be formed of a rigid plastic or metal material by molding, wherein the same mold may be used for forming the first, second and third rigid container elements 30a, 30b and 30c, since they are modular elements having substantially identical geometries. The modular structure hence decreases manufacturing costs and further allows easily accessing the interior cavities <NUM> and <NUM>, for example if necessary for replacing the first bag <NUM> or the second bag <NUM>.

<FIG> shows a schematic representation of a printing device <NUM> according to an example. The printing device <NUM> comprises a printing fluid inlet <NUM> to receive a printing fluid from a printing fluid supply <NUM>. The printing fluid inlet <NUM> may be a printing fluid port connectable or connected to the printing fluid supply <NUM>. The printing fluid supply <NUM> may be a consumable ink cartridge.

The printing device <NUM> further comprises an intermediate printing fluid tank <NUM> connected to the printing fluid inlet <NUM> to receive printing fluid from the printing fluid inlet <NUM>. The intermediate printing fluid tank <NUM> can hence receive printing fluid from the printing fluid supply <NUM> through the printing fluid inlet <NUM>.

The printing fluid tank <NUM> may correspond to a printing fluid tank according to any of the previously discussed examples and comprises a rigid container <NUM> and a bag <NUM> arranged therein. In other examples, the printing device <NUM> may comprise in addition to or instead of the printing fluid tank <NUM>, more than one printing fluid tanks, for example a plurality of printing fluid tanks <NUM>, <NUM>' arranged in a staggered configuration as shown in <FIG> or a plurality of modular rigid container elements 30a, 30b, 30c, with a corresponding plurality of bags <NUM>, <NUM>, as shown in <FIG>.

The printing device <NUM> further comprises, a printhead <NUM> to print a print medium <NUM> with printing fluid. The printhead <NUM> may be connected or connectable to the intermediate printing fluid tank <NUM> to receive printing fluid from the intermediate printing fluid tank <NUM>. The printhead <NUM> prints the print medium <NUM> with the printing fluid by firing the printing fluid upon a surface of the print medium <NUM>.

The rigid container <NUM> of the intermediate printing fluid tank <NUM> may comprise a pressure fluid valve <NUM> to control a flow of air into and out of the interior of the rigid container <NUM> through a corresponding pressure fluid opening <NUM> and a printing fluid valve <NUM> to control a flow of printing fluid from the printing fluid inlet <NUM> into the bag <NUM> through a first printing fluid opening <NUM>. As shown in <FIG>, the printing device <NUM> may further comprise a second printing fluid valve <NUM> to control a flow of printing fluid from the interior of the bag <NUM> to the printhead <NUM> through a second printing fluid opening <NUM>. Each of the printing fluid valve <NUM>, the second printing fluid valve <NUM> and pressure fluid valve <NUM> may be self-sealing valves, which automatically seal when they are not actively actuated.

Thus, printing fluid may flow from the printing fluid supply <NUM> to the printhead <NUM> through the printing fluid tank <NUM>, i.e. through the first printing fluid opening <NUM> and the second printing fluid opening <NUM>, driven by pressure exercised by pressure fluid, for example pressurized gas such as air, in the rigid container <NUM> through the pressure fluid opening <NUM>. The pressure inside the rigid container <NUM> may be monitored using a pressure sensor <NUM> connected to the interior of the rigid container <NUM>. In some examples, the printing fluid may further flow directly from the printing fluid supply <NUM> to the printhead <NUM>, such that the printhead <NUM> may receive printing fluid both directly from the printing fluid supply <NUM> and from the printing fluid tank <NUM>.

The bag <NUM> is such that, printing fluid received within the bag <NUM> can be driven out of the bag by a difference of pressures between the interior and the exterior of the bag <NUM>. For example, when pressure fluid, such as compressed air or water, is pumped into the interior of the rigid container <NUM>, the bag <NUM> may be compressed by the pressure fluid, thereby ejecting printing fluid through the second printing fluid opening <NUM> (and possibly also through the printing fluid valve <NUM>) to the printhead <NUM>.

A perimeter of the bag <NUM> (not shown in <FIG> but similar to the perimeter <NUM> of the bag <NUM> discussed with respect to <FIG>, and <FIG>) extends in a first direction and in a second direction. The rigid container <NUM> limits an expansion of the bag <NUM>, such that the perimeter of the bag <NUM> is movable in no more than the first direction and the second direction. The first and second directions may correspond, respectively, to the first and second directions x and y discussed within the context of the previously presented examples. Thus, when printing fluid enters or exits the bag <NUM>, the perimeter <NUM> of the bag <NUM> is movable in no more than the first direction x and the second direction y.

According to some examples, the printing device <NUM> may further comprise a printing fluid pump <NUM> to pump printing fluid from the printing fluid inlet <NUM> into the bag <NUM> of the printing fluid tank <NUM> through the first printing fluid opening <NUM> and the first printing fluid valve <NUM>. Additionally or alternatively, the printing device <NUM> may further comprise a pressure fluid pump <NUM> to pump air into the interior of the rigid container <NUM> through the pressure fluid opening <NUM> and the pressure fluid valve <NUM>.

Claim 1:
A fluid tank (<NUM>) comprising:
a rigid container (<NUM>, <NUM>'); and
a bag (<NUM>) to receive a fluid, wherein the bag is arranged within the container and comprises a fluid opening (<NUM>) to allow a fluid to flow
therethrough, wherein a perimeter (<NUM>) of the bag extends in a first direction and in a second direction;
characterised in that the perimeter (<NUM>) is supported within the container such that the perimeter of the bag is movable in at least one of the first direction and the second direction and the rigid container is to restrict a movement of the perimeter in a third direction perpendicular to the first direction and the second direction.